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View Full Version : Are G Claron lenses interchangeable with the same shutter?



DannyTreacy
6-Nov-2017, 08:19
Hi,

So I have a 210mm f9 g claron, I bought it years ago for 10x8 macro photography, which it was very good for.

I plan on using it outside to see how it performs as a wide lens, I understand that it may have limitations when movements are used, so if I wanted to get a 270mm g claron to use instead of the 210mm would I be able to just swap out the front and rear elements, using the shutter that the 210mm is currently in?

The shutter was re-marked by the previous owner so that the aperture was appropriate for the 210mm, if I swapped for a 270mm would it need to be recalibrated again?

Thanks

Corran
6-Nov-2017, 08:44
would I be able to just swap out the front and rear elements, using the shutter that the 210mm is currently in?

Not necessarily. Even different G-Clarons of the same focal length may use different shutters depending on their age as the design was changed during their production life. First off you didn't say what shutter your 210mm is in. If it's a Copal 1, as it probably is, you'll need to see if the 270mm goes into a Copal 1 as well. I know the older GC lenses are bigger and therefore if the 270mm you are looking at is older than around 11 million it definitely needs a larger shutter.


The shutter was re-marked by the previous owner so that the aperture was appropriate for the 210mm, if I swapped for a 270mm would it need to be recalibrated again?

Thanks

The aperture is only good for the focal length it is made for. You can get a rough approximation though - a 210mm lens at f/16 would have an apparent aperture of 13.125mm. A 270mm lens with that opening would correspond to an f-stop of f/20.6. Basically you can "correct" the aperture by adding about 2/3 of a stop to the written number in your head.

By the way, 270mm GC lenses are probably a bit rarer than other focal lengths. Possibly look for a 305mm - which newer ones should fit into a Copal 1 shutter I believe. Older ones do NOT, I have two of this type.

xkaes
6-Nov-2017, 08:54
All of the G Clarons cover at least 8x10" -- but only at 1:1. At infinity, you have to use a 270mm or longer. Others will chime in, but I assume that at least two shutters were used, for example, #1 and #3 (on the longer lenses). As to using a 270mm as a not-terribly-wide-angle taking lens, you'll need to get the elements -- without a shutter -- then figure out if they fit your shutter, and then realize you will probably get better results if you reverse the lens!

Corran
6-Nov-2017, 09:05
In response to the above, it's not good to generalize the G-Claron line. Older "Dagor" type lenses have massive coverage - the 305mm covering ULF up to 8x20. Newer "Plasmat" lenses at 240mm and above cover 8x10 with plenty of movement, and even the 210mm from what I understand covers 8x10 barely. I state this with experience - I have a 240mm GC Plasmat for my 8x10 and the 305mm Dagor for 8x20. When you get down to the 150mm GC Plasmat, yes you'd need to focus close up to get coverage on 8x10. I use that lens for macro 4x5 images occasionally.

I have never wished for more sharpness from my GC lenses regardless of the element placement. Use them as-is at near infinity and you will be just fine.

Dan Fromm
6-Nov-2017, 09:18
According to the catalog, the 210/9 G-Claron's cells fit a #1. So do the 270/9 G-Claron's cells. This is true for dagor type and plasmat type G-Clarons.

A #1 Compur/Copal/Prontor shutter is a #1 Compur/Copal/Prontor is a #1 ...

Just do it. Yes, the shutter will have to be scaled for the 270.

Drew Wiley
6-Nov-2017, 16:32
My 240 G-Claron easily covers 8X10 at infinity. Don't get confused by the official specs intended for graphics rather than general photography standards. And these are very sharp lenses at infinity, as well as close up.

Greg
6-Nov-2017, 17:09
Can not remember where I read this but someone wrote that they took the front elements from one Computar lens and combined them with the rear elements of another focal length Computar to get, I believe, more coverage. If true, I wonder if this could be done with a pair of G-Clarons? Obviously both G-Clarons have to be using the same shutter. Just a thought...

Does anyone have a list of the shutter sizes that the G-Clarons came in?

Dan Fromm
6-Nov-2017, 18:23
Greg, go here: http://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses Schneider URLs are in the list. Look 'em up.

Jim Galli has advocated using unequal cells from dagor type G-Clarons to make a casket set. I don't see the point of it, the possible combinations have focal lengths fairly close to those of G-Clarons with matching cells, but that's not a good reason not to play.

