Leica lenses -- sharp and soft

[Troll]

I've often seen Leica lenses described this way, especially Elmars. It is

interesting that when the negative or trannie is blown up to huge dimensions

(as in 6' projected onto a flat surface screen with a Leica slide projector

lens), or printed 16x24, it continues to look "soft" without actually

looking "fuzzy." Can anyone explain this apparent paradox?

[jtdnyc]

Interesting observation, Bill. I've noticed the same thing.

 

I don't really have an explanation, but I'll take a stab at one. Perhaps our perception of sharpness in a picture is determined by the outlines of familiar objects. As long as these are rendered recognizably, our impression will be that the image is sharp. However, an absence of very fine detail might render the image soft in a certain sense.

 

By this reasoning, as long as the lens is capable of recording large details with good contrast, a great reduction in contrast of the smaller details would give a print that looks "sharp but soft."

 

Don't expect me to defend this theory. It's a guess.

[jerry_lehrer]

Bill,

 

Are you angling for someone to bring up that phrase "Leica Glow"?

 

Jerry

[canfred]

This so called Leica Glow is in fact relatet to spherical aberration.

Even well corrected lenses still have this but to a lesser degree.

Out of focus sections will take on this " glow " more pleasant to view than the patchy look of undercorrected optics.This is not just a Leica observation other lensmakers have well designed lenses too.

If I am wrong here please feel free to flame.

Some useful and detailed articles on most lens shortcomings can be found here.

http://www.vanwalree.com/optics

[Troll]

No. "Leica glow" is a different phenomenon entirely (if it really exists at all).

[dfeingold]

Many older lenses suffer (or benefit :) depending on the photographer and the usage) from curvature of field that may explain this softness where there are also sharp areas that seem to be in the same plane of focus. Maybe the most legendary example is the pre-aspherical 35mm Summilux. That lens exhibits it at wider apertures and stopping down after 5.6 it improves; of course DOF must contribute to the improvement in sharpness.

[sergio_ortega7]

I've had both a current 50mm Summicron and a 5cm 3.5 collapsible Elmar. For years I've tried to understand and describe the differences between these two lenses; my eyes see the differences, but I cannot find the vocabulary to adequately explain what I'm seeing. In the end I believe it has to do with the contrast levels.

 

The Summicron is very sharp and produces almost too much contrast with most B&W films. The much older Elmar produces images that, while they contain as much detail and information as the Summicron, have far less contrast. Perhaps this produces that "soft without actually looking fuzzy" characteristic. I've also noticed this phenomenon when comparing modern and vintage large format lenses.

[ronald_moravec1]

Hard to describe is correct. That`s what gives to older lenses the charm. Sharp but soft.

 

I think it has to do with the ability of the lens to hold sharpness in high contrast, object edges, but lose a little micro contrast of objects where is contrast is not so high, skin textures.

 

New lenses recover the micro contrast and appear sharper, when in fact they are not except at large apertures, compared to older lenses.

 

Glow is uncontroled flare either by less than perfect lens design or internal haze.

[john_camp]

Photographer Frances Schultz (wife of Roger Hicks) wrote an article I believe for Shutterbug

magazine a few months ago in which she investigated the "Leica glow" phenomenon. She

says it definately exists, because Roger gets it and she doesn't. IIRC, she says it tends to

happen in high contrast situations when Roger is shooting quickly, and where he tends to

over-expose (while she tends to be fussier with correct exposure.) So it apparently involves

over-exposure and high contrast. I'm not sure that I got this exactly right, and I no longer

have the magazine, but it certainly can be an attractive attribute of some photographs.

 

JC

[rick_keir]

Manfred's link brings up a "Forbidden" warning when you click on it, but you can get to it at

http://www.vanwalree.com/optics.html

 

Thanks for the link - it looks interesting.

[peter]

I believe the comment attributing this to residual spherical abberation is quite correct.

 

I have also seen such pictures in books occasionally - One good one I often refer interested people to is Ivor Matanle's book "Collecting and Using Classic Cameras." This is a great book for any old camera buff to buy incidentally - but don't confuse it with his later book specifically on classic SLRs although that too is excellent in its field of subject matter.

 

In particular there is a lovely picture of a little girl on a swing which exhibits this characteristic (and some fine Bokeh - which I think also comes from the same abberation.) In this case the camera was, from memory, a Rollei not a Leica but the same principle applies.

 

To explain how this might look to someone who has not seen this effect, I like to say that I think of this simultaneous sharp / blurred look as something that you should be able to get using Photoshop - at least as a reasonable approximation.

 

You take a very sharp photo and open it in Photoshop, then create a layer which you make partially transparent. Then apply Gaussian blur to this layer. Or maybe the sharp layer has to be partially transparent I cant recall - anyway, making sure the partially transparent layer is uppermost, overlay the two layers (sharp and blurred) and you may have some idea of the result you get from these lovely old lenses (OK lets qualify that - Approximately and only if done by an expert! Don't try this at home! - Please do not flame me for this statement I repeat - approximately. I have been flamed before by Leicaphiles baying for blood at the thought that digital processing can approach the look and feel achieved by a particular piece of glass, even in principle.)

 

You would probably also have to add some specific blurring / flaring to highlights to get a closer approximation as these old lenses - especially the uncoated ones can give a flared look to the highlights, that also can be very attractive. (See the Matanle book.)

[peter]

Here is a plugin that does not really do the job I was thinking of but adds some blur and glow. It still falls short by quite a lot in my opinion but gives an idea of how software can do "something" more or less similar.

 

http://www.xero-graphics.co.uk/set2/softmood.htm

 

Bear in mind this is freeware - there is a lot of payware out there that may do muchbetter in terms of approximating the effect produced by old glass.

[g-man1]

Glow requires radioactivity:<div></div>

[mark_erickson]

Mike Johnston wrote a nice article describing how to get <a href="http://luminous-landscape.com/columns/sm-02-04-28.shtml">The Glow</a>. It's not really Leica-centric, but it makes good reading....