How often do you tilt for Theo? [Archive] - Large Format Photography Forum

Doremus Scudder

23-Mar-2014, 04:09

@Cor: The situation you describe is tailor-made for using tilt! If you can't get the flat plane of the ground in focus using tilt, then something is quite wrong. It should be really easy and the basic tilt application. Maybe I don't understand your situation exactly...

As to the question: I use swings and tilts a lot for a number of different purposes. Squaring things up, adjusting the plane of sharp focus (PoSF) and squeezing some extra shift/rise from my camera.

Tilting or swinging either standard moves the plane of sharp focus away from parallel to the film. Swinging or tilting the back also changes the rendering of parallel lines in the subject on the ground glass/film. Some use back tilt/swing to bring architectural subjects into the desired perspective rendering. I prefer to set up my camera with the back in the correct position (e.g., parallel to a building face) instead of using tilt/swing. Nevertheless, using movements works too and I do this sometimes to fine tune; the only thing that matters for achieving the desired rendering of parallel lines on the ground glass is the position of the back in relation to the subject.

When shooting architectural subjects, things usually work out so that the front and rear standards are parallel and the plane of sharp focus in the scene parallel to them. Stopping down achieves the desired depth-of-field. However, I have had many instances when applying a little front tilt and skewing the PoSF in the scene allows for a smaller focus spread and the use of a bit wider aperture, thereby giving me better sharpness and a bit faster shutter speed. A situation like this would be a building at the end of a courtyard with a foreground object (say a bench or sculpture) low to the ground. Tilting just a bit to put the near part of the PoSF between the building and the foreground object actually reduces the overall focus spread.

Using tilt/swing on either standard to adjust the plane of sharp focus has a bit different goal. Usually there is a plane we wish to focus on. If I'm taking an oblique shot of a building facade, I'll use swing ("horizontal tilt") to make sure that plane is in focus. If I'm taking a landscape shot where the plane of the ground is the main subject, I'll use tilt to adjust focus to it, keeping in mind the other objects in the scene and compromising as needed to achieve the smallest focus spread.

Finally, most of my folding cameras have limited shift and rise. I can use the "point and swing/tilt" method to get more. Basically it is just point the camera where you want the center of the image to be and then swing/tilt back and front standards parallel; voilà, more shift or rise.

FWIW, I check to make sure my standards are in the right position relative to each other every time I shoot, and often adjust the front standard a bit since it is often deflected by bellows pressure, or isn't exactly centered in the zero detents, or my desired plane of sharp focus is just a bit off from parallel. In effect, I'm applying and correcting tilt every time I shoot, even if it is "zero tilt."

Best.

Doremus

Ed Bray

23-Mar-2014, 05:37

I struggled at times with tilting to get a desired plane of focus until I watched the Fred Newman video on youtube here (http://www.youtube.com/watch?v=0JU-eHpk97Y), it may not be everybody's way of doing it but it worked for me as I have both front and back base tilts on my Canham MQC.

Sibben

23-Mar-2014, 06:31

besides, haven't you heard, the new thing is razerthin DOF ;)

Open wide and slice it thin like all the cool kidz on the internet! ;-)

Greg Miller

23-Mar-2014, 07:56

I pretty much just started out with LF but now that I've shot a couple of sheets I begin to wonder on movements, specifically Scheimpflug tilting. I'm trying to learn a bit how to do it and while I kind of get the idea I find the practise challenging but fun. My question is how often you seasoned veterans use it. Always? Sometimes? I shoot mainly landscape/cityscape and if I stop down to 32 or even 64 it's still super sharp and I find as soon as I tilt the front it's harder to focus.

How big of a deal is it really? Would you say it's essential or just a near trick you do sometimes if you have objects close by in the composition?

From a technical point of view, you can make a decision based on the f-stop required to get the depth of field that you need. Most lenses are at their optimal sharpness at a middle f-stop. Let's say that, for a given lens, once you stop down past f32 you start losing sharpness due to diffraction (and many will argue that diffraction is not worth worrying about with LF). So if you find yourself stopping down to f64, that would be a reason to use tilt, so that you can achieve the depth of field that you want, while also using a more optimal f-stop.

This situation can many times be avoided by using what I consider to be the optimal camera set-up process:
1) level the camera
2) use rise/fall (rather than aiming the camera up or down) to position objects in the frame where desired (from a vertical stand-point).
3) decide desired depth of field, what should be in-focus or out of focus, and choose f-stop accordingly
4) if after #3 you are at a sub-optimal f-stop, or if you need to increase or decrease depth of field, or you want to alter the plane of focus of depth of field, then use tilt/swing.

Pawlowski6132

23-Mar-2014, 08:21

Theo, short for Theodor Scheimpflug.

How annoying.

Vaughn

23-Mar-2014, 08:52

...How big of a deal is it really? Would you say it's essential or just a near trick you do sometimes if you have objects close by in the composition?

My camera does not have zeroing indents, so I am in the habit of using all the movements all the time -- it is just some of the settings are at or near 'zero'. It is all about how it looks on the GG!

David A. Goldfarb

23-Mar-2014, 10:35

For architecture, I tend to use only rise/fall and shift (except when using parallel tilt on both standards to get indirect rise/fall beyond what the camera allows), because buildings and structures tend to have flat surfaces at right angles that don't benefit from tilt or swing, or there may be parallel planes at different distances, and if you use rear tilt to make one facade square, the others farther away or nearer will not be square. Ansel Adams made a photograph illustrating the latter effect, shooting a church through an archway that is actually at an angle to the facade of the church, and the church is square, but the archway is skewed like something from a surrealist nightmare (which isn't always a bad thing, actually).

I'm more likely to use tilt and swing for landscapes, but usually the amount needed is subtle, rarely more than 5 degrees, and often just 1 or 2. If you've got a landscape where the ground is a flat plane and there is some tall object like a tree or a rock formation in the foreground or midground, tilt won't help usually, and you have to think of it as an architectural subject.

Here's a typical subject that uses front tilt:

112662

The 4x5" camera with a 75mm lens is pointed downward, and I've got a tiny amount of front tilt, maybe 1 degree, to bring the foreground, the ocean surface, and the rock in the distance into sharp focus. My notes from this period are inaccessible at the moment, but I'm fairly sure I would have been using a center filter, so the aperture is probably f:22-32.

Cor

24-Mar-2014, 05:34

I wrote:

I recently tried to get a ploughed bare field and distant tree lines all in focus with tilt..could not get it working and resorted to stopping down with the 90mm lens to f32, which solved it

On which Doremus replied:

@Cor: The situation you describe is tailor-made for using tilt! If you can't get the flat plane of the ground in focus using tilt, then something is quite wrong. It should be really easy and the basic tilt application. Maybe I don't understand your situation exactly...

I see now I did not take a good example. I have used tilt successfully in similar (but not the same!) situation. It was a field with chopped off maize sticks (in winter) and a barren single tree about 300 meters away. I used a 150 mm lens and I tilted such a degree so the plane of sharp focus started on one of those maize chops (about 5 meters away from me) and the middle of the tree. Stopping down rendered the whole tree sharp (alas the upper branches not due to strong wind).

The situation I was referring to above was a bit different, mainly because I choose my 90 mm lens (for the perspective effect I wanted), wanting to have the ploughed flat field from about 50 cm from my tripod all the way to the tree line about 750 meter away in sharp focus.

My camera has limited tilt, and the bellows started to vignette, so it was more a problem of my lens choice (and in hindsight my unnecessary decision to keep the back panel level) than tilt on it self.

Best,

Cor

ROL

24-Mar-2014, 09:22

How annoying.

Yeah, all this time I thought it was Jerry Scheimpflug. I will tilt for beers on occasion.

Sibben

24-Mar-2014, 10:07

Yeah, all this time I thought it was Jerry Scheimpflug. I will tilt for beers on occasion.

Yeah, Jerry was the other brother who invented shoes made of cheese. His work is largely forgotten today.

C. D. Keth

24-Mar-2014, 11:23

Theo, short for Theodor Scheimpflug.

Yeah, nobody says that.

Lenny Eiger

24-Mar-2014, 15:44

I like DOF. I use tilts all the time, but its usually very little. Mostly I use the lens all the way closed down. Life is much happier that way. (at least for me.)

Lenny

Drew Wiley

24-Mar-2014, 16:21

Alan Gales

24-Mar-2014, 17:06

I use some kind of view camera movement virtually every single shot, mostly front or rear tilt, sometimes swing, often rise or fall too. ... I've never heard of shoes
made from cheese... but my grilled cheese sandwich today did smell like old shoes!

I saw the Brewers play in Milwaukee the year before they tore the old Comiskey Stadium down. A lot of the fans were wearing cheese hats.

David Lobato

24-Mar-2014, 19:01

When I was brand new with 4x5 I learned that you need far less tilt than the pretzel twisted view cameras in printed ads, or in the diagrams showing angles with the Scheimpflug principle. At infinity, a 135mm lens needs only a small amount of tilt, a 210mm lens a little more so. I over-tilted the front standard so much it's a wonder I didn't quit the whole LF thing. Also, look up base tilt versus axis tilt techniques, there is a significant difference on how to effectively use each of them.

Leigh

24-Mar-2014, 19:41

To answer the original question... pretty seldom. I usually use DoF.

The only occasion I normally have to need Scheimpflug is with architecture, if I'm shooting
a house with a front yard full of flowers or other interesting stuff.

In the more general case, I either ignore the foreground and let it go soft, or re-frame the
image so that area is not in the photo in the first place.

As David said, the amount of tilt required is quite small, usually only a couple of degrees.

I always tilt the back, leaving the front vertical, since doing so does not change the framing.

- Leigh

ROL

25-Mar-2014, 07:49

In the more general case, I either ignore the foreground and let it go soft, or re-frame the
image so that area is not in the photo in the first place.

Huh? By changing lenses? Are you perhaps referring to cropping, post exposure?

djdister

25-Mar-2014, 08:12

Vaughn

25-Mar-2014, 09:13

When one works primarily in the dense temperate rain forest, one uses any method possible to create a well focused/DoF image. First two are in the redwoods (8x10 and 4x5), the third one in the beech forests of New Zealand (4x5).

