Minimum f-stop?

[Lffbug]

I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited. But in practice, what do you use? For stills? Portraits? Landscapes?

I am new at LF photography, so I thought I would just try a comparison. Here's a hat of mine, first at f/5.6, then f/8. DOF is shallow, especially at f/5.6

9249492495

The first doesn't really seem usable, but by f/8, things look better, and the DOF could be quite useful, depending on the situation.

So, again, in practice, what f-stops do you find that you use the most. Do you ever shoot wide open?

[C. D. Keth]

I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited. But in practice, what do you use?

f/16 to f/64. Most commonly my pictures are at f/22, probably followed by f/45 and f/16 in that order.




Do you ever shoot wide open?

Very, very rarely. Even portraits I prefer to be in the f/8 to f/11 realm.

[Lachlan 717]

Seems to me that you have the tail wagging the dog by asking what we use.

I think you'll get a much better explanation of DoF by explaining what you're trying to do. Or, put a different way, what you have pre-visualised.

If your questions are as basic as what do you use for landscapes and what do you use for portraits, well, you generally use small apertures for the former and large for the latter. No different to any other format.

But, I suspect that you want to know something different to that...

[Bob Salomon]

Most large format lenses are diffraction limited at f22. Some at f11. Go beyond these stops you will degrade the image from diffraction.

[Heroique]

My personal experience w/ landscapes...

Using movements, I can bring the elements of most of my landscape shots into focus and use what is normally considered the optimal aperture for most LF lenses – f/22.

But in most situations, the 4x5 photographer can go one, two, three “clicks” narrower and not worry about diffraction.

For even strict standards for coc in prints up to around 16x20 will allow one to use f/45 without generating discernable diffraction. And if the print is smaller, the aperture can be narrower. Sure, diffraction is “setting in” on a theoretic level as you click down from f/22 to f/32 to f/45 and narrower, but to a degree that a field photographer can often ignore, so that more critical issues can be addressed – like performing magic tricks to make the wind subside.

[SergeiR]

Whatever works for subject and picture, light and composition. Whatever dictated by distance, lens itself and plan.

With LF you can just close and inspect..

Whole lot of people are after LF for shallow DOF. Thus your mileage might vary.

[C_Remington]

I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited.

Isn't the whole point of tilt and swing so one doesn't have to shoot at such a small aperture?????

[E. von Hoegh]

The basic rule of thumb which I follow is to use the camera movements to place the plane of focus where I want it, as accurately as possible. I then stop the lens down until the DOF is adequate. Obviously, this rule cannot be followed in every case, there are times when you simply cannot get everything you want sharp, sharp. The laws of physics don't allow it.
I try to use f:16 to f:22 as my standard apertures, for general subjects. Portraits can be done wide open, the residual spherical aberrations in some of the lenses I use then give a nice glow with a sharp core.

If you take the time to learn and understand the functions of movements and DOF, you will have no trouble choosing the appropriate aperture for a given situation. It's a learning curve, and it takes time and practice.
You don't have to use up film, though, you can set up still lifes on a table top and just practice focussing on the groundglass. This is where a good loupe and an effective darkcloth become important - if you cannot see the image on the GG clearly, you won't know what you have until you see the film - which situation sometimes entails a great waste of film. Have patience, and practice!

[E. von Hoegh]

Isn't the whole point of tilt and swing so one doesn't have to shoot at such a small aperture?????

C, the movements are used to correct perspective distortion and place the plane of focus where you want it.Simply stopping the lens down to extend DOF will still leave you with a plane of focus parallel to the film, and will do nothing for perspective distortion.

[Brian Ellis]

IMHO (and the opinion of many others here based on previous posts about this subject) diffraction is essentially a non-issue with 4x5 film and prints in the range of maybe 20x30 or smaller (I'm guessing about maximum size here, it may very well be even larger than 20x30 but I've never printed that large from a negative made with a very small aperture - I do know from experience that my 16x20 prints show no effects of diffraction from negatives made even at f/64). IMHO far more photographs are ruined by inadequate depth of field when the photographer was overly concerned about diffraction and so didn't use a small enough aperture than have ever been ruined by diffraction when using LF film.

[Leigh]

Diffraction is one of those monsters that parents use to frighten their kids, like the headless horseman.

In any normal image diffraction effects are slight, though measurable, and indistinguishable from poor focus.

