hyperfocal distance/ tilt ????

[sammy_5100]

Hi, (beginner question)

I’m confused. I read some of the archives about hyperfocal distance when tilting, and basically came
to the conclusion that after tilting I just need to stop down until everything is in focus and forget about hyperfocal distance.

However, when reading here: http://largeformatphotography.info/how-to-focus.html (http://largeformatphotography.info/how-to-focus.html), it suggests focusing on far, then tilting until near is sharp, then refocusing…etc…
Or focus on near, and tilt until far is sharp, and repeat …etc…

Then it says that if you have asymmetric tilt, you only need to tilt once.

Now here is the problem: if I have asymmetric tilt, I can either focus on far and tilt until near is in focus, then I’m done. (one iteration)

Or focus on near and tilt until far is in focus, then I’m done. (also one iteration)

But wait, if that’s the case, and both are correct…….in each case, the standards are different distances apart(!), right?

Is one more correct than the other, what’s the difference?

If I’m just using regular (non-asymmetric tilt), then I assume that weather I start by focusing on near or far, with the
Iterations, I’ll end up with the standards the same distance apart.

Thanx in advance,

sammy

[Ralph Barker]

Yeah, sure. Absolutely. But, not necessarily. ;-)

Assuming that all the variables aren't, that is, that camera position, lens, subject distances and placement of the plane of sharp focus are all held constant between the two scenarios, you should end up with the standards in about the same relative positions, and the same distance between the lens and the ground glass - if the same stuff is in the same focus.

What's missing from the concept, however, is that not all scenes are created equal, and with different subjects, you may want different parts of it critically sharp. The classic example, I think, is the situation where you tilt the plane of sharp focus down to the horizon to get "everything sharp" from the ground in front of the camera to those distant hills. Then, when you start to print the negative, you discover that the nifty foreground post you included to give depth to the composition extends out of the DOF wedge, making the negative worthless.

So, I think it's best not to forget about hyperfocal distances, or any other available focusing method, until you've determined what the scene requires to give you the image you want. There's no universal "solution" because the "problem" keeps changing.

[Doug Dolde]

With real asymetric tilt for instance like some Ebony and Sinar cameras have, you focus on the tilt axis then tilt the top of the back toward you (Ebony) until the foreground pops into focus. You should not have to worry about the background being in focus as it is gonna be close plus you have the hyperfocal to cover you assuming you stop down to at least f16.

If you are using a base tilt then it's more fiddly and you will have to just keep trying various degrees of tilt until you get it right. Usually though a few degrees say 2 or 3 should be sufficient.

Then there is center axis tilt which is more like asymetric tilt in that you focus first on the axis line then do your tilt until you get the in focus effect you are seeking.

Don't worry so much about the process but look at the gg with your lupe and take your time to get it right. No one ever said shooting large format was a fast process.

[sammy_5100]

>The classic example, I think, is the situation where you tilt the plane of sharp focus down >to the horizon to get "everything sharp" from the ground in front of the camera to those >distant hills

yes, this is what i want to do. can i so the following:

1) focus on the hyperfocal distance

2) (asymetric) tilt getting a flower (foreground) and mountain (backround) in focus - (one iteration)

3) stop down until everything is in focus

and shoot!!!

ps. what would the hyperfocal distance be for the 47 mm xl? i'll probably be shooting 6 x 9.

thanx

[Ralph Barker]

I might be wrong, and if so, I'm sure I'll be corrected, but the hyperfocal distance assumes a vertical plane of sharp focus and vertical near and far DOF planes, based on whatever Circle of Confusion assumptions are being made to arrive at the DOF at a given aperture. Once the lens is tilted, all of that changes, as the near and far DOF planes also get tilted into what roughly amounts to a wedge.

The real issue, I think, is to choose a focusing method that fits with the scene, and what you want in sharp focus. In some situations, tilting loses more than it gains. So, you might be better just using DOF, or you might need to choose a different composition. No focusing method will work for all possible objectives.

[Brian Ellis]

Maybe hyperfocal distances work well for some people, they never have for me. Tables of hyperfocal distances are all based on certain assumptions made by the person constructing the table (print size, acceptable size of the circles of confusion, print viewing distance, etc.) some or all of which may not be applicable to you. If you have a front base tilt camera and are in a situation where front tilts will be useful just focus on the farthest object that you wish to appear sharp, then tilt to bring the near into focus, refocus if necessary to bring the farthest object back into focus, etc. etc..until both are in focus or until you're as close to having both in focus as you can get, then stop down as needed. Do the opposite with an axis tilt camera (i.e. focus on the near, then tilt for the far etc.). The article you mention explains this better and in more detail than I can here but that's the basic idea.

