Large format camera and vintage lens question

[DHodson]

I'm just starting to look into vintage lenses so hopefully you can help me understand them. My Shen Hao 4x5 has a maximum bellows extension of 340mm.

That works out to around 13.4 inches so would that be the maximum vintage lens I could use and focus at infinity or do these lense have their focal point somewhere up the barrel? I'm guessing I could still use a 15" lens but just couldn't focus at infinity. Can anyone tell me how I could estimate the usable focus distance of a 15" lens on my camera?

Thanks for any help you can give

Dave

[djdister]

A telephoto lens allows you to focus on infinity or closer with less bellows draw than a normal lens of the same focal length. So if you can find a vintage 15" telephoto lens, it may be usable on your camera. However, you will not be able to focus a normal 15" lens (either at infinity or closer) on a camera with only 13" of bellows draw unless you can use a top hat (extending) lens board. You need more bellows draw to focus closer than infinity, not less.

Information about telephoto lenses: https://en.wikipedia.org/wiki/Telephoto_lens

[Dan Fromm]

It depends on the lens and on how it is mounted.

A couple of rules of thumb:

Most lenses used on LF cameras (not telephotos) have rear nodes close to the diaphragm. At infinity, the rear node will sit one focal length from the film plane. At closer distances, farther away. If the rear node is less than one focal length from the film plane, it will be focused beyond infinity, where there's nothing photogenic or even photographable.

If the lens is in shutter, it will probably be mounted with the shutter against the board, i.e., slightly in front of the front standard. If it is in barrel, it might be mounted entirely in front of the board. This will add extension.

Go figure.

[Xipho]

No, you only can use shorter lenses. The infinity position is the shortest position, if you go closer you need evem more bellows...

Infinity should be approx. the focal length extension from film to about middle of the lens/shutter.

Practically, you can eaily use lenses to 240mm at least, 300mm may work but limits you in close up.

What are "vintage lenses" for you. Normal analstigmats like Tessars with Compur shutters or older Brass lenses?

[DHodson]

Thanks for all your quick replies - all very helpful.

In answer to Xipho, I've been thinking in the context of the half plate lenses of the late 1800's but that could change as I learn and understand more.

Thanks again
Dave

[Xipho]

as half plate, as far as I found (it is not a common size in europe) is only slightly larger as 4x5 inch, these lenses should have focal lenth about 160-180 mm, so no problem with them...

[Ken Lee]

You might find this page helpful: Formulas for Bellows Extension and Compensation

[Two23]

As a previous owner of a Shen Hao 4x5, I will add that most of the longer lenses are also very heavy. They will crush lightweight field cameras.


Kent in SD

[DHodson]

Thanks Ken and good point Kent. I have a Wista D and a Crown Graphic that might be better for starting out.

One question I have if anyone has an older brass lens (say 12" or 15"). When you have it mounted and focused at infinity, what's the distance from the film plane to the front of the lensboard (base of the flange). Is it the same as the focal length (12 or 15 or whatever) or is the lens focal node (I think that's what it's called) somewhere up the barrel? If so, how far?

Thanks
Dave


Update:

I just saw an old post that called this the flange focal distance (FFD) and suggested that, with in-shutter lenses, it would be pretty close to the lens focal length but with other older lens designs (ie barrel lenses) the FFD will be less than the FL. I think this is what Dan was pointing out. My question would be whether the difference would be enough to let me mount a lens longer than my bellows and still have it focus. How would a person know?

[Xipho]

for example, the FFD of a Schneider Xenar 4.7/135 is 126 mm