760mm Apo Nikkor f/11 vs Nikkor-T ED 800mm f/12

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Originally Posted by EdSawyer

APO as referred to by the APO nikkor is not true APO either. You have to go to the Apo El Nikkor if you really want truly corrected apochromat performance. The Nikkor-T will be better corrected for "normal" photography, e.g. not graphic arts at close to 1:1 and with monochromatic light, which is what the Apo Nikkor is designed for. I would take the Nikkor-T over the apo-nikkor.

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I agree, the "APO Nikkor" is more "APO" than the similar "Process Nikkor" and "Nikkor-Q", but I wouldn't say a T is less APO than APO-Nikkor.

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Originally Posted by tgtaylor

I would guess that the apo-nikkor would be optically superior for reason that:

1. It's front element, which is coated, is larger resulting in a greater light capture per unit of time.
2. Tt focuses the light rays directly onto the film and does not bounce those rays around to make up for the shortened bellows.

Of course I could be wrong.

Thomas

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Well, perhaps I wouldn't say that an APO Nikkor is better than a T for distant subjects. A Process/Reproduction lens is optimized for close projections, 1:1 or 1:5 (x1, x5 scale, better said), not for infinite. While a taking lens may work best from 1:10 or 1:20 magnifiction. So a test would be required to compare...

APO Nikkor is said to also work well for distant subjects, but it would be interesting to know the lp/mm depending on aperture for distant focus.


Another factor is the nice coating in the T if we plan to shot into the sun, anyway in that situation the critical thing is a front hud, because if not 80% of the circle of image (if 4x5) will be illuminating the bellows inside, with rays dancing there and ending in flare.

Finally the T is very fieldable if we add (to what said) that we can haul 2 additional rears to have 3 long focals. And three long focals in the backpack are not a joke :)


Both the T and the APO Nikkor are simple designs that trade having small coverage angle for other things. In the APO Nikkor absolute priority is focus field flatness and negligible distortion for repro environment. I guess the T priority is fielding 3 long focals, and this includes saving bellows draw, and smaller filters, while still having excellent Pro performance.

Got one to look through? Apo Nikkors (4-element) are probably better at infinity than any ordinary view lens, esp a Tele.

Because they're damn bulky and relatively heavy, esp since the 760 requires a no.5 shutter. I use my Fuji 600C instead - a really fine lens and remarkably portable for something this focal length, and in no.3 shutter. But the Apo Nikkor is optically superior - overkill, really,if 8x10 film is in question. People get nitpicky about their lenses but don't even bother to think about the fact that an ordinary 8x10 holder doesn't keep the film flat! Lots of people on this forum
know about the superiority of graphics lenses, and some might remember when the cost of these was above that of view lenses, even without a shutter. They were typically used in process cameras equipped with an electronic shutter. I use 240,305, and 360 Apo Nikkors for darkroom applications, where they exceed enlarging lenses per se in every optical category except max aperture, which is sometimes important. There is also the question of image "look. Apo Nikkors are clinically
sharp-sharp, but have busy background out-of-focus characteristics, or "bad bokeh". Therefore I do sometimes use another
type of process barrel lens on the 8X10 via lenscap exposure - an older Zeiss tessar-design 360 which is plenty sharp, but
has lovely bokeh too. Not in the same league as the Nikkors, but plenty good for what I use it for.

You're welcome to your opinion; but you're guessing. I'm not. I own a whole set of these lenses and know what they can do. They're extremely well corrected over a very wide range of magnifications. I use them not only for general enlarging but for very low magnification dupe and interneg work. There is a fellow in this are who specializes in extreme telephotography and uses Apo Nikkors on a Toyo G 8x10 with a Nikon on the film plane, and he owned a telescope store! The fact is, the standards for graphics lenses are higher than for general-purpose taking lenses. They have to be unless it's just a cheap WA process lens meant for the stat camera in a T-shirt silkscreen shop. The big labs around here preferred Apo Nikkors for mural printing. They certainly aren't as big and clunky as large-aperture studio plasmats of comparable focal length, those these generally went only to 450 - after that, no choice but either a graphics lens or a Tele. There are plenty of past threads discussing these kinds of lenses by people who use them.