=====

To answer the OP...
Most of my lenses are f/5.6, and I typically shoot them at f/16 or f/22.
If the manufacturer states an optimum aperture, I use that value when possible, or adjacent settings.
I would not hesitate to go smaller if dictated by image considerations.

I shoot wide open if that setting produces the desired effect in the image.

- Leigh

[Vaughn]

Photographing in the dense redwood forests where camera movements have to be kept to a minimum and a deep requirement for DoF -- usually f64 or f90.

8x10 and 11x14. Contact printed.

[Bernice Loui]

This is a question of what the image maker wants in the image to be in focus.

One of the great advantages of a view camera is the ability to alter and change the plane of focus which is a very powerful tool in the image making process.

When I first began using a 4x5 the typical rule was to stop down to f16 or f22 to "optimize" the lens and get everything in the image in focus (actually apparent focus). After many thousands sheets of film past. Using both aperture and camera movement evolved to a wonderful selective focus tool. This also drove my preferences in optics in ways I never imagined.

Initially all my lenses were the latest modern multi coated on the market. In time most of them were passed on to new owners and the optics became a mix of vintage, and modern.

I do use vintage optics wide open and stopped down to not more than f32.. almost as a rule. I have tried the smaller than f45 routine and did not like the reduction of image quality. This was one of factors why I stopped using 8x10 film. I do believe 8x10 and larger makes wonderful contact prints (my 8x10 days with AZO paper) and this can reduces some of the requirements on optics.

If the image requirements were "everything in the image sharp" modern lenses stopped down to f22 or so with 5-7 bladed iris shutters would be fine, but once one develops a taste and need for highly selective focus, preferences for out of focus rendition, tonality and all those other qualities in the image, the expectations of how a lens behaves at a given aperture does matters a lot.

There appears to be a fashion trend among digital and smaller format image makers to produce Bokeh based images where the points of light becomes out of focus shapes in the background. This is not new as film makers have done this for a long time and no reason why LF based images cannot use the same technique for similar effect.

I did post an image like this in another thread about Goerz lenses.. That color image was made at f16, at almost life size (1:1).
http://www.largeformatphotography.info/forum/showthread.php?101713-What-are-your-favorite-Goerz&p=1008090&highlight=goerz#post1008090


Bernice

[C. D. Keth]

Diffraction is one of those monsters that parents use to frighten their kids, like the headless horseman.

In any normal image diffraction effects are slight, though measurable, and indistinguishable from poor focus.
- Leigh

That's a good way to put it. I do pay attention to it and I don't shoot deeper on stop than I need to. That said, I'll come home with a slightly less sharp negative because I had to stop down further rather than come home empty handed. I won't avoid pictures because the setup will require a deep stop.

[Mark Sawyer]

Diffraction is one of those monsters that parents use to frighten their kids, like the headless horseman.

Pretty much what Leigh said... Apo-Ronars close down to f/256, and when I first got one for my 8x10 I just had to try it. Contact printing, the negative was still as sharp as the eye could resolve, and I'm sure it could have handled moderate enlargement well.

[IanG]

Pretty much what Leigh said... Apo-Ronars close down to f/256, and when I first got one for my 8x10 I just had to try it. Contact printing, the negative was still as sharp as the eye could resolve, and I'm sure it could have handled moderate enlargement well.

I have to agree with you and Leigh.

While I usually use f22 for 5c4 work I have used f32 quite a bit and f45 on the odd ocassion - some of my 5x4 lenses stop down to f64. It's so dependant on what the lens is, focal length etc taht there's no hard and fast rule. In practice it's usually fine to use up to 1 stop off the minimum aperture with no discernible loss of quality and even the last stop isn't bad. Many of my lenses stop down past the minimum aperture.

It's really about knowing your own lkenses and their capabilities.

Somewhere there's a breakdown of the apertures used by John Sexton and he goes past the f22 recommendation with stunning results/

Ian

[Lffbug]

Seems to me that you have the tail wagging the dog by asking what we use.


Fair enough statement, and some further clarification. One area that I am interested/curious about is portraiture. I'm curious about how large an aperture setting you use (i.e. lowest f-stop value) and successfully get good results.

Available light portraits would have painfully slow shutter speeds even with ISO 400 film, so I figure that's out except for extremely still subjects.

