Contrast (1 Viewer)

I was looking at 8x reviews on the Norwegian website Kikkert Spesialisten AS. The top 3 (FL, Ultravid, EL) all scored 10 for resolution (out of 12), but the FLs won on brightness (8 as against 7+) and contrast (11 as against 10+ and 10-). The Opticron SR.GA, which I'm interested in, scored 10 for resolution and 8- for brightness, but "only" 9+ for contrast. Is that a negligible or significant difference? And if other things, such as resolution and brightness, are equal, are the models with the greatest contrast necessarily better optically? Is it ever possible for binoculars to have too much contrast?

Michael.

Hi Michael,

Have a look at the community pages at www.zbirding.info, under 'the truth about contrast' heading. This article by Steve Ingraham explains some of the things that you might be interested in knowing. Also explains some other stuff about optics, although with a bias towards Zeiss products. Otherwise very good opinion.

Jon |;|

Michael,
You might find the current Nikon Thread on the '"E Series and Low Dispersion Glass" helpful. There are alot of comments in it about the effects ED Glass and other Low Dispersion Glass have on Contrast, CA etc. It gets pretty technical but, who knows, maybe you will have started another long educational discussion.

Cordially,
Bob

Q. Does CA come from aberrant chromosomes or am I in the wrong forum?

Thanks for the links; I found them interesting. The Ingraham article might shed some light on those posts that go: "I bought these insertnameheres for £5/€8/$10 and am amazed at the quality. I compared them with my friend's/father's/uncle's Ultravids/FLs/ELs and they were just as good/nearly as good/better, if anything." I wrote one or two of these myself about my wife's 7x21 Olympus PC III Classics.

Michael.

MacGee said:

Thanks for the links; I found them interesting. The Ingraham article might shed some light on those posts that go: "I bought these insertnameheres for £5/€8/$10 and am amazed at the quality. I compared them with my friend's/father's/uncle's Ultravids/FLs/ELs and they were just as good/nearly as good/better, if anything." I wrote one or two of these myself about my wife's 7x21 Olympus PC III Classics.

Michael.

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Yes, that article really does shed some light on things I had not been aware of. Very interesting comparison of those two pictures. And at first sight, the lower one does seem contrastier. But the loss of fine gradation becomes obvious on second sight.

Hi Robert,

Just to expand on what you wrote, I have a pair of Swarovski 8.5x42 which I have used for some time, and I have always found them to have 'good' contrast. Just this week I treated myself to a pair of 8x32 Zeiss FL's and my first impression was that they seemed 'soft' when it came to contrast against the Swarovski's. However, comparing them side by side it is clearly seen that there is more detail visible in the Zeiss view, esp at the extreme ends of the range, with the Swarovskis now appearing 'harsh'. I think a lot depends on personal preference. I used to work in photographics and people used to swear that they could always tell when a black and white picture had been taken with a Nikon lens, since the contrast was obvious, while Minoltas were compared with top quality german lenses, since they didn't have the hard look of the Nikons. In fact minoltas were always called 'soft'. I realise now that what Steve Ingraham was explaining in his article on contrast may go some way to illuminate these views. One thing I do think, though, is that it takes some time to acclimatise to a new set of optics, and first impressions may not be as relevant as I thought. Anyone contemplating buying a new set of optics should really try and get a good look through them in the field before parting with what nowadays can be a lot of money.

Jon :scribe:

Jon, the worst is when you are committed to your new pair and sell the old one, realizing later, with some use, you liked the old one better.

Hi Tero,

too right, that's the excuse I gave the wife when she asked me if I was going to sell the old ones! Maybe after a year or two...or three..or four..

Jon :hi:

Swissboy said:

Very interesting comparison of those two pictures.

