What lens would you consider the sharpest wide open?

[lbenac]

Any slower lens will be sharper wide open. For example, a Protar V. For non-wide angle lenses, a Tessar IIB at F6.3 is sharper than a Tessar IC at F4.5. A Dagor at F6.8 is sharper than most faster lenses, etc.

An easier question to answer (although still largely in the realm of anecdotal evidence) would be which lens is sharpest at f/2.8, or f4.5, or f/5.6...
I can tell you that at f5.6 my 150mm Sironar-S is sharper than my 150mm Xenotar at f2.8 (which is true), but is that a reasonable comparison? Or perhaps it would be better to say that f5.6 my 150mm Sironar-S is sharper than my 150mm Xenotar at f5.6, (also true). Which do you mean? Or better yet, what f/stop do you want to work at?
If you want shallow depth of field you might be better off looking for a long lens, say a 450mm f/9 than a fast and short lens.

Which complicate matters further for un coated lenses, as to me a lens stopped down to 6.3 or 7.7 is not the same than a lens wide-open at the same apertures.
I often like the look of un coated lenses shot with specular highlights on close-up or short distance scenes (ok I might be the only one to like this...).
If the lens is wide-open or in a barrel with 18 aperture blades than the highlights are nice and roundish and blend nicely in the background.
On a "modern" five or even seven blades shutter they are harsh and pentagonal.
Lately I am shooting dialytes (Kodak Anastigmat 203/7.7 and 152/7.7) and tessar (CZJ 135/4.5) wide open and provided the subject can leave with a reduced DOF I am very happy with the sharpness and more importantly how it blends smoothly with the out of focus areas.
So I have contradictory evidence as I would favor slower lens wide open (dialyte 7.7 and tessar 6.3) but the exception is the 135/4.5 which is great even wide open for close-up - key word be for that specific purpose.

Cheers,

Luc

[jbenedict]

205/7.7 Ektar and 127/4.5 Ektars are pretty darn sharp,wide open. "Sharpness to $$$" Ektars are about the best you can get. Remember, you can use tilt to modify your DOF as you wish.

[8x10 user]

The Apo Lanthar and Cooke XYa are said to be good wide open.

[Bob Salomon]

Any slower lens will be sharper wide open. For example, a Protar V. For non-wide angle lenses, a Tessar IIB at F6.3 is sharper than a Tessar IC at F4.5. A Dagor at F6.8 is sharper than most faster lenses, etc.

And quite frequently the 50mm 1.4 was always sharper then the same manufacture's 50 mm 1.8 And the 4.5 Grandagons and 5.6 Super Angulons are better then the same focal lengths in 6.8 or 8.0.

[goamules]

Bob, when you get down to the small format, it was all over the map, I concur. But a Canon 50/1.8 is sharper than their 50/1.4, seemingly. Their 50/1.2 is quite soft. And a Jupiter 50/2 seems sharper than a Jupiter 3 50/1.5. I'm sure we agree it's hardest to reduce aberrations in a fast lens. That's why the Elmar 50/3.5 is always stood up as an example of how sharp a lens can be.

[Drew Wiley]

It's a loaded question for several reason, the first being, maximum aperture on some lenses is a lot smaller and better corrected than others. Then you've got cases where a film which covers 8x10 only needs the better corrected center portion to expose 4x5. But in the real world people normally don't have a truly flat
film plane with sheet film anyway, so get misleading results.

[lbenac]

It's a loaded question for several reason, the first being, maximum aperture on some lenses is a lot smaller and better corrected than others. Then you've got cases where a film which covers 8x10 only needs the better corrected center portion to expose 4x5. But in the real world people normally don't have a truly flat
film plane with sheet film anyway, so get misleading results.

Should will call it - luck of the draw - as we can also add sample to sample variation.
Would you say that there is a good chance that an Ektar 203/7.7 will be decently sharp wide open and as there were a lot produced and they are generally cheap, once you get a good shutter, you can swap around lens cells until you find what you want and then keep it. More difficult to do on an expansive or limited production lens.

Cheers,

Luc

[Darko Pozar]

205/7.7 Ektar and 127/4.5 Ektars are pretty darn sharp,wide open. "Sharpness to $$$" Ektars are about the best you can get.

Yes, I found this somewhat sharper than my 152mm/4.5 Kodak Ektar. Could this be because the 127 is slightly wider?

[jbenedict]

Good question. I don't know. Might be a compromise between coverage and sharpness with the 127. It actually was the standard lens for quarter plate and just barely covers 4x5

[IanG]

The 203mm f7.7 Ektar is a Dialyte and so quite different to the 127mm f4.5 Ektar which is a Tessar.

My experience is the Dialytes are sharper at full & faster apertures I have 2 203mm Ektars one in a Prontor SVS #0 (UK version) the other in a Compur #1 (US version), same goes for my pre-WWI 170mm f7.7 Kodak Anastigmat also a Dialyte.

Ian