Bernice Loui

25-Mar-2014, 10:07

Camera movement really depends on what needs to be done. For the majority of outdoor stuff where the lens is used at near infinity focus, camera swing/tilts are not used much if at all. Shift/rise is more common to position the image on the ground glass along with moving the camera and tripod as required to get the expected composition on the GG. If the entire area needs to be in focus, I'll use anything between f11 to f45, most often being f16-22. This applies to 5x7 or 13x18cm film format.

Once the image is no long focused much at infinity, it all changes. I'll use swing/tilt/shift/rise on front/rear as required to get the areas that must be in focus at the largest aperture, then stop down only as much as required to meet this requirement. This could be any aperture from full lens aperture (typically f4.5 to f11) to f45.

It requires precision to do this as swing/tilts are usually less than 5 degrees, often just 1-3 degrees. If the camera detents do not allow this fine degree of adjustment, it is off my list. The other requirement is absolute camera alignment, both front and rear standards must be parallel with absolute repeatability. While many value light weight allowing the camera and all to be easy to carry and back pack, the trade off is stability and precision. On a good high quality geared movement view camera controlling camera movements to one degree is not too difficult, doing the same on a very light weight field camera is not as easy and the weight of a camera helps reduce camera movement during exposure and control the impact from shutter release. This is real world trade off between studio mono rail cameras that are un-reasonable to go back packing with vs field camera being used for studio table top work.

Camera movements are extremely useful and another image making tool that makes a good view camera special.

Bernice

I pretty much just started out with LF but now that I've shot a couple of sheets I begin to wonder on movements, specifically Scheimpflug tilting. I'm trying to learn a bit how to do it and while I kind of get the idea I find the practise challenging but fun. My question is how often you seasoned veterans use it. Always? Sometimes? I shoot mainly landscape/cityscape and if I stop down to 32 or even 64 it's still super sharp and I find as soon as I tilt the front it's harder to focus.

How big of a deal is it really? Would you say it's essential or just a near trick you do sometimes if you have objects close by in the composition?

Greg Miller

25-Mar-2014, 10:11

It requires precision to do this as swing/tilts are usually less than 5 degrees, often just 1-3 degrees. If the camera detents do not allow this fine degree of adjustment, it is off my list. The other requirement is absolute camera alignment, both front and rear standards must be parallel with absolute repeatability.

Bernice

So, obviously no wooden cameras for Bernice ;)

Bill_1856

25-Mar-2014, 10:18

How often do you tilt?

Virtually never with 4x5, 5x7, and Whole plate -- just stop 'er down all the way, and accept a little softness at infinity if need be. 8x10 might be a different ballgame, however.

Leigh

25-Mar-2014, 11:20

So, would it be fair to say that if you are planning on stopping down to f32 or smaller anyway for DOF purposes, there is little value (in general) to applying tilt/swing?
Of course, generalities are their own worst enemy. :cool:

I think in many cases movements are over-used.

Viewers get uncomfortable when a scene looks "odd".

For example, when shooting a multi=story building I may use movements to partially correct the convergence toward the top, but not completely. When a person looks at that building, they see the top of the facade smaller than the street-level portion. They expect a photo of that building to look essentially the same.

Only the photographer can determine what's important in an image, and what is extraneous to his intent.

- Leigh

Leigh

25-Mar-2014, 11:21

Huh? By changing lenses? Are you perhaps referring to cropping, post exposure?
I don't understand your questions.

I said nothing about changing lenses, and did not infer that.

As to post-exposure, I may re-frame an image on the enlarger when I print it.

- Leigh

djdister

25-Mar-2014, 11:29

Of course, generalities are their own worst enemy. :cool:

- Leigh

Yeah, generalizing can be dangerous to one's health :o

Anyhoo, going the other direction, the movement I use absolutely the most is rise/fall of the lensboard...

Leigh

25-Mar-2014, 11:35

...the movement I use absolutely the most is rise/fall of the lensboard...
Same here, followed by shift.

I shoot a lot of architecture.
You can't always position the camera where you'd like relative to the building centerline.

- Leigh

Drew Wiley

25-Mar-2014, 13:55

View cameras were designed with movements for a reason. Otherwise, if you just want a fuzzy image on a big piece of film, just use a cardboard shoe box with a
pinhole in it, or some overpriced nicely lacquered hardwood equivalent of a shoebox, or switch to medium format, where stopping down is your only option to get more depth of field. Rising front was probably the first major improvement to the basic hardwood box, way back in the 19th C, though lensboards with offset hole accomplished something similar. Wonder who first patented those things?

Leigh

25-Mar-2014, 14:01

View cameras were designed with movements for a reason.
True.

And they all have neutral positions for a reason.

Movements are a tool, to be used or not as appropriate for the image.

- Leigh

Drew Wiley

25-Mar-2014, 16:16

Yeah, and other than a straight-on portrait shot from time to time, I can't even remember a shot when I haven't used at least one of those tools.

ROL

25-Mar-2014, 16:32

I don't understand your questions.

I said nothing about changing lenses, and did not infer that.

As to post-exposure, I may re-frame an image on the enlarger when I print it.

- Leigh

I was simply offering blind clues as to what you may be doing, since re-frame means nothing specific to me, because I am obviously not as smart or accomplished as you. I believe most people understand "re-frame an image on the enlarger" to be cropping.

So then allow me try once more. You said: "re-frame the image so that area is not in the photo in the first place".

How do you re-frame at the same settings, and yet keep near and far in focus? Please forgive the suggestion, but I suppose one conclusion may be that you actually change your composition so that there are no near–far out of focus outliers, in effect shooting only within your DOF. If that is the case, without changing to longer focal length lenses which then only further restricts your DOF, that seems a tad limiting for most shooters. (I know that can't be the answer, but it's all my little pea brain can muster).

Leigh

25-Mar-2014, 18:03

So then allow me try once more. You said: "re-frame the image so that area is not in the photo in the first place".
How do you re-frame at the same settings, and yet keep near and far in focus?
Raise the camera... duuuh.

- Leigh

Bernice Loui

25-Mar-2014, 18:51

I still own a 5x7 Wisner technical field camera, it is wood, but just cannot get into using it.

Over the years, there have been a Linhof Master Technika 4x5, Technika V (5x7-13-18cm), Dorf, Toyo 8x10M (gray), B&J as cameras owned and numerous others that have been tried. After all this it ended in a Sinar system. This appears to be the camera with the fewest limitations if you're into precision, variety of configurations and a shutter that works with repeatable-reliable each time it is run. The only down side is size and WEIGHT... Since I don't hike or back pack much if any at all it works for me..

Some examples images of using combined tilt, swing, rise-fall.

http://photos4.meetupstatic.com/photos/event/3/3/e/2/highres_337633282.jpeg

5x7 Sinar C2, 110mm Symmar XL with a bag bellows @f22. Camera and me was flat against a wall and the scene was not that bright which made focusing and setting camera movements less than easy. Swing & tilt used less than 5 degrees, significant amount of rise/shift used adjust composition due to camera position.

Image holds focus from the left hand power panel to the sign on the far wall (good enough to easily read the writing), the fluorescent light fixture is in focus and the only light source in this scene.

http://photos4.meetupstatic.com/photos/event/3/3/d/8/highres_337633272.jpeg

5x7 Sinar C2 with Sinar shutter, 8-1/2" Kodak Commercial Ektar @f16. Swing and tilt used to bring the wall of this building into focus, tilt used to bring the pine cone on the traffic cone into focus. Camera movement are one to three degrees off the detent.

These scans are dark and contrast is higher than it should be.. still learning.

One of the very best features of a view camera is the ability to alter the plane of focus as required, to get the best out of the lenses, camera and such is to use every tool in the kit as required.

Bernice

So, obviously no wooden cameras for Bernice ;)

Cor

26-Mar-2014, 01:26

Bernice,

interesting examples, but I do not "see" the swing and tilt in the first image. For instance if you would use swing to get the grey cabinets on teh left in focus, wouldn't you loose sharpness on the pipes/boxes far right?

Likewise: tilt to get the fixture in the back in focus with ter foreground, wouldn't you loose sharpness on the fixture in the front?

Or am I completely off?

Best,

Cor

Doremus Scudder

26-Mar-2014, 07:53

So, would it be fair to say that if you are planning on stopping down to f32 or smaller anyway for DOF purposes, there is little value (in general) to applying tilt/swing?

How often do you tilt?

Virtually never with 4x5, 5x7, and Whole plate -- just stop 'er down all the way, and accept a little softness at infinity if need be. 8x10 might be a different ballgame, however.

Bernice,

interesting examples, but I do not "see" the swing and tilt in the first image. For instance if you would use swing to get the grey cabinets on teh left in focus, wouldn't you loose sharpness on the pipes/boxes far right?

Likewise: tilt to get the fixture in the back in focus with ter foreground, wouldn't you loose sharpness on the fixture in the front?

Or am I completely off?

Best, Cor

Now this is getting interesting!

Dan, One of the reasons to use tilt/swing is to be able to use a larger aperture (smaller f-number) and still have everything you want in sharp focus. There are a couple of reasons for this. One is simply to be able to use a faster shutter speed to counter the effect of subject movement (think windy day or moving waves). The other reason is so that you do not have to stop down to f/45 or more, which degrades the image due to diffraction. Yes, I will use f/45 or more if I have to, but then I limit the print size. I can see the effects of diffraction at f/45 (4x5 film) in a 16x20 print.

When using tilts/swings for these purposes, I usually use the front standard movements to place the plane of sharp focus so that the focus spread is at its minimum. That allows me to use an optimum aperture for the DoF I want and still have the fastest possible shutter speed. Sometimes I use both tilt and swing together to accomplish this.

Another reason to use back tilt/swing is to change the size relationships of objects in the scene (this includes making parallel lines parallel). Sometimes I want to emphasize the size of a foreground object; then I'll tilt the back. Or, I might want to make the near part of a building face large and emphasize the converging lines; then I'll use back swing. (If I don't want these effects, but still need the movement, then I'll use the front standard movements.)

Bill, I don't see why I have to "accept a little softness" when I don't have to. Usually movements used sparingly allow me not to have to compromise.

Cor, A lot of times one places the plane of sharp focus somewhere intermediate, i.e., not parallel to one of the obvious faces in the subject, in order to reduce the focus spread to a minimum and thus use a more optimum f-stop. I believe that is what Bernice was doing in her examples. One stops down to keep everything desired in focus; if the plane of sharp focus is optimally positions using swings and tilts, then one doesn't have to stop down as far.

