Exposure compensation for small apertures

Anyone trying to measure the shutterspeed of a leaf shutter needs to know how an aperture (shutter's iris or any aperture produced by the device) affects the results.

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Originally Posted by Bernice Loui

If larger lens apertures are needed for sheet film/LF view camera images, apply neutral density filter to move the shutter speed down as needed.

Given the types of images made using a view camera with sheet film, high shutter speeds (1/500 to 1/125 sec) is extremely questionable.

Back to the "red herring" again, this question might be of intellectual-academia curiosity. In real world sheet film image making, does any of this uber shutter speed discussion apply_?_


Examples of sheet film images made at f22 or smaller lens aperture with a shutter speed of 1/500 second or so outside of specialized scientific and similar images_?_

Bernice

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It can definitely be encountered, but not at small apertures.

For example, I have a few f2.8 lenses for 4x5 so if I used them wide open for outdoors portraits with Hp5+ (iso 400) at 1/500 I would get an exposure of 12 EV (which corresponds to “Moment before sunset on a clear day”). So definitely on a bright day shooting outside with fast lenses you can encounter it.

One of the reasons I use a Graflex with a focal plane shutter in those settings — offers up to 1/1000 and it does not have this issue.

ND filters are definitely viable but it’s one more thing to take care of… and clean… and remember … and dims the GG….

large lens aperture are often the driving factor for higher shutter speeds. Lower shutter speeds are definitely achievable using ND filters like the Lee "big stopper" 3.0 aka 10 f-stop ND filter.
https://www.bhphotovideo.com/c/produ...4_x_4_Big.html

Ground glass focusing is not really an issues, focus at the large lens aperture as needed, once set, apply the "big stopper" ND filter ideally into the compendium lens shade filter holder, make the exposure.

Been doing stuff like this for decades from 35mm film to digital to sheet film. Negates the need for uber shutter speeds.
If the combo of large lens apertures are needed with high shutter speeds tools involved will be 35mm film or digital as they are the better tool for images of this type.


Bernice

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Originally Posted by Kiwi7475

It can definitely be encountered, but not at small apertures.

For example, I have a few f2.8 lenses for 4x5 so if I used them wide open for outdoors portraits with Hp5+ (iso 400) at 1/500 I would get an exposure of 12 EV (which corresponds to “Moment before sunset on a clear day”). So definitely on a bright day shooting outside with fast lenses you can encounter it.

One of the reasons I use a Graflex with a focal plane shutter in those settings — offers up to 1/1000 and it does not have this issue.

ND filters are definitely viable but it’s one more thing to take care of… and clean… and remember … and dims the GG….

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The bigger problem with faster shutter speeds and clockwork shutters is that those speeds are commonly significantly slower than marked. If one does use these faster speeds and needs to avoid even small amounts of overexposure, they should be worrying about the actual shutter speed vs. the marked one first. I test all my lenses and indicate the actual speed at each setting on a sticker on the lensboard. I don't think I have a single lens where 1/250th and 1/500th are anywhere close to the marked speed.

Only after dealing with that would one ever need to make the exposure compensations that Stroebel suggests. That is, if anyone really uses the fastest shutter speeds together with the smallest apertures. Those two things tend to be mutually exclusive...

Doremus

I just use slower film to avoid the entire controversy.

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Originally Posted by Doremus Scudder

The bigger problem with faster shutter speeds and clockwork shutters is that those speeds are commonly significantly slower than marked. If one does use these faster speeds and needs to avoid even small amounts of overexposure, they should be worrying about the actual shutter speed vs. the marked one first. I test all my lenses and indicate the actual speed at each setting on a sticker on the lensboard.
Doremus

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That's a good approach, but there's just one thing that makes matters ever worse -- like all of us, things gradually slow down even more as they age.

Suspect this is a case / example of text book theory meeting the harsh realities of image making using real world devices such as mechanical shutters and the like.

"information" from a book is not always the absolute de-facto way of how stuff is done. Does this book by Leslie Stroebel offer any real world image examples of how and why exposure compensation for small apertures combined with high shutter speeds is used and how often it is used? Or, an example of what is known in academia as "mental Masterbation" ?


Bernice

Kodak didn’t offer examples either.

Rare example of image made demanding small apertures at high shutter speed can be recording atomic bomb blast on photographic film. This was accomplished by using a shutter made with a Faraday cell & Polarizing filters. This was done in the Rapatronic Camera, part of the work done by Doc Edgerton and others at EG&G..
https://www.sonicbomb.com/rapatronic.html

Over the decades of making sheet film images, not once has the combo of requiring high shutter speeds combined with small lens apertures was ever needed, not once over many, many, many thousands sheets of film burned. Thus, the Red Herring comment.


Bernice

I notice some want 1/3 stop accuracy with film aperture and shutter speed

What is the ANSI spec?

Maybe plus/minus 30 percent!