I hear alot about lenses performance in term of Color rendition, Flare, Vignette, Sharpness... but what about Compression. One of my friend who was buying an old IIIF with a 50mm f/3.5 did a test roll before buying it. He took the IIIF and is Olympus, put them one at the time on a tripod and shot a landscape picture using the same roll of film (Same film, exact location, aperture...except camera and lens). He then show me the two print. The framing was almost the same (difference was due to Real focale lenght and negative size). There were severals obvious differences between the two (colors, contrast, sharpeness...you name it) but...the most obvious (for me) was the difference of compression between them. The Olympus was the one with the most compression, flatter image. The leica was more alive, 3d effect.

I know alot of people place emphasis on "botek" (sorry about the spelling...) but what about this "Compression effect" among the same focale lenght due to different optical formula. What are your thoughts on that? Would you consider it before color rendition or whatever other criteria use norwadays to describe a lens performance?

-- Eric Laurence (Edgar1976@hotmail.com), May 28, 2001

Answers

I wonder if it isn't really a difference in contrast you're seeing, Eric. A finer contrast image produced by the Leica lens might impart more feeling of depth - less blocking up therefore more gradual change in tones and a "tunnel" or 3-D effect. Less contrast means more blocking up, harsher borders between values, and a flatter overall appearance.

-- Ken Shipman (kennyshipman@aol.com), May 28, 2001.

Thanks for your reply Ken,

I know what you mean about contrast (The Leica lens had indeed more contrast than the Olympus lens.) but the "Compression effect" is an entirely different issue. I'm sure the subtlety reside in the optic formula, not the coating.

-- Eric Laurence (Edgar1976@hotmail.com), May 28, 2001.

I think I know what you´re talking about Eric, compression is afected by the same aberration correction that nice "bucke" blour is, (what ever it´s spelling), but one into the hiperfocal the other out of it, old leica lenses are so precios for that quality of the image into the hiperfocal distance, new fast lenses are so precious for what is out of the hiperfocal, that blur images that thank´s to the grade of correction have that sense of plasticity.Hard topic to be explained.

-- R Watson (al1231234@hotmail.com), May 28, 2001.

This again just shows how impossible it is to compare test results of lenses to determine which one you'd like the best. The intangeables that give images from certain lenses a special quality are very hard to quantify. I have a 105mm f2.8 Kiron Macro for my Nikon that has a certain quality that makes it one of my favorite lenses. It's a combination of many factors I'm sure that make the images from that lens stand out, but just exactly which ones, I'm not able to put my finger on. Nor do I lose sleep over it either! Hope your friend enjoys his old Elmar-I just picked one up and shot my first roll with it and will be picking up the photos later today.

-- Andrew schank (aschank@flash.net), May 29, 2001.