A question for lens aficionados

jcc · Sep 18, 2014

Which 8x10 lens has the shortest focusing distance (from front standard to subject) at infinity (no bellows extension)? New or old designs, doesn't matter.

ic-racer · Sep 19, 2014

Do you mean "front standard to FILM" ? In that case I'd put my money on the Hypergon 75mm.

ntenny · Sep 19, 2014

Assuming "front standard to film", isn't this just a roundabout way to ask "what's the widest lens that covers 8x10 at infinity"?

-NT

Dan Fromm · Sep 19, 2014

jcc said:
Which 8x10 lens has the shortest focusing distance (from front standard to subject) at infinity (no bellows extension)? New or old designs, doesn't matter.

They're all the same. Infinity + x = infinity.

jcc · Sep 19, 2014

Subject <---distance---> lens

I mean shortest distance without extending the bellows beyond its spec'd flange focal distance from the film, when focused at infinity.

I'm just searching for "X lens can focus down to Y distance at infinity" without having to resort to Scheimpflug.

jcc · Sep 19, 2014

Maybe another way to phrase it is which lens has the greatest depth of field.

Dan Fromm · Sep 19, 2014

jcc said:
Maybe another way to phrase it is which lens has the greatest depth of field.

Depth of field is not an attribute of a lens. Depth of field is determined by the Circle of Confusion (user has to decide how much fuzz is tolerable), desired enlargement to the final print (what matters is fuzziness in the final print), aperture (f/ number, not physical size) and magnification. There is no magic way to increase depth of field. There is a non-magic way, focus stacking, but this is rarely practical with LF.

jcc · Sep 19, 2014

Dan Fromm said:
Depth of field is not an attribute of a lens. Depth of field is determined by the Circle of Confusion (user has to decide how much fuzz is tolerable), desired enlargement to the final print (what matters is fuzziness in the final print), aperture (f/ number, not physical size) and magnification. There is no magic way to increase depth of field. There is a non-magic way, focus stacking, but this is rarely practical with LF.

Michael R 1974 said:
To make a long story short, depth of field is not a function of lens design. Strictly speaking you can't design more or less depth of field into a given focal length.

At its core, depth of field essentially depends on a chosen acceptable circle of confusion (which can be somewhat subjective and depends on enlargement/print viewing distance).

Duly noted. Now which lens has the smallest CoC for close objects at infinity, at its optimal aperture? Just toss lens names out there (not focal lengths or designs) with whichever subject distance it can relatively keep in focus at infinity. Doesn't have to be "the" shortest... Something like "Rodenstock APO Sironar-N 240mm can focus down to X feet at f/22" or somewhere along those lines.

Mark Crabtree · Sep 19, 2014

Same answer as above. They're all the same. Circle of confusion is simply the degree of unsharpness allowed to be considered adequately in focus; just a part of the formula for depth of field.

I do find older lenses like Dagors and Protars can give the impression of slightly move depth of field, but that is due to them not being as wiry sharp at the focus point so the transition is less obvious. This is not as apparent at the small apertures normally used with large format. And I think there can be slight differences with major differences in lens design, but really the answer is still the same.

Dan Fromm · Sep 19, 2014

jcc said:
Duly noted. Now which lens has the smallest CoC for close objects at infinity, at its optimal aperture? Just toss lens names out there (not focal lengths or designs) with whichever subject distance it can relatively keep in focus at infinity. Doesn't have to be "the" shortest... Something like "Rodenstock APO Sironar-N 240mm can focus down to X feet at f/22" or somewhere along those lines.

As has already been pointed out several times, you choose CoC. It isn't an attribute of the lens.

Now, what are you trying to do? So far you've asked questions that can't be answered as specifically as you'd like.

You originally asked, I think, which lens for 8x10 has the shortest extension at infinity. The 60/22 Goerz Hypergon (old version with central propeller), and good luck finding one. Otherwise a 120/14 Perigraphe, much less rare than a Hypergon.

michr · Sep 19, 2014

According to the online DOF calculator, the 75mm lens mentioned above has a hyperfocal distance of 4.32ft on 8x10 at f/22. Everything from 2.16ft to infinity is in acceptable focus.

I think closest hyperfocal distance is what OP is asking for. I believe a wider field of view is the answer, and that would indicate a short focal length is required for a given format.

The other option is to stop down the lens as far as possible. A very small f/stop like those used in pinhole photography, like the classic f/295, can be used to render objects from the lens to infinity, basically everything in focus. The same would apply to a small aperture behind any lens.

jcc · Sep 19, 2014

michr said:
According to the online DOF calculator, the 75mm lens mentioned above has a hyperfocal distance of 4.32ft on 8x10 at f/22. Everything from 2.16ft to infinity is in acceptable focus.

I think closest hyperfocal distance is what OP is asking for. I believe a wider field of view is the answer, and that would indicate a short focal length is required for a given format.

The other option is to stop down the lens as far as possible. A very small f/stop like those used in pinhole photography, like the classic f/295, can be used to render objects from the lens to infinity, basically everything in focus. The same would apply to a small aperture behind any lens.

That's the term! I am asking about which lenses have the shortest hyperfocal distance. Yes, what I'm looking for will most likely be a wide angle lens.

I'll look into the 120mm Perigraphe. Hopefully, I won't have to resort to a pinhole lens.

