About flange-to-film distances and field cameras

[Ulophot]

Perhaps no one else may need to dodge the particular proverbial bullet that I recently did, but I’ll share my experience briefly, just in case.

As posted last month, I had started looking for a wider lens to complement the 210mm on my 4x5 Tachiraha. I was strongly inclined towards a 135 (roughly equivalent to 35mm on a 35mm camera), but was sort of considering a possible 120 (from which I’d likely be cropping) for the greater coverage—i.e., lens movements—afforded by some designs.

I did find a 135 that met my needs, and just as well. Before the lens arrived, I was measuring extension on my camera and was dismayed to find that it would not allow the 135 to focus at infinity—the back and the front were too far apart at their minimum! Well, that was mistaken; after a moments shock I recalled that the back can be moved forward, after which the actual minimum is just barely less than the lens requires to focus at infinity.

Yes, a recessed lens board could be used. The slight disadvantage in my present situation would be that the camera would not close with the lens on; it does with each of my lenses when the lens is reversed. Handy sometimes.

Anyway, how focal length—both at the short and long end—will work with a given camera’s minimum and maximum extensions is a consideration to bear in mind.

[Oren Grad]

I did find a 135 that met my needs, and just as well. Before the lens arrived, I was measuring extension on my camera and was dismayed to find that it would not allow the 135 to focus at infinity—the back and the front were too far apart at their minimum! Well, that was mistaken; after a moments shock I recalled that the back can be moved forward, after which the actual minimum is just barely less than the lens requires to focus at infinity.

Something doesn't sound right here. The Tachihara "Fielstand" 4x5 is specified for a minimum flange distance of 65 mm. Compact 4x5 wooden field cameras usually have no trouble with lenses down to at least 90mm; shorter than that, as the bellows get compressed, movements may be compromised, but it's common at least for infinity focus to be achievable for lenses somewhat shorter than 90. So while your caveat about paying attention to minimum and maximum extensions is always good advice, a 135 should be not even close to being a problem with your camera.

Perhaps I'm misunderstanding something about your situation, or perhaps you're missing something about the operation of your camera. Maybe both!

[drew.saunders]

I purchased a Tachihara new with a 120/5.6 APO-Symmar and it worked just fine. You have to pre-set the distance from the front standard to the rear, if I remember correctly (it's been years since I sold it). I think there will be two levers that you can release that will allow you to push the front standard back some, then you re-engage them to use that lens. I had marks on my camera for where to put the front standard to be in the right place to work with the 120. Hopefully someone with a Tachi will be able to give you a better explanation.

[Oren Grad]

Some version of what Drew describes is true in general of field cameras. Some have infinity stops that can be set at intermediate positions on the focusing bed so that you can snap the front standard into position for shorter lenses without having to pay close attention, but the key point is that the front standard isn't pulled out to its far limit unless you're using a lens with a long focal length that requires all the extension you can get.

[drew.saunders]

Here's the manual: https://www.largeformatphotography.info/TachiharaManual.pdf
You release the levers referenced as #24 to move the front standard back, then reset them once you have the standard at a good starting point for your lens. It's described as item 1 under "How to use your camera."

[md-photo]

4X5 cameras should allow a range of ~75-300mm with the regular bellows. This is just a matter of getting the bed moved back far enough. My Wista field has a 3-section extension bed and depending on whether I have them all the way in or the the sections extended all the way out there's a corresponding focal length range that will focus correctly.

[Ulophot]

Yes, drew, Oren, and all, you are quite right. The front standard moves back as well. I have used only the 210 on this, my first field camera, since I got it, and have had no cause to move either standard from its normal position, i.e., front all the way forward, back all the way back. Not that the fron standard has ever become inadvertently loose and moved; I just wasn't thinking clearly. Thank you.

[Jac@stafford.net]

Thank you to the OP. Anecdotes are helpful. Some of them remind us of what we know or should know then we move on for the better of our craft. All is good.

[Neal Chaves]

I have an older Toyo 4 3/4 X 6 1/2 all metal folding field camera, its leather and silk bellows still supple and light tight. I made up a modified non-revolving back using recent Toyo 4X5 components. Now I can use all recent viewers, roll holders, etc. and I can focus the 47mm SA XL on a flat Graphic board to infinity easily with the bed dropped.