Best,

Doremus

Bernice Loui

26-Mar-2014, 08:24

Hello Cor,

Camera movements done properly and used to increase perceive sharpness in the image is not apparent at all unless rear camera movement is used to intentionally alter the image's geometry.

In the first example, the gray power panel on the left is in focus, by using front swing, the plane of focus runs as a curved sheet from left to right where the "pipes/boxes" are located. Apply just enough swing and it all comes into focus with the lens at wide open.

The conduits or pipe in the center of the image is at a different distance than the fluorescent fixture on the ceiling, to bring these two into focus a tiny amount of front tilt was used. Then shift/rise was applied to adjust the overall composition. The lens is stopped down just enough to achieve apparent focus overall and not any more. This particular image could have been exposed at f16 or f11 with similar depth of focus.

It is also worth noting that light fall off from using more image circle built into the 110mm Symmar XL. The film used was 13x18cm Agfa APX100. The image is brighter in the center than at it's edges and it is not due to the light falloff of fluorescent fixtures alone. To make this image technically more correct, the camera alignment should be further fine tuned and a center filter used to correct the light fall off that is part of this len's innate personality and the way light behaves when being subjected to this degree of bending.

Keep in mind, what comes into focus happens faster on the image area further from the len's point of focus. Look at the focus scale on a manual focus lens, notice that the amount of lens travel away from the camera body is low from say 30 ft to infinity. Then rotate the lens to it's minimum focus distance, say 12 inches and notice how much more the lens must move between 12 inches and say 10 feet. All this applies to camera movements as the greater the difference between points of focus, the larger amounts of camera movements must be used and it might require using very small apertures (f45 or..) to achieve apparent focus.

The way I'll use camera movements is to achieve the largest possible aperture with the greatest depth of focus. This is how to get the best out of view camera lenses and achieve depth of focus far greater than a camera that has a fixed lens to it's body.

It takes patience and practice to learn how to use camera movements properly. Key to this is to try and use as little camera movement as required to achieve the overall focused area in the image. Think of camera movements like spices, a little goes a long way and when properly combined, they can add much to the end result.

Bernice

Bernice,

interesting examples, but I do not "see" the swing and tilt in the first image. For instance if you would use swing to get the grey cabinets on teh left in focus, wouldn't you loose sharpness on the pipes/boxes far right?

Likewise: tilt to get the fixture in the back in focus with ter foreground, wouldn't you loose sharpness on the fixture in the front?

Or am I completely off?

Best,

Cor

Bernice Loui

26-Mar-2014, 08:36

Yes, this is correct. Apply camera movements to "size" the curved focus area sheet, then put the actual focus point at a compromise where the overall image focus is balanced enough to deliver most of the image in good focus. Then, stop down just enough to bring it all in.

This is why most all of this image is in focus with the lens at it's largest aperture or wide open. This way, the need to stop down to extremes is minimized.

Bernice

Cor, A lot of times one places the plane of sharp focus somewhere intermediate, i.e., not parallel to one of the obvious faces in the subject, in order to reduce the focus spread to a minimum and thus use a more optimum f-stop. I believe that is what Bernice was doing in her examples. One stops down to keep everything desired in focus; if the plane of sharp focus is optimally positions using swings and tilts, then one doesn't have to stop down as far.

Best,

Doremus

Lenny Eiger

26-Mar-2014, 11:15

Now this is getting interesting!

Dan, One of the reasons to use tilt/swing is to be able to use a larger aperture (smaller f-number) and still have everything you want in sharp focus. There are a couple of reasons for this. One is simply to be able to use a faster shutter speed to counter the effect of subject movement (think windy day or moving waves). The other reason is so that you do not have to stop down to f/45 or more, which degrades the image due to diffraction. Yes, I will use f/45 or more if I have to, but then I limit the print size. I can see the effects of diffraction at f/45 (4x5 film) in a 16x20 print.

I would say yes, and then no. I have done plenty of tests on this and I am certain that there is no degradation due to diffraction that anyone should be concerned about - not with large format lenses. The effect is so small as to be meaningless, or invisible, IMO. On the other hand, the effect of opening up is dramatic. Of ten people complain to me about some part of their scans not being sharp and I have to tell them to close down some more... This "word on the street" about opening up to avoid diffraction is hurting a lot of people, IMO.

Of course, you are perfectly correct about opening up to stop movement.

Another reason to use back tilt/swing is to change the size relationships of objects in the scene (this includes making parallel lines parallel).

I find this a very interesting effect. Leaving aside the obvious building-straightening for architectural photography, in portraiture its often desirable to have that "straight-on" look. (Or, at least it is for me.) However, shooting people straight on often makes their heads look as wide as basketballs. It's easy enough to slide the camera over so that one side of the face is seen fully, drawing the eye back, and giving the effect of a more elongated look (or thinner face). To keep the straight on look, all one has to do is slide the front shift over (same as swinging) and it appears as if they re looking at you straight on.

In landscape this gives you some interesting control over what is in and out of the frame.

Lenny

Drew Wiley

26-Mar-2014, 12:08

I'll never stop down past f32 on 4x5. By f45 you are into conspicuous diffraction territory, and it will show on enlargement. I can visibly detect diffraction on the
8x10 groundglass at f/64 (even that dim), but sometimes do go there when the enlargement itself isn't over 20x24. With 6x9 roll film backs, I don't like stopping
down lower than f/16, but often need to. Roll film is really a compromise anyway. Diffraction is a scientific fact, but the practical effect just depends what you are
doing with your shots. When I am trying to make a little chihuahua 6x9 shot pretend to have the bite of a true large format rottweiler, every little foible counts.
But I routinely enlarge my shots. Contact prints or stock shots in a magazine or something like that wouldn't reveal much difference, if any.

Lenny Eiger

26-Mar-2014, 12:46

I'll never stop down past f32 on 4x5. By f45 you are into conspicuous diffraction territory, and it will show on enlargement.

No way! You're mistaking the out of focus for something else..

Greg Miller

26-Mar-2014, 15:38

No way! You're mistaking the out of focus for something else..

Given the coarseness of ground glass, I cannot fathom seeing diffraction on the ground glass either.

Drew Wiley

26-Mar-2014, 15:38

Absolutely, positively, unequivocally not, Lenny. 101% certain about this. This is just basic fact known to every optical engineer, and I can easily detect it in enlargements. Has nothing to do with "out of focus". Remember, I don't do inkjets, but have a history of big Cibachromes.

Drew Wiley

26-Mar-2014, 15:42

ROL

26-Mar-2014, 16:16

Raise the camera... duuuh.

- Leigh

Wow. What is your major malfunction, son?

Ring ding ding! Ladies and germs, we have a winner! Leigh only tilts for theo! Theory, that is. And thus having come full circle, the OPs journey complete and once again satiated, I bid a fond adieu. Good night… and God bless.

Preston

26-Mar-2014, 16:45

While diffraction is an inescapable fact of the physical world, it may, or may not be visible in print for a whole host of factors that most of us are aware of. To me, it makes sense to use camera movements to correct perspective and/or adjust the plane of focus in order to achieve the best image we can for a given set of circumstances.

There are some good suggestions and illustrative images (thanks Bernice) in this thread that should prove useful despite the minutia regarding diffraction.

--P

tgtaylor

26-Mar-2014, 19:29

Unless I'm shooting an image that I want "soft" (in which case I now use a soft focus lens) I'm normally a sharp image freak and I want both the immediate foreground (hopefully interesting) and the background both in sharp focus. Before I moved to LF I learned to accomplish this in MF by focusing at the hypofocal plane by focusing first on the foreground then the background and then setting the focus point half way between the two and stopping down the aperture to the f-stop on the lens encompassing both points. I have used that procedure very successfully with Pentax 67 lens which seem to be constructed with that procedure in mind and often find that a tiny spec of dust laying propitiously on the distance scale serves as a visual aid in determining the half-way point of focus. In LF the same is accomplished focusing on the near, tilting for the background, refocusing on the near, re-tilting for the rear....as set out above in the Fred Newman link above. The advise given to stop down to bring the middle sharp is time saving. I can't begin to tell you about the many times I went back and forth reinterating before it finally dawned on me to stop the lens down and take a look upon which I found that everything was in sharp focus! So tilt (and rise) is the movements I use most and probably 90% of the time. With a monorail I also use Shift but probably 100% of the time if only to check the composition but only rarely with a field. That inconsistency is no doubt due to the fact that front shift is ungeared on my fields but geared on the studios. It's a natural thing to do with a geared camera.

Thomas

Sibben

27-Mar-2014, 00:34

Thanks for all the answers to my question. And thanks Bernice for showing beautiful work illustrating it. Did I get any wiser?

The way I read all the answers is as follows. Stopping down and tilting are two ways to achieve the high level of perceived focus I associate with large format cameras. Stopping down is the more straight forward of the two with plane of focus manipulation being the one that requires time and work. This is pretty much what I had figured out but wanted some confirmation of. So I got my answer. Thanks all.

I am making the assumption that tilting and stopping down are not mutually exclusive, that is, one does not hinder the other. As in stopping down is fine and adding a few degrees of tilt or swing for good measure is fine. Is this assumption correct?

Leigh

27-Mar-2014, 00:44

Hi Sibben,

Yep. You got it.

One fine point that may or may not be obvious is how tilt (or swing) affects depth of field (DoF).

We tend to think of DoF as a pair of planes, one in front of the subject and the other behind it.

When you add tilt (or swing) to the equation, those two planes are no longer parallel.
They converge at the camera, and diverge as your subject moves toward infinity.

At any given distance, DoF will be the same as if the camera was focused at that distance with no movements.

- Leigh

Doremus Scudder

27-Mar-2014, 02:50

... Before I moved to LF I learned to accomplish this in MF by focusing at the hypofocal plane by focusing first on the foreground then the background and then setting the focus point half way between the two and stopping down the aperture to the f-stop on the lens encompassing both points. ... In LF the same is accomplished focusing on the near, tilting for the background, refocusing on the near, re-tilting for the rear ... Thomas

... I am making the assumption that tilting and stopping down are not mutually exclusive, ...

... One fine point that may or may not be obvious is how tilt (or swing) affects depth of field (DoF).

We tend to think of DoF as a pair of planes, one in front of the subject and the other behind it. When you add tilt (or swing) to the equation, those two planes are no longer parallel. They converge at the camera, and diverge as your subject moves toward infinity. At any given distance, DoF will be the same as if the camera was focused at that distance with no movements. Leigh

More interesting stuff.