Depending on the distance and angle of the near and far objects you may have to go through this a couple times, more so with base tilts than with axis tilts, but with some experience it's pretty simple. Many beginners make the mistake of thinking the tilt needs to be much greater than it usually needs to be so they "over tilt," everything gets out of whack, and frustration sets in. You can tell when you've tilted too much by observing what is happening as you refocus after a tilt. Normally moving a lens forward will tend to bring near objects into focus and moving it backward will tend to bring distant objects into focus. If the camera starts doing the opposite (i.e. moving the lens forward brings distant objects into focus and vice versa) then you've tilted too much.

[Ole Tjugen]

If you find you get poor results with hyperfocal focus, go here (http://www.trenholm.org/hmmerk/) for some explanation of why.

Then throw away your hyperfocal distance table.

[sammy_5100]

thanx for the responses...but they still did *not* answer my question.

if i want a flower and mountains in focus using *asymetric* tilt, i can focus on near
and tilt until far is in focus or the opposite -- both in *one* iteration. but either way, the
standards are at different distances apart. when i'm finished, where should i focus?
I'm still lost! somebody help!!!!!

[Glenn Kroeger]

Sammy:

Your last statment is impossible... if you have the camera adjusted so that both the flower and the mountains are in focus, the lens and the groundglass are in the same relative positions regardless of what order of movements brought you there.

[sammy_5100]

yeah,

i guess thats whats confusing!

but Gelnn, can't i focus far, and tilt once (asymmetric) until near is
in focus?

if this is the case, then i could *not* do the same by focusing on near and tilting once until far
is in focus - because either way the standards are a different distances apart...

which way is correct?

boy am i confused...

[Ellis Vener]

hyper-focus technique really just means determining the optimum depth of field achieved by stopping the lens down to an aperture that thickens the depth of field around the focus plane.

here is how it should work asymmetric, base or axis tilt:

Point your camera directly at your subject or if a landscape, what you plan to be the center of your subject & focus on that point.

Tilt until the near point and the far points that you want sharp are both in focus. are both in focus. (You can tilt either the film plane or the lens plane but tilting the film plane changes perspective rendering as well as determining what the focus plane is. Tilting -- or swinging - -the lens plane only changes the focal plane.) to get the desired near and far points in focus, the point at the center of the image may now be out of focus.

Stopping down the lens extends the depth of field around the plane you have chosen. If , in the case above you can't get that desired spot also in focus at a reasonable f-stop you may need to refocus the camera (don't change the tilt!) so that both the plane you focused on and the points above or below the plane that you also want sharp are now all in focus at the desired f-stop.

With a camera that has true asymmetric tilts like a Sinar C, P, or X this process is simplified: you compose the image and pick a point in the distance that you choose as a near point that lines up with the indicated line near the bottom of the frame (I can only speak to how Sinar's wrk in this regard.) That line tells you where the axis that the back tilts around is located. You then tilt the back towards or away from you until the far point that you want in focus is sharp at the reference mark at the top of the screen. You can then transfer the tilt to the front standard and move the rear standard back to the zero tilt position. You may then need to do some minor refocusing

here is where it gets a little tricky, if only because it sometimes feels a little counter intuitive and my limited ability to explain it better.

Once you tilt either the front or rear standard of the camera you have to stop thinking about what is nearest to you and furthest away from you as necessarily being the near or far points you want to have in focus. Generally, parts of the subject in your composition are bound to lie above or below this plane. The Sinar F, C, P & X cameras use a built-in depth of field calculator that aids you in determining what is the optimal f-stop and hyper focal position. You focus the camera (using the rear standard, not the front standard to focus with) first on the part of the composition that is further away from that new plane of focus and turn the sliding indicator on the focus ring so that the zero mark on the indicator lines up with the reference point. You now turn the focus knob back towards you until the nearest point you want in focus is in focus as well. Now you read the required f-stop off of the indicator: for sake of an example let's say it says you need f/22. Make a mental note to set the aperture on the lens to that setting and focus back two stops ( in the case of the example to f/11). You have now established the correct focal plane for using that f-stop to have your subject or as much as you desire of that subject in focus. Think of it as a smart (smart because it is subject/ camera position/ lens / & tilt plane informed --not formula driven ) hyper-focus technique.

Sound complicated? It really isn't. Once you have the hang of it (takes about thirty minutes of practicing) you can do it in the time it takes to just read the above paragraph or less.