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It is an interesting comparison indeed and may help to understand the "different approaches" to achieve good perceived contrast, but I don't think the analogy works quite like that. The optics manufacturers can "play with the glass types and coatings", but in practice they only can affect to transmission at certain wavelengths (colours) which is more related to brightness and colour balance. Binocular glass/coatings can't distinguish levels of brightness like Photoshop "Levels" does. Binoculars can modify colour balance, which *may* sometimes enhance perceived contrast (eg. like yellow filters in B/W photography), but IMO a more appropriate Photoshop action would be a mixture of hue/saturation/lightness adjustments with infinite number of colour channels (= continuous spectrum) - but that probably wouldn't make the point any easier to understand.

Steve also does not mention about baffling, which in a way brings me to the original poster's subject . I think the Opticron's coatings inside the binoculars may not be quite as good as they are in the "top guns", but they seem to be both bright (8- ) and the baffling against flare is apparently very good ("lite sløring") - which are IMO more important than small differences in personally perceived "contrast".

Best regards,

Ilkka

iporali said:

...I think the Opticron's coatings inside the binoculars may not be quite as good as they are in the "top guns", but they seem to be both bright (8- ) and the baffling against flare is apparently very good ("lite sløring") - which are IMO more important than small differences in personally perceived "contrast"...

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Thanks, Ilkka. Maybe you can tell me if my translation from the Norwegian is okay. I used an automatic translator and some guesswork.

Original
Uvanlig god i motlys (lite sløring). Meget lys. Gummiarmert med gummitype som gir godt grep under alle temperaturforhold. Bredt,
gummiert fokushjul funksjonelt også med votter. Meget god nær-
grense. Nedbrettbare okularkapper for brillebrukere. Kompakt og
lett.
Glimrende optisk. Mye for pengene.

My Translation
Uncommonly good in the gloom(?) (very little flare). Very bright. Armoured with rubber that gives a good grip at all temperatures. The wide, armoured focus control also works with gloves. Very sharp to the edge. The eyecups fold down for use with glasses. Compact and light.
Splendid glass. Good value for money.

Michael.

Thanks Ikka. I think your analysis of the Photoshop analogy is exactly on the money. I don't know anything about Photoshop, but I know that manipulation of glass and coatings could not affect image contrast in the way illustrated in the photos. Loss of contrast in optics is nearly always caused by one thing; scattered light. Aberrations cause light to spread out in rings beyond the area of the Airy disc and every glass surface in an optical device, even coated ones, causes some light to be incoherently scattered. Unbaffled internal reflections will contribute more incoherent light. Essentially light is robbed from the bright areas and spread as a gray film across dark areas. This is is almost the opposite of the "bad" Photoshop image in which the details of highlights are blown by being brightened to a featureless white and details of dark areas are lost from over darkening to black. If you want to see what really low contrast looks like in optics try looking through some old uncoated binoculars in which half the light that enters the objective winds up absorbed as heat in the binocular innards or scattered across the image. As Ikka says manipulation of color transmission, typically suppressing blue/violet transmission compared to yellow, can create an enhanced perception of contrast in daylight where the eye is most sensitive to yellow and does not focus blue/violet as well. Its the idea behind some contrast enhancing sunglasses and yellow tinted shooting glasses. Swarovski binoculars used to be rejected by birders for their yellow image tint, which was just what hunters liked.

I don't think Zeiss need to make up dubious explanations or apologies for the contrast, brightness or color transmission in their binoculars. I agree that the light transmission of the FL's beats any other roof prism bin I've seen and if there is any perception that contrast is compromised it is almost certainly because the light transmission in the FL's is still reasonably high at blue wavelengths. Maybe that's what they mean by "full natural contrast".

MacGee said:

Maybe you can tell me if my translation from the Norwegian is okay. I used an automatic translator and some guesswork.

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Hi Michael,

I think your translation was correct (although I know some Swedish, my Norwegian is mainly guesswork ). That "motljus" is "against the light" - I don't know if you have identical expression in English, but in German it would be "Gegenlicht".

Ilkka


ps. That Opticron sounds really interesting. Hopefully it is also on Kimmo Absetz's "To be tested"-list. :t:

I see that LCE are advertising an ex display 8x32 Opticron SR.GA for £129, if you are interested Michael. LCE Opticron offer .

