Differences between 150mm Apo Sironar S and N

[ruilourosa]

These discussions tend to be boring, yes... "my mercedes is bigger than yours... bla bla bla..." but there is always something that we can draw out of it. Resolution although measurable and very scientific is a very vague concept when looked through: visual perception, then we reach to: aparent sharpness, that has a lot to do with who is seeing. But good lenses are good lenses and i always liked more rodenstock than scheneider... but i don´t think it´s sharpness it´s more the general "tone" of the lenses. Large format because borders and movements and selective focus... well that´s no excuse, you can do it easly with digital, either you don´t like computers (like me) or you like the LF process (like me). LF is a way of doing things, not better, not worse, just different and in my case the way.

[VictoriaPerelet]

Oh also one should understand that MTF charts are created on precise optical benches.

Typical LF introduces at least folowing "incorrections":

1.Focusing gear on most LF cameras is far from precise, backlash on Sinar and Arca is about 0.5mm, most of woodies are way worse.

2.Standard planes are rarely parallel on any camera.

3.Fresnel/GG geometry usually introduces optical error.

4.Is diopter correction on your loupe set? Is plastic loupe extension exact? Oh, some do not even use loupes

5. Film flatness in holder.

Add all of that - typical LF shot is way far from MTF produced on optical bench. MTF is common "shopping" comparison catch. Also MTF's and "sharpness" topics are usually madly debated by people who rarely take pics


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[Sal Santamaura]

Hey! What about the 150 apo sironar W? anyone has any info about it?...

I own neither a 150mm Apo Sironar N nor S, so can't comment on how a 150mm Apo Sironar W compares to either of them. However, since a quote of mine was apparently what inspired this thread, and I do have a 150mm Apo Sironar W, I'll offer the following observation.

Recently I tested my sample of the 150mm Apo Sironar W under identical conditions (scene, lighting, aperture, film, development, examination loupe) that lead to my post describing my sample of the 135mm Apo Sironar N as sharper (near infinity) than my sample of the Apo Sironar S. The 150mm Apo Sironar W was less sharp than even the 135mm Apo Sironar S.

That's a lot of "my sample" qualification, but the caveat is very important. I've no idea what the results might be were a large number of each lens design tested under these real world, outdoor, distant-scene conditions. Unfortunately, it's several decades too late and I'm orders of magnitude too unknown for a stocking dealer to provide multiple copies of each for comparison. The best anyone can do today is "buy and try" what is affordable to them.