'Better' contrast??

[stoogest]

Hi all,

On the forum and other sites I've seen people make comments regarding particular lenses stating that they provide 'better contrast'. What are they meaning when they say that?

Does 'better' = 'more', or perhaps 'better' = 'higher quality'??

edit: does anyone have some images they can post that show this difference?

Cheers!
Andrew.

[ricktas]

There is a good article on Wiki that details the meaning of contrast and has some great photos on the right to demonstrate the result of good contrast in a photo.

http://en.wikipedia.org/wiki/Contrast_%28vision%29

[stoogest]

Thanks Rick. I understand the basic principles of contrast, but was trying to apply it to the lens situation. Is it the lens coating that provides 'better' contrast, or perhaps it's the physical design of the lens?

It seems to me that when people say 'better' they actually mean more contrast, but there comes a point at which too much contrast just looks unnatural.

Is the contrast provided by a lens more desirable than the contrast provided through post processing?

[arthurking83]

Because all lenses are made up of a series of many lenses connected together to create an image forming beast, those series'es of lenses reduce contrast by vast amounts if soem of the individual glass elements are not coated or manufactured from some exotic material.

Easy way to see living proof of that is to take a series of (say) wine glasses and line them up so that you can see through all of them lined up in a row. Just as the Wine glasses will have air to glass surfaces, so do the internals of lenses.

L glass in Canons HMC coatings in other brands.. ED and nano coatings in Nikons.

In Nikon terms, you get ED glass.... and ED glass(elements) is a great way to boost the ability for the lens to produce better contrast. Now it's nano coatings that are Nikon's super hero trick, and they also have Super ED glass elements too.

Their greatest lens(the only one I currently know of. can you guess which one?) has one single Super ED lens element and many ED elements in the optical formula.

Contrast is also associated with sharpness too.

To make an image look sharper, you design the lens to have better contrast.
Afterall, if you can design the lens so that the difference between contrasting areas stand out more it appears as tho there is a greater separation between those two areas and that looks 'sharper'.

When I got my 18-105VR a while back, I was amazed at how sharp the images looked.. especially compared to the Tammy 28-75.. but then again all of my lenses. it; just looked super sharp and more contrasty.. but what the buggers did, is design it in a way that every image is under exposed by a fraction.. maybe up to -2/3rds less than all my other lenses. Under exposing a little also creates the illusion of more contrast.
Once I compensated a little when I finally worked out what was going on, I had to shoot the 18-105 2/3rds slower shutter speed to achieve the same exposure value.. it still looked good, but not as brilliantly as I originally thought it was.

But the basic guts of the story is the glass to air surfaces. Like looking into the sun when wearing sunnies. Without them you can generally see more of the scene around the sun(with the naked eye.. even though it's bright), whereas the glass surface will reflect back a lot of the light causing flare and reflections and stuff, you get less contrast in the scene you're trying to see. Add a less than ideal glass surface, standard glass is less than ideal, and coated glass is better and the lack of contrast becomes greater. Think of those coated elements(such as ED, or Canons fluorite lens, where the actual element is made of the fluorite compound, and not coated with it!).. anyhow think of those coated elements as sunnies that have been meticulously cleaned and have no dust or marks on them at all. And think of standard optical grade glass elements as slightly dusty and slightly hazy afected sunnies. Look into the sun and watch ..... probably nothing!.... its like a white out.

I think from memory the new 70-200VRII has no less than 7ED lens elements in it. But then again the lens has something like 130 billion lens elements in 27 zillion groups.. or words to that effect.

Then have a look at an old 45/2.8P Pancake lens. I think 4 standard elements and maybe one coated with SIC(Nikon's original high performance lens coating.. before ED glass).
The 45P still produces lots of contrast though even though there are 'technically' better lenses with more uber performing lens elements in them.
Lots of professional togs rave about those pancake lenses, and they may well be right, but a damned expensive lens for what it really is(4 magnifying glasses stacked together within a metal sleeve with a convenient metal plate to mount it onto your Nikon camera ).

[stoogest]

Thanks Arthur, you've used some good analogies there. I hadn't thought about the link to sharpness as well.

One of these days I'll have the cash to get myself a pro lens and see for myself what the difference is!

[arthurking83]

....

One of these days I'll have the cash to get myself a pro lens and see for myself what the difference is!

You don't need too!
believe when I say the 18-105 will put a smile on your face with respect to sharpness and contrast.

The main difference you will see between it and say a 17-55 f/2.8 is the aperture!(Doh!) and the 17-55 images will be a lot more 'brightly exposed'(compared to how they look with many kit lenses)
of course there will be massive advantages to the build quality and speed of focusing with the 17-55 compared to the 18-105 too, but the images are what counts.

You'll simply find less of a need to PP the images to the point you want them to be with a pro lens, whereas with the consumer lenses you may find that they need a little touch here and a dab there to bring out their best.

My only Pro Nikon lens is the 105VR. And it's easier to get easy shots, that need less PP with it. Colours are more vibrant.. not overly saturated as you'd get with PPing an image.. naturally bright and contrasty at the same time.

i've compared my three 105mm capable lenses, and I have images form my old 80-200/2.8 lens to compare as well.. but they are mainly for sharpness and focal length comparisons, and less so for overall image rendering judgements.

From memory the 105 macro is better, but images captured with the 18-105 can be as good with some due care taken for the final output.

Don't confuse contrast in the native image with contrast added in PP either!

USM is adding contrast, Adding contrast via the brightness contrast tool can yield those unnatural looking images you referred too earlier. Sometimes if I add contrast to the image with software, I invariably find myself reducing saturation a little bit too. Not much(maybe 10%??) and not always, but I have done it on many occasions.

[stoogest]

Definitely agree regarding your last comment on reducing saturation as I experience the same thing.

The next couple of lenses I was thinking of getting were the Tokina 11-16 and the Nikon 16-85 (to replace my 18-55 kit).