Hard Aperture Stops on Large Format Lenses

wiltw · Aug 18, 2023

Alan Edward Klein said:
Donald, I'm a little confused. Aren't all let's say Copal 0 aperture settings marked the same regardless which lens they're mounted on? Couldn't those hash marks have click stops?

Alan, let's start with the understanding that the Copal 0 shutter comes with a click stop at 50mm diameter and 35mm diameter and 25mm diameter, to represent Aperture 1 and Aperture 2 and Aperture 3, one EV different from each other.
Now let's install three lenses onto Copal 0 shutter with those click stops...150mm and 200mm and 250mm FL

Aperture 1: 150mm FL with 50mm aperture is f/3, while 200mm FL with 50mm aperture is f/4, and 250mm FL with 50mm aperture is f/5
Aperture 2: 150mm FL with 35mm aperture is f/4.2, while 200mm FL with 35mm aperture is f/5.7and 250mm FL with 25mm aperture is f/10
Aperture 3: 150mm FL with 25mm aperture is f/6, while 200mm FL with 25mm aperture is f/8, and 250mm FL with 25mm aperture is f/10

IOW the same click stops with the Copal 0 shutter would represent different f/stops, dependent upon the FL of the mounted optics, and the oddball f/numbers on lenses would drive folks nuts.

abruzzi · Aug 18, 2023

BradS said:
Notice how those little metal plates that have the f-numbers engraved in them are easily interchangeable

for some reason the ƒ numbers on copals sold with Nikkor and Fuji actually aren't removable. but other than that nitpick

Donald Qualls · Aug 18, 2023

faberryman said:
So you are saying 4x5 is hard?

After learning 35 mm and adjustable cameras at age 9, yes, I found sheet film (9x12 and 4x5) significantly harder. Not to mention the barriers to entry; equipment costs more (and requires more knowledge and skill to use), film costs more, processing (if you pay to have it done) costs more or is more effort-intensive than processing your own roll film, enlargers that take 4x5 cost more than ones that top out at 6x7 or 6x9 cm (and 150 mm enlarging lenses cost more than 105 or 80 or 50 mm). All those costs MAKE 4x5 HARDER than roll film formats. I've been shooting large format of one sort or another for almost twenty years, and I still misload a film holder on occasion (probably because I don't do it often enough because of the cost of film).

Large format was invented first because with early materials (Talbotype or collodion) there's a lower limit to what's practical to work with. Photography in general, however, got easier over time as dry plates replaced wet plates, flexible film (on a roll, yet!) replaced dry plates, and cameras did more and more for the user. Even today's 4x5 cameras don't do much of the job for the user, and for darkroom handling, 35mm to 120 are easier than sheet formats.

In part, like Kennedy said in 1961, we do this "because it is hard." If the photographic industry (especially professionals) had wanted 4x5 to be easy, someone would have made it easy, but the easy followed down the smaller film trend (110 cameras were almost universally point and shoot).

BrianShaw · Aug 18, 2023

LOL... you girls are going to be arguing for a long time if you keep using value judgements like 'easy' and 'hard'. For some people hard things are easy and for some people even easy things are hard. And for others, 'hard' is mostly a distant memory.

Doremus Scudder · Aug 18, 2023

Alan,

If you're routinely bracketing your LF shots, you're not metering carefully enough and/or you haven't done the requisite testing for E.I. At some point, bracketing LF exposure should be reserved for tricky situations only, where there is a large possibility of ruining a shot at the chosen exposure.

Heck, when I make a second exposure of a particular set-up it's rarely because I'm unsure of the exposure. Other things, like subject movement, changing lighting or clouds, fear of damaging the only negative of a really great image, etc., are what prompt me to make that extra negative.

Maybe you could elaborate why you need to change quickly in 1/3- or 1/2-stop increments?

Doremus

David Lindquist · Aug 18, 2023

abruzzi said:
all of my later Compur shutters have clicks on the aperture--00, 0, 1, & 3. One of these days I'll take them apart remove the clicky thing.

Edit: here is a Compur #0 with click stops--in the photos you can see on the rear of the shutter the click stop mechanism:

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I'll try to post a picture of the click stop mechanism on one of my No. 1 Compurs. The Compurs with click stops have linear diaphragms, of course. None of my click-stopped Compurs have the intermediate stops marked. I have some literature from Prontor/Zeiss Gruppe with a date code of 1988 showing what I think is probably the last of the line of the Compur shutters. The No. 3 Compur now has a top speed of 1/250. The No. 1 and No. 3 have intermediate marks corresponding to 1/3 stops; the No. 0 has a half stop marked between each full stop. Descriptive text says "They have a diaphragm with marked click-stops in 1/3 steps (size 0: 1/2 steps)." Wonder what the actual production numbers of these were.

