Could anyone explain me what microcontrast is?

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Marsopa

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Just a question, sometines I read that a lens has greater/lower microcontrast than another one... could someone explain to this newbie what are you referring when speking of microcontrast?

Thanks in advance...
 
I would describe microcontrast as a wide range of light value at a very small level, such that a leaf shown small in a print would exhibit detailed complexity of light values on the scale from white to black. A lens with less microcontrast might render the same leaf more or less as gray.
 
The best way I can think to explain it is looking at a brick wall. With good macro contrast (the kind people usually talk about) the mortar of the wall would show up white and the bricks a dark gray. Good Micro contrast would give good definition WITHIN the brick showing the texture. The more micro contrast, the more variations from the 'grey' of the brick will be seen. You can also just think of it like this. If you zoom in to 100% on one brick so it fills the screen, is the screen now basically all the same grey, or does it exhibit a good range of contrast as if you weren't zoomed in and this was actually the whole photo?
 
It's what lets you clearly see every pore and laugh line on a bride's face, even though her face is reasonably uniform in color and flatly illuminated. Three cheers for the wonders of modern optics!
 
I've always thought of it as the gradation of tones from light to dark (as on a child's face, very smoth skin) being very gradual, imparting more roundness to the face. I think it's micro contrast that gives a portrait a 3-D quality. I think my summicron lenses are very good at this.
Vic
 
You can have two lenses that will each resolve 100 lines per mm on a test target. One might resolve them as light grey against dark grey. You can count the lines but there's not that much difference between the two greys. Another lens might resolve them as black against white. A lens that can barely resolve 60 lines per mm, but does it stark black against white will seem to be sharper, have more definition, than a lens that can resolve twice the lines per mm but only in very low contrast.
 
Could I suppose then that microcontrast is related to sharpness by the way the lens render the transiction between black/white or two different grey levels?... I'll try to explain myself: higher microcontrast means that the change in the image between i.e. black and white is more "abrupt" while lower microcontrast means that there is some gradient in the transiction...

I hope my english is not a torture or pain for your ears/eyes...

Thanks
 
"...the ability of the lens to differentiate between smaller and smaller details of more and more nearly similar tonal value. This is also referred to as "microcontrast." The better contrast a lens has (and this has nothing to do with the light dark range or distribution of tones in the final print or slide) means its ability to take two small areas of slightly different luminance and distinguish the boundary of one from the other..."

quoted from luminous landscape article
http://www.luminous-landscape.com/tutorials/understanding-series/lens-contrast.shtml
 
Al Kaplan said:
It's what lets you clearly see every pore and laugh line on a bride's face, even though her face is reasonably uniform in color and flatly illuminated. Three cheers for the wonders of modern optics!
Click to expand...

Ha ha! Exactly, Al...

That is why I am the proud owner of a Summarit 50mm 1.5 lens and looking for another out-dated lens. Which brings up the question of why anyone would shoot portraits with a D3X or whatever. I have done so with my D2H and D2X and wished I had a softer image. (So did the ladies...):eek:
 
Jeepers, Dave! Wouldn't it be more fun to have a brand new Apochromatic Aspheric Wonderlens than the crummy old Summarit? Think of the fun you're missing out on your computer softening all 32,817 of the bride's pores one at a time!
 
Recent versions of leading photo software including Photoshop, Corel PaintShop Pro Photo and Ligthroom all have a slider to adjust micro contrast in photos. (At least I think this is what they do - don't ask me how though. These filters certainly seem to work differently but in a complimentary way to the sharpness filters.)

In Corel (which I use) its called the "clarity" filter and in Photoshop and Lightroom it has other names (sorry I have only seen / used trial versions and do not use these regularly so cannot recall their particular terminology but I think you find the relevant sliders in the same suite as the sharpeness filters. They work terrifically to increase apparent sharpness of photos by changing contrast locally in the images. The overall image brightness and contrast is not much different but there is a big difference at the detail level. However, these filters do have to be used judiciously or they can produce weird and potentially unpleasant aritfacts. They are seldom suitable for portraits for example, but work often very well to bring out the texture in buildings, rocks, landscapes etc. If you are shooting with a lens that has poor MC, or shooting in conditions that are not conducive to producing good micro contrast these filters do appear to help considerably. The before and after result can be startling and I can well see why Corel call their's a "clarity" filter. The before photo often looks distinctly muddy by comaprison and it looks almost as if the processed version has had a kind of "veil" lifted on it. There is a real "pop" to the image that was not there before.
 
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