I have some low powered monolights, 150 w-s actual, but I figure that I can only get to about f/11 with 400 speed film. Forget 100 speed film, unless I shoot nearly wide open. I really don't want to buy higher power strobes, and would like to see what I can do with what I have. I supposed I could push the film, but that seems to go against the point of using studio lighting.

Probably I just need to try some things out, first. But I am curious how others deal with this (I know - buy a bigger light - but I am cheap, uh, frugal).

[ic-racer]

I read that LF photography is often performed at very small apertures.

You can (and should) read the much better information on selection of the aperture on this site's home page : http://www.largeformatphotography.info/fstop.html

[Bernice Loui]

This brings up an interesting bit of view camera and photographic history. The first common photographic lenses were single element or "landscape" lenses. They had less than ideal color correction, small effective f-numbers, a good number of lens aberration and limited field of view. When these single element lenses were used for portraiture along with the slow speed plates of the day, head clamps and sitting chairs were invented to deal with the long exposure times.

In time Jozef Petzval invented a lens with two groups corrected for color, spherical aberration with a wide enough aperture (effective f-stop) to reduce exposure time required for portraiture. This was a very significant advance for photography.

Eventually the Petzval evolved along with other lens designs like the Triplet and Dagor..

This is likely the origins of a portraiture style that lives on to this day.

As lens development proceeded, soft focus lenses and others were developed to meet the needs and demands of portrait and other photographic image makers.



Bernice



Fair enough statement, and some further clarification. One area that I am interested/curious about is portraiture. I'm curious about how large an aperture setting you use (i.e. lowest f-stop value) and successfully get good results.

Available light portraits would have painfully slow shutter speeds even with ISO 400 film, so I figure that's out except for extremely still subjects.

[paulr]

Diffraction is generally better than defocus blur, if you have to choose. If you're working with any digital steps, diffraction is much more amenable to reversal by sharpening. The slopes of the airy disk mimic the gaussian function of a standard unsharp mask fairly well. More advanced deconvolution sharpening algorithms, like those used in Lightroom and in Photoshop's Smart Sharpen, handle it even better. Defocus blur has a much more variable and complex point spread function, and so it's probably not going away.

Here are some charts that show actual MTF effects of diffraction, both in pure form, and when diffraction is combined with the MTF of a typical sensorand various degrees of defocus blur (COC stands for circle of confusion, if you haven't already guessed).


http://paulraphaelson.com/downloads/DiffractionLimitedMTF.png

http://paulraphaelson.com/downloads/DiffractionLimitedMTF_f08.png

http://paulraphaelson.com/downloads/DiffractionLimitedMTF_f22.png

The short of it is that with circles of confusion greater that 10 microns (this is really small) there are only benefits to being stopped down to f22.

These are interesting especially if you consider that with low-noise images, detail rendered at 10% MTF should be completely recoverable (meaning, you can make it sharp). For film that's faster than ISO 100, I imagine you could recover most detail as low as 20% MTF. I'd like to find charts calculated for smaller apertures. From these we can extrapolate that at f32, MTF will drop below 20% somewhere around 35-40 lp/mm, which means that it will start irrecoverably eating detail in larger prints from 4x5.

[sanking]

Diffraction is an optical fact, not an opinion. How much of it you can tolerate clearly depends on many factors, as others have noted. With 5X7 format, where I never intend to enlarge beyond about 5X, I try to use swings and tilts to avoid stopping down to more than f/45.

In my experience one needs to carefully evaluate the results of diffraction even when contact printing. I have done a lot of work in contact printing with ULF formats, including 7X17, 12X20 and 20X24. I tested several times with various lenses, using apertures ranging from f/90 to f/256, and even in contact prints I definitely could see a difference in print quality comparing negatives exposed at f/90 and at f/256. The difference in print quality appeared to be due more to loss of local contrast than to loss of absolute resolution, and was clearly visible at normal print viewing distances.

Sandy

[Nathan Potter]

I just use a simple guide in the field to estimate how much deep doo doo I'll be in as a function of f/stop and the degree of enlargement I intend to make. That amounts to (diffraction limit at f/stop X enlargement). The simplifying assumption is that the diffraction limited airy disk diameter is approximately equal to a visible line width. In my prints I want to resolve roughly 4 mil (100µm) lines. Thus for example, for making a 16X20 print from a 4X5 film the enlargement is 4X so the acceptable COC needs to be 1/4 of 100µm or 25 µm. 25 µm is a diffraction limit at about f/22. Seldom would I go above f/32 for most critical purposes where resolution is paramount.