Paul

MacGee said:

I was looking at 8x reviews on the Norwegian website Kikkert Spesialisten AS. The top 3 (FL, Ultravid, EL) all scored 10 for resolution (out of 12), but the FLs won on brightness (8 as against 7+) and contrast (11 as against 10+ and 10-). The Opticron SR.GA, which I'm interested in, scored 10 for resolution and 8- for brightness, but "only" 9+ for contrast. Is that a negligible or significant difference? And if other things, such as resolution and brightness, are equal, are the models with the greatest contrast necessarily better optically? Is it ever possible for binoculars to have too much contrast?

Michael.

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Hi Michael
I've owned the previous model (8x42 High Resolution) for about 18 years. The current SR.GA adds rubber armouring and I assume the coatings have improved over that time too. In terms of optical performance my old 8x42 is still excellent even in direct comparison to far more expensive modern roof prism binoculars. It's very light and the handling is excellent. I really like the large central focussing wheel - it's very smooth and precise. I wish Nikon had used the same design on the SE range. I really don't think you'd be disappointed in the optics. It's more question of whether you like a porro design (I do). Hope that helps.
John

Paskman said:

I see that LCE are advertising an ex display 8x32 Opticron SR.GA for £129, if you are interested Michael. LCE Opticron offer.

Paul

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Thanks, Paul. I'm tempted by that; I'll mull it over.

Michael.

solentbirder said:

Hi Michael
I've owned the previous model (8x42 High Resolution) for about 18 years. The current SR.GA adds rubber armouring and I assume the coatings have improved over that time too. In terms of optical performance my old 8x42 is still excellent even in direct comparison to far more expensive modern roof prism binoculars. It's very light and the handling is excellent. I really like the large central focussing wheel - it's very smooth and precise. I wish Nikon had used the same design on the SE range. I really don't think you'd be disappointed in the optics. It's more question of whether you like a porro design (I do). Hope that helps.
John

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Thanks, John, that's helpful. I do like porros. I was only turned towards them because I find large eyecups uncomfortable, but I bought an old pair of 8x30s for £15 to see if I would get on with them - and I do.

Michael.

henry link said:

...If you want to see what really low contrast looks like in optics try looking through some old uncoated binoculars in which half the light that enters the objective winds up absorbed as heat in the binocular innards or scattered across the image...

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Henry, that exactly describes my old Samsung 10x25 reverse porros, even though they are coated.

I haven't forgotten your Habicht recommendation. The Opticrons I'm looking at just seemed so close in quality and at £129 as against £369 for the Habicht, much cheaper. They're not waterproof, of course, so if a second-hand pair of Habichts should turn up I'll probably get them as well.

Michael.

...If you want to see what really low contrast looks like in optics try looking through some old uncoated binoculars in which half the light that enters the objective winds up absorbed as heat in the binocular innards or scattered across the image...

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And the Bushnell 10X Sportsman explained! It gives it a soft look, and the sweet spot is a little hard to recognize. Other models, more expensive, have a much more clear sweet spot and then less focused areas around the edges. Overall dimness kind of hides a lot of problems.

edge1255 said:

Hi Michael,

Have a look at the community pages at www.zbirding.info, under 'the truth about contrast' heading. This article by Steve Ingraham explains some of the things that you might be interested in knowing. Also explains some other stuff about optics, although with a bias towards Zeiss products. Otherwise very good opinion.

Jon |;|

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Unfortunately, his diagram is for secondary or longitudinal color, while his photos illustrate lateral color or variation of magnification with wavelength. The former is shown for the objective, while the latter is largely caused by the eyepiece.

One diagram, for the "super ahromat," has a caption that says "using ED, fluorite, or High Density glass." This claim that High Density glass can improve color correction is just plain odd, and greatly hurts the credibility of a number of "optics experts."

Clear skies, Alan

Hi Alan,

one thing I do know is that the thoery, maths and physics of optics is WAY beyond me! I think I'll stick to looking through them instead of trying to understand them!!!

Jon (....my brain hurts... :brains: )