Let's clear up a basic misconception that seems to underlie part of this discussion. Leigh, just above, has it right, but has maybe not laid it out as clearly as it could be :)

@Thomas: Yes, to the first part of your quote above; finding the middle of the focus spread and then stopping down to a depth-of-field that makes sure both extremes are in focus is the correct way to ensure all is sharp. However, even with movements (tilt/swing) we still have to do this. Keep in mind that tilting or swinging does not increase the depth-of-field. It only moves the two-dimensional plane of sharp focus around in scene. We still need DoF in front and in back (or above and below) this two-dimensional plane to ensure sharpness.

So, tilting or swinging are definitely not the same as stopping down. What we try to do when tilting/swinging is to bring the parts of the scene we want in sharp focus closer to the plane of sharp focus in order to reduce the focus spread so we don't have to stop down as much as without the tilt/swing.

After applying movements, we still have to measure the focus spread and choose the optimum aperture to keep everything desired in sharp focus. I do this for every shot I take.

The whole thing about reiteration of tilt/swing movements is to place the plane precisely ... It has nothing to do with depth-of-field, which extends on either side of the plane of sharp focus and is dependent on f-stop and distance.

@Sibben: Your assumption is 100% correct: tilting and stopping down for depth-of-field are separate issues entirely. Just to recap the above: tilting moves the two-dimensional plane of sharp focus - stopping down controls the depth-of-field on either side of this two-dimensional plane. If we can position the plane of sharp focus optimally, then we don't have to stop down as much to keep everything sharp. You do, however, still have to find the "near" and "far" focus points (which may be in unintuitive positions when tilt is applied!), find the focus spread between these, and use the optimum or "hyperfocal" f-stop for that spread to keep everything desired sharp enough.

Lastly, to augment Leigh's point just a bit: When focusing on something near to the camera position, the depth-of-field for any given f-stop will be shallower than it as for an object farther away. When we have repositioned our plane of sharp focus by tilting, parts of it is now closer to the camera that others. The depth-of-field for a part that is close to the camera will be shallower than the depth-of-field for a part that is farther from the camera.

A concrete example: We tilt the back backward a bit (or the lens forward) to bring a foreground flower head (say a 2-foot-tall yellow daisy) into focus and at the same time keep a distant mountain range in focus. We place the plane right on the bloom and the mountain tops (warning, this is a mistake in placement of the plane of sharp focus, don't really do this!). Now we stop down to f/16 and shoot. All may be well at the farthest distance with depth-of-field, but just possibly the base of the mountains might not be very sharp, since they are a long, long, way apart (some thousands of feet possibly). Nevertheless, at that far distance, we have DoF that likely covers some thousand feet or so below the plane of sharp focus.

The flower in the foreground is another issue, though. More than likely, the bloom itself will be in focus, but the ground below the flower will be out of focus. Why? Because the DoF at that close distance and aperture does not extend the two feet below the blossom in order to keep it sharp. Our near DoF is less than two feet!

BTW, in the above example, we should place the plane of sharp focus at points halfway between the ground and the blossom in the foreground and at the mid-point of the distant mountain range. That gives you DoF on both sides of the plane and likely keeps everything sharp.

Hope this helps,

Doremus

Cor

27-Mar-2014, 03:51

Bernice,

First: thanks for your time and the elaborate answer

Hello Cor,

Camera movements done properly and used to increase perceive sharpness in the image is not apparent at all unless rear camera movement is used to intentionally alter the image's geometry.

I understand, that's why I put the word "see" between quotes, I meant not seeing in the literal sense, juts trying to understand how you accomplished the image

In the first example, the gray power panel on the left is in focus, by using front swing, the plane of focus runs as a curved sheet from left to right where the "pipes/boxes" are located. Apply just enough swing and it all comes into focus with the lens at wide open.

Now I am confused by the plane of focus as a curved sheet. I always understood the plane of focus as a straight line or sheet (depending if you look from the camera or from the side, and this line can be manipulated to run at an angle in respect to the back (or front) panel.

Or is this curve caused by this particular lens ?

Best,

Cor

Cor

27-Mar-2014, 04:22

Excellent article, Doremus !

I am glad that my basic understanding of movements fits with your writings, I do have a question though:

After applying movements, we still have to measure the focus spread and choose the optimum aperture to keep everything desired in sharp focus. I do this for every shot I take.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
BTW, in the above example, we should place the plane of sharp focus at points halfway between the ground and the blossom in the foreground and at the mid-point of the distant mountain range. That gives you DoF on both sides of the plane and likely keeps everything sharp.

Hope this helps,

Doremus

How do you measure above focus spread after applying movements in said example:
so the f stop needed to get the whole flower in focus ?

best,

Cor

Doremus Scudder

27-Mar-2014, 06:44

Excellent article, Doremus !
I am glad that my basic understanding of movements fits with your writings, I do have a question though:

How do you measure above focus spread after applying movements in said example: so the f stop needed to get the whole flower in focus ?
best,
Cor

Hi Cor,

Glad you found my advice helpful.

Measuring focus spread is not all that difficult. You simply focus on the farthest object you want in focus and note the position of the focusing standard on the rail or camera bed. Then you focus on the nearest object you want in focus and, again, note the position of the standard on the rail or bed. You then position the standard exactly in the middle and choose the f-stop based on the distance between the two farthest points.

Of course, you need some way to measure the distance! Many cameras have millimeter scales already on the rail or the bed, so no problems. For those that don't, it's pretty easy to add a sticker with mm marks or a rule of some kind. I have some rulers I can print onto labels and cut to the appropriate size that work really well.

As for choosing the f-stop: now you're getting into another can of worms :)

While many 35mm and medium-format camera lenses have "hyperfocal" scales printed on them, we LFers have to make them ourselves.

I highly recommend checking out the two articles on the LF homepage, "How to Focus the View Camera" http://www.largeformatphotography.info/how-to-focus.html and "How to Choose the F-Stop" http://www.largeformatphotography.info/fstop.html .

Yeah, they are a bit ponderous to dig through if you're not familiar with the material already, but well, well worth the time.

I have stickers on all my cameras with the optimum f-stop for balancing focus and diffraction based on focus spread as well as stickers for maximum print size for my chosen circle of confusion for f-stops from f/22 on up.

In practice, it is real easy: just find your focus points, note the distance, position the standard at the halfway point, and stop down to the optimum f-stop from the table corresponding to the focus spread.

The only thing you have to watch out for if you've used tilt or swing is to really find the points farthest from the plane of sharp focus both near and far. Since that plane is no longer parallel to the camera back, you have to imagine where it is in the scene and find the true "near" and "far" points.

In my example, I would place the plane of sharp focus halfway up the flower stalk and the mountain range, then check the distances to theflower top and ground in the foreground and the peaks and base of the mountains in the distance (both "near" and "far" from the plane of focus respectively, or perhaps better understood in this case as "above" and "below") . The greatest "near" and "far" distances would determine my focus spread and be what I used to base my choice of f-stop on.

Oh yes, one more thing: the plane of sharp focus is exactly that, a two-dimensional flat plane; it is not curved. The depth-of-field for a plane of sharp focus that that has been, say, adjusted as in my example, ends up being a wedge, with the small end closest to the camera. Many photographers (like maybe Bernice) visualize this wedge as a curve of some kind, which is really not accurate.

Hope this helps,

Doremus

Leigh

27-Mar-2014, 07:18

in the above example, we should place the plane of sharp focus at points halfway between the ground and the blossom in the foreground and at the mid-point of the distant mountain range. That gives you DoF on both sides of the plane and likely keeps everything sharp.
Minor correction...

Depth of Field is asymmetric.
The in-focus distance behind the subject is twice as deep as the in-focus distance in front.

When the focus plane is rotated, the in-focus distance farther from the camera is twice the closer distance.

- Leigh

wombat2go

27-Mar-2014, 07:26

Hi Cor,

Oh yes, one more thing: the plane of sharp focus is exactly that, a two-dimensional flat plane; it is not curved. The depth-of-field for a plane of sharp focus that that has been, say, adjusted as in my example, ends up being a wedge, with the small end closest to the camera. Many photographers (like maybe Bernice) visualize this wedge as a curve of some kind, which is really not accurate.

Hope this helps,

Doremus

But, for a perfect lens, it has to be a curve, does it not?
Reason : (1/u) +(1/v)=(1/f)
And I attach a graph of variation of subject focus distance (u) with linear changes in v for the case where a flat film sensor plane is inclined with respect to the lens axis.

Cor

27-Mar-2014, 07:30

Thanks for elaborating Doremus, most of your reply I know and understand, it's when ,such as the example, tilt comes in.

So if I follow you correctly below: say the flower is 20 cm tall, you focus half way at 10 cm, so you'll need 10 cm below and above the flower as your focus spread (will be roughly equal close by). Then you use a table to find the needed f stop ?

As for the mountains say 1 km away; it seems hard to guess the "above" and "below" (and there will be more "below" right ?)distances from the plane of sharp focus.

(I would approach it more pragmatic I think: I would try to place the plane of focus as you suggest, and then look through the ground glass while stopping down the lens and hopefully it's clear which F stop to use, and than I would add (close down) 1 more stop)

Best,

Cor

Hi Cor,

In my example, I would place the plane of sharp focus halfway up the flower stalk and the mountain range, then check the distances to theflower top and ground in the foreground and the peaks and base of the mountains in the distance (both "near" and "far" from the plane of focus respectively, or perhaps better understood in this case as "above" and "below") . The greatest "near" and "far" distances would determine my focus spread and be what I used to base my choice of f-stop on.

Doremus

Vaughn

27-Mar-2014, 07:52

To determine if I have placed the plain of focus in the optimal place, I close the lens down while looking at the GG. If near and far come in to focus at the same time, then I have placed the plain of focus in the right place. If the background comes into focus first, then I need to move the plain of focus closer to the camera, etc.

Bernice Loui

27-Mar-2014, 08:26

As others have already replied...

The plane or "sheet" of focus is flat IF.. If the lens is precisely or near absolute perfectly parallel to the film or imager plane. Once the lens is no longer parallel to the film or imager plane, the resulting plane or sheet of focus will curve.

This is why taking two points between the swing or tilt and adjusting the focus between these two points can render a good overall perception of focus.

