Can lens or camera have a 'clinical' rendering?

Started 1 month ago | Discussions thread
57even Forum Pro • Posts: 14,722
Re: Can lens or camera have a 'clinical' rendering?

Erik Kaffehr wrote:

57even wrote:

fPrime wrote:

57even wrote:

fPrime wrote:

57even wrote:

fPrime wrote:

I’ve certainly described some lenses as clinical. To me a “clinical” lens is simply one that is highly corrected for optical aberrations, distortion, vignetting, and soft corners when shot wide open. I use the term dispassionately. For some applications (like astrophotography, for example) a clinical rendering quality is actually preferable.

The downside of clinical lenses is that they tend to draw less microcontrast and 3D Pop once stopped down. That can be counterproductive to some photographic use cases.

fPrime

This doesn't make a lot of sense. Why can't a well corrected lens have good microcontrast?

It’s likely that my definition of microcontrast differs from yours.

fPrime

That doesn't answer my question.

I didn't want to sidetrack Erik's thread on clinical rendering into yet another microcontrast debate. But basically, if microcontrast is defined as simply an extension of global contrast with respect to higher spatial frequencies which yields more “bite” in the fine details of an image, then extremely well-corrected lenses will certainly deliver more of that quality.

If, however, we view microcontrast as tonal gradation, then these same, sharper, clinical lenses deliver less image microcontrast. How so? High Refractive Index glass elements differentially absorb fragile blue wavelengths over green and red wavelengths. The more elements that designers use to correct for aberrations and un-sharp corners, the more that low-gain blue wavelengths in the scene are gated out. This muddies the scene's microcontrast globally but especially so in the shadows and dark portions where low-gain blue wavelengths often dominate.

fPrime

Did you just make that up or read it on an internet site?

Well, just that someone said something doesn't turn it into a fact.

Personally, I would think that there are a lot of myths about photographic rendition.

Not so long ago, I made a small test, comparing four lenses of widely varying design and looking at color reproduction. This simple demo kept all factors constant, same camera was used with just different lenses, using adapters when needed.

https://www.dpreview.com/forums/post/63505345

This comparesint turn Sigma 24-105/4 Art, Contax Sonnar 35-135/33-4.5 and Zeiss Planar 100/3.5 to the Canon 24-105/4L. Note that each square is split in two triangles, top-left shows Canon and bottom-right the compared lens. Theses samples where white balance matched for second brightest white patch and exposure matched grey patch 4, mid gray.

This is like above, but without WB matching.

The Sigma is a modern design, with 19 elements in 14 group while the Planar 100/3.5 made 1984 having just five elements.

To me, all the lenses are remarkably similar.

Best regards

Erik

Yeah, that's a pretty definitive test...

The optical quality of modern lenses is in a different league from former years. Unfortunately the same cannot be said of factory quality control...

But you really don't have to pay the same (relative) prices these days to get very sharp and well corrected lenses, which is to say the biggest differences you are likely to notice are down to the sensor and editing software profile, not the lens.

Other than flare spots and bokeh of course.

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