"Contrasty" lens terminology

[Pherdinand]

Since we are detailing terminology here . . . .

Is "color contrast" a reality different from "contrast" ?
For example, a polarizer reduces glare, separates colors, but I don't think that it blocks up shadows or burns out highlights, so I don't think that it changes overall image contrast. (Do I ? )

contrast increase does not mean blocking shadows or burning out highlights, only in photoshop extreme. Contrast increase in your example means exactly reducing the glare.

 

[Ko.Fe.]

I'll put it simple.
If I look at the darkroom print or color neg scan and "decontrast filter" is in my mind, the lens is contrasty.
And I have one like this...

 

[Sparrow]

... is there also a micro contrasty lens then?

 

[Sparrow]

I thought that's what people meant when they say a lens is contrasty, since contrast in printing terms is a different beast. Take, for example, the ZM Planar. People seem to think of it as a high contrast lens because the blacks get really black. I'm under the impression the black look black because, as Roger said, the lens is well-corrected for veiling flare. At least I hope that's the case.

... sorry I was being facetious

I've always thought that people try to use 'contrasty' (an adjective) as the noun simply to validate some pet opinion or other, 'micro contrast' is the same as far as I can tell

One of those odd side effects of the interweb, people take a precise term play about withe it and then try to misuse its authority to support some fancy ...

Lots of stuff like that these days ... BFA degrees ... Artist prints and the like.

 

[harpofreely]

Simple.

Contrasty = not like a Summar

Some good points in this thread, but - the above is as good a "working definition" of "Contrasty" as I've seen. So long as you are attentive to the Summar's love of flare, it can be a good tool for taming sunny days:

Summar in North Carolina summer sun, Fuji XE-1

By the above definition, my most contrasty lens is probably the Fuji x-mount 18-55 "un-kit" zoom.

 

[Sparrow]

Deadpan deliveries should display in a high resolution/low contrast font.

... yes, probably ... I just don't keep up with modern fonts these days

I tend to use a 35 and 50 skopar with colour neg film, and a f2.8 summeron and mkII 50 summicron with monochrome because I get prints I like with those

 

[jonmanjiro]

exactly. Therefore,
1. it does not add detail, only makes existing shadows lighter
2. it does not keep highlights from blocking - actually it even blocks highlights more, since it adds a tiny bit of extra unifom exposure to the highlights too, but this is tiny so it might not matter.

If you get less blown highlights with a less contrasty lens on the same scene, film, processing, postprocessing compared to a more contrasty lens, it only means your exposure is not the same. E.g. the metering got fooled. Or, even with full manual and therefore identically theoretical exposure, a lower contrast lens will let less light through (a tiny bit) which might help not blowing the highlight.

Take this example:
You have a street lamp on the black night background. The lamp produces an amount x of light that is captured buy a say f/2 lens.
A contrasty lens transmits some 99% of the light hitting its front surface and focuses all of this on the image of the lamp, keeping the background as black as it is.
A less contrasty lens, on the other hand, transmits say 90% of the light that hits its front surface and focuses this on the image of the lamp so it gives less exposure to the lamp. Additionally, from the thrown away 10% something like 5% will be reflected back towards the scene, 2% absorbed by the lens' edge or other camera parts painted black, and say 3% will be, after several internal reflections, hitting the film on a randpom spot (thus adding uniform exposure increase). So the lamp itself willl have only 93% of the full light compared to the 99% of the high contrast lens, while the background will have 3% extra.

If you were exposing EXACTLY for the highlights, i.e. to get the lamp the same brightness for both scenes, you'd need to increase the exposure time slightly to bump up the lamp highlight to the 99% but then you'd bump up the shadows' black even further. This way you change exposure - you DO get possibly more shadow details due to the longer exposure but you do need to change exposure time. (Or aperture.) If, however, you do NOT change the exposure, you do get some extra exposure in your black shadow but you do NOT get extra detail there, only a uniform greyness.

Excellent explanation. Thanks!

 

[jcb4718]

What an interesting discussion. Here is my input: there are two types of contrast. There's 'veiling flare' which is due to stray light in the lens getting into the dark areas of the print. It spills into the negative, maybe all of it, and has nothing to do with lens aberrations. Of course an uncoated lens will allow more stray light because of the increased reflections from the lens surfaces. 'Micro contrast' has a different origin. Imagine taking a photo of a series of black and white strips which get progressively narrower. 'Ideally' the image will reproduce all the strips with the black being 'black' and the white being 'white'. In practice as the strips become narrow (and therefore affected by lens aberrations), they 'spread out', the black becomes 'less black' and the white 'less white'. A lens can have high resolution (showing very narrow strips) but also low contrast ('less white' and 'less black' in each strip). Strangely these images do not look sharp. Often the best looking images show contrasty strips but not necessarily at high resolution. Very contrasty lenses show high resolution and contrast. The images can look 'cut with a razor' if you get my meaning. Lenses that maintain contrast at moderate resolution are often portrait lenses. They have 'punch' while being forgiving on the eye (and the subject). Zeiss have always emphasised the 'modulation transfer function' of a lens (which is a fancy way of saying how, exactly, a lens images the progressively narrowing black and white strips). They rightly point out that the modulation transfer function is much more important than simple lens resolution.

 

[Roger Hicks]

The Focal Press repeatedly compared high contrast, low resolution images (Zeiss) and high resolution, low contrast images (Leica): the image was of a playing card. At first sight, as reproduced, the Zeiss images look better, but for a real print a lot would depend on subject matter, print size and contrast.

Cheers,

R.

 

[DominikDUK]

Resolution beats contrast in the real world if you enlarge an Image you will have a loss of detail and a gain in contrast. If you start out with a contrasty Image that has less Resolution the Image will get contrastier but will lose even more detail than the less contrasty image. Extreme B/W contrast can only be the result of loss of Information. Therefore a super contrasty lens can not be both very high Resolution and very contrasty at the same time.

 

[jcb4718]

I don't understand why its 'one or the other' with lens resolution and contrast. If you said: a high resolution lens has more elements so there are more reflections then I could see a reason why more resolution = less contrast and vice versa. If on the other hand you said: 'contrast depends on the lens coatings' then in principle you could have both (I'm not putting forward either of these as explanations by the way!). I just don't understand what it might be about lenses that would make this 'one or the other' relationship always hold.