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  1. #61
    Ian Grant's Avatar
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    Not sure where the Myth of "Less Contrast" comes from Dago's were always good contrast for their date of manufacture, and better than many other lenses with more air/glass surfaces. Certainly on a par with Tessars and sharper overall.

    Of course if you compare an old uncoated Dagor to a modern lens then yes less contrast but that goes for any uncoated lens. but compare a coated Dagor to a modern lens and the Dagor is up there close in contrast, certainly mine isn't far behinf my Sironar's and Symmar's at all, and in practice the results are indistinguishable.

    Ian

  2. #62

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    I wonder why so many people praise them for their lower contrast then. It must be one of those Urban Legends.

  3. #63
    Ian Grant's Avatar
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    They say the same thing about single coated lenses, but there's poor and adequarecoating and excellent coating, my mid 50's East German CZJ f4.5 150m Tessar has superb coating although a touch blue for colour work, and is far better coated than 50'/60's Xenars etc and almost as good as Multi Coating.

    As David says it depends on the quality/ageing of the optics, older glass was softer so more prone to problems over time so many Dagor's may suffer from lack of contrast but so do Tessar's made of the newer glasses made in the 1930's and many other old lenses.

    Lack of any coating does mean softr contrast due to internal flare and most Dago's particularly German are uncoated.

    Ian.

  4. #64
    David A. Goldfarb's Avatar
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    Also, at wider apertures, Dagors have some spherical aberration (more, it seems, with older versions) that is responsible for the illusion of focus shift that some mention and that causes a little glow, which might also be interpreted as a reduction in contrast. For portraits and still life sometimes that slight glow around f:8-16 can be desirable. To get the wide coverage of a Dagor though, you need to be at f:22 or smaller, which will eliminate that issue.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
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  5. #65

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    I should have realized the contrast/aberation issue is something that changed over time. This is something not always mentioned when describing atributes of a particular lens brand/series. So, if one is looking for those qualities (lower contrast/glow) then they should be seeking the earliest models... makes sense now that I think about it. The latest DAGORS are more like G-Clarons, right?

  6. #66
    Ian Grant's Avatar
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    G-Clarons aren't optimised for normal use like Dagors, all Dagor's a re based on the original 1890's design, but optical glass improved over the years so the design evolved but only in the same way as say the Tessar design. So even a late Dagor is still the same fundamental design as the first.

    If you specifically wanted a lower contrast model then any uncoated version will fit the bill, but contrast shouldn't be that much lower except when shooting into bright light, etc. I was shooting with an uncoated Tessar and under some conditions the loss of micro contrast was noticeable.

    Ian
    Last edited by Ian Grant; 12-21-2009 at 12:07 PM. Click to view previous post history.

  7. #67

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    Interesting... thanks, Ian.

  8. #68

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    Quote Originally Posted by Ian Grant View Post
    G-Clarons aren't optimised for normal use like Dagors, all Dagor's a re based on the original 1890's design, but optical glass improved over the years so the design evolved but only in the same way as say the Tessar design. So even a late Dagor is still the same fundamental design as the first.


    Ian
    Just for the record, many of the early G-Claron lenses are of Dagor design, not plasmat. I own two lenses of this type, a 210mm and a 240mm. They are single coated and excellent performers, giving more contrast in fact than single coated plasmat type lenses because of fewer air to glass surfaces.

    Sandy King

  9. #69

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    Quote Originally Posted by Mike1234 View Post
    I should have realized the contrast/aberation issue is something that changed over time. This is something not always mentioned when describing atributes of a particular lens brand/series. So, if one is looking for those qualities (lower contrast/glow) then they should be seeking the earliest models... makes sense now that I think about it. The latest DAGORS are more like G-Clarons, right?
    Mike,

    No, the earliest G-Clarons are a Dagor design, a 6-glass, 2 group lens, or a lens comprised of 2 cemented triplets. Dagors never changed in the design of the groups while the G-Claron did.

    Single coated lenses have more contrast than uncoated, and at least to me, modern multicoated lenses have more contrast than single coated. The effects of coating boosting contrast was mentioned by Ansel Adams in one of his books, and he suggests that development may have to be altered because of it.

    Richard Knoppow on the old usenet stated that he felt that "haze", even a little, cut contrast significantly, and based on my experience with old lenses I'd agree. I'm extremely suspicious of any lens with haze. And you see a lot of them because unlike a dead shutter, it doesn't impair you from physically making a photograph, and people will accept haze soooner than a dead shutter. I'd MUCH rather have crystal clear glass and a fixable shutter versus hazy glass and a good shutter, although the latter always seems to bring more when sold. I've seen haze easily cleanable on coated and uncoated lenses, and some that was not. Deteriorated cement or Canada balsam can also have the appearance of haze.

    Finally, a lot of people made a lot of Dagor design lenses, in a lot of different barrels and shutters. Internal baffling of a barrel/shutter can produce general flare that significantly reduces contrast, and obviously when you have dozens of companies making a similar design over a hundred years, some will be worse than others.

    According to an 97-year old friend who's been in commercial photography for well over 60 years, all lenses will shift focus somewhat when stopped down, and the final focus check should be as near to the taking aperture as possible. Sounds like good discipline in image-making to me.

    Cheers, Steve
    Last edited by Steve Hamley; 12-22-2009 at 08:04 AM. Click to view previous post history. Reason: typo

  10. #70

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    That's a nice thorough explanation Steve. I appreciate it as I'm sure the OP does too.

    I bought lenses reputed to be both sharp and contrasty. Regarding focus shift, I chose slower lenses to save weight and they're all modern so I hope focus shift will be negligible. BTW, I know this is considered "evil" here but if I want SF (Imagon-type effect) or brighter shadows or whatever I can do that in Photoshop. I prefer to have a "sterile squeaky clean" image that I can work with... I like to keep my options open.

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