Fitting Graphic-Kowa 210mm F9 in Copal 1

[Sam L]

I'm in the market for a wide-angle 8x10 for field use.

If I buy a Graphic Kowa 210mm f/9 in barrel, can I fit it in the Copal 1 shutter with f/9 scales that I already have without much fuss? From this thread. It sounds like the you can screw the elements all the way in and it will work. Or, maybe you need a small spacer for perfection:

https://www.largeformatphotography.info/forum/showthread.php?120783-Please-Help-With-Graphic-Kowa-150-and-210mm-Spacing-in-Shutter

Will the existing f/9 scales on the shutter work correctly for any f/9 lens elements?

[Dan Fromm]

Will the existing f/9 scales on the shutter work correctly for any f/9 lens elements?

Any? Not guaranteed.

[Tin Can]

my strobes adjust in exact 1 stop at a time, I have checked with a good DSLR lens

Find f9 then check for yourself

some apertures start and end a bit off

[Steve Goldstein]

Not all 210mm f/9 Graphic Kowa cells will fit a Copal 1. I have a recollection that some versions don't allow removal of one of the cells (rear, I think, but I'm not sure). And I could be wrong. Best to verify that both cells can be unscrewed from the barrel before you purchase, or get right of return.

[Sam L]

Thanks, Steve. I'll make sure to ask any potential seller to unscrew both front and rear to check.

With respect to the f/stop scale, I didn't mean to ask about perfect calibration. Rather, are scales that start from a specific f/stop supposed to work with lens elements that match that aperture? I've never moved lens elements between shutters before.

[Dan Fromm]

Rather, are scales that start from a specific f/stop supposed to work with lens elements that match that aperture?

Still not guaranteed.

[Kevin Crisp]

It depends completely the the focal length of the lens. F:9 on 150mm g claron will not match f:9 on a 305....

If the donor is a 210, then it should be really close.

[Sam L]

Thanks, Kevin.

If they don't align correctly, would the problem typically be with where the scale starts (need to shift the scale over) or with the spacing between stops (need to make a new scale)?

[Corran]

Some Copal shutters have aperture scales that can be removed and replaced. Find one for a 210mm lens and you'll be "close enough" for most things. If you need extreme precision get one made or buy a lens already in the shutter that's been marked properly. All my Copal shutters have identical aperture scales but in slightly different places, so I think it's where the scale starts that's important, but I've never tested that. Older shutters have scales where the numbers gradually get closer and closer. I think it depends how the aperture mechanism works, logarithmic or linearly.

[Sam L]

Corran, exactly what I wanted to know.

Thanks!

[Conrad . Marvin]

Not guaranteed, but I fit a 210 GK to a copal press shutter with complete success a few years ago. It was a little tricky removing the front lens cell from the barrel because it was set into the mount a bit, but I was able to make a tool to remove it without damaging the glass. The scale that was on the shutter was marked 210 and the f stops turned out to be correct. The largest stop it turns out is more like f6.3 than f9 when the lens is mounted in a shutter. There is a “trim ring” in some lenses for spacing the rear lens cell a bit further, but you may find that it works better without it for the kind of work you do. It’s a fabulous lens on 5x7 with tons of movement. I’m sure that it will cover 8x10 beautifully.

[Sam L]

Conrad, great intel. I have a set of rubber cones for removing lens elements (e.g. https://www.amazon.com/gp/product/B0013HFYKK). Does that seem like the right tool?

[Conrad . Marvin]

That might work, but I think if you have a spanner wrench with the right width it will be more secure. I made a simple tool out of a piece of thick shim stock or maybe an old hack saw blade and ground away the middle because the lens element rises above the level of the two slots and it was easy to unscrew the cell.

[Kevin Crisp]

Copal shutters have evenly spaced f stops on the scale. But changing focal length can throw everything off. After you do the math on the change, you should be able to shift the scale, but of course the threaded holes for the scale don't line up. Or you could just remember the difference. For example, my 305mm R Claron fits the shutter meant for a 240 Symmar. If I remember that f:22 is what shows as f:16 on the old scale, everything is great. For one lens, the adjustment isn't so hard, and hopefully it will work out to exactly one stop. If you are going from one 210mm lens to another (or using a scale off a 210mm shutter) I'd be amazed if there is any difference worth caring about.

I have many lenses where a put a white section of P touch labeler tape on there. (It really stays put) Then I just write the f stops on there.

[Sam L]

I found Kowa 210mm and 150mm lenses in some kind of process camera double-lens assembly on ebay. The lens elements came out of the assembly easily using rubber cones. The 210mm lens elements fit perfectly in the Copal #1 from my Nikkor-W 210mm f/5.6. I used the shim from the barrel behind the rear element, which brings its stack height to 40.5mm, just shy of what it was in the barrel.

I installed the lens in my 4x5, focused at infinity, and pointed a laser pointer at the center of the ground glass and put a white card about a foot away, as suggested in this thread on calibrating f/stops:

https://www.largeformatphotography.info/forum/showthread.php?55665-how-do-you-calibrate-f-stops-on-a-lens/page2

I first measured the projected circle with the original Nikkor lens elements installed and indeed (210 / diameter) closely matches the markings on the f/stop scale. With the kowa, the wide open setting measures about f/7.5 but the projected circle is limited by the lens not the aperture. The aperture kicks in where the lens indicates f/5.6 + 1/2. At f/8 and beyond, the scales seem accurate (for both lenses).

It appears to be a drop-in replacement.

Not sure what to make of the 150mm lens yet. It is a few millimeters too small for a Copal 3. I suspect people use some sort of shim or adapter.

[Conrad . Marvin]

Glad to hear that the 210 was an easy match. If your 150 is the f9 version it will probably work in a copal #1 as well. It also covers 5x7 easily and is sharp and small. The f4.5 150 is big and the one that I got not very sharp until about f16. I did manage to make some adapter rings to get it into an Ilex #4 shutter, but I seem to use the smaller f9 and leave the big fuzzy one at home even though it covers 5x7 at f8-f11.