This is the basis of the Sinar tilt/swing focus system built into their cameras. I'm not sure if their explanation of this is on line, Sinar built this optical reality into their cameras and made it easier for the user to apply in real world image making.

IMO, don't get too bound up in the math or curves or etc. Once the concept is understood well enough, it is applying it to real world image making that matters. Knowing this is how a lens behaves with a camera that allows this to be used to it's fullest becomes another tool that can be used in the image making process. It will also set limits for what can be rendered in and out of focus and will affect subjects and composition.. there is a balance to all this.

Bernice

Bernice,

Now I am confused by the plane of focus as a curved sheet. I always understood the plane of focus as a straight line or sheet (depending if you look from the camera or from the side, and this line can be manipulated to run at an angle in respect to the back (or front) panel.

Or is this curve caused by this particular lens ?

Best,

Cor

Drew Wiley

27-Mar-2014, 08:28

Tabletop photography in a studio is one thing with regard to ideal "Scheme-pflug" (I'll deliberately misspell it this time, since I never seem to spell it right anyway).
In the field, at least the places I go, real world planes are never simple, and I tend to use long lenses, so I really need to make specific aesthetic decisions exactly
what I need to place in the most acute focus. Usual it's some critical detail. Then I do my swings and tilts, as needed, and check things under the loupe stopped
halfway down to my intended final setting. It's at this point that I make minor adjustments for hyperfocal depth of field, again, aesthetically or compositionally. I don't give a damn about the math. Then the final aperture setting. This is what, in a practical sense, works for me.

Greg Miller

27-Mar-2014, 12:19

Greg - a 7X magnifier on a 10-inch groundglass is like getting nose to nose with a print six feet wide. A big print optically-printed Ciba or Supergloss is an even better
indicator. This is what I do.

Yes, a 7x loupe on a ground glass is very close. But I'm having a hard time understanding how anyone could distinguish between ground glass grain and diffraction at that magnification level. Especially in the eery darkness of f64.

Jim Noel

27-Mar-2014, 14:51

When in the field my camera is set for a permanent tilt which then may be altered slightly for each image.
So my answer to the original question is -Essentially always.

tgtaylor

27-Mar-2014, 15:07

Why in the world would you have your camera set to a permanent tilt? If you do that, assuming that you can even close it, you can't bring everything to the zero position which is a starting position for me and from what you can make an accurate determination of the adjustments to make for the photo.

Thomas

Drew Wiley

27-Mar-2014, 15:27

Well yes, Greg... f/64 can be eerily dark. But there is enough light coming thru to evaluate the difference in certain critical details between f/45 and f/64. Or with
certain subjects like fresh snow, specular highlights can be used quite easily to make the determination - a bit of sparkle, for example. In dimmer studio setups I've
sometimes set a bit of shiny tinsel or tinfoil temporarily in the scene to help. Now with 8x10 film this only becomes critical is it is something I think I might want to
enlarge up to 30x40 or so, and of course, everything else in the workflow has to follow suit, like the use of adhesive filmholders for a true film plane. Yet all this becomes far more critical with smaller film sizes. Like I already mentioned on other threads, and hinted at on this one, a real challenge is to get really crisp 16x20 or
20x24 prints from 120 film. With view camera movements, I can achieve this by using medium lens apertures, say around f/11, which will degrade the image far less
than using a conventional medium format camera, where the only option is to stop down even further, and even that won't accommodate the kind of near/far
circumstances often encountered in landscapes. Each type of gear has its own advantages and disadvantages, but once a tripod is involved, a precisely employed
good view camera wins hand-down in terms of detail rendition.

tgtaylor

27-Mar-2014, 15:54

Oh, I get it: It's bent!

Thomas

Drew Wiley

27-Mar-2014, 16:06

Thomas - if you were just out in the middle of the ocean floating at eye-level on a calm sea, the ideal film plane would be permanently corrected for the curvature
of the earth. That's a very common scenario, as we all know.

Doremus Scudder

28-Mar-2014, 02:52

Minor correction...

Depth of Field is asymmetric.
The in-focus distance behind the subject is twice as deep as the in-focus distance in front.

When the focus plane is rotated, the in-focus distance farther from the camera is twice the closer distance.

- Leigh

Leigh,

An intentional over-simplification on my part. However, I believe that the 1/3 to 2/3 relationship is only valid fairly close to the camera, and that as focus approaches infinity, the difference is less. Nevertheless, you are correct in pointing this out.

What makes this sometimes less than useful in the field when applying movements is that many of us (at least me :) ) think in terms of "either side of the plane of sharp focus," i.e., in lines perpendicular to the plane. When the plane is tilted or rotated, it is the distances along a line parallel to the lens view that exhibit this relationship, not distances along lines perpendicular to the plane of sharp focus itself (i.e., "above" and "below," or "right" and "left" of the plane).

Anyway, yes, we should take this into consideration too and be aware of this when choosing focus points. The nice thing is, when you measure focus spread and then focus halfway between, this is automatically compensated for. So, in practice, we don't have to think about it too much.

But, for a perfect lens, it has to be a curve, does it not?
Reason : (1/u) +(1/v)=(1/f)
And I attach a graph of variation of subject focus distance (u) with linear changes in v for the case where a flat film sensor plane is inclined with respect to the lens axis.

Wombat,

Maybe I'm not exactly understanding your graph. Certainly the lens-to-film distance changes in a curve as we focus from nearer to farther, but that doesn't necessarily mean the position of the focus in front of the camera is not planar.

Everything I've read (Merklinger, Scheimplug, et al.) talks about planes... If the "plane" is curved, then it must be very slightly. Of course, we are always speaking "theoretically" and simplifying things to abstract generalities. I've had a bunch of lenses with curved fields of focus. I think, however, for practical purposes, we can envision a plane of sharp focus and not worry about curvature too much.

Thanks for elaborating Doremus, most of your reply I know and understand, it's when ,such as the example, tilt comes in.

So if I follow you correctly below: say the flower is 20 cm tall, you focus half way at 10 cm, so you'll need 10 cm below and above the flower as your focus spread [this is not what I mean by focus spread; see below]. Then you use a table to find the needed f stop ?

As for the mountains say 1 km away; it seems hard to guess the "above" and "below" (and there will be more "below" right ?) distances from the plane of sharp focus. [You don't have to estimate distances... just play with the focus knob and see which is farthest from the plane of sharp focus, i.e., where the camera standards are farthest from and closest to each other.]

(I would approach it more pragmatically I think: I would try to place the plane of focus as you suggest, and then look through the ground glass while stopping down the lens and hopefully it's clear which F stop to use, and than I would add (close down) 1 more stop)

Best, Cor

Emphasis and comments added.

Cor,

Just a couple corrections: when I speak of focus spread, I'm talking about the real physical distance in millimeters (or inches if you prefer :) ) between the position of the standards (i.e., lens standard and camera back) at the two positions "near focus" and "far focus." What you refer to is depth-of-field, which has to do with an area of acceptable sharpness on either side of the plane of sharp focus.

I recommended a "near-far" approach and looking up optimal f-stop on a table. As you can see from some of the posts above, many use a visual method: basically stopping down after applying movements and observing the sharpness to determine f-stop. This works well, especially for larger formats (8x10 and larger). For me, the table method works better. Try both and see what works for you.

And, if you are following all the above about the relationship of the areas of depth-of-field in front of and behind the plane of sharp focus, be aware that choosing near and far focus points and finding an f-stop that keeps them both in focus (whichever way you end up with) automatically takes this into consideration.

As for my example: it's really not as precise in practice as you want it to be :) I would choose focus points somewhere between flower bloom and ground and about halfway up the mountain side, then check focus spread for the extremes, i.e., the mountain tops and base, and the flower top and ground. Then use the extremes (i.e., largest combination) of spread to use to choose my f-stop. You could just observe those things on the ground glass while stopping down, as you suggest; when everything seems sharp "add as stop" and shoot. Many good photographers work this way.

Whichever method you end up using, it still helps to find the "near" and "far" focus points and set the focus halfway between. What I'm talking about here again is the position of the lens standard and camera back relative to each other. Let's say I focus on my near focus point. I then look at the millimeter scale on my camera and see that my indicator dot is pointing at, say, 95mm (this scale is completely arbitrary; it is only to find the difference). I then focus on the far and check again; now my indicator is opposite 91mm. I have a 4mm focus spread. I then position my indicator dot halfway between the extremes, at 93mm. Then I consult my table and find my f-stop, in this case, f/45- (1/3 stop wider than f/45). I stop down to that and shoot. BTW, 4mm is a rather large focus spread.

Hope this helps,

Doremus

Cor

28-Mar-2014, 05:58

Doremus,

Thanks again for the elaborate answer, I'll leave it at that..;-)...in practice I mostly get were I want, but I also like to indulge in the exact science behind it once and a while

Have a nice weekend (and I much prefer mm over inches)

Best,

Cor

Leigh

28-Mar-2014, 07:25

I believe that the 1/3 to 2/3 relationship is only valid fairly close to the camera, and that as focus approaches infinity, the difference is less.
Certainly if the plane of focus is located at infinity, the idea of a far focus limit beyond infinity lacks credibility.

Duhhh.

- Leigh

Greg Miller

28-Mar-2014, 08:42

Drew Wiley

28-Mar-2014, 09:24

I do it all the time, Greg. No need to second guess me. Not all groundglasses are the same. Nor is the amount of luminance coming in to begin with always equal.
I could make this practice work even shooting in a cave (and have). All I need is a bit of tinfoil and a laser pointer temporarily in the scene for critical focus. I often carry a little bit of tinsel with me for extreme closeups, just like in studio shots, which are also relatively dim. But like I also said, I'm more likely to use f/32 to estimate what will happen at f/64. It's generally three steps for me : composition and true focus wide open, but second, acute focus with hyperfocal consideratons halfway down to my final aperture, then that final aperture itself.

Greg Miller

28-Mar-2014, 11:30

I do it all the time, Greg.

I'll never stop down past f32 on 4x5. By f45 you are into conspicuous diffraction territory, and it will show on enlargement.

Hmmm. Which is it?

Drew Wiley

28-Mar-2014, 11:35

I already spelled that out, Greg. F/32 for 4x5, f/64 for 8x10. Given the magnification ratios, doesn't that make perfect sense, apples to apples?

