Plasmat vs Tessar vs Dialyte

[Richard K.]

OK,I've been *curious about this for a while...

What is the advantage of using say a Sironar 480 mm f/8.4 vs a 19" f/11 Red Dot Artar vs a 450 mm Nikkor f/9 other than the slightly faster maximum aperture (ignoring the slight difference in focal lengths)?

Could you please tell me, specifically, by comparing, the performance attributes each design has in terms of coverage, sharpness across the field and evenness of illumination...maybe relate in terms of covering 11x14...

*to put it in a more pragmatic way, why spend more money and take on more weight with the Sironar compared to the Nikkor when the Nikkor is just about as bright and only 1/3 the weight? What, if any, disadvantage is there to the Nikkor?

Thanks all!!

[Arne Croell]

Coverage is larger for the Plasmat - so for your example (480mm), if 8x10 is the largest film format you use and you're not doing skyscrapers, the other two will have enough coverage. Typically, a dialyte is about 42-48°, a Tessar around 55°, and a Plasmat around 70°.

[Richard K.]

Thanks Arne. So it's to do strictly with coverage? But the Nikkor has a rep for extended coverage. I guess it's really just a large circle of illumination rather than definition (and probably more than OK for contact printing)? What about central and edge sharpness (on 8x10) for the 3 mentioned lenses?

[E. von Hoegh]

The Artar may be set up for close ratio work. Supposedly, the ones factory mounted in shutter were optimised for general use, and the barrel versions for copy cameras ( close ratio).

But a barrel Artar does a damn good job at infinity.

Check that the Nikkor coverage is not specified at 1:1.

[Arne Croell]

Thanks Arne. So it's to do strictly with coverage? But the Nikkor has a rep for extended coverage. I guess it's really just a large circle of illumination rather than definition (and probably more than OK for contact printing)? What about central and edge sharpness (on 8x10) for the 3 mentioned lenses?

Richard, both Tessars and Dialytes have much larger circles of illumination than of sharp coverage. Of course you can use that if there is no defined feature in the corners (sky), or by stopping down a lot you can extend the official coverage, especially if contact prints are the final result. Of the three lenses I only know the 450mm Nikkor, but since 8x10 is my largest format, I have not used it beyond its official image circle.

Arne

[cdholden]

I can't quote specs, but the Sironar was designed to be a photographic lens, where the other two are process lenses. As Arne pointed out, that version of the Nikkor will have more coverage than the Artar.
Any of the 3 will work fine for 8x10. As the format gets larger, those comparisons will change as they approach their design limitations.

Chris

[Richard K.]

Thanks Chris and Arne. Hey Chris, was that you that commented on my book on ebay?

[Mark Sawyer]

The Nikon 450-M is a lf camera lens, not a process lens. (There is a 480mm Apo-Nikkor that is a process lens.)

Tessars are one of the most versatile designs to modify for whatever purposes. Besides the standard Tessar, there are macro-Tessars, micro-Tessars, aerial Tessars, wide-angle-Tessars, tele-Tessars, enlarging Tessars, BioTessars, process apo-Tessars, soft focus Tessars...

[cdholden]

Mark,
Is this M lens not the same design as the older Q? I was under the impression it is. The Q's were marketed as process lenses. I don't have any cut away drawings for reference (wish I did!). I'm going from memory.

Richard,
Yes, that was me. Now I know who you are!

Chris

[Gem Singer]

The Nikon/Nikkor f8 450M is a four element lens.

Nikon made 200M, 300M, and 450M Tessar lenses .

I have owned all three of them. Still own the 300M.

Even though they have smallish maximum apertures, they have large enough image circles to enable bright focusing on the ground glass.