How often do you tilt for Theo?

[Drew Wiley]

Apparently a lot of folks here live in a small world that ignores an awful lot of sheer optical research and even what has been considered standard practice by
careful practitioners for decades. Typical of the instant quasi-info web era, I guess. Like I said, you don't even have the basis for judging diffraction if your film plane is off in the first place, which it will be for most of you, because that's yet another thing you haven't realistically reviewed. And frankly, I doubt some of you even know how to do objective testing. And "normal viewing distance" is basically an excuse for sloppy results. And Leigh ... find me anyone, anywhere in the image reproduction industry who ever ever used process lenses below f/22. If you want to do it on a ULF camera that understandable, esp for contact printing needs - but it won't rewrite the laws of physics. Nowadays expensive machine optics are routinely made at FIXED aperture just because they need to simultaneousl be optimized for both diffraction, resolution, apochromaticity. Gosh, do you guys even read anything that isn't some shoot-from-the-hip web blurb? Get an optics textbook. If it's academic to you, that's fine. It is not academic to me. It a real factor that plays into image reproduction, and always has. And
maybe someone else has similar needs. .. No, I'm not always obsessed with detail. There are times I like to print nonglossy and even prefer lenses that aren't so
hard-sharp, though I'm not in the soft-focus camp. But many other times I am after detail, and all these seemingly little steps add up to an effective chain. This
is old old hat to me, and I'm just a bit perplexed at how some of you seem ignorant of the basics.

[Drew Wiley]

Cor... your standards seem atrocious to me, starting with that center column. No wonder it's academic to you. Off on the wrong foot to begin with.

[Leigh]

find me anyone, anywhere in the image reproduction industry who ever ever used process lenses below f/22.

You are apparently claiming that you have surveyed every photographer in the image reproduction industry.

That is such obvious nonsense that it doesn't warrant comment.

I challenge you to prove that nobody ever shot below f/22.

- Leigh

[Drew Wiley]

Maybe somebody hokey like a T-shirt shop used cheap stat camera lenses in some so-so fashion, but the kinds of process lenses we covet tended to be associated with serious process work, always flat copy, and it was important to keep dot shape very precise clear out to the corners. There are some interesting past threads about why the mfg of these lenses put f/stop markings on them which were never used ... but that's like having 200mph markings on the speedometer of an ordinary car, or shutter speed settings on camera shutters where the extreme speeds are never accurate or realistically usable anyway. The most logical explanation was that this was just the way the shutters were made to begin with, and had nothing to do with the routine process usage of per se. But these lenses have also obviously found their way into general photography as well as darkroom use. But in process use the copy lighting was matched to the f-stop, and there was no need to stop further down for depth of field issues. Pin-registered vacuum frames were routine.

[Drew Wiley]

High-end process lenses were pretty damn expensive back in the day, not like the used bargain they sometimes are now. Nearly all went to the printing industry for
which they were designed, but a small number were sold to photolabs for mural enlarging. But in the latter case they were likely to be used at relatively wide stops,
esp since they tend to be around f/9 max aperture to begin with. But unless you're talking about a Rodagon G, something like a process Nikkor was actually a better performer between f/11 and f/22 than an ordinary enlarging lens at that scale of magnification. The nitty-gritty of specific focal lengths became a bit debatable. I have a whole set of the things, and they are incredible good for enlarging if you don't mind a max focus aperture a bit small. The working aperture would often come out the same, cause these things were so sharp only a stop down. Process apochromaticity has somewhat more stringent standards, so nearly all these kinds of things were recommended for f/22 use. Beyond that, diffraction might become a quality issue. In general photography we can relax these rules a
bit, depending on just what we place the priority upon, but the optical result does not and cannot change. It's inherent.

[djdister]

Nobody is saying diffraction doesn't exist. What I'm saying is that in some cases it doesn't matter, or it is not noticeable. And yes, I do put my nose right up to a print to really get a good look at it, but that type of examination does not constitute the proper assessment of a work of art.

Technical perfection is nice if you can get it, and a technically perfect print can just as easily be a boring waste of silver/platinum/carbon...

[Drew Wiley]

I'd certainly agree with that, Dan. Diffraction is a real technical issue that needs to be recognized. After that, we decide at what point to trade it off with depth of field, and whether or not we need to be nitpicky about it. Scientific photography would have a different bias. A view camera has great advantages in this respect, because we also have tilt and swing controls. But don't narrow your definition of "art" (whatever that means) to your own personal taste. A perfectly "un-technical" print can be pretty damn boring too, and most are. These are simply tools. It's what one does with them that counts. Your argument could simply be taken a step further to, why bother with a clean lens when one with fungus in it creates interesting images. If that's what one like, fine. I happen to enjoy fine-tuning my craft, and other people seem to appreciate the effort when they view the prints. It sets them apart. But I'm not claiming that's the only way to do it.

[Cor]

Cor... your standards seem atrocious to me, starting with that center column. No wonder it's academic to you. Off on the wrong foot to begin with.

Talking you do a lot, but listening is kinda hard for you, isn't it Drew ?

Let me quote myself once more:

Used a steady tripod, but had to raise the centre column to not get the building too strangely inclined (raising the centre column is a no-no I learned from one of my teachers, he is right stability wise, but composition wise I had to resort to it).

I am happy to report that I just returned from the darkroom, and I am perfectly happy with the print made from the shot I took of this building last Saturday, nothing wrong with the sharpness

Cor

Oh btw I am not at all pleased with the use of the term atrocious..although thinking of your colour prints as judged on your web site..you made it to my ignore list so please do not bother

[Jody_S]

I challenge any member of the diffraction degradation camp to explain why process lenses, being the highest-quality photographic optics ever manufactured, commonly go down to f/128 or even f/256.



- Leigh

I'm pretty sure it was on this forum that someone explained how process lenses were often used at extremely small apertures to use diffraction to create a 'screen' for printing purposes. I haven't sat through an optics lecture in more than a decade, I don't remember much about it even as I had pretty much given up on photography at the time. But it would explain why it is (AFAIK, I'm sure someone will prove me wrong) only process lenses that ever stop down to f128.

[djdister]

Drew, you brought up an area that frankly was not in my thoughts at all -- scientific or technical photography. Certainly the issues of diffraction, resolving power and etc. have to be considered at a micro level. I recall seeing something about the standards of photolithography that was pretty exacting. So one answer is -- it depends what you are doing, or trying to do.