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ari velazco
20-Apr-2019, 19:26
Hello, found this lens for sale locally here in the Philippines. Seems like there are a lot of variations of these lens and could not find the exact one for this about its exact specification and coverage and if its worth it. Seller is asking $200 for it. Thank you very much.

https://uploads.tapatalk-cdn.com/20190421/2b5c9a2bd5899386a9259523358eaa34.jpg


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Mark Sampson
20-Apr-2019, 22:23
That's an older, (pre-WWII) example. You can look on the front page of this site for a little info on Goerz serial numbers by date. This one looks to be uncoated, it will certainly cover 4x5 (and likely 5x7).
Someone thought it was good enough to mount it in a much newer Copal shutter; if the shutter is working then the asking price seems fair- although I've never used this exact version of the Dagor.

Pere Casals
21-Apr-2019, 01:17
and if its worth it.

I depends on what you shot and on what you want.

In performance terms you have much better choices, for example you may get a Symmar-S 180mm search: https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1312.R1.TR0.TRC0.A0.H0.TRS5&_nkw=symmar+s+180&_sacat=0

These are usually multicoated and the resolving power may be two fold linear and four fold area than the dagor.

_____

...But optical preformance can be irrelevant in photograhy !!!

A Dagor is a character on its own, it may deliver a particular look you may like for portraiture or to match ancient aesthetics... Dagors have not an excellent bokeh if wanting that, but a photographer may want a Dagor...

For general photography you may prefer a modern lens like a Symmar-S that perhaps lacks "character" but's it's optically sound. If you pay a plus for an antique lens, performing worse, then you should have clear motivations for it.

Please see here the Dagor section: https://www.largeformatphotography.info/portrait-lenses/

ari velazco
21-Apr-2019, 01:26
Thank you very much Pete, I understand a newer lens maybe a better option for general photography. I wanted to see whether this might be worth it since I do not have to import the lens from abroad. I live here in the Philippines. I do not have a lens wider than my 210mm for my 4x5-5x7 deardorff and this would be a likely candidate if this can cover it.


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Andrew Plume
21-Apr-2019, 02:01
Hi Ari

In the UK we frequently see the Berlin made Dagor's. I'm a real fan of them - in a barrel mount they're small, compact and with a large coverage. I currently own the 120, 150, 180, 240 and 300mm versions. I used to own a 210mm, that covered 10 x 8, I'm fairly sure that the 180mm will cover 5 x 7 and will test later today

regards

Andrew

Pere Casals
21-Apr-2019, 02:02
if this can cover it.

It has to cover 5x7. The 150mm version covers a 210mm circle, so the proportionally larger circle of the 180 has to cover well 5x7, as Mark guessed. https://www.graflex.org/lenses/lens-spec.html

5x7" requires a nominal coverage of 208.7mm

Dan Fromm
21-Apr-2019, 05:20
According to P-H Pont's Goerz chronology, the lens was made around 1921.

Goerz' claimed that Dagors cover 85 degrees stopped well down. A 180 should, then, cover 330 mm. But and however, my friend Eric Beltrando put Dagor prescriptions (from patents) and Boyer Beryl prescriptions (from the remains of Boyer's archives) through his ray-tracing program and found that 70 degrees is much more realistic. 252 mm for a 180. Visit Eric's site dioptrique.info.

See https://www.largeformatphotography.info/forum/showthread.php?13109-Lousy-Dagor for a lengthy and in places hilarious discussion of Dagors' in general and the 180/6.8 in particular coverage.

With respect to resolution, I've never had so haven't tested an f/6.8 Dagor but own and have tested f/6.8 Beryls, which are very similar. Papi is mistaken, these lenses are fully competitive with modern lenses at my usual shooting apertures of f/16 and f/22. Wider open, not quite but still very usable.

Pere Casals
21-Apr-2019, 08:45
, these lenses are fully competitive with modern lenses at my usual...

Depending on the print size and viewing distance.

A 1920s dagor may deliver a flawless 20" print from 4x5". At 40" a 1980s Symnar S sure it is better... no doubt

Dan Fromm
21-Apr-2019, 09:27
Depending on the print size and viewing distance.

A 1920s dagor may deliver a flawless 20" print from 4x5". At 40" a 1980s Symnar S sure it is better... no doubt

Have you tried it?