When I used to do critical work in 8X10 with contact printing the 100µm criteria would be the diffraction limit of 100µm which would be f/90. I might go to f128 on occasion where the limit is 150 µm (6mils) but 6 mils become slightly visible at normal reading distances. At f/256 the diffraction limit is 300 µm (12 mils) and distinctly visible at normal viewing distances with a contact print.

Such a simple estimate says nothing about the micro contrast that will result from a particular f/stop and diffraction limit. I think Paul in an above post has alluded to that and suggested methods of altering it using digital sharpening techniques. I deal with contrast in all analogue silver printing by varying the contrast of the enlarger light source but that clearly does not have the capability of digital processing software.

Nate Potter, Austin TX.

[paulr]

...and even in contact prints I definitely could see a difference in print quality comparing negatives exposed at f/90 and at f/256.

Yikes! I would assume so. At f256 your airy disks are over 1/3mm.

[Bernice Loui]

Approaching a pin hole camera.....


Bernice


Yikes! I would assume so. At f256 your airy disks are over 1/3mm.

[Bernice Loui]

Defocus blur = insufficiency samples to recreate the original information..

Diffraction = distorted samples that might recreate the original information.

Choices, choices...


Keep in mind information created that is not gathered initially cannot be accurately re-created, it can be imaginatively put back in. Or, sharpening can give the appearance of sharpness, but it it in appearance only and not real resolution faithful to the original item being imaged. There is a whole lot more to this than just MTF, LPM and etc...


Bernice






Diffraction is generally better than defocus blur, if you have to choose.

These are interesting especially if you consider that with low-noise images, detail rendered at 10% MTF should be completely recoverable (meaning, you can make it sharp). For film that's faster than ISO 100, I imagine you could recover most detail as low as 20% MTF. I'd like to find charts calculated for smaller apertures. From these we can extrapolate that at f32, MTF will drop below 20% somewhere around 35-40 lp/mm, which means that it will start irrecoverably eating detail in larger prints from 4x5.

[Nathan Potter]

I have been contemplating the recovery of detail in an image through sharpening or contrast enhancement and the notion that some sharpening or contrast enhancement can recover resolving power at very low MTF contrast values. In fact I can do this by upping the contrast in an image to an extreme degree. This, in effect, takes a slice of the film dynamic range and dramatically ups the resolution of fine detail at that particular density by dropping out the low contrast parts of the detail robbing high frequency components. The disadvantage is that limiting the film density to such a narrow range eliminates the information at other densities above and below the slice chosen. The result is a very high contrast image which provides high resolution of features at the chosen density but destroys structures above and below that density. Sharpening does something similar in that it increases contrast at an edge of a structure by increasing the high frequency components at a step in density.

I just find there are tradeoffs between the contrast enhancement technique and sharpening which introduce artifacts from sharpening or eliminate density details during contrast enhancement. OTOH I'll use both techniques with a modicum of restraint to achieve a particular effect. In deference to Bernices' comments (I think) above, I've found that in fact one can certainly enhance detail that was truly muddy or soft in the original film but obviously additional detail cannot be found. If fine detail is what you are after then you'd better get it on the film, and the diffraction limits are important.

Nate Potter, Austin TX.

[patrickjames]

I would rather have something in the image out of focus than deal with diffraction. Use movements. Isn't that what they are for? I try to keep it at f/32 or wider. I prefer f/11 through f/22. Occasionally I bite the bullet and go smaller. With my Polaroid conversion I will shoot even wider still. I prefer f/5.6 to f/8 with that camera.

Personally I never have understood the "everything has to be sharp" mantra of people who use big cameras.

[Mark Sawyer]

Approaching a pin hole camera...

Yes, but a really cool pinhole camera...

[Brian Ellis]

I would rather have something in the image out of focus than deal with diffraction. Use movements. Isn't that what they are for? I try to keep it at f/32 or wider. I prefer f/11 through f/22. Occasionally I bite the bullet and go smaller. With my Polaroid conversion I will shoot even wider still. I prefer f/5.6 to f/8 with that camera.