Ginette

28-Mar-2014, 22:04

Interesting info about, with illustrated pictures http://www.ebonycamera.com/media/asymmetrical.movements.pdf

Greg Miller

29-Mar-2014, 05:51

I already spelled that out, Greg. F/32 for 4x5, f/64 for 8x10. Given the magnification ratios, doesn't that make perfect sense, apples to apples?

Yes, you are correct. I apologize. Too much noise between the pertinent details to keep things straight I guess.

Thom Bennett

29-Mar-2014, 10:45

112950

Lenny Eiger

29-Mar-2014, 11:11

Only that differentiating between ground glass grain and diffraction distortion with a 7x loupe, especially closed down to f64, seems like a stretch. Perhaps a double blind trial is in order.

I've done my tests. My Sironar S's close down to 45, both 4x5 and 8x10, without any problem whatsoever. This whole 2 stops down from wide open doesn't hold true at my place. But don't trust me. Do that study. It only takes two sheets of film. Only do it with a print vs what you can see up at 200% on your monitor.

Lenny

Sibben

31-Mar-2014, 07:38

So I tried this weekend to combine the two methods as described here. I stopped down to 22 and added a few degrees of tilt and a few near-far focus/tilt-iterations. The tree line on the horizon seems a bit soft compared to the rest but it's really hard to see on the GG when you move past the point of "nothing is equally sharp" and into "everything is slightly less but equally sharp".

https://farm8.staticflickr.com/7205/13495508125_7acd5cbeba_c.jpg

Drew Wiley

31-Mar-2014, 08:19

Lenny - there's loads of hard research on this depth of field business going back decades. I don't think spinning a few offhand loose opinions on a web chatter thread
is going to change the laws of optics any time soon. Do you even have a true film plane? If you are making these kinds of tests with with ordinary filmholder, you
don't. So your "test" is bogus to begin with. "Two stops down from wide" has nothing to do with it. Never did.

Drew Wiley

31-Mar-2014, 08:21

Sorry, didn't mean to say, "depth of field", but "diffraction". (Not quite awake... need another dose of coffee)

Lenny Eiger

31-Mar-2014, 11:57

I just pulled up my tests from a couple of years ago. I zoomed up to 200%. They were scanned softer than I scan these days, at 13 vs 8 or 10 microns. I'm pretty sure these were from Delta, developed in D-23. I later moved to Xtol, which is also sharper. The one at left is f22, on right is f45. The letters at top are less sharp at f22 than the f45, but if you look at the letters on the bottom, the f22 is sharper. I obviously refocused between shots. These are from 1/4 of an inch of an 8x10.

Even if one could discern a difference, which I don't believe you can, the print will not show it. The resolution of printers, even with b&w ink only, just isn't that good. When I started out I asked another printer if he spotted images at 100%. He laughed at me and said, no, you won't see anything past about 33%. It's arguable of course, size dependent and all, but its pretty clear that you will see difference in the print that you can see on the monitor in the 33-50% range.

I uploaded a screen snap at 200% and another at 50%. Contrast was adjusted (a point or two) to try and match them exactly but no sharpening or other manipulate was done. I will state unequivocally - diffraction is not a factor in this medium. I won't argue with optical mathematics, but this is reality here not theory. By the time you get thru a scanner and to the print, there is no difference. These were done on one of the best scanners made (an Aztek Premier). If you are using a consumer level flatbed, like many here, there is certainly going to be no difference at all. You can forget it.

Lenny

113075113074

Drew Wiley

31-Mar-2014, 12:54

Nonsense, Lenny. Utter nonsense. Ask any scientific photographer who has worked with large format. Try real optical printing on a high-resolution media like Ciba
or Supergloss. Not all of us scan and print inkjet, by the way. .. So it does matter.... to what degree depends what you're doing. For me it IS a significant factor.
I can spot it in a heartbeat on a large print.

Drew Wiley

31-Mar-2014, 13:35

... (back to it, Lenny, raining like insanity here, probably like it is right now in your neighborhood, and I had to check for roof leaks in the warehouse)... but anyway,
to properly assess the effect of diffraction you have to isolate it from all the other variables, just like in any other scientific question. That means doing it on an
optical bench with either a vac filmholder, glass plates, or some kind of direct observation. Your way of trying to evaluate it tangles up with depth of field, lack of
a precise film plane, scanning and printing variables, etc. Just get ahold of a decent text on optics. This is old, old hat. How one uses the information is up to them.

Darin Boville

31-Mar-2014, 13:51

Drew Wiley

31-Mar-2014, 13:57

So how can you improve the "system" if you can't isolate the variables, or don't even know what they are? Gosh... Darin, your "logic" is even worse than his.

Sibben

31-Mar-2014, 14:13

I really can't see a difference. Not saying it ain't there but can't see it. Wonder what it would be on f64. I tested all my m43-glass I while back and it was like a knee sort of. Sharper, sharper, sharper and then just softer. Every lens had a stop where it just went straight the other way.

Darin Boville

31-Mar-2014, 14:16

So how can you improve the "system" if you can't isolate the variables, or don't even know what they are? Gosh... Darin, your "logic" is even worse than his.

I typed out a detailed response to this.....but then came to my senses and deleted it. This text here is just a placeholder and perhaps a warning to others.

--Darin

Drew Wiley

31-Mar-2014, 14:20

Well, I'm glad you're not my doctor. "I don't feel too well"...."Take two aspirin and go home. We just try to improve the overall system".... "But I seem to have broken
my arm.." "What's an arm?"

Lenny Eiger

31-Mar-2014, 14:59

Drew, I'm sorry, but you are off the mark on this one. Darin is correct. I would never consider printing on Ciba, or anything glossy. I absolutely hate that look. I'm not shooting tabletop, either. (These are my subjective decisions.) Most importantly, I am not trying to prove that diffraction doesn't exist. I was only interested in whether or not it was a factor in my system. I don't go against math.

What I can say is that it is clearly not a factor in my system. I'm guessing that it isn't a factor for most of us here. For everyone that uses a scanner, for everyone that wants to print with an inkjet, or on matte surface papers, this simply isn't a factor. If it is, the effect is so small that a tiny bit of sharpening, or a tiny increase of contrast will render it appropriately meaningless.

Earlier today I replied to a thread in another forum where Andrew Rodney stated that he and his friends, Jeff Schewe, Mac Holbert, John Paul Caponigro and Greg Gorman, all felt that Epson printers did not need resizing to a multiple of 300, provided at least that the image was in 180-480 range. That goes against the conventional wisdom about setting a file with the exact pixel dimensions so that these printers can print it. I'm in agreement, I've always known that you didn't need a multiple of 300 to succeed. Certainly not 363, like one famous person suggested. People didn't want to believe him. It was a little surprising, I've disagreed with Andrew in the past, but all of them at once? They are probably right. At least one of them would have tested it.

I also will happily go against this conventional wisdom of "two stops down from wide open". I think it just doesn't apply for large format lenses, and the materials that most of us use. I can't tell you how many people I've scanned for that are disappointed with the depth of field they are missing in their images - because they followed this rule. It may work very well for digital cameras, or something else. It just doesn't apply here. Its totally unnecessary in this context.

There is no improving a variable in the system, and thereby improving it all, if the bottleneck is at the end of the process, and tighter than this variable. Weakest link in the chain, etc. Further, if I had to give op 3% in sharpness to get full depth of field, I'd make that bargain. It's nice that I don't have to give up anything. If my little jpegs don't prove this for anyone, by all means do your own testing, on your own equipment, all the way out to the print, and see what happens.

Lenny

Drew Wiley

31-Mar-2014, 15:35

If you're happy with your results, no need to fuss about things. That's like saying, if you're happy with your gas mileage, no need for a tuneup. But otherwise, even
a competent car mechanic has to have an inkling of scientific method, and know how to diagnose the various mechanisms at work, and how to either repair or improve them. The weakest link in the chain is normally the film plane, esp with 8x10 or larger. That is easily solved. But few bother. Then what? These little things
all add up. And like I said, two stops down has nothing to do with it. Where on earth did you get that? Large format lenses operate by the same laws of optics and
diffraction as any other lens. This is just an engineering and scientific fact that has been thoroughly studied by both lens and camera manufacturers. You say it doesn't matter. OK. It doesn't matter to you. Not everybody is limited to what inkjet will do. Post-"sharpening" is not the same thing as a sharp original. It's faking it, and I knew you'd bring it up. I'm not condemning the use of that tool aesthetically. It is a tool. Just realize that to be objective, this thread has not been narrowed to "tilts for inkjet printers only". One of the great values of controls like tilt is that one has an option to simply stopping way down for depth of field.
One often can select a superior working aperture. I do it all the time, and it absolutely makes a difference in the quality of the print. If you don't need this degree
of control, that is your option. But you'd have a mighty rough day getting sandwiched into a conversation between me and somebody like Joe Holmes over here,
when we start talking about technically optimizing images - and he is an inkjet guy these days. Not everyone is addicted to the "good enough" formula.

Drew Wiley

31-Mar-2014, 16:02

A little more. There have been quite a few 4x5 careers where the f/32 boundary was never violated. Most often this applied to people using high-quality camera and
lenses, and who were concerned about technical crispness, even in publication. I guess that what one considers conventional depends on what crows one runs in.
Contact printers might go clear down to f/256 with a ULF, and their contact prints look wonderful; but probably would look like hell modestly enlarged. With 8x10, I'll never use f/64 if I intend to print the image up to 30x40. That's only a 4X enlargement, but the difference of one stop can make or break the "wow" factor. And it's not just me. I can think of other former Ciba printers who religiously followed the same rule, cause it truly made a difference. If the detail is there, people will put their noses in it. Some of us threw out that "normal viewing distance" nonsense long ago. And it isn't just Ciba. I took an 8x10 black and white shot yesterday
where I limited the aperture to f/45 even though I only had a 16x20 print in mind. Why? Because in this case, I had a high degree of microtonality in mind, which
would have been compromised (but will require a supplementary mask to realize - but please don't tell me I'm the only person that does that. I'm not.) So I view
these discussions about intelligent use of the tools. If you prefer other tools, that's perfectly OK. But there are options.

Leigh

31-Mar-2014, 16:29

... discussions about intelligent use of the tools.
Speaking of tools... There's one on the right side of the keyboard called the Return key.

Also, there are many books available on proper prosaic style, including the use of paragraphs.

