305 g-Claron with 14" bellows

[gth871r]

I have a Toko (that's not a typo) field camera with a bellows of 355mm (measured from lensboard to ground glass at maximum extension). I'm thinking of getting a 305 f9 g-Claron and I'm concerned about how close I will be able to focus. I've run the numbers and according to the thin lens equation (1/s1+1/s2=1/f) I should get a close focus of 2165mm. However, the thin lens equation relies on assumptions that aren't exactly applicable to this lens. Given that I'm using this right at the edge of where the math says it'll work, the little things might matter. Does anyone have experience using a 305mm on a camera with only 355mm extension. How well does it work? How much movement is available? My primary application is landscape and nature photography.

Thanks,

-Mike

[Dan Fromm]

Mike, here are two useful equations that are widely used in closeup photography and photomacrography. I find them easier to use and think with than the equation you posted:

extension (film plane-to-lens rear node) = focal length * (1 + magnification)

Your G-Claron's rear node is near its diaphragm.

The equation can be rewritten as magnification = (extension/focal length) - 1

355 mm of extension (probably plus a little 'cos the diaphragm is in front of the lens board) with a 305 mm lens gives m = .16, i.e., roughly 1:6

Lens front node-to-subject distance is f * (m + 1)/m In your situation, it gives the 2165 mm you already found.

Your G-Claron's front node is near the diaphragm.

[genotypewriter]

Not familiar with that camera but fwiw, there are "extension lens boards" which are pretty much the opposite of the recessed lens boards. I've seen them on the auction site in the Wista-style with a 72mm extension. Some of these sellers custom make such things too.

[Jim Noel]

I also have a Toko.
I use a 300mm Nikkor on it for field photography and have no problem with the bellows length. Of course, there is not enough length to go 1:1, but if I want that, I just change lenses.

[E. von Hoegh]

I have a Toko (that's not a typo) field camera with a bellows of 355mm (measured from lensboard to ground glass at maximum extension). I'm thinking of getting a 305 f9 g-Claron and I'm concerned about how close I will be able to focus. I've run the numbers and according to the thin lens equation (1/s1+1/s2=1/f) I should get a close focus of 2165mm. However, the thin lens equation relies on assumptions that aren't exactly applicable to this lens. Given that I'm using this right at the edge of where the math says it'll work, the little things might matter. Does anyone have experience using a 305mm on a camera with only 355mm extension. How well does it work? How much movement is available? My primary application is landscape and nature photography.

Thanks,

-Mike

As you already calculated the close focus limit, the only issue will be that when the bellows are extended near their limit, movements will be limited. I'm not familiar with te camera you hve, so I can't say how limited. You will likely be fine with landscapes, maybe a bit less than fine for nature closeups. An extended lensboard will give a bit more leeway.

[Dennis]

Toko is a pretty obscure camera. It is interesting to see it mentioned here. I have one I bought in the early 1980s new from a camera shop. The extra bellows (compared to a Wista) allowed me to use the beautiful wooden field camera as a table top camera in a commercial studio.. usually using a 210 lens. That camera is a battle ax and took lots of use and abuse from me and still is good today, 25 years later, though a bit loose at the sliding back part.
Dennis
I do have a 305 G claron and used it once for a 4x5 shot but that is all.