Given that exposure indices proceed in 1/3 stop increments, it makes a certain amount of sense to me to have the aperture scale graduated in 1/3 stops. Certainly, as Dan has suggested, working to the precision of 1/3 stop isn't necessary in the practical world (or arguably not even possible.)

As I like to say, in the photographic process, Ray's Rules of Precision usually obtain:

1. Measure with a micrometer
2. Mark with chalk
3. Cut with an axe.

David

Alan Edward Klein · Aug 18, 2023

xkaes said:
If a shutter and lens are fixed together, as with the RB lenses, sure you can have f-stop click stops, but with large format lenses and shutters, they are separate parts combined. A #0, #1, or #3 shutter never knows what lens it will be attached to. It can't know anything about f-stops.

Aren't the hash marks the same location on all Copal #0 shutters/aperture control attachments? Aren't these swappable between lenses?

abruzzi · Aug 18, 2023

Interesting, my Compur #3 has a top speed of 1/200. I have no idea if it actually gets there. I have a transplanted Apo-Ronar 480/11 in it and the click locations aren't perfect, but as you say--close enough.

Alan Edward Klein · Aug 18, 2023

nmp said:
I have a Schneider Kreuznach 150/5.6 that has 1/4 f-stop clicks. Shutter clicks a single stop.

:Niranjan.

Who makes the shutter portion?

Dan Fromm · Aug 18, 2023

On the whole, convenience is convenient.

abruzzi · Aug 18, 2023

Alan Edward Klein said:
Aren't the hash marks the same location on all Copal #0 shutters/aperture control attachments? Aren't these swappable between lenses?

the lens elements are swappable, but the aperture plate is specific to the lens that it was made for. For an angulon 90mm f6.8 you have to close the aperture a third of the way down before you get to 6.8, and if you look through the lens as you stop down, you won't see any change until you sit that 6.8 mark. Swap in elements from a 150/5.6 and 5.6 and 8 will come before the 6.8 mark (for the angulon.)

Alan Edward Klein · Aug 18, 2023

Dan Fromm said:
Thanks for the reply. Are you shooting reversal film? I ask because most negative film (is that the right word?) has enough latitude that +/- half a stop makes no difference.

Yes I shoot Velvia Ektachrome and Provia. But even with BW film, I might add a filter after taking a shot without, and have to change it let's say one stop for yellow. It's so much easier just to click the change than have to come around to the front and look at the hash marks while adjusting. Of course, I could click the shutter speed. But that might get me into too long shots. It would just be a little more convenient to have clicks on the aperture as well.

Alan Edward Klein · Aug 18, 2023

abruzzi said:
all of my later Compur shutters have clicks on the aperture--00, 0, 1, & 3. One of these days I'll take them apart remove the clicky thing.

Edit: here is a Compur #0 with click stops--in the photos you can see on the rear of the shutter the click stop mechanism:

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Why would you remove it?

Alan Edward Klein · Aug 18, 2023

BradS said:
No. the f-stop number is defined as the focal length of the lens divided by the diameter of the aperture (well, technically, I think it is the diameter of the entrance pupil, but close enough) and, on a Copal #0, for example, the diameter of the aperture is directly proportional angular displacement of the aperture but the Copal #0 is used for many different focal lengths - everything form say, 75mm to 200mm. For any particular the position of the aperture selector, the f-number is gonna be different for different focal lengths. So, no. The scales are not the same.

Look closely at your LF lenses. Notice how those little metal plates that have the f-numbers engraved in them are easily interchangeable - that's because they're specific to focal length and many differnt focal length cells can be fitted to the same shutter. If you have two different focal length lenses, each mounted in a in a copal #0, the spacing of the f-numbers will be different between the two.

All that said, clicks stops are of course possible,they would just have to be custom done for each focal length. Which would cost extra.

Thanks for explaining that, Brad. I didn't know. What's interesting is that if you have a problem with shutter speeds, and want to replace it, you have to get the right metal plates to match your lens. I would never had known that if I didn't ask this question.

