Super Symmar 110 XL -- optimal aperture?

[Jon Warwick]

For the Super Symmar XL 110/5.6 ...... has anyone tested to see what's the optimal aperture for this lens to achieve its highest resolution / "sharpness"?

Without testing it, I'm assuming the sweet-spot is somewhere around f22 or f32?

Also, does image quality degrade if you stop it down to its maximum (ie, to f45)?

Thanks.

[Bruce Watson]

I think you are a bit optimistic. I suspect that maximum resolution from a 110mm SS-XL is going to be around f/11 or so.

Try a test. Set up on a fairly brightly lit scene that includes some distant trees. Under the dark cloth now, reach around and move the aperture lever. You can see on the ground glass how the image gets softer (due to diffraction) as you make the aperture smaller.

That said it's important to note that sharpness and resolution are related but aren't the same. You can have a sharp photograph with relatively low resolution. It's a matter of focus -- what's in focus, and what's out of focus, and what's in "acceptable" focus. What it comes down to is that people seem to object (a lot) more to a lack of acceptable focus than to a lack of resolvable detail. So a diffraction limited photograph is often perceived as "better" because more of it is in acceptable focus. It's perceived as being sharper.

This kind of mind bending exercise is par for the course in LF photography however. There are lots of decisions to be made, tradeoffs to be managed, with each and every photograph. Choice of f/stop is just one decision among many.

[ic-racer]

Also, does image quality degrade if you stop it down to its maximum (ie, to f45)?

Thanks.

Schneider MTF curves shows that the center is best at f11 but then decreases in resolution at f22 and will continued to degrade at f45 (not shown). Diffraction at f45 will be the same as any other 110 at f45.

Edges are much better at f22 than f11. I would guess the edges would continue to improve at f45.

So, if I were using just the center of the image for 6x9 I'd use f11 or f16. If I were using the whole image circle I'd probably use f45.

http://www.schneideroptics.com/pdfs/photo/datasheets/super-symmar_xl/super-symmar_xl_56_110_2.pdf

[JPlomley]

The aperture required will depend on your focus spread. Try to minimize focus spread first through tilts/swings and than set the appropriate aperture to cover that zone of focus. I've shot the 110XL at f/32.2 many many times and the RVP-50 chromes are tack sharp under a Schneider 6x7 (3x) loupe and the Tango drum scans are pretty spectacular as well. I would not get too hung up on diffraction.

[Richard Wasserman]

The aperture required will depend on your focus spread. Try to minimize focus spread first through tilts/swings and than set the appropriate aperture to cover that zone of focus. I've shot the 110XL at f/32.2 many many times and the RVP-50 chromes are tack sharp under a Schneider 6x7 (3x) loupe and the Tango drum scans are pretty spectacular as well. I would not get too hung up on diffraction.


That's my experience exactly, except that I shoot black & white. This lens never disappoints me.

[Jon Warwick]

That's all very helpful. Many thanks.

I'm new to LF. To be honest, part of the reason for me using the lens at f45 is because I haven't really got Front-Tilt (center / axis tilt) figured out 100% yet!

So, I'm just not using front-tilt at the moment. I've got books on the subject, but just seem to be confused when it comes to various aspects, and when I try to use it, what I see on the GG starts looking more and more like a mess:

I think the biggest problem to me understanding its use is the concept of "plane of focus".

** I think what's also confusing me is what part of the ground glass am I meant to be focusing on, when it comes to the "top" and "bottom"? ie, which of the following 3 things am I meant to be doing??

1) Do I need to select specific "key objects" on the GG to focus on? A typical image I might take is a bridge in the distance, and I want the river all the way in the foreground to be in sharp focus too. However, that bridge could quite feasibly be on the GG right at the very bottom (ie, top of the photo), or it could be slightly more towards the middle -- or pretty much any other variation of that. So do I first focus exactly on the bridge wherever it is positioned in the background, then apply tilt until the river in the foreground comes sharp?

2) Or instead, should I firstly focus on the bottom 1/4 of the GG (ie, the background), and then apply tilt until the top 1/4 of the GG comes into focus -- regardless of where the bridge is positioned?

3) Or -- once I've composed the scene -- do I focus on whatever is on the horizontal line across exactly the middle of the GG? ie, in the situation above, that would probably be part of the river that's in the middle of the GG that's still flowing towards the bridge. And then from there, I apply front-tilt?

Really confused, I'm afraid. If I do it correctly.... should everything look perfectly in focus on the GG when the aperture is wide open, or do you still need to stop down a lot to get the end image into sharp focus??

Thanks a lot if there are any secrets to success you can provide!

[poco]

Jon,

Here's a good rule of thumb when tilting: when the view on the ground glass has "become a mess," it's because you've WAY over tilted. Back off, or better yet, zero the standards back out, and start again.

The general advice to focus on the far and tilt for the near works for me. Start with front and back standards parallel and focus on the furthest object in the scene (which will often fall on the lower part of the ground glass) and then tilt the front standard forward until the nearest thing you want sharply focused (falling generally on the upper part of the ground glass) snaps into place. You might need to do this two or three times, each time re-sharpening the far object using focus and the near object by adjusting the tilt. Once both are as sharp as possible, stop down to whatever is necessary to pull it all together.

