300mm f/9 Rodenstock Apo-Ronar soft image

I recently mounted my in barrel Apo-Ronar for use with my 4x5 camera. I got the lens

because it stopped down to f/260 and I was interested in playing around with the

resulting amount of depth of field. I was surprised, however, to find out that the image

produced at that aperature was completely soft and fuzzy. Does anyone know whether

this is just the particular lens I have or whether this is the case with all of these? any

suggestions for other lenses that can be stopped down to a pinhole would also be

welcomed. My goal is to achieve infinite depth of field in macro work.

Thanks

You have exceeded the diffraction limit of the lens. I am not an expert on the subject nor can I quote formulas to determine the diffraction limit that you could expect. I am sure there are other users on this format that could explain it better than I can, but basically at very small aperatures, the "wave" pattern of light doesn't pass through the diaphraghm consistently, and any specific ray of light is diffused around the expected landing point on the film.

Pinhole photos fundamentally must be soft. If the pinhole is too large, then there is geometric blurring. If the pinhole is too small, then diffraction causes blurring. There is no middle size that makes a sharp image. If you stop a lens down so far that it is effectively a pinhole, then diffraction will blur the image. There is no way to avoid diffraction when the aperture is f/260 -- diffraction is inherent in the wave nature of light.

 

My experiments with several modern LF lenses (but not including an Apo-Ronar) showed the image to be somewhat less sharp at f32 than f22, and substantially less sharp at f45. I didn't try f64. As you stop down, at some point diffraction will be so strong that the optical design will hardly matter and you might as well use a simple pinhole.

 

You can't get infinite depth of field with normal optics, especially for marco work. There have been some special scanning cameras that successively illuminated planes of the subject, moving the lens to focus on the illuminated plane to assemble a sharp image.

H. Lou Gibson's large pamphlet Photomacrography, published as Kodak publication N-12B, describes the limits of what can be accomplished very clearly. Buy a copy, read it, and weep. Also buy a copy of Lester Lefkowitz' book The Manual of Closeup Photography, which is a bit easier going. IMO, the two books complement each other.

 

Both books are out of print but copies can usually be found via, in alphabetical order, www.abebooks.com, www.addall.com, www.amazon.com. I bought mine, including ones I've given away to friends, via eBay. Buying 'em via eBay can take a while.

 

I don't mean to be insulting, but you've committed such a wonderful boner that I have to wonder about your education as a photographer. This even though you're shooting 4x5. My favorite basic text on photography, and the one I give to friends, is A. A. Blaker's book Field Photography. Get a copy of it too. It is also long out of print.

 

Good luck, have fun, please don't be offended, and most of all buy the books,

 

Dan

A bit too harsh post from Dan but the info he gives are right on the money.

 

As noted above, you have diffraction problems. Don't worry as you are not the first one to commit this "boner"as Dan puts it (and won't be the last either!).

 

Just shoot at wider apertures than f/32 for 4x5. If the DOF is limiting, if your camera supports it, use shift, tilt, swing, etc to maximize overally sharpness.

>>I don't mean to be insulting, but you've committed such a wonderful boner that I have to wonder about your education as a photographer.

 

Hmmm . . . anyone else here ever make a systematic error and later find out it was wrong?

 

Nah. Didn't think so. Sorry.

 

There's a similar story about Edward Weston. Apparently Weston was using extremely small apertures, to maximize depth of field for his still life photographs. When the negatives came out unsharp, he thought the problem was vibration from trucks on the nearby highway, given that the exposures were very long. Apparently his pal Ansel was the one who explained the concept of diffraction to him.

 

So Geoff's in good company anyway.

These lenses must stop down to f260 for a reason. What would be a practical application for f260?

Sensible question, Tom. I've asked it before and have never got an answer I could understand that seemed reasonable.

It's a very sharp lens at f/22 to f/32. One of my favorites to use for certain intents and purposes.

Just because something is there does not mean that should be used for picture taking. For example, I have an Angenieux lens (ENG lens) that has a provision to close down its diaphram completely. Rodenstock does not advise anyone to use the aperture settings below f/64 for repro work.

Wow, what an interesting pieces of questions!? thanx to Geoffrey

 

(far from dumb questions Dan! i totally disagree with you on putting all the money into books! would rather grab my sinar and go get in between the sand, waters, sun and rainy storms to capture the truth, and when found a soft images at f/giant then ask that here :O)<div></div>

Vivek, some cine lenses and lenses made for ENG have diaphragms that close completely to allow in-camera fades, in and out, and dissolves. My aged Canon 814LS has one. My nearly as old 814E has a variable shutter.

 

A shutter fade, as can be done with a cine camera with a variable angle shutter that can be closed completely is preferable to a fade done with the aperture. This because with an aperture fade, DOF changes. But I think that camcorders used for ENG have a fixed framing rate and no shutters, so for them aperture fades are it.

 

Take up cinematography. It will raise your level of frustration. Low-budget operations can't afford the gear and specialists that Hollywood can, have to make do without. Sound familiar?