APO Nikkor in particular should work well for distant subjetcs, here we have a 7.44 x 5.58mm crop (1/1.7 inch sensor type) of the image circle of an APO Nikkor 760mm

using a Pentax Q-S1 (https://en.wikipedia.org/wiki/Pentax_Q-S1)

So the posted image shows how it may look a x50 enlargement, this would be a real size crop (in a 27" monitor) of a 12m print from 8x10 negative, if I calculated well...


https://c2.staticflickr.com/6/5555/1...be24ee72_b.jpg

https://www.flickr.com/photos/ydaisu...fjwyhw-W7ZJWW/


Of course reproduction optimization may penalize a bit performance for long distance, because that some ULF photographers do unscreew a bit the front cell when possible with process lenses, to optimize a bit better for long subjects.

Also probably by stopping the lens the problem disapears, and we are not speaking about fast lenses.

I'm not Dan, but let me say that...

The effect of focus distance lens optimization can be more or less noticeable, for example a Rogadon-G enlarger lens should work perfect for distant subjects as it is recommended for 20x enlargementes, but a Rodagon-R or Rodagon-D would be bad for distant subjects, and perfect for 1:1 macro work.

And between the G and the R/D we have the plain Rodagon with no letter and the N.

I'd say that if "Process lens" is recommended for x10 work then it's easy it can work well for distant subjects, as the angles on the rays at x10 are not much different than those comming from moon, probably stopping a bit will make the difference difficult to notice.

If the repro lens is for 1:1 work, like the Rodagon D, then rays arriving from a subject's point to the glass have very different angles so that lens has an specialized design for that.

I find jergon a bit confusing, Rodenstock changed the Rodagon-R (reproduction) to D (duplication) to clarify, as it works for 1:1.

Process vs Repro vs Duplication has some confusion, and also some "Process" are APO without that lettering.

What I say is that, IMHO, if a Repro lens is intended to work for large scales it should also work for distant subjects, with only an slight performance loss perhaps.

It would be interesting to see an lp/mm measurement of an APO Nikor for distant subjects.

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Originally Posted by Pfsor

It would indeed, as nobody goes into the optimization business for no gain.

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Anyway, IMHO, this test http://www.largeformatphotography.in...=1#post1440564 shows that an APO Nikkor with 8x10 will deliver an insane amount of resolving power, enough to not worry about that. Shutter, coating and bokeh can be a concern.

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Originally Posted by Pfsor

I'm glad for you. The picture in the post is pretty fuzzy. I like my Nikkor 800mm much more. I was even taking pics of the Venus atmosphere with it while it was passing in front of the Sun.

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Read well the post and you will see that this is a 50x enlargement form a 7.44 x 5.58mm region on the image circle of the APO Nikkor 780mm.

https://c2.staticflickr.com/6/5555/1...be24ee72_b.jpg

Reduce the image by 5 and you will see a perfectly sharp x10 enlargement result, for a 2.5m print.

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Originally Posted by Pfsor

he picture at that magnification

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Is not that difficult to understand the quality of a LF negative seen with a high magnification of a 7.44 x 5.58mm crop.

If you don't realize that an APO Nikkor is a competent LF glass, don't use it, no problem.

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Originally Posted by Pfsor

I know, but it starts to be more difficult at the 7.58mm x 6.02mm crop, doesn't it?

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Don't mind the crop size, just judge from enlargement ratio, if the 7.58mm are displayed in the monitor with 340mm then you have x45 (340/7.58) enlargement.

If you are used to evaluate negatives with loupes you know how the image has to look at X20 and x40.

Also you can resize the image to 75mm and you will know how it will look in a x10 print. Anyway when resizing with Ps it's important to set "Bicubic, ideal for reductions", and consider that monitors are not sharp. Mine has 1920 pix in 600mm, this is 1.5 Lp/mm (1920/600/2 = 1.5). For this reason with monitors it's better to use enlarged images to compare, IMHO.

Anyway that 7.58mm crop from the Nikkor 760 is amazingly good... I was not suspecting it could be so good from an APO Nikkor. (I've a Lomo O-2 600mm... not the same...)