[sammy_5100]

thanx Ellis,

one more question. i read that when using no movements, you just focus on near, then on far, then
just focus at the midpoint - and that would be the hyperfocal distance.

does this work with tilts? in other words, i tilt, then focus on near (nearest possible, not necessarily the "near point" when tilting) and far (farthest possible), then just focus on the midpoint, and that would be the optimal focus???

thanx to all who responded. this stuff if tricky for a beginner w/o (yet, at least) a camera.

sammy

[Brian Ellis]

The system of focusing on the near, focusing on the far, and placing the standard midway between the two points isn't limited to situations where there are no movements employed. It's used with movements as well. You first go through your "focus - tilt - refocus" procedure and only after you have obtained the optimum tilt do you check the near and far points and place the standard midway between the two points. Of course you need to use a ruler or scale of some so that you'll know where the midpoint is and also to use tables for selecting the optimum aperture based on the distance the standard travels when focusing on the near and the far points if you want to use such tables.

You don't focus on the nearest and farthest possible points when using this method, you focus on the nearest and farthest points that you want to appear "sharp" in the photograph. That's often not the nearest and farthest points on which you possibly can focus. .

Two suggestions for understanding focusing with a view camera. First, forget hyperfocal distances, put the phrase out of your vocabulary. Second, forget asymetrical backs (unless of course you plan to buy a camera that has such a back). I don't mean that such backs are useless, they certainly aren't, but very few large format cameras have them and unless you plan to buy such a camera I think worrying about how the backs work is only going to confuse you.

[Ellis Vener]

First, forget hyperfocal distances, put the phrase out of your vocabulary. Second, forget asymetrical backs (unless of course you plan to buy a camera that has such a back). I don't mean that such backs are useless, they certainly aren't, but very few large format cameras have them and unless you plan to buy such a camera I think worrying about how the backs work is only going to confuse you.

Brian said it very well. Once you get your camera, invest in a Polaroid 545 or 545i back, a few boxes of Polaroid Type 55 (so you can inspect the negative) and another $30.00 for the Rodenstock depth of filed /Schiempflug calculator which will work with any camera and format.

You need to start thinking in terms of geometric planes; the optimal subject plane, the lens plane and the film plane. When you focus a camera with the lens wide open you have a very thin plane of focus. Anything in that plane will be in focus. Stopping down the lens"thickens" that plane of what is considered acceptably in focus (AKA: "sharp", which is a subjective description meaning the ability to resolve fine details). This is true whether the three planes are parallel to each other or are intersecting because they are tilted relative to each other. A special case of this is where you have all three planes tilted at an angle to each other so they intersect in a single line (line is defined in Euclidian geometry as the geometric relationship between two points. ) when this happens avery point in the subject plane at any distance fro mthe lens will be rendered in as sharply in focus at all apertures. This is the heart of the Scheimpflug Principle. The poblem is, as I stated above whhow do you also make sharp the parts of the subjectthat are above or below this subject plane? You do this by stopping down. yo ucan get all three planes to focus in a single point by swinging the lens and film planes. With a wide open aperture you will then be focusing on a single point.

[sammy_5100]

thanx so much Ellis!

i think things are getting clearer in my mind.

here is another question.

i really want everything in focus, because i want to have the flower (foreground) and mountains in focus. suppose i'm using a 75mm lens. if i start by focusing on far, and tilt on near etc... when i refocus to get far back in focus, (assuming that i would want to refocus using only the *back standard*), would i be moveing the back standerd farther away from the front standard, or closer?
i think you expained above, that if i do it right, the answer would be that i would move the back standard farther.

infinity focus without tilt would obviously be the focus to flange distance, right? suppose that's 80mm.
after tilting would it ever be possible that (with this landscape shot), that the standards could ever be less the 80m apart?

thanx again,
sammy

[Glenn Kroeger]

Sammy:

Maybe this will help. I am assuming asymmetric back tilts here.

With asymmetric tilts, you aren't going to have a choice where to focus first. Asymmetric tilt means that the tilt axis is not in the center of the groundglass, but off center, and in every case I know of (Sinar, Ebony etc), it is off center toward the bottom of the groundglass. This axis is where you should focus first, before tilting, since this axis will not move and therefore this part of the image will remain in focus.

Now lets say you are doing a landscape. Given that the tilt axis is below the center of the image, and the image is inverted, distant objects like the mountains will be on this axis. So you will need to focus them first. Then, as you tilt, you will be able to bring closer objects, like flowers, near the top of the groundglass into focus as well, while the distant objects along the tilt axis remain in focus.

If you focused on the flowers near the top of the groundglass first, and then tilted, they would go out of focus, and the mountains would NOT come into focus since that part of the groundglass near the tilt axis is not moving.