After the first few times that you line up a shot like this, I'd suggest you take a moment to really look at the camera and note how surprisingly little amount of tilt it took to get your focus. Get the idea that it doesn't take more than a few degrees firmly in your head.

[Bruce Watson]

Jon,

Here's a good rule of thumb: when the view on the ground glass has "become a mess" when tilting, it's because you've WAY over tilted. Back off, or better yet, zero the standards back out, and start again.

The general advice to focus on the far and tilt for the near works for me. Start with front and back standards parallel and focus on the furthest object in the scene (which will often fall on the lower part of the ground glass) and then tilt the front standard forward until the nearest thing you want sharply focused (falling generally on the upper part of the ground glass) snaps into place. You might need to do this two or three times, each time re-sharpening the far object using focus and the near object by adjusting the tilt. Once both are as sharp as possible, stop down to whatever is necessary to pull it all together.

After the first few times that you line up a shot like this, I'd suggest you take a moment to really look at the camera and how surprisingly little amount of tilt it took to get your focus. Get the idea that it doesn't take more than a few degrees firmly in your head.

What Poco said.

[Jon Warwick]

Great, thanks for that.

To help me understand a little better on when to apply tilts, please see this link from Wikipedia that has a bridge taken by the photographer at a gentle angle.

http://en.wikipedia.org/wiki/Image:Albert_Bridge.jpg

I'm assuming, ideally, that I'd use both front-tilt and swing (given the plane of focus is on both horizontal and vertical lines).

However, my camera can only use front-tilt (no swing).

Acknowledging the limitations of movements on my camera, would front-tilt alone be beneficial?? Or does this type of angle of view really just demand swing?

If you think just using front-tilt would be of some benefit, what would you focus on? ie, would you focus on the end of the bridge in the distance on the far-side of the river, and then apply some minor front-tilt to benefit the part of the bridge in the foreground? Or would you not bother using front-tilt (or even swing) at all in this instance?

Thanks again.

[Ralph Barker]

Great, thanks for that.

To help me understand a little better on when to apply tilts, please see this link from Wikipedia that has a bridge taken by the photographer at a gentle angle.

http://en.wikipedia.org/wiki/Image:Albert_Bridge.jpg

I'm assuming, ideally, that I'd use both front-tilt and swing (given the plane of focus is on both horizontal and vertical lines).

However, my camera can only use front-tilt (no swing).

Acknowledging the limitations of movements on my camera, would front-tilt alone be beneficial?? Or does this type of angle of view really just demand swing?

If you just using front-tilt would be of some benefit, what would you focus on? ie, would you focus on the end of the bridge in the distance on the far-side of the river, and then apply some minor front-tilt to benefit the part of the bridge in the foreground? Or would you not bother using front-tilt (or even swing) at all in this instance?

Thanks again.

For an image like that, I'd use swing only. Since all of the image elements are essentially vertical, you only need to swing the plane of focus to run along the bridge.

[Brian Ellis]

A few suggestions. For simplicity sake I'll assume you're focusing with the front standard rather than the back and I'll ignore swing and talk only about tilt since that's the movement you mention:

If your camera has axis tilt you focus on the near and tilt for the far. If your camera has base tilt do the opposite.

How to tell when you've tilted too much: normally as you move the front standard farther away from you (i.e. extend the bellows) things closer to you come into focus and as you move the front standard closer to you things farther away come into focus. When the opposite starts happening you've tilted too much and you need to back off a little.

Whether everything will look "sharp" at the widest aperture once you've properly tilted and focused depends on several variables, there is no general rule, sometimes yes, sometimes no. For example, if you picture a scene that includes a rock in the foreground, trees in the mid-ground, and a mountain in the background, whether you need to stop down to make everything appear sharp at the widest aperture depends on how high the trees are.

The short and oversimplified but more or less accurate answer to your question about the "optimal aperture" is that the optimal aperture is the widest aperture you can use and still get the depth of field you need to make the photograph you want to make. But it's a little more complicated than that. I strongly suggest that you study two articles written by Q.T. Luong in the technical section of this forum. One is titled "How to Focus the View Camera" and the other is "How to Select the Optimum F Stop." If you read those articles carefully you'll know all you ever need to know about everything you've asked here and more.

[Jon Warwick]

Ralph -- thanks for your reply.

Out of interest .... if I did attempt to apply simply front-tilt (no swing, given the limitations of my camera) for that sort of scene, what would be the impact? Would it do nothing to improve near and distance-focus? Make it worse even?

[Don Hutton]

Ralph -- thanks for your reply.