Alan Edward Klein · Aug 18, 2023

Donald Qualls said:
Surely, but between handling sheet film in the dark (vs. roll film), dealing with film holders, learning "the dance" as Matt Marrash calls it, and dealing with the larger, heavier, less automated cameras and so forth, 4x5 isn't even the kind of "easy" 120 in, say, a 1950s TLR is. There's a learning curve, and a fairly steep one, even for experienced manual photographers in smaller formats, and the more of the "real" 4x5 experience you go for (movements, for instance, ground glass focus and composition, or color) the less "easy" is left in this form of photography. And never forget the cost, which makes learning more stressful, but without the instant feedback of similarly or higher priced Polaroids.

Donald, I just started LF during Covid after decades of MF and 35mm. Yes it's been a real challenge especially with movements and the "dance". I've stepped on my own toes too many times.

Alan Edward Klein · Aug 18, 2023

Doremus Scudder said:
Alan,

If you're routinely bracketing your LF shots, you're not metering carefully enough and/or you haven't done the requisite testing for E.I. At some point, bracketing LF exposure should be reserved for tricky situations only, where there is a large possibility of ruining a shot at the chosen exposure.

Heck, when I make a second exposure of a particular set-up it's rarely because I'm unsure of the exposure. Other things, like subject movement, changing lighting or clouds, fear of damaging the only negative of a really great image, etc., are what prompt me to make that extra negative.

Maybe you could elaborate why you need to change quickly in 1/3- or 1/2-stop increments?

Doremus

Doremus, It's not a deal breaker. It's just easier to lock in the setting with clicks than eyeball it. Especially because the lens is so high I sometimes have to strain to see it. Plus, I'm use to clicks because I shot MF and 35mm for so many years. That's why they call them stops, after all.

faberryman · Aug 18, 2023

Alan Edward Klein said:
Doremus, It's not a deal breaker. It's just easier to lock in the setting with clicks than eyeball it. Especially because the lens is so high I sometimes have to strain to see it.

If it is hard for you to see the aperture setting because the lens is too high, how are you able to compose and focus on the ground glass? Do you frequently shoot upward at a steep angle with the legs of your tripod fully extended?

MattKing · Aug 18, 2023

faberryman said:
If it is hard for you to see the aperture setting because the lens is too high, how are you able to compose and focus on the ground glass?

The numbers are probably on the top.
Can the lens plus shutter be rotated to the side?

nmp · Aug 18, 2023

Alan Edward Klein said:
Who makes the shutter portion?

Synchro Compur. This is the lens I have:

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:Niranjan

ic-racer · Aug 18, 2023

Donald Qualls said:
I'd expect most large format shutters not to have any click stops in support of the ability to mount any lens with the correct thread (more or less standardized) and engrave an aperture scale for the specific focal length. Click stops would make sense only on a shutter (almost) exclusively used with a single lens.

Exactly, the clicks would have to be tied to the scale.

abruzzi · Aug 18, 2023

Alan Edward Klein said:
Why would you remove it?

mostly becasue I dislike it, I prefer smooth moving apertures on my LF lenses.

David Lindquist · Aug 18, 2023

Here's the click stop thingy on one of my No. 1 Compurs, one more piece of evidence that such things actually exist. The detent engages in the toothed sector to the right. Not sure of the function of the toothed sector to the left.
David

exist .

abruzzi · Aug 18, 2023

David Lindquist said:
Not sure of the function of the toothed sector to the left.

Wild guess, but some Compur shutter were equipped with a vertical shaft that stuck up above the front standard that you could use to view and change the aperture. I wonder if those teeth were used to engage that.

(that image if for a Prontor, but I'm, pretty sure I've seen similar on a Compur.)

David Lindquist · Aug 18, 2023

I don't think that's a wild guess at all. Looking at the back of my shutter, the device you show and the "Aperture setting devices" for the Compur shutters shown in the literature I referenced above, I'll bet you've nailed it. My literature doesn't show the details but says one of these devices could be added later by the end user.

David

xkaes · Aug 18, 2023

abruzzi said:
for some reason the ƒ numbers on copals sold with Nikkor and Fuji actually aren't removable. but other than that nitpick

They are removable on all of mine -- you can see the two screws that hold it in place. Each Fuji has a small number pertaining to exact lens that it is designed for. Here's a #53 for a 150mm f5.6 on a Copal #0

If you change the lens, and not the scale, exposures will be messed up.

Hard Aperture Stops on Large Format Lenses

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