[Emmanuel BIGLER]

Sammy. Since ou mention a 75 mm lens, you should be aware that tilt angles required to bring in focus both the flower on ground and the distant moutain are very small, only a few degrees. So forget about all advertising images you might have in mind with view or technical cameras tilted in all directions with angles well above 30 degrees ;-);-)

If your 75 mm lens is located 750mm (2 feet 1/2) above ground, the required tilting angle to bring the plane of focus to ground is 1/10 radian (75/750) i.e. about 6 degrees. If the camera is located 1.5 metre (5 feet) above ground, 3 degrees will be enough, if you are close to ground at 375 mm (1 foot 1/4, this is very low actually !!) you'll need 12 degrees, this might be considered as an absolute extreme in landscape shots ; at least as far as I have experimented so far the problem is to precisely set angles of about 5 degrees.

If the distant objet is elevated like a tree or a really high mountain, the point if you want to use the Scheimpflug rule is to estimate the angle between the top of the mountain and the ground plane. You'll easily admit that the Rockies as seen from Denver, Colorado require a much smaller angle than the top of the Matterhorn as seen from the Zermatt train station ;-);-)

In the case of a distant tree, in the situation of a 75mm lens located at 750mm above ground, you might have to compromise and tilt only by 3 degrees instead of 6 in order that the wedge-shaped locus of sharpness contains both the ground and the top of the tree, with the actual plane of sharpness aiming at the middle of the tree. It is useless to extend the depth of field wedge below ground level when stopping down, doing so you'll waste some good depth of field ;-);-)

So in your case do not tilt beyond, say 5 degrees...

[Ellis Vener]

i really want everything in focus, because i want to have the flower (foreground) and mountains in focus. suppose i'm using a 75mm lens. if i start by focusing on far, and tilt on near etc... when i refocus to get far back in focus, (assuming that i would want to refocus using only the *back standard*), would i be moveing the back standerd farther away from the front standard, or closer? i think you expained above, that if i do it right, the answer would be that i would move the back standard farther.

Why complicate things? With a 75mm lens you may not need to use tilt at all unless the flower is very, very close to the camera.

[sammy_5100]

yes ellis, i want the flower very very close to the camera. thats what my question was predicated on- perhaps i should have my that clear before. whats the answer? thanx again

also, here: http://www.toyoview.com/Products/45C/45C.html (http://www.toyoview.com/Products/45C/45C.html)
it says "Center tilt maintains focus as you tilt" . does this mean aysemmetric front tilt?

[Scott Fleming]

Sammy,

You'll never understand it untill you get a camera. I quit using my LF gear and sold it. It's been about a year. I've forgotten things I will have to relearn but I know that once I start studying the gg again it will come back to me. I used to set up my camera at a window inside my house that looked out on a pretty varried scene. I would arrange the camera so that I could sit in a comfortable chair and study the glass without a dark cloth. No lights on in the room. I worked with my different lenses and tried every technique recommended. I also set up distance targets ranging from 5' from the camera to 150'. I put a millimeter scale on the rail of my camera and noted the reading for each lense for each distance. Especially the hyper focal distance. This allowed me to better estimate distances when actually out photograhing and by consulting my little chart I made to go along with the millimeter scale on the camera I could pre focus any given lense without even looking at the gg. All I had to worry about was the tilts.

You are worrying over a problem that does not exist. Once you understand through experience how a view camera works ... you can focus and tilt it in about a minute .... or less. Most times with WA lenses you don't need a tilt. A 72mm lens will focus from 3.47 ft to infinity at f/32 . The frigging hyperfocal distance is 5.31 ft for gawds sake. This is with the 72 ... I don't even have stats for a REALLY wide angle lens.

It 'can' get a bit more complicated if you are shooting something like a cascading waterfall and you are not using WA ... and rather than one smooth stairstep you have larger boulders sticking up out of it. But if you know the hyper-focal distance of your lens and you can estimate the distances you are looking at ... the gg glass will tell you what you can and can't do. Sometimes you just have to stop down. Or go to WA. Or forget about having something three feet from the lens in sharp focus. (everybody does that shot these days anyway) Or give up on some weird scenes.

It's exposure you have to worry about. :-))

[Ellis Vener]

also, here: http://www.toyoview.com/Products/45C/45C.html (http://www.toyoview.com/Products/45C/45C.html) it says "Center tilt maintains focus as you tilt" . does this mean aysemmetric front tilt? NO! centertilts are by definition symmettric. by vrey close i mean within two feet. You probably aren't going to be able understand what we all have been writing about unless you get a camera in your chands and some 4x5 Polaroid.

[Frank Bagbey]

Sammy, get the Jack Dyginga book on large format photography. He regularly accomplishes what you are wanting. Inspired by him, I have done the same thing with my 75mm SA.