 

Regards,

A diffraction limited lens is what a lens designer wants. Those who think diffraction is a bad thing must be confused. a diffraction limited lens is as good as it gets; perfection. Where did this BS start aboiut thinking diffraction is bad? It is the ultimate limit a lens can do; a perfect lens. <BR><BR>At F260 one cannot get better that a diffraction limited lens at F260. The trouble is with using a lens too stopped down; were the resolution is poor. This is not a diffraction problem; but a fundamental educational issue. Any lens at F260 is not going to resolve much; due to limits of resolution that drops with a perfect lens; as the iris is closed way too much.. At F260 you are in the roughly crappy 5 line per mm region; even with a perfect lens.<BR><BR>In process camera work; Apo Ronars we have are used at F22; the scales run from F9 or F14 wide open; and close to F90; the wand on the lens board doesnt allow one to get in the absurd f260 regions; unless a pin is removed. <BR><BR>At F260 with a 300mm PERFECT lens; you still are going to get only 1/4 the resolution of a 100 year old box camera.

Well, OK, Kelly's the lens guy, but I would respectfully suggest that:

 

(a) Diffraction is indeed a Bad Thing.

 

(b) Being diffraction-limited doesn't mean that a lens is perfection. At f/260, the bottom of a Coke bottle is damn near diffraction-limited. (If your lens were to be diffraction-limited at f/5.6, that's a different story.)

There are possibly two reasons for the F260 stop on an APO Ronar, with the glass in place you get fantastic 'glow' around the highlights, without the glass you have an adjustable pinhole camera!! ;-)

 

CP Goerz

Well, so much for the Group f64 Manifesto and it's name being derived from the smallest aperture therefore the greatest "sharpness". I wonder how much confusion has resulted from that statement made by an extraordinary group of artists? Anyhow, it sounds like Geoffrey has learned a valuable lesson and that "stopping down" and "sharpness" are often contradictory. I suggest you take a series of images as you stop the lens down from f9 on and then examine how quickly the resolution goes into the trash as the aperture gets smaller. It inspires most photographers to use their view cameras wisely and stop down only as much as needed for depth of field and not just automatically take 'er all the way down.

That said, your stated goal of infinite depth of field in macro work indicates you are either a machochist or just begging to take more shots from Dan! (Just kidding, Dan. You explained yourself.And hopefullly we all continue to make dumb mistakes every so often or it is evidence that we are not trying to advance our knowledge and experience by avoiding unfamiliar turf) There is an elegant solution to your quest that should satisfy all goals, and that is some software from a small outfit called Helicon. They (or he, as it is this brilliant fellow slaving away at his programs night and day trying to make them better and better) have a couple of programs that really stand out from the endlessly redundant fix it software for managing digital image files. The one that applies to your goal is Helicon Focus. You simply make as many exposures of your subject as needed to record the entire stillife in perfect focus from front to back (by varying the lens to film distance, not the subject to lens, so the image size does not radically vary) Then these different planes are listed in the software and Presto! Infinte Depth of Field! It works very well and if there are irregularities in the finished sandwich, there are corrections that can be made to resolve those problems. His other program is more typical in many ways, but Helicon Filter has some innovations that are very useful. The one I find most interesting and useful as a solution to a heretofore frustrating defect caused by another pesky optical reality: Chromatic Abberations. They can be reduced or eliminated in some cases by carefully tuning the software to detect the offending color that bands areas of high contrast in an image. Check them out. I believe he has free trials without any destructive window shots or whatever that prevents the use of the final product for anything but a kind of anticlimactic effort to take an image that small step further to sublime. So if you like the results, buy it! This guy has earned it and deserves the support to keep him thinking and doing. Good luck with that Apo Ronar at f16 or f22 and some assistence from Helicon. The results should be stunning.

 

www.helicon.com.ua

Well, this is the large format forum, so let me state the obvious: f/64 is a very plausible aperture if you're shooting large formats.

Hi,

 

I heard that those very small apertures were used for diffuse pre-exposures in repro shops, these very low apertures were not to be used to create sharp images. Stopping down to f=22 at 1:1 is an effective f=45 though.

 

Best

 

Joerg

Don't know how well this will read, but here is a quicky "Before & After" at the f stop the layers were shot at.<div></div>

There was a discussion somewhere on photo.net not all that long ago over the use of a shorter lens to gain depth of field. In general this doesn't work, but there is a special situation ... One of the points made in that discussion was that what matters is DOF in the final print, not in the negative.

 

If the desired resolution in the final print is 8 lp/mm and the best attainable resolution is more or less 1600/(f/number), the shooting at an effective aperture (marked aperture corrected for magnification) of f/200 should produce a negative that's fine for contact printing.

 

If shooting at 1:1, this limits us to a marked aperture of f/100. You can see that when the print is to be larger than the negative, the limiting aperture will be larger (smaller f/number) still.

 

Scanning is a way to get around these limits, but for most of us it isn't very practical. People who have access to scanning devices, e.g., scanning electron microscopes, have been making stunning images for a while now.

 

Sometimes, alas, much the wrong images. I have in mind a paper describing Poeciliopsis scarlii, a fish. In its group, what matters for species recognition (by ichthyologists, not fishes) is the bones inside the male's anal fin. The paper's authors illustrated a male's anal fin with some nice SEM shots. Problem is, they showed the surface, not what lay under it. Nice work, badly off-target.

