Lens Sweetspot

[venchka]

DOF issues aside, I recall from the old Pop Photo lens tests that any given lens had a particular f-stop where everything came together. The optimum aperture I suppose is a good way of expressing it.

I went looking for the Optics Forum and it seems to have gone away. So, why don't we start a list of Leitz lenses and their "sweetspot"?

I'm too new an owner to have a clue about the lenses I own so would someone point me in the right direction for these two lenses:

50 f=2.0 DR Summicron, second version with both feet & meters scale, circa 1961

90 f=2.8 Elmarit, circa 1965

I will ask the same question in the Canon and Nikon Forum.

 

[peterc]

I'd suggest testing the lenses you have yourself. Run through the apertures with a few shots of the same subject and see where it looks best to you.

Peter

 

[Finder]

Easy. f/11. And it does not matter which lens.

 

[waileong]

5.6

5.6

Nope. Most Leica lenses peak at 5.6. The 1.4 lenses tend to peak at f4.

Read Erwin Puts if you want more discussion, and learn to read MTF charts from Leica as well to satisfy your curiousity.

However, I am less interested in optimum distance than optimum aperture. You can't usually dictate the distance you want to shoot at, it's ruled by composition. You can however choose the aperture more easily by using the right film and deciding where you want to shoot, how much light there is.

Easy. f/11. And it does not matter which lens.

 

[kvanderlaag]

I've found most of my lenses to be at their best between 5.6 and 8

 

[peter_n]

There was a comprehensive table posted on the old Leitz forum by Australian member Justin Scott a couple of years or so ago. It had all the optimal apertures for almost every Leica lens. Long gone unfortunately. However I remember they ranged around the f4 to f8 mark.

 

[StuartR]

Yep, f/4 or f/5.6. Actually, for some of the APO R lenses and the tele-photos, it is wide open or one stop down. So the 100mm APO macro is best at f/2.8 or f/4, and the 180mm f/2.8 APO elmarit is best wide open or f/4 as well. The reason for this is that Leica lenses are so good, that when you stop down past f/8 or so you are losing performance due to diffraction rather than problems with the lenses. Obviously, most fast lenses are not at their best completely wide open, but generally two to three stops down. My experience has been that the 35mm f/1.4 ASPH, 50mm f/1.4 ASPH and 75/1.4 are best at f/4, the 75mm APO Summicron is best at f/5.6, as is the 135 Tele-Elmar. The ZM 25mm f/2.8 is a bit of an exception, and it is best at f/4 (where it is evidently diffraction limited).

All that said, Leica lenses (meaning the modern versions) are made to be great at every stop. I think it is pretty certain to say that at f/5.6 any Leica lens will be superb.

 

[StuartR]

I suppose I should add that this is only given a situation where depth of field has no bearing on the picture. Otherwise, it is wisest to choose your f stop based on what sort of depth of field you want, as well as shutter speed. Another reason to shoot Leica lenses at f/4 or f/5.6 even in bright light is that it gives you a higher shutter speed, minimizing camera shake. I think Ansel Adams said that he would not shoot 35mm cameras at a shutter speed under 1/250th, with any lenses...so it does not hurt to be conservative in this matter.

 

[Ronald M]

All the Leica 50`s do best at 4 or 5.6 and things start to deteriorate at 11. I have most every one ever made and they are all the same.

One would need very sophisticated test equipment to detitmine the very best spot. Then the analysis would not necessarily extend to other samples.

When you examine them full open, what you find is the circle of good definition is quite small with older lenses like the Summarit and as each generation is produced , the circle gets bigger and it reaches peak performance a little faster as you stop down.

 

[telenous]

Very well said. This is my experience too - f4-f5.6 is the sweet spot for Leica lenses. I definitely try to tame them below f11 whenever I can.

 

[rich815]

Pretty much 2 stops from wide open is the typical sweet spot, for sharpness. But this falls more into the navel-gazing technical testing area than having real world value for creative photography. Automatically using every lens for it's sweet spot makes no sense unless that combination of sharpness, contrast, DOF, and the shutter speed you would get at that aperture is what you works for your desired look and effect.