Are the higher shutter speeds on large format lenses always off?

[Pere Casals]

Not really. If one uses each of their lenses to run tests for personal film speed, then each lens would have its own correction for the film ASA (ISO)...that is all one would need to remember. Again, this is assuming one always uses the same range of shutter speeds per lens (such as 1/500 for aerial photography, or always 1/15 to 1/60 for some reason.) If one lens is a stop slow in shutter speed -- the adjusted ASA of the film derived through testing for that lens will be doubled compared to a shutter that operates at the correct speed.

All just a thought exercise...I do not work this way. Way too much testing -- but experience certainly taught me to cut back a stop if using 1/125.

I guess that in general what you say is to work very well, at the end negative film has a lot of highlight latitude and by adding some exposure as safety factor we ensure perfect results. Perhaps exception is when a shutter has one or more speeds that are really faulty, or when we require top precision to nail slides.

One of my shutters had inconsistent speeds... with too much variability, anyway I guess that an experienced photographer detects that condition by simply listening the sound the shutter emites.

[Jody_S]

The whole point of using lenses wide-open these days is for the effect, not because we're sports or news photographers tying to stop action with fast shutter speeds. Not that lf can't do that, just that I'm pretty sure most sports and news photographers are now using digital, not their 1940s press cameras.

So you spend mega bucks buying, say, an f3.5 Xenar or Planar or whatever in shutter, you head out to your favorite stream or meadow or rock pile, or bribe your kid to sit for an outdoor portrait, and proceed to shoot the lens wide open, at top shutter speed. Your lens is no longer effectively wide open. What effect does this have on image, given that your effective aperture is 1) moving, 2) not circular?

I propose the following two tests, that require a few sheets of film, a fast lens in shutter, and an ND filter: shoot the same scene wide-open at 1/15s and 1/400 or whatever the shutter's top speed is. Shoot the proverbial ruler used to check focus, but in this instance for measuring depth of field, and shoot something with an OOF background with pinhole light sources. I expect the DoF will be increased using the shutter at max speed, negating the money you put into that fancy lens, and I expect OOF highlights will be very undefined but in some scenarios might be starfish-shaped?

The test could also be done with a Speed Graphic, using the same shutter speed on the leaf shutter and then with the lens open, using the roller-blind shutter. That might remove 1 variable for the OOF highlights (reflections off the ND filter). I'm not doing this myself for the very good reason that I don't own any fast lenses in shutter, unless you want to count a Verito in a non-working Studio shutter. The same effects will be present in slower lenses, but the demonstration will not be as interesting.

[JimboWalker]

I believe the faster speeds are optimistic as Mr. Crisp said. My Supermatics all run a stop slow at the fastest setting, even though the slower ones are dead on. I just received a Linhof Synchro-Compur shutter that Carol Miller at Flutot's CLA'd and the top two speeds are slow. I think it is the nature of the beast on large format shutters. As mentioned earlier, you generally never use speeds higher than 60th anyway. My exposures generally run much slower.

[grat]

I realize I'm being terribly simplistic, but to get an approximate idea of my shutter's calibration, I just put a USB microphone up to it, and recorded the various shutter sequences into Audacity, and measured the length between the clicks.

My faster speeds are within a few percentage points, but the 1s is "only" 0.860 seconds.

It doesn't give me ramps or photon counts, but at least I know whether or not 1/30th of a second is actually close to 1/30th of a second (it is).

And if I knew what to compare it with, I'd know how fast it opens and closes.

[Dan Fromm]

Jody, I've never noticed vignetting from my lenses in shutter. And I sometimes use high speeds. What am I doing wrong?

[Jody_S]

Jody, I've never noticed vignetting from my lenses in shutter. And I sometimes use high speeds. What am I doing wrong?

I think we've established already that center-mounted shutters in modern lenses will not cause vignetting, as they are at the optical node of the lens. However front and rear-mounted leaf shutters will cause a darkening of the extremities if used at speeds above 1/15 (per the Sinar sales brochure, most noticeable at speeds above 1/100), or on 'Instant' with a LUC-type shutter activated by a cable release. I believe Packard used their blade design to advantage because of this effect, with the top blade darkening the sky, and the side blades opening fastest along the middle third of the image to clear the horizon, leaving only dark corners at the lower right and left of the image. The weight of the top blade also helps close the shutter by gravity, of course.

That's what left me wondering what effect high shutter speeds have on lenses when used wide open, and my conclusion was that they would deepen depth of field (because the shutter blades are obstructing the light's path for virtually all of the exposure, leading to a reduced effective aperture for purposes of DoF, even if the total volume of light passed does correspond to the faceplate aperture and speed for exposure calculations) and possibly insert artifacts in OOF areas (because the shutter blades act as an aperture while opening and closing, and they do not form a circle but rather a starfish shape).

[Drew Wiley]

Things are getting fun (a bit of the usual food fight). Focal plane shutters have to be measured differently from leaf shutters, and so forth. Even the top speed of my Nikon FM2n is off. Not only the instrumentation says so, but densitometer-measured comparisons on the same roll of film. So I don't take anything for granted. Back when I shot a lot of color chromes, I'd note down anything deviating more than 1/6th stop. Relying on film "latitude" is a good way to ruin a shot. But all my own view camera lenses have very predictable shutters. If certain speeds are a tad off one way or the other, that seems to be the case year after year. I don't trust lenses that have lain around for many years unused, no matter how clean they look.

[Jody_S]

I don't trust lenses that have lain around for many years unused, no matter how clean they look.

Where's the fun in that? Half the lenses I use on a typical outing are either being used for the first time (by me), or I don't remember how they performed the last time I used them. But then obtaining a 'perfect' image isn't the main reason I go out shooting; it's the process I love. The discovery. When I want a perfect photo, I use my phone like a normal person.

[Drew Wiley]

Oh, the fun is the predictable back n' forth of conflicting opinions. It's just nice to see everyone still alive and ornery. Right now I'm salvage printing a number of early negs that were overexposed or whatever. But for many years now I've rarely goofed an exposure unless I neglected to use a magnifier or reading glasses with the meter or shutter dial. But I'm apparently not a normal person, because I don't know how to take a picture with a phone. It's hard enough to make a phone call with it. Yesterday our cellphones stopped working because my wife couldn't pay the bill because the DSL was down, but couldn't get that serviced without a phone call! Had to drive her clear out to her office on her day off to use the computer there. Speaking of hillbillies on another thread, where I'm from the only phone was about a mile away in a little store smaller than a mobile home, and it was a mahogany box with a crank on it. The operator was across the River in another county, and not a little river, but a deep uninhabited canyon. The first modern phone lines were strung by Cherokee work crews brought in from many states away, and the sons of a couple of them became good hiking pals of mine when I was around 16.

[GoodOldNorm]

As the detective "Columbo" would say, "just one more thing", when I tested my shutter speeds I fired the shutter 6 times at each speed and took an average. I noted that there was no appreciable difference from the first firing of the shutter to the sixth. From this I concluded that firing the shutter to "exercise" it made no difference to my readings.