Your posts would be much easier to read if they followed compositional norms more closely.

- Leigh

Lenny Eiger

31-Mar-2014, 18:28

Drew, I am the last person to consider things as "good enough". My printing is quite highly regarded. I just happened to have tested things and know a bunch about my process. I wouldn't be the first person here to suggest that you are all wet about things. I think the idea about using only the best f-stop causes a lot of people to waste a lot of time trying to figure this out - and they lose their depth of field. The effect is clearly overblown.

People should also be aware that there are plenty of places where tilts are not really useful. If you tilt to show the foreground and some object far away you might just lose all the things that are higher than your focus plane, like the tops of the trees. Sometimes it looks quite contrived. Like everything, these techniques should be used judiciously.

Lenny

tgtaylor

31-Mar-2014, 19:11

I am inclined to agree with Lenny on this. Although I mentally limit my aperture to f11 with 35mm, f16 with MF, and f22 - F32 with 4x5 and 8x10, I have on occasion stopped down much further because of the circumstances and have never noticed and evidence of diffraction in the prints or negatives. Of course I rarely print beyond 16x20 and as far as I am aware none of my lens close down to f256. Well known and respected landscape photographer Bruce Barnbaum seemingly arrives at the same conclusion when discussing "thin negatives" on page 10-6 of The Art of Photography, Edition 3.1, 2006, he writes: "...I close down several more stops. Don't worry about any supposed lack of sharpness as you stop down, because you'll never see the difference. It may be visible on a super-enlarged optical bench, but it isn't visible to the naked eye at any enlargement that you (or I) will ever make."

Thomas

djdister

31-Mar-2014, 19:17

Ultimately it's about what the eye can see when looking at the print from a reasonable distance, such as the distance of the diagonal of the print. Diffraction as has been discussed would never be visible at "normal viewing distance", and put the print behind glass and even less chance of seeing a lack of sharpness from stopping down.

Besides, if f/64 was so bad to use, then why didn't Adams and Company found the f/22 Group?

Leigh

31-Mar-2014, 19:29

I challenge any member of the diffraction degradation camp to explain why process lenses, being the highest-quality photographic optics ever manufactured, commonly go down to f/128 or even f/256.

Those lenses had the sole purpose of reproducing the finest detail as accurately as possible.

For example, there is currently a 30" Red Dot Artar in a #5 Ilex for sale. It goes down to f/128.
http://www.largeformatphotography.info/forum/showthread.php?112414-FS-30-inch-Goerz-Red-Dot-Artar-in-Ilex-no-5-1500

Drew??? We're waiting.

- Leigh

Greg Miller

31-Mar-2014, 19:51

Drew??? We're waiting.

I'm waiting for someone besides Drew who can see diffraction on the ground glass by changing from f32 to f64 (I guess an optical bench is not required for that test, nor perfectly aligned front and rear standards and a vacuum back). Or even someone who can reach around their 8x10 while under the dark cloth and holding their 7x loupe to the ground glass and change the aperture setting.

Cor

1-Apr-2014, 00:53

As a mere mortal doing some architecture photography last weekend..

Used a steady tripod, but had to raise the centre column to not get the building too strangely inclined (raising the centre column is a no-no I learned from one of my teachers, he is right stability wise, but composition wise I had to resort to it).

Used a monorail (Linhof Color) can be tightened down rock solid, so we can take that one out of the equation, providing any operator errors off course.

Used various (older to more modern) lenses: 65 mm f5.6 SA, 90mm f8 SA, old 120 mm f 6.8 Angulon, 150mm f5.6 Symmar S, old 180 and 210 f5.6 Symmars, quite good work horses but not top of the line.

Film : Fomapan 100, semi-stand in PyrocatHDC, will be printed to 30*40 Ilford FB (tests sometimes on on RC) with a Durst Laborator 1200 condensor, 150 mm Companon-s.

Will I see diffraction effects in the f22-f45 range ?

I do not with this set up, and I dare say that most others who work as me will not see either.

Oh and I forgot my mixed bag of Fidelity holders (20 or so)

I guess it is all nice to have an academic discussion (and I must say I do not like the tone of some contributions, but hey I am Dutch, English is not my native language) but in the end we go out to shoot, and there is already so much to think about, I find it liberating that I can stop down to f32, and get that sharpness I want.

Best,

Cor

Drew Wiley

1-Apr-2014, 08:28

Apparently a lot of folks here live in a small world that ignores an awful lot of sheer optical research and even what has been considered standard practice by
careful practitioners for decades. Typical of the instant quasi-info web era, I guess. Like I said, you don't even have the basis for judging diffraction if your film plane is off in the first place, which it will be for most of you, because that's yet another thing you haven't realistically reviewed. And frankly, I doubt some of you even know how to do objective testing. And "normal viewing distance" is basically an excuse for sloppy results. And Leigh ... find me anyone, anywhere in the image reproduction industry who ever ever used process lenses below f/22. If you want to do it on a ULF camera that understandable, esp for contact printing needs - but it won't rewrite the laws of physics. Nowadays expensive machine optics are routinely made at FIXED aperture just because they need to simultaneousl be optimized for both diffraction, resolution, apochromaticity. Gosh, do you guys even read anything that isn't some shoot-from-the-hip web blurb? Get an optics textbook. If it's academic to you, that's fine. It is not academic to me. It a real factor that plays into image reproduction, and always has. And
maybe someone else has similar needs. .. No, I'm not always obsessed with detail. There are times I like to print nonglossy and even prefer lenses that aren't so
hard-sharp, though I'm not in the soft-focus camp. But many other times I am after detail, and all these seemingly little steps add up to an effective chain. This
is old old hat to me, and I'm just a bit perplexed at how some of you seem ignorant of the basics.

Drew Wiley

1-Apr-2014, 08:35

Cor... your standards seem atrocious to me, starting with that center column. No wonder it's academic to you. Off on the wrong foot to begin with.

Leigh

1-Apr-2014, 09:09

find me anyone, anywhere in the image reproduction industry who ever ever used process lenses below f/22.
You are apparently claiming that you have surveyed every photographer in the image reproduction industry.

That is such obvious nonsense that it doesn't warrant comment.

I challenge you to prove that nobody ever shot below f/22.

- Leigh

Drew Wiley

1-Apr-2014, 10:23

Maybe somebody hokey like a T-shirt shop used cheap stat camera lenses in some so-so fashion, but the kinds of process lenses we covet tended to be associated with serious process work, always flat copy, and it was important to keep dot shape very precise clear out to the corners. There are some interesting past threads about why the mfg of these lenses put f/stop markings on them which were never used ... but that's like having 200mph markings on the speedometer of an ordinary car, or shutter speed settings on camera shutters where the extreme speeds are never accurate or realistically usable anyway. The most logical explanation was that this was just the way the shutters were made to begin with, and had nothing to do with the routine process usage of per se. But these lenses have also obviously found their way into general photography as well as darkroom use. But in process use the copy lighting was matched to the f-stop, and there was no need to stop further down for depth of field issues. Pin-registered vacuum frames were routine.

Drew Wiley

1-Apr-2014, 11:00

High-end process lenses were pretty damn expensive back in the day, not like the used bargain they sometimes are now. Nearly all went to the printing industry for
which they were designed, but a small number were sold to photolabs for mural enlarging. But in the latter case they were likely to be used at relatively wide stops,
esp since they tend to be around f/9 max aperture to begin with. But unless you're talking about a Rodagon G, something like a process Nikkor was actually a better performer between f/11 and f/22 than an ordinary enlarging lens at that scale of magnification. The nitty-gritty of specific focal lengths became a bit debatable. I have a whole set of the things, and they are incredible good for enlarging if you don't mind a max focus aperture a bit small. The working aperture would often come out the same, cause these things were so sharp only a stop down. Process apochromaticity has somewhat more stringent standards, so nearly all these kinds of things were recommended for f/22 use. Beyond that, diffraction might become a quality issue. In general photography we can relax these rules a
bit, depending on just what we place the priority upon, but the optical result does not and cannot change. It's inherent.

djdister

1-Apr-2014, 11:22

Nobody is saying diffraction doesn't exist. What I'm saying is that in some cases it doesn't matter, or it is not noticeable. And yes, I do put my nose right up to a print to really get a good look at it, but that type of examination does not constitute the proper assessment of a work of art.

Technical perfection is nice if you can get it, and a technically perfect print can just as easily be a boring waste of silver/platinum/carbon...

Drew Wiley

1-Apr-2014, 11:32

I'd certainly agree with that, Dan. Diffraction is a real technical issue that needs to be recognized. After that, we decide at what point to trade it off with depth of field, and whether or not we need to be nitpicky about it. Scientific photography would have a different bias. A view camera has great advantages in this respect, because we also have tilt and swing controls. But don't narrow your definition of "art" (whatever that means) to your own personal taste. A perfectly "un-technical" print can be pretty damn boring too, and most are. These are simply tools. It's what one does with them that counts. Your argument could simply be taken a step further to, why bother with a clean lens when one with fungus in it creates interesting images. If that's what one like, fine. I happen to enjoy fine-tuning my craft, and other people seem to appreciate the effort when they view the prints. It sets them apart. But I'm not claiming that's the only way to do it.

Cor

1-Apr-2014, 11:37

Cor... your standards seem atrocious to me, starting with that center column. No wonder it's academic to you. Off on the wrong foot to begin with.

Talking you do a lot, but listening is kinda hard for you, isn't it Drew ?

Let me quote myself once more:

Used a steady tripod, but had to raise the centre column to not get the building too strangely inclined (raising the centre column is a no-no I learned from one of my teachers, he is right stability wise, but composition wise I had to resort to it).

I am happy to report that I just returned from the darkroom, and I am perfectly happy with the print made from the shot I took of this building last Saturday, nothing wrong with the sharpness

Cor

Oh btw I am not at all pleased with the use of the term atrocious..although thinking of your colour prints as judged on your web site..you made it to my ignore list so please do not bother

Jody_S

1-Apr-2014, 11:41

I challenge any member of the diffraction degradation camp to explain why process lenses, being the highest-quality photographic optics ever manufactured, commonly go down to f/128 or even f/256.

