lens that can take advantage of hi resolution films like CMS20

[Drew Wiley]

I've seen true-color film shots that make any lens you've ever seen look like a pathetic toy by comparison. Two things I wasn't allowed to see is the lens itself,
or what the film was. Let's just say whatever the film was made the resolution on something like Ektar or Velvia look like shotgun splatter by comparison. In fact,
I wasn't even allowed to know what kind of vessel or plane or whatever had the camera, but I suspect it was a surfaced sub.

[Jac@stafford.net]

I've seen true-color film shots that make any lens you've ever seen look like a pathetic toy by comparison. Two things I wasn't allowed to see is the lens itself,
or what the film was. Let's just say whatever the film was made the resolution on something like Ektar or Velvia look like shotgun splatter by comparison. In fact,
I wasn't even allowed to know what kind of vessel or plane or whatever had the camera, but I suspect it was a surfaced sub.

Seems like a legend to me. No image, no source, no facts, no nothing.
.

[Carsten Wolff]

True. I forgot how expensive the Zeiss 75/4 is. Here is a PO in an Alphax #5 shutter. With 20/20 hindsight it appears it could have been machined to take a smaller shutter. Both my #5 shutters have broken.

Thats not an Alphax shutter either.

[Jac@stafford.net]

Thats not an Alphax shutter either.

What is it, then? Did I misspell?

[Dan Fromm]

Originally Posted by Carsten Wolff
Thats not an Alphax shutter either.

What is it, then? Did I misspell?

Ilex, not Alphax. Quite a bad spelling error

[Jac@stafford.net]

Ilex, not Alphax. Quite a bad spelling error

Ach! getting old sucks.

[Emmanuel BIGLER]

Hi!

Thanks all for the nice exchange regarding this ultimate quest for the highest possible number of cy/mm in a photo-chemical detector combined to an ultimate lens.

I fully agree with Drew Wiley that for our photographic uses, we prefer good tonality and a nice gray scale to no-grain. And those microfilms require such a very special low-contrast chemistry in order to deliver some acceptable gray scale. A burden, to say it bluntly: an we can no longer use our own beloved soups!

In other terms, at least for Kodak, there is a market for Tri-X film, but no longer for hi-res plates type 1a

Well, not kidding, thanks to Nathan for reminding us the good ol' days of Kodak hi-res plates type 1A in a square 2"-1/2 size. At the time, I was told that type 1A was similar to 649-F, but non-chromatised, blue-sensitive only. I suspect that Kodak had the technology to make those plates before the laser era, and that people experimenting with the first holograms in the sixties naturally used them as commercially available hi-res plates.

It also should be mentioned that hi-res silver halide plates are old stuff, suffice to remember Lippmann plates, fabricated before 1900.

And also, in a totally different resolution range, that photographic paper being a very slow medium exhibits fine silver grains, I would say a few microns in size. But nobody cares for a visual examination of a print!

To continue with the good old days, I can say that actually I have used Hi-Res Kodak type 1A plates during my Ph.D. years, we exposed them to X rays with synchrotron radiation.
Colleagues told us: you are crazy! The plate will be fogged at its maximum density in a microsecond! But since this was not a X-ray film, with an emulsion thickness of a few microns, X-ray sensitivity was exceedingly low. Definitely unusable with a conventional X-ray source.
And exposed to X rays, the type 1A plated retained its no-grain capabilities, and, surprisingly, featured a certain amount of nice gray levels. The X-ray imaging process was contact imaging.
We processed the plates in red safelight with a GEPE COMBI-PLAN tray, with Kodak D-19, a standard high-contrast microfilm developer.
A no-grain silver-halide image seen through an optical microscope is fascinating, this is the reason why, in those years, for my personal photographic activities, inoculated with the no-grain-Hi-res virus, I only swore by AGFA APX 25 and never experienced Tri-X ;-)

I have recently browsed through the Harman-Ilford web site (actually looking for fresh info about their direct-reversal paper, which is back again, this is another story)
http://www.harmanexpress.eu/holo.html
and found the price list for their holographic plates ; the 2"-1/2 square glass plate standard is still in use, 2 mm thickness, and a box of 6 plates costs only £20.25 (excluding postage), about the same price as 4x5" colour slide cut film ;-)
Resolution specs are: 7000 cy/mm!!! But holography is also another game.
To the best of my knowledge, Slavich in Russia also sells holographic plates, hence the know-how behind those strange beasts is not lost.

And just for being very precise in the explanations, when Dan says (hello, Dan!)
Everything scales with size, including aberrations. When a prescription is scaled up, resolution attainable given aperture falls.
we could add that in an hypothetic diffraction-free word, only governed by geometrical optics, aberration spots would scale exactly like lens element radii and spacings. In this imaginary world, for a given lens prescription, scaling up the design would scale the focal length and the image size in direct proportion of the scaling factor, and would scale the achievable resolution exactly in the inverse proportion.

Diffraction works quite differently. In another imaginary world, free of all geometrical aberrations, scaling a design would not change the diffraction spot size at all, if we keep the same f-number!
Hence in this other dreamed world, bigger lenses would achieve the miracle of keeping the 450 cy/mm of the green-light-only 100 mm CERCO lens, up to focal lengths of 1000 mm for ULF use, covering an image field of 25"x25"!!

Our real world combines both physical phenomena ... plus some other discouraging, down-to-Earth practical things ... fortunately we do have discussion forums to let us dream of those imaginary optical worlds

[Bill Burk]

I'd be happy to have a sheet of this film, on which a resolution test chart was step-and-repeated each 3/16ths of an inch, either as a full sheet full of these marks or a few columns, to use in contact printing test strips on my everyday film tests... So that I can include resolution information in my test results for the film I use every day.

[Dan Fromm]

I see that adox CMS20 can resolve 800 line pairs
are there any lenses in any format that can get any where near this ?

Hmm. Lessee now. The aperture at which the diffraction limit is around 800 lp/mm on axis is f/2. So, before we start to worry about practical matters like portability and shutters and off-axis performance, are there any f/2 and faster lenses that cover 4x5 or larger?

I looked in my USAF data sheets, which are incomplete. They list several lenses f/2 or so lenses as covering 4x5 but their focal lengths and claimed angular coverage come out smaller than 4x5. Then there's the 12"/1.5 Perkin-Elmar Recon 660 that covers 162 mm. Its AWAR (area weighted average resolution, gives more weight to far off-axis than near the axis) on Aerographic 5424 is 34 lp/mm. Not quite 800.

The French Air Force flew Omera aerial cameras, some with a 200/2 S.F.O.M. lens. I've had one, it wasn't easily usable. I saw one on offer that was engraved "Kinoptik" so its probably a decent lens but ...

Dallmeyer made a line of f/1.9 Super Six lenses, 6/4 double Gauss types. The longest two were 6" (late ones engraved 152 mm)/1.9 and 8"/2.0. Perhaps decent lenses but its hard to believe they cut 800 lines on axis wide open.

If there's a wonder lens for 4x5 or larger I'm not aware of it. Can anyone direct us to one?

At the tiny tiny end, I recently used a Leica stereo microscope. Sorry, not sure which model, but a very recent one. I liked it so much that I fantasized buying one, even looked in Leica catalogs. Their best will resolve slightly more than 1,000 lp/mm. "This resolution means you can see details that are smaller than a hundredth of the diameter of a human hair." Naturally I can't afford one.

Hi, Emmanuel.