Is it possible for a lens to produce too much contrast?

Question

I came across a complaint that a certain lens produces too much contrast. The lens was described as rendering "cartoonish" contrast when shooting a portrait with diffused light from a window, where other lenses are said to give a soft transition of light. The claim is that the lens eliminates midtones. The argument continues that contrast can be increased in post-production, but, like adding salt to soup, you can't really go back if there's too much.

Now, as I understand it, this isn't the way it works; when a lens is said to produce good contrast, this is about microcontrast and is really more related to resolution than to overall tonal rendering. Poor lens designs can reduce overall contrast by allowing stray light (flare or veiling glare), but that's uniformly a bad thing — it's not a tunable with a sweet spot which can go too far. Contrast in a print (or global contrast in an image file) can certainly be over-done, but that's a totally different thing.

So, is there something to this complaint? Is this really a possible flaw in a lens? Can a lens "eliminate midtones"? Can lenses have too much global contrast — or, too much microcontrast after all?

Answer

You haven't said whether it is film or digital or given any details of lens or camera type/size/brand. Poor quality film (or film stored or used on poor quality conditions) can affect contrast a lot too. In addition many digital cameras automatically apply a sharpening effect as digital sensors are inherently 'blurry', if the settings of the camera have this turned up (which the cheaper ones tend to do) then the resulting image can have that 'cartoony' look due to the excessive sharpening.

Never heard of a lens having that effect though.

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