Personally I never have understood the "everything has to be sharp" mantra of people who use big cameras.

Not every photograph is susceptible of movements accomplishing anything.

Not sure exactly what you mean by "deal with diffraction." You don't have any noticeable diffraction to deal with using LF film unless you're making a really huge print. And I don't know that people who use a LF camera think "everything has to be sharp." I see plenty of photographs in the various threads here where everything isn't sharp (apparently by design).

But if you do want everything sharp you sometimes are faced with having to make a choice - "do I want to stop down far enough to make everything sharp and then have to worry about diffraction or do I want to use a wide aperture to avoid diffraction and risk everything that I want to be sharp not being sharp." IMHO it's usually a no-brainer because insufficient depth of field (arising from using too wide an aperture because of worries about diffraction) in a photograph where everything is supposed to be sharp is usually far more noticeable and distressing than are the effects of diffraction with LF film and even a large (say 20x30) print.

I kind of harp on this subject here and elsewhere only because I think some newcomers get overly concerned about diffraction when they read statements like "you're diffraction limited at f/11 and smaller" and think that if they use a small aperture to obtain desired depth of field diffraction will ruin their photograph. So instead they use a wide aperture and then wonder why everything they wanted to be sharp isn't.

Personally I don't care. If anyone wants to make a photograph at f/5.6 because they're worried about diffraction, and if that works for them, have at it.

[E. von Hoegh]

Not every photograph is susceptible of movements accomplishing anything.

Not sure exactly what you mean by "deal with diffraction." You don't have any noticeable diffraction to deal with using LF film unless you're making a really huge print. And I don't know that people who use a LF camera think "everything has to be sharp." I see plenty of photographs in the various threads here where everything isn't sharp (apparently by design).

But if you do want everything sharp you sometimes are faced with having to make a choice - "do I want to stop down far enough to make everything sharp and then have to worry about diffraction or do I want to use a wide aperture to avoid diffraction and risk everything that I want to be sharp not being sharp." IMHO it's usually a no-brainer because insufficient depth of field (arising from using too wide an aperture because of worries about diffraction) in a photograph where everything is supposed to be sharp is usually far more noticeable and distressing than are the effects of diffraction with LF film and even a large (say 20x30) print.

I kind of harp on this subject here and elsewhere only because I think some newcomers get overly concerned about diffraction when they read statements like "you're diffraction limited at f/11 and smaller" and think that if they use a small aperture to obtain desired depth of field diffraction will ruin their photograph. So instead they use a wide aperture and then wonder why everything they wanted to be sharp isn't.

Personally I don't care. If anyone wants to make a photograph at f/5.6 because they're worried about diffraction, and if that works for them, have at it.

To me, that means the lens is doing a good enough job that the limiting factor in resolution is the physical behaviour of light, rather than the lens' aberrations.
As I mentioned above, my favorite apertures are 16 - 22, for general picture taking with 4x5 and 8x10. With 35mm, it's 4 - 8; and I'll use other apertures on any format if that gives me the picture I want.
I don't think I've ever noticed diffraction in a LF print.

[Bob Salomon]

"IMHO it's usually a no-brainer because insufficient depth of field (arising from using too wide an aperture because of worries about diffraction) in a photograph where everything is supposed to be sharp is usually far more noticeable and distressing than are the effects of diffraction with LF film and even a large (say 20x30) print. "

That assumes that the camera was properly focused so the near and far points will fall into the DOF at the largest useable aperture for those two points.

Too many people that we talk to over the years focus on the far point and then stop down until the near point appears sharp. And that ends up with apertures that are beyond the optimal ones for the lens design.

Also, the DOF attained is also effected by the magnification one wants for the print. Assuming you are using a 4x loupe and are checking the DOF at shooting aperture on 4x5 then you are seeing the DOF on a 16 x 20"print. If you then make a larger print you will no longer appear sharp at the same near and far points.

It is not just a matter of f64 and be dammed.

[Ken Lee]

I have been contemplating the recovery of detail in an image through sharpening or contrast enhancement and the notion that some sharpening or contrast enhancement can recover resolving power at very low MTF contrast values. In fact I can do this by upping the contrast in an image to an extreme degree. This, in effect, takes a slice of the film dynamic range and dramatically ups the resolution of fine detail at that particular density by dropping out the low contrast parts of the detail robbing high frequency components. The disadvantage is that limiting the film density to such a narrow range eliminates the information at other densities above and below the slice chosen. The result is a very high contrast image which provides high resolution of features at the chosen density but destroys structures above and below that density. Sharpening does something similar in that it increases contrast at an edge of a structure by increasing the high frequency components at a step in density.