Dan Fromm · Sep 19, 2014

jcc said:
That's the term! I am asking about which lenses have the shortest hyperfocal distance. Yes, what I'm looking for will most likely be a wide angle lens.

I'll look into the 120mm Perigraphe. Hopefully, I won't have to resort to a pinhole lens.

Other things equal, the shorter the focal length the shorter the hyperfocal distance. That's the law. You want a wide angle lens, the shorter the better subject to covering 8x10.

Now, what are you trying to accomplish? If you want to make a fixed focus 8x10 box camera using a short lens might make sense. Might.

If, however, you want to maximize depth of field in the final print you have to understand that for the same image in the final print all lenses shot at the same aperture will give you the same DoF. The shorter the lens used, the more enlargement needed ...

ntenny · Sep 19, 2014

jcc said:
That's the term! I am asking about which lenses have the shortest hyperfocal distance. Yes, what I'm looking for will most likely be a wide angle lens.

Ah! Now it makes more sense.

But hyperfocal distance is itself just a function of focal length and aperture, so you're *almost* asking "what's the widest lens I can use at infinity"---for a wide lens and a reasonably small aperture, the hyperfocal distance won't be physically too far removed from infinity focus, so I think it ends up being functionally the same question.

You need to determine for yourself how tight you're willing to go with the aperture.

Others have given good answers with the expensive word "Hypergon" in them, but realistically I think you're looking at the usual suspects for wide-angle 8x10 lenses, like...

I'll look into the 120mm Perigraphe. Hopefully, I won't have to resort to a pinhole lens.

...Dagor designs (which is what the Perigraphe is, more or less). I have a 120mm and it's a fun little lens. Dan and I had a discussion about it when I acquired it, and we came to the conclusion (by which I mean: he told me, and I bullheadedly insisted on checking for myself) that it needs to be conventionally mounted in a shutter (or in barrel with a shutter in front, or something) for use on 8x10. The thing oozes character and is a charming little fetish object; it isn't as stupid-sharp as the best modern lenses, and focusing at f/14 can be sort of an interesting process, but the latter isn't an issue for hyperfocal use.

I've read of people using the 120mm Super Angulon on 8x10 successfully; Schneider's own data say it won't quite cover, but maybe they're being conservative. In general, the 120mm neighborhood seems to be your practical limit without getting into exotica like Hypergons.

-NT

jcc · Sep 19, 2014

Great! We're on the same page, but what is the hyperfocal distance of your 120mm @ its smallest or optimal aperture?

jcc · Sep 19, 2014

Dan Fromm said:
Other things equal, the shorter the focal length the shorter the hyperfocal distance. That's the law. You want a wide angle lens, the shorter the better subject to covering 8x10.

Yes, but I don't imagine all XXX mm (or inches) focal length lenses have the same hyperfocal distance.

Dan Fromm said:
Now, what are you trying to accomplish? If you want to make a fixed focus 8x10 box camera using a short lens might make sense. Might.

Let's go with this one.

E. von Hoegh · Sep 19, 2014

jcc said:
Yes, but I don't imagine all XXX mm (or inches) focal length lenses have the same hyperfocal distance.

Let's go with this one.

All 6 inch lenses will have the same hyperfocal distance for the same CoC. It's physics, independent of the optical design.

ederphoto · Sep 19, 2014

I suggest the 61/4" 159mm Wollensak EXWA . Simple , effective and sometimes affordable mounted on a shutter .

Ian C · Sep 19, 2014

In hyperfocal focusing we choose an aperture number N, circle of confusion diameter c, and compute the hyperfocal distance H. Then when we use the aperture N and set the focus to H, everything is acceptably sharp from H/2 to infinity.

Heres a hyperfocal chart for a 120mm f/8 lens that covers the 8 x 10 format (like the 120/8 Nikkor SW) and using a circle of confusion diameter of c = 0.2mm.

The numbers are: aperture, H/2, and H.

f/8, 4.5m, 9.1m

f/11, 3.2m, 6.5m

f/16, 2.3m, 4.6m

f/22, 1.7m, 3.3m

f/32, 1.2m, 2.4m

f/45, 0.9m, 1.7m

f/64, 0.6m, 1.2m

At the smaller apertures, the increasing percentage of diffracted light grazing the edges of the aperture will begin to degrade the overall image. How much softening of the image due to diffraction you can tolerate is something youll have to discover by shooting some test shots.

L Gebhardt · Sep 19, 2014

jcc said:
Yes, but I don't imagine all XXX mm (or inches) focal length lenses have the same hyperfocal distance.

That seems to a commonly held misconception. As others have said all lens of the same focal length have the same depth of field and hyperfocal distance at the same settings. Look at the formula for these and it becomes apparent.

jcc · Sep 19, 2014

Thank you, all!

David A. Goldfarb · Sep 19, 2014

The 120mm Perigraphe is a fun lens. I should use it more often. I had mine mounted in an Ilex 3 shutter, and it just covers 8x10 when stopped down to about f:32 or so. I've mounted a 3" filter holder behind the lensboard, because anything in front of the lens reduces coverage.

You might find composition on the groundglass a bit of a speculative exercise, but a Silvestri tilting loupe helps, and be sure to let your eyes get used to the dark under the darkcloth.

Here's an old sample image I've posted before:

A question for lens aficionados

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