 

Incidentally, most people who describe fish present line drawings, not photographs. The drawings are made using a microscope with a camera obscura attachment and have effectively infinite DOF. An example of scanning, been in use for centuries.

The low tech version of the SEM would be the studio setup where the object to be photographed is on a stage that can move parallel to, and centered on, the axis of the lens. The film is exposed with an open shutter in a dark room with the lighting being provided in a thin plane perpendicular to the lens axis. The example used was a slide projector with two razor blades edge to edge forming the slit. Exposure is controlled by the speed at which the stage is moved through the plane of light. The results were fantastic but it's probably a son of a gun to set up.

Dave; one WANTS A DIFFRACTION LIMITED LENS. This means one has a lens "as good as it gets" at THAT F stop. One strives for a diffraction limited lens at all f stops. This means the lens is sharpest wide open; and hits the diffraction limit for resolution at all f stops. This is like paying NO TAXES; one gets all of ones paycheck.<BR><BR>To All; One dosent want a lens that is not diffraction limited at F260. Using a lens at this F stop is NEVER going to make a super sharp image. The diffraction limit sets a fundamental limit on resolution; for a given wavelength of light. A PERFECT diffraction limited lens would resolve twice as much at F130 than F260. <BR><BR>Using a lens at f260 is really absurd; you are boxing yourself in with a well known low resolution limit; of a few line pairs per mm; no matter how good the lens is made.<BR><BR>The statement of "avoiding diffraction" is absurd. One wants a diffraction limited lens.<BR><BR> A better lens will be diffraction limied at faster f stops than a lessor lens<BR><BR>The Three Apo Ronars we have are made to be used at F22; stopped down to quash field curvature. These are NOT flat field lenses; like the peanut gallery regurgitates over and over in a chant. These lenses require stopping down a few stops; to get the corners in line; in focus.<BR><BR>Apo ronars were made for low distortion; for copying maps. Sharpness and lens speed was a secondary issue. <BR><BR>Using as 300mm lens at F260 means a wider depth of field; but a few line pair per mm resolution; because of the goofy too small of Fstop used. Thus with Large format you will get a great negative for contact printing; and maybe/passable of for a 2x enlargement. <BR><BR>With a closeup situation; the F260 setting is really slower; it would be only F520 at 1:1 ; and maybe just place 2 or 3 line pairs per mm on a negative.<BR><BR><BR><BR>Using a shorter lens; with a quicker f stop at the minimum end; can give you a sharper image; with the same DOF

<i>Dave; one WANTS A DIFFRACTION LIMITED LENS. This means one has a lens "as good as it gets" at THAT F stop. One strives for a diffraction limited lens at all f stops.</i>

<p>Correct so far.

<p>

<i>

To All; One dosent want a lens that is not diffraction limited at F260. </i>

<p>

It is hard to conceive of any lens, other than a pinhole, that is <b>not</b> diffraction limited at f/260. For a lens to be diffraction limited at f/260, it only has to resolve about 6 lp/mm.

<p>

<i>

The statement of "avoiding diffraction" is absurd. One wants a diffraction limited lens.

</i>

<p>

Read that first sentence again and think about it. The second sentence is broadly correct.

I hope I'm not repeating here, but I think some of the wording here is vague thus maybe a bit confusing. I think we all concur that diffraction is indeed the fault here causing your fuzzy picture. The term diffraction limited just means that the lens has corrected all optical aberrations and the only performance flaw present is caused by diffraction. When you stop down enough to this point, this f stop setting is the diffraction-limited aperture, beyond which stopping down further will degrade image resolution by diffraction. I regularly stop down to F64 on the 8x10, but would not go smaller than this. For 4x5, I think the diffaction limited aperture is around F32. Hope this helps,

Henry

I wonder if the very small apertures on this lens might have some application peculiar to the graphic arts.

 

For example, when shooting a half-tone, sometimes it is desirable to give a slight additional exposure without the screen in place -- called a "bump" -- to increase contrast and remove dots from the white areas.

 

I would imagine that using a very small aperture could help accomplish this with maximum control, considering that the lights used in this kind of photography are very bright. Even though the films are very slow, it is also hard to control contrast, because they are inherently very high contrast materials. The smaller the aperture, the longer the exposure to create any effect at all, which translates into real control.

 

That's the only sane thing I can think of to do with f/260, unless you're going for a soft overall effect on the film in regular photography.

 

As for your experiment with your new lens, good work! You learned something by actually doing something and viewing the result!

 

Regarding working at small-ish apertures at long focal lengths -- I think it's a useful option! On an 8x10, I won't hesitate to shoot at f/64 because the resulting depth of field increases apparent overall sharpness in the print; even f/90 in a pinch.

 

I bear in mind that paper is often not capable of resolving as highly as film anyway, so the difference won't be apparent until good-sized enlargements are made. And, to me, the bigger the print, the more important depth of field becomes.

 

Theory is great -- essential -- to know, but you gotta cut yourself some slack sometimes, and go for what will *look good in the print*.