- Leigh

I'm pretty sure it was on this forum that someone explained how process lenses were often used at extremely small apertures to use diffraction to create a 'screen' for printing purposes. I haven't sat through an optics lecture in more than a decade, I don't remember much about it even as I had pretty much given up on photography at the time. But it would explain why it is (AFAIK, I'm sure someone will prove me wrong) only process lenses that ever stop down to f128.

djdister

1-Apr-2014, 11:44

Drew, you brought up an area that frankly was not in my thoughts at all -- scientific or technical photography. Certainly the issues of diffraction, resolving power and etc. have to be considered at a micro level. I recall seeing something about the standards of photolithography that was pretty exacting. So one answer is -- it depends what you are doing, or trying to do.

Drew Wiley

1-Apr-2014, 11:57

Indeed. I don't always follow a hard-sharp style myself. I go media schizophrenic from time to time and shoot in an entirely different style, often small format with
grainy high-speed film. Right now I'm trying to accommodate a less-than-adequate old process lens to a shutter specifically for a slightly off result. ... But as far as
using small apertures on process lenses, it would kinda defeat buying them in the first place. What I was referring to was industry convention dictated by what things were routinely engineered for. It was not intended as an absolute statement about potential anomalous incidents. We say, wine is for drinking and gasoline is for putting in the gas tank. But there are obviously a few people who drank gasoline and either got mighty sick or killed doing it. We say hedge trimmers are for trimming hedges and circular saws are for cutting plywood; but there have been a few fools who tried cutting plywood with a hedge trimmer and got hurt. Some of my ordinary view lenses, esp ones in older shutters, have very small f-stop markings where I never go. But I never use the fast speeds on view shutters either.
In fact, I only had one view shutter ever, a late 3 Compur, where the fastest speeds were even remotely accurate. So why are they there, if they're not usable?
I don't know.

Drew Wiley

1-Apr-2014, 12:04

... I only half answered that, Jody. No, the very small apertures had nothing to do with the screen. Quite the opposite. The screens had to be cleanly rendered,
which would dictate a sharp f-stop with minimal diffraction, yet small enough to assure evenness of field illumination and very tight apochromaticity with color
separations. Hence f/22 was considered the industry standard with process lenses. The nice thing about small aperture markings would apply to the ULF crowd,
who often turn to barrel process lenses for contact printing shots, where the visual effect of diffraction is minimal. But when one hooks up a sheet film holder to
an optical microscope, diffraction becomes the four-hundred pound gorilla in the room, and cannot be ignored.

Greg Miller

1-Apr-2014, 13:06

Like I said, you don't even have the basis for judging diffraction if your film plane is off in the first place, which it will be for most of you, because that's yet another thing you haven't realistically reviewed. And frankly, I doubt some of you even know how to do objective testing.

You mean like the "objective" testing some people perform by looking for diffraction on a ground glass with a 7x loupe? That meets exactly what principals of objective testing???

Drew Wiley

1-Apr-2014, 13:26

Not everyone who uses a view camera happens to be a bearded ole man trying to do something artsy/craftsy. The late Johsel Namkung transferred his meticulous
skills as a professional scientific photographer into his personal work. I have a friend who became a multimillionaire doing 8x10 Sinar tabletop photography on extreme precision, and then immaculately printing it large on Cibachrome, mostly to the Japanese advertising market. His technical precision is what made him successful - a unique look that stood out and gave him a distinct market niche. I don't think he ever stopped below f/22; but most of us aren't working with shallow planes we set up ourselves. My own critical test isn't even so much at the upper end (for me, the 8x10 format), but as I've already alluded, at the lower end, where I try to make a 6x9 roll film back behave as if it were 4x5. The proof is in the pudding. Given tilt control, I can take a shot on roll film at a more ideal aperture than using the same film in a conventional MF camera, and get a far crisper shot - certainly not equal to true LF, but good enough to not look odd framed next to one. Gosh... I get pounced for stating the obvious? This thread is honestly the first time in my life I've heard the diffraction issue challenged in its practical
implications, even by dedicated large format photographers.

Drew Wiley

1-Apr-2014, 13:55

Greg - I have no idea where you're coming from. I typically check my 8x10 shots wide open, halfway down, then finally at the working aperture. Scientific testing of lens performance is something else. And no, I don't need either long arms or a cowboy hat to readjust the aperture. ... it is actually possible to get out from under the darkcloth and move to the front of the camera to reset things like the aperture, shutter, close the shutter etc. Now I suppose someone will want to contest that. Back when my brother was studying photography at Brooks in the 60's the first thing they told them was to buy a 210 Symmar S, a 90 Super-Angulon, and the "f/22 rule" (f/16 for the 90). Things like lens coating have gotten better, but the optical effects of diffraction are inherent. I had to break my own rule myself the other day due to a lot of rise on an architectural front, because of mechanical vignetting with the particular lens I was using. But I knew the
reason and the potential penalty. In this case, the shot was 8x10 black and white, and intended only for a 16x20 print for 8x10, so negligible. But if it had been
for a large print, I would have rethought the composition and avoided f/64.

Greg Miller

1-Apr-2014, 14:12

Drew - where i am coming from is your earlier proclamation that you can see diffraction on your ground glass with a 7x loupe. Hardly a scientific assessment. Especially since eyesight, like sound and and smell, are very subjective with poor memory accuracy (which has scientifically been proven)(so you can't get out from under the dark cloth, change the aperture, get back under the dark cloth, and objectively say you see more diffraction at f64 than at f32 - diffraction just doesn't change that radically with one stop on a quality lens, even if you could see diffraction over the grain of a ground glass). And a scientific proof of seeing diffraction would not include a ground glass, or be conducted in the field, or involve eyesight memory in comparing mutliple f-stops. But your an expert on objective tests so I probably should not have to explain that.

Drew Wiley

1-Apr-2014, 15:25

Sure I can see it on the groundglass. That's what the magnifier is for. But the scientific basis for my statement has mountains of research behind it. I just wasn't aware that I'd stumbled into a Medieval outpost when I mentioned it. It seems to be common knowledge everywhere else. There is a reason most LF lens brochures
gave the specs at f/22, or sometimes at f/16 for wide-angle lenses. But apparently, the people who designed those lenses don't know anything either. Maybe they
don't have cowboy hats and beards, or long arms. I already mentioned optical benches as the standard way of isolating variables. Gosh Greg, I have optical supply
house catalogs two inches thick apiece. I wasn't born yesterday.

Greg Miller

1-Apr-2014, 15:29

You have scientific basis for the fact that you can differentiate between diffraction at f32 on a ground glass with a 7x loupe and at f64 on a ground glass with a 7x loupe?

Drew Wiley

1-Apr-2014, 15:48

No. It's all just a great big hoax, just like global warming. My eyes never see anything. It's just an illusion. Cameras and lenses don't even exist because experience
cannot be existentially proven. Maybe we're all just brains floating in jars of liquid hooked up to little hoses, just like in '50 B-movies... Oh scuse me, that would be
digital photography... But yeah, in a common sense application it can be seen. If the light is too dim, then place a little foil in the scene and hit is with a flashlight
or laser. After awhile, one knows what to expect anyway. I never use a fresnel screen, so the groundglass does give a pretty crisp rendition of what's really there.

Drew Wiley

1-Apr-2014, 16:15

On a less sarcastic note I should have added that I standardized all my groundglasses on Satin Snow, which do make focus on very fine detail rather easy compared
to other types of groundglass, and they don't have too much of a hot spot with short focal lengths. Only with architectural interiors would I want a coarser GG or
possibly a fresnel, but I don't do that kind of thing very often. More frequently, a tunnel or cave entry. So I am aware that critical viewing at f/64 with some
ground glasses seems a stretch. Sorry not to have kept that in mind. The alum foil trick with a flashlight is something I sometimes use on the copystand or tabletop
setups when I don't want the hotlights on. Sometimes I use it for extreme closeups in the woods, where the GG view is also obviously very dim.

sanking

1-Apr-2014, 18:05

Peter Collins

1-Apr-2014, 18:10

What I learned: You don't have to tilt very much--at all. I had a very hard time with tilts--never could make them work--because I tilted much too much. A little goes a long way. Better to creep up on the plane of focus than tilt right through it and then wonder, like I did: What the heck?

tgtaylor

1-Apr-2014, 18:49

I think it's important to remember that using the focus on the near and tilt for the rear method as set out in the Fred Newman link above establishes a plane of focus encompassing those two points. By definition a plane is a two dimensional object in space and has no depth or volume - length and width only. To establish the volume you stop down. The "how to" books that I consulted when first starting out in LF didn't explain that and I would go through endless repetitions of focusing on the near point and tilting for the rear point before I finally (!) decided to just to stop down and see. In reflecting back on that, I think it was due to the absence of depth of field scales on LF lens and that I had the mistaken idea that it wasn't necessary to stop down with LF lens: just focus and tilt and everything will be kosher. You can also achieve the same result by using the hypofocal point as you would with a 35 or MF camera with DOF scales on the lens by simply noting the position of the standard at the near and far point and positioning it exactly halfway between those two points on the rail/bed and then stopping down to bring everything into sharp focus. Having two methods to arrive at the same result is sometimes handy.

Thomas

Greg Miller

1-Apr-2014, 19:16

One can certainly differentiate diffraction between f/4 and f/22 on the LCD screen of a D800E in Live View, assuming the target is sufficiently defined. Just put your camera on a tripod, focus on the target in Live View, and compare the image at f/4 and f/22 using the Playback/Zoom In button to view at maximum magnification.

There is no question but that the use of swings and tilts with view cameras can in many cases allow us to use the lens at a wider aperture and get equivalent depth of field, and greater sharpness, than just stopping down the lens. Diffraction is, as has been pointed out, a law of optics and just because it does not apply to one's specific kind of work does not mean that it does not apply at all in general view finder photography.

To differentiate between f/32 and f/64 on a view camera would be a tall order. On the other hand, the difference in depth of field is not all that great either if you compare f/32 to f/64. A better test would be to compare the effects of diffraction and depth of field on the extremes, say f/8 and f/64.

Sandy

Finally a post I can agree with. And similar to what I wrote in post #8 of this thread:

From a technical point of view, you can make a decision based on the f-stop required to get the depth of field that you need. Most lenses are at their optimal sharpness at a middle f-stop. Let's say that, for a given lens, once you stop down past f32 you start losing sharpness due to diffraction (and many will argue that diffraction is not worth worrying about with LF). So if you find yourself stopping down to f64, that would be a reason to use tilt, so that you can achieve the depth of field that you want, while also using a more optimal f-stop.