Jim Noel
21-Apr-2019, 09:41
I have had and used a non-coated 10.75 DAgor for more than 50 years.I like it so much I have purchased , and used, several more "pre" Dagors,also uncoated and love them. I once used a friends coated Golden DAgor with the thought of buying it. I gave it back because the images seemed unreal with their too-sharp rendition of everything, particularly portraits, forests and other natural scenes.

Bernice Loui
21-Apr-2019, 10:09
1) What lens used?
190328


2) What lens used?
190329



Bernice

Pere Casals
21-Apr-2019, 10:14
Have you tried it?

No, just guessing from other tests. But I think I made a good guess...

have you a doubt that LF optical manufacturing improved a lot since 1925 until 1985 ?

What I tested is my Symmar-S 135 and it delivers 80 lp/mm. C. Pérez found peak 86lp/mm in a Symmar-S 180mm, with 60 in the corners http://www.hevanet.com/cperez/testing.html

Dan, how many lp/mm do you think a 180mm 1920s dagor can have ? 25? 35?

A 1920s dagor it isn't the same than a late model MC Kern...

How optical performance translates into max print size it's 'à chacun son goût', but 85 and (say) 35 are not the same.

Dan Fromm
21-Apr-2019, 10:45
Bernice, you cheated by posting sample shots with no detail in the corners.

Dan Fromm
21-Apr-2019, 10:52
Papi, the question is entirely empirical. Assumptions and "it stands to reason" are irrelevant.

Bernice Loui
21-Apr-2019, 11:02
First image made using a Dagor, Second image made using a 150mm SSXL, same film, same processing batch then scanned.

Point being, web transmitted images tell just about zero regardless of image size or etc... Only way to really know if any given lens is for you do your own testing to see if that specific optic is for you, if not pass it on.


Bernice







It can even be an holga or diana... these are 0.4Mpix images !

Dan Fromm
21-Apr-2019, 11:25
Bernice, agreed.

Pere Casals
21-Apr-2019, 11:30
Papi, the question is entirely empirical. Assumptions and "it stands to reason" are irrelevant.

Dan, can you tell me examples of 1920s LF lenses performing better than 40 lp/mm ? anything in the 30 range ? all in the 25 range?

You know, resolving power in the taking tells what happens when enlarging to a certain X...

An optic is for me if it's cheap :)

Pere Casals
21-Apr-2019, 11:49
Only way to really know if any given lens is for you do your own testing to see if that specific optic is for you, if not pass it on.


I make my own tests, but I've also learned a lot from good tests made by others and from datasheets, in special those tests by Pérez and by Croell teached me a lot.

In general LF image quality is a coarse overkill, me I think that this is a bonus and that LF has many other resources beyond those equivalent effective 600 MPix we easily get from a 8x10. Anyway it's great to know how glass works.

Luis-F-S
21-Apr-2019, 11:52
An optic is for me if it's cheap :)


Some may have a little more refined criteria.

Pere Casals
21-Apr-2019, 11:55
Some may have a little more refined criteria.

Probably, I'm only a learner, and I've a lot to learn (from wise people) before I'm able to shape my photography from the kind of glass I select.

Robert Opheim
21-Apr-2019, 16:14
I would have thought the the lenses were just the opposite with the dagor being the last image. Your images show how important lighting is. Thank you.

Greg
21-Apr-2019, 16:28
A 1920s dagor it isn't the same than a late model MC Kern...

Obviously the 1920 will not be coated and the Kern multi-coated. What are the other differences? I'm guessing the kind of glass used will be another difference.
thanks

Dan Fromm
21-Apr-2019, 17:06
Dan, can you tell me examples of 1920s LF lenses performing better than 40 lp/mm ? anything in the 30 range ? all in the 25 range?

Read my lens diary -- there's a link to it in the list -- to see how I did acceptance tests. These are not formal resolution tests, they divide lenses into good enough/not good enough. They were/are reproducible, subject to changes in color rendition due to the sun going behind a cloud. Roses are red, shadows are blue.

They addressed my major concern, "should I use this lens on 2x3?"

Several of my pre-WW I Tessars came out much better than good enough, one, a B&L 85/6.3, didn't. I've had few lenses from between the wars. One that I sold, a 40/4.5 CZJ Mikrotar is the best macro lens of around that focal length that I tested with a USAF 1951 on glass target.

