Goerz Dagors...What's so special?

[Ian Grant]

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

[Mike1234]

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

[Ian Grant]

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.

[David A. Goldfarb]

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.

[Mike1234]

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?

[Ian Grant]

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

[Mike1234]

Interesting... thanks, Ian.

[sanking]

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

[Steve Hamley]

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

[Mike1234]

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.

[Ian Grant]

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

My point was more that the G-Claron's are Repro lenses and not optimised for Infinity or normal use,of course there were Repro Dagors to. In many cases that in itself may make little difference but there can be problems.

One problem with any Graphics/Repro lens is they are optimised for flat field work usually at 1:1 and in the case of the G Claron best between 5:1 and 1:5.

While Schneider state they can be used for normal photographic work they state they can be used up to an angle of view of 64 degrees, less than a Symmar or Sironar.

The image circle might be much greater but there are issues of spherical distortion using process lenses at or near infinity. This may be an problem at the edges/corners, obviously some designs will be worse than others.

It's possible that the early Dagor type Claron's are better than the later Plasmat designs in this respect but they still aren't optimised for normal use.

Ian

[sanking]

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.

Cheers, Steve

Some years ago I owned and used mostly vintage lenses for my ULF work. That included several uncoated Dagors and Protars. When I replaced one of the uncoated Dagors with a modern multi-coated Nikkor M lens I had to decrease development time by about 25% to account for the much greater contrast of the multi-coated lens.

That said, the single coated Dagor design G-Claron lenses are great value. Late model coated Dagors of the same vintage, Kern for example, generally sell for a lot more than the Dagor type G-Clarons, in part I think because not many people are aware of the fact that early G-Claron are in fact Dagors.

As for the ultimate in contrast, try a multi-coated Dagor, say the 14" Kern Dagor or the Schneider 550 XXL. With only four air to glass surfaces and multi-coating you get a very contrasty negative with these lenses.

Sandy King

[df cardwell]

There's an exchange between Paul Strand and Ansel Adams, published (IIRC) in AA's Letters.

Strand had his prized Dagor coated after WW2, and it forced him to change his way of shooting: single coating a Dagor (or Protar) removes the flare from the deepest shadows which affectively provided the Zone I density; like a single exposure unit of Pre-Exposure. To compensate, Strand (and all of us since) had to double his exposure. A MC lens might approach a two Zone loss of density compared to an uncoated Dagor/Protar.

The higher up the scale, the less the effect of flare. By Zone III, flare is non-existent. But an uncoated lens is perfectly capable of extremely contrasty results. Only when we compare contrast side-to-side, do we se the difference. If you increase the development, you get sufficient contrast with an uncoated lens fir B&W. Color is a different set of issues.

Then again, coating 'flare monsters' like Plasmats and Cooke Convertibles made them far more useful.

[Steve Hamley]

Hey Sandy,

On what formats do you find the 450mm Nikkor M usable for contact printing?

Cheers, Steve

[sanking]

Hey Sandy,

On what formats do you find the 450mm Nikkor M usable for contact printing?

Cheers, Steve

The 450mm Nikkor M is a great lens for 14X17, 12X20 and 16X20, if you stop down to f/22 or so. Also works for 20X24 if you stop down to f/64 or f/90, but the corners will be soft.

Sandy

[Steve Hamley]

Thanks Sandy.

Cheers, Steve

[Mustafa Umut Sarac]

I become a crossfield 656 drum scanner operator after seeing ansel dagor prints.
After 10 years of research and entering to internet age , I wrote to Zeiss Archives and asked what do they have in their hands about dagors. They sent two pages scan , prescriptions of Dagor 300 and 350 mm.
After looking , thinking about hundreds of lenses , you can see how dagor design is genius , rafinery and intelligent. At 350 , there are two symmetric group of glasses and a middle air section.
There is no air gap between each glass of these groups and it impress the observer.
I discussed the cooke xv design with cooke head designer and he sent me prescriptions and glass details.
It is now impossible to find every detail of these glasses for these lenses. It is lost.
May be I will buy them , disassemble and send them to analysis. Than copy with sol gel :)

Mustafa Umut Sarac

[luvcameras]

For you antique Dagor Fans, a catalog section of all the Goerz Dagor lenses as of 1904 here

http://antiquecameras.net/1904goerzlensads.html

Dan