I just find there are tradeoffs between the contrast enhancement technique and sharpening which introduce artifacts from sharpening or eliminate density details during contrast enhancement. OTOH I'll use both techniques with a modicum of restraint to achieve a particular effect. In deference to Bernices' comments (I think) above, I've found that in fact one can certainly enhance detail that was truly muddy or soft in the original film but obviously additional detail cannot be found. If fine detail is what you are after then you'd better get it on the film, and the diffraction limits are important.

Nate Potter, Austin TX.

One reason I like 5x7 over 4x5 is that less sharpening is required, and there is less demand on my humble scanner. With less sharpening, many of my images have a more natural appearance.

I can't demonstrate this theoretically, but I routinely see it practice. I presume it relates to your observations above. Sharpening may seem to take place only at a local level, but it can affect the tonality of an entire image. That's one reason I sharpen different parts of the tonal scale, separately.

[Drew Wiley]

Contact printers can get away with lot in terms of diffraction. But once you start enlarging signifcantly it can spoil critical sharpness. I never stop down 4x5 more than f/32. With 8x10 black and white I'll go down to f/64 because I don't intend to print it larger than 20x24, but for any color work intended to be printed up to 30x40, I prefer to stay within f/45. I was printing some 6x9 Ektar work last nite up to what I consider utter madness for a subminature format like this (20X24 high gloss prints); but the lenses were top notch and I think I had exposed at f/22, so the results were impressive anyway. Don't
know if I'd risk that degree of enlargment of 6x9 if I'd used f/32, but will have to test that theory some day.

[Mark Sawyer]

Contact printers can get away with lot in terms of diffraction...

That's the key. The little bit you lose to diffraction is nothing unless the image is greatly enlarged, but significant out-of-focus is obvious in any print big enough to view. Remember that Edward Weston used pinhole apertures in his lens (and all-day exposures) to get enough depth of field for his still lifes. No one ever says his 8x10 contact prints of peppers and nautilus shells aren't sharp enough. But for Ansel Adams, who'd push a 4x5 negative to a 20x24 print, it was a different story...

[Drew Wiley]

What Edward also routinely got away with was wide apertures, as in those classic Point Lobos shots with crisp waves splashing due to short shutter speeds. If any of these so-called "f/64" style shots were actually enlarged to 16x20, I think the results would be atrocious. The whole point is to understand your end result. There's no way to make one shoe size fit
everybody, or every situation.

[unixrevolution]

Short version: I have used everything up to and including F/64 for extreme situations where DoF is necessary, but generally I shoot most work at f/16 and f/22.

Long version: on 4x5 I typically have enough DoF wide open for landscapes that I don't need to worry too much. On occasions where I need to get right up to the camera sharp, a little tilt and f/22 works wonders. I do wide-open portraits on 4x5 all the time, cause I like the look. Typically those are with a 210 and seated a bit away from me. With polaroid backs handheld, my super graphic is frequently used with its 135mm lens wide open at f/4.7 due to light. I shoot a lot in fairly dark places so I make more use of the wide end of the aperture scale than most do.

On 8x10, which i've been shooting for a little under a week, I find that even with seated portraits, f/16 and f/22 produce a nicely blurred background. Any wider, and you don't get the whole subject in focus. In practice on landscapes i"ve used F/64 once, and f/22-f/32 for most of the remainder. I could see getting away with wide open on 8x10 if your perched somewhere high, such that you don't have anything close to the camera in shot.

[Drew Wiley]

With sheet film, shooting at large apertures can have the distinct disadvantage of not giving enough depth on an uneven
film plane. This is especially a problem if the camera is pointed down. Film sags in the holder unless you are using some kind of vacuum or adhesive holder. Maybe for soft focus work like certain portraiture projects you can get away with this,
but I think not, because I personally like at least some point in the subject, like the eyes, to be crisply focussed. Shallow
depth of field and sloppy depth of field are not synonymous. Fortunately, some black and white sheet films are fairly stiff.
Most color films are not.