All of my Beryls -- post-WW II coated Dagor clones -- came out much better than good enough except a 1937 or so f/10 (fixed aperture) prototype of a design that never went into production. My 210/7.7 Beryl S matched a 210/9 Konica Hexanon GR II for sharpness from f/16 down, beat it for contrast at all apertures. The only Dagor I have, a 45/9 CZJ Goerz Dagor, is marginally usable on 2x3 because of mechanical vignetting at larger apertures. On the whole a 47/5.6 Super Angulon, especially with center filter, is much preferable.

However, you're the person making what seem to be unfounded claims and demanding that we test to find out whether you are right. Do your own tests.

Pere Casals
21-Apr-2019, 17:14
Obviously the 1920 will not be coated and the Kern multi-coated. What are the other differences? I'm guessing the kind of glass used will be another difference.
thanks

By 1920s lens manufacturing was not as good as post wwii. Of course lens manufacturing has many factors, from metrology to glass uniformity, tolerances, collimation, numerical methods to combine the right elements in the crop that have an optimal compensation, etc, etc.

WWI and specially WWII pushed design/manufacturing technology forward.

It would be interesting to see test of ancient glass ratings and see how optical performance increased.



unfounded claims and demanding that we test to find out whether you are right. Do your own tests.


Dan, I've tested my lenses, but I've no antique glass to test. What I've been reading in several sources is that usual peak performance in 1920 was around 25lp/mm for LF lenses, while MF lenses in the late 1930s could reach around 65. If you can point reliable performance information about 1920s LF glasses this would be nice.

What is clear to me is that 1980 LF glass resolves way more than 1920 LF glass, I cannot say if the ratio is x2 or x3 for the average LF lens, but IMHO it's around that...



acceptance tests

To me a 25lp/mm 8x10 "lens is of course an acceptable lens, it would deliver a 1m flawless print !!!

Dan Fromm
21-Apr-2019, 17:34
Papi, we recently discussed what I think is your source for changes in lenses' performance by era. My reading of the source is that the author pulled his numbers of of somewhere dark and smelly.

Pere Casals
21-Apr-2019, 17:48
Papi, we recently discussed what I think is your source for changes in lenses' performance by era. My reading of the source is that the author pulled his numbers of of somewhere dark and smelly.

Well, we don't have reliable data for exact numbers... but do you have any doubt about that average LF lp/mm at least doubled since 1920s ?

Dan Fromm
22-Apr-2019, 05:25
Well, we don't have reliable data for exact numbers... but do you have any doubt about that average LF lp/mm at least doubled since 1920s ?

Papi, this is an empirical question that can be answered only by testing. I have an opinion -- not doubled -- but it is not well-founded.

Pere Casals
22-Apr-2019, 12:50
this is an empirical question

Here we have an example. Berthiot Anastigmats, Série Ic – 135mm Flor f/4,5 (1921). Berthiot submitted a copy of their new lens to Société Française de Photographie for testing: “It is among the best lenses we have been given to examine.”

"Wide open it resolves 10 lp/mm over a 170 mm circle, 20 lp/mm over a 120 mm circle." See section 7.2.4 in:

http://www.galerie-photo.com/berthiot-anastigmats-en.html
https://web.archive.org/web/20190416045330/http://www.galerie-photo.com/berthiot-anastigmats-en.html

________________

Eurygraphe Extra Rapide f/5,7 (1894), at full aperture for a resolution of 10 lp/mm

________________

Still we should consider that these ratings are wide open, performance may be well better at optimal aperture...

Dan Fromm
22-Apr-2019, 13:27
Papi, its nice that you found my Berthiot article. Now use the list to find the 1963 GOI catalog and my collection of USAF datasheets. You'll find that many lenses for aerial cameras have low resolution off-axis wide open. On axis too, for that matter.

So what? LF shooters rarely use their lenses wide open.

Pere Casals
22-Apr-2019, 15:06
LF shooters rarely use their lenses wide open.

Except wet plate ones !!!

In the past photographers were more motivated to shot wide open because of lower sensitivity and poor illumination gear. I guess that because of that the Société Française de Photographie was testing wide open.

Inisisting in what I mentioned in that other thread, in the late 1920s LF photographers considered that f/64 generally delivered the sharpest negatives with the available glasses. If it was like this then diffraction was limiting to 25lp/mm.

But as you said it would be interesting to test ancient lenses...