Out of interest .... if I did attempt to apply simply front-tilt (no swing, given the limitations of my camera) for that sort of scene, what would be the impact? Would it do nothing to improve near and distance-focus? Make it worse even?If you applied downward front tilt, you'd have the top of the pylon of the bridge in foreground out of focus. In the vertical, the plane of focus is the same (you want that entire pylon in focus from top to bottom. On the horizontal, you want a little swing - the bridge sweeps from near to far on the horizontal. A little swing (front or rear) and probably some front rise (compose with the camera level and move the front standard up with front rise so that the composition contains what you want) or you will have a lot of convergence of the pylons. The single biggest mistake new users tend to make is too much tilt and swing! With the 110XL, I am certain that you could make this composition work at f22 or so without any swing too! I'd suggest that you think about keeping the standards parallel to each other - no tilt; no swing (shift, and rise/fall are for composing and don't affect the standards being parallel to each other) and only change them when you are certain you need to.

[Bruce Watson]

If you think just using front-tilt would be of some benefit, what would you focus on?

That is the quinesential question of LF photography I think. What do you focus on? Or, where do you position the plane of exact focus?

I've been trying to think how to explain this for a while. I'm going to try an analogy -- please don't hurt me if it doesn't work ;)

There are several concepts involved. One is the plane of exact focus. Another is depth of field. Think of it like a peanut butter sandwich. The peanut butter is the plane of focus while the bread on either side is how much depth of field you have. The bread is technically out of focus -- but this is acceptable because it's not out of focus my much and human perception being what it is, things in the zone of the bread appear to be sufficiently in focus. Yes?

Now, when your front and rear standards are parallel, the plane of focus and the plane of the film are also parallel. When you apply a bit of tilt to the lens you are tilting the plane of focus. Think of tilting the sandwich forward.

You would do this where you had a scene where you wanted the plane of focus tilted. Sounds obvious but often isn't. For example, say you are on a bridge over a river. There's a rock in the river a few meters away from your feet, and a mountain in the distance. You want both in focus. So the plane of focus you want extends roughly from the rock to the mountain. Clearly this plane is tilted. Assuming your camera has base tilt, you then focus on the near (rock in river). Then you tilt for the far (mountain).

If you do what most people do when they first try this, you'll focus from the top of the rock to the top of the mountain. That might work and it might not. What might happen is you throw your middle ground out of focus because it's beyond the depth of field. How to cope? Well, think back to that peanut butter sandwich. By extending the plane of focus from the top of the rock to the top of the mountain you are only using the bottom slice of bread for depth of field. You've got depth of field on both sides, might as well use both slices. So your plane of focus should usually run from the middle of the rock to the middle of the mountain. Now your middle ground will be closer to the plane of focus and you can probably bring it into acceptable focus by stopping down (making the slices of bread thicker).

Did that make any sense at all, or did it just make you hungry? It's the best I can do -- if I could write well I wouldn't need photography so much! ;)

And clearly, you wouldn't need tilt with your bridge picture. You might want some swing however, which is just tilt turned 90 degrees on it's side.

I find in landscape work I very seldom use any front swing. I nearly always use a little front tilt. But it's always on the order of just a couple of degrees. A little tilt goes a log way.

The best way to learn this stuff? Go out and use it. You don't have to burn film every time. You'll learn plenty just setting up for a shot. The more you physically do, the more you'll learn. It'll become second nature after a while. And at some stage you'll cease seeing everything upside down and backwards on the ground glass too.

[KenM]

When looking at a way to visualize what movements you need to apply, put a virtual box around what you want to be sharp. If the box is a cube, then you're hooped, since there are no movements you can apply that won't result in at least something being unsharp. However, the 'flatter' the box is (the more 2-dimensional) then you can start to look at movements.

For example, with the bridge you mentioned, the box would be rectangular, with a little bit of horizontal depth. This implies that swing would be the best option, since the surface you need to focus on is vertical, and receding away from you. Likewise, if the box was flat, you would use tilt to focus on the primary plane.

Once the primary plane is in focus (or as close as you can get it), you look to see if you need to apply the other movement.

BTW, I can't take credit for the 'box' analogy - I believe I read the description either here or on apug.

Check out this article, which has a good description of how to use camera movements:

http://www.viewcamera.com/documents/FieldCameraMovements.pdf

[Lachlan 717]

Here's a good little video as well.

http://au.youtube.com/watch?v=gR4m70xr9mE

Really helps get the idea...

Lachlan.

[archivue]

in 4x5, i'm using F22
in 6X8, i'm using F16

[BennehBoy]

I've been practicing applying tilts on my P2 using this: http://web.archive.org/web/20040407221535/www.sinarbron.com/123.htm

It's all well and good when shooting a scene which has definite fixed objects on the ground glass lines, but when it comes to landscapes (I'll be shooting a lot of environmental stuff, and yes I'm mental to use a P2) I don't see how I can focus on the bottom dotted line which will be covering sky much of the time...

I guess I'll have to abandon that method and use trial and error?

[Bjorn Nilsson]

BennehBoy!
You can shift the back standart upwards until the bottom line no longer is in the sky, but on the part of the scene which you want to have in focus. (E.g. those mountains in the horizon.) Then you find your tilt angle and (optionally) transfer it to the front and zero the back again. Then you shift the back down to where you want it again.
This kind of temporary shift have no implication in finding the tilt angle.
(Eh, if you transfer the tilt angle to the front, you do have to refocus, but you always have to do that if you apply tilts or swings to the front.)

//Björn

[BennehBoy]

Ah yes of course.