Luis-F-S
6-Nov-2017, 20:37
As to using a 270mm as a not-terribly-wide-angle taking lens, you'll need to get the elements -- without a shutter -- then figure out if they fit your shutter, and ..............

My 270 Dagor type lens is in a Compur #1 shutter! Schneider literature also lists the 270 in the #1. My 240 Dagor type and 210 Plasmat type both also fit in a #1.

DannyTreacy
7-Nov-2017, 02:36
Thanks for all the info on this.

What's the difference between a plasmat and dagor type g claron and how can I tell which type my 210 is?

Thanks

Dan Fromm
7-Nov-2017, 05:51
A plasmat has six elements in four groups. The outer two groups are cemented doublets, the inner group is a singlet. A dagor type has six elements in two groups. Each group is a cemented triplet.

To tell whether a lens is a plasmat type or a dagor type, take a single cell, shine a point source of light into it and count reflections. A plasmat cell will have four strong reflections, one from each of the four air-glass interfaces, and one weak reflection, from the glass-cement-glass interface. Weak reflections are often hard to see. A dagor cell will have two strong reflections and two weak ones. Again, the weak reflections can be hard to see.

In the G-Claron line, dagor types (serial number probably < 12,000,000) were replaced by plasmat types (s/n probably >= 12,000,000) in the early 1970s. There's considerable doubt about where the s/n break is. Count reflections unless the s/n is > 13,000,000.

Luis-F-S
7-Nov-2017, 06:41
Thanks for all the info on this.

What's the difference between a plasmat and dagor type g claron and how can I tell which type my 210 is?

Thanks

Search the threads

Corran
7-Nov-2017, 09:23
You might find this thread I started useful, comparing Dagor and Plasmat versions of the 305mm:

http://www.largeformatphotography.info/forum/showthread.php?122121-A-Tale-of-Two-305mm-f-9-G-Claron-(Dagor-type)-Lenses-Cell-Spacing

But Dan pretty much gave you the rundown.

DannyTreacy
7-Nov-2017, 10:59
A plasmat has six elements in four groups. The outer two groups are cemented doublets, the inner group is a singlet. A dagor type has six elements in two groups. Each group is a cemented triplet.

To tell whether a lens is a plasmat type or a dagor type, take a single cell, shine a point source of light into it and count reflections. A plasmat cell will have four strong reflections, one from each of the four air-glass interfaces, and one weak reflection, from the glass-cement-glass interface. Weak reflections are often hard to see. A dagor cell will have two strong reflections and two weak ones. Again, the weak reflections can be hard to see.

In the G-Claron line, dagor types (serial number probably < 12,000,000) were replaced by plasmat types (s/n probably >= 12,000,000) in the early 1970s. There's considerable doubt about where the s/n break is. Count reflections unless the s/n is > 13,000,000.

Thanks for the great info Dan, no need to search any threads with concise details such as this.

xkaes
7-Nov-2017, 11:23
A plasmat has six elements in four groups. The outer two groups are cemented doublets, the inner group is a singlet. A dagor type has six elements in two groups. Each group is a cemented triplet.

Just curious, what is a six element in six group lens called -- a Fujimat or a Fujigor? :confused:

Dan Fromm
7-Nov-2017, 14:23
Thanks for the great info Dan, no need to search any threads with concise details such as this.

Danny, I'm all for solidarity among Dans, but on the whole you'd be better off if you searched. This forum's search function isn't very good, use Google advanced search. Instructions can be found via http://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses.

To add insult to insult, you've been asking questions that you should have been able to answer for yourself. The link I posted above will take you to a list of useful links that will make it easier for you to help yourself. Remember, LF helps those who help themselves.

Luis-F-S
7-Nov-2017, 15:03
Dan, this is probably a stupid question, but I've never figured out how to get it to search on more than one word. For instance, how do I do a search for say "DeVere Enlargers" or "12" Dagor", etc. I looked in the link above, but could not find any answers. Thanks, L

Dan Fromm
7-Nov-2017, 15:34
Dan, this is probably a stupid question, but I've never figured out how to get it to search on more than one word. For instance, how do I do a search for say "DeVere Enlargers" or "12" Dagor", etc. I looked in the link above, but could not find any answers. Thanks, L

Fair question, Luis. Look under "Web sites/Forums:"

I think perhaps I'll add a section "Searching in web sites/forums:" Do you think that would be easier to find?

Cheers,

Dan

Luis-F-S
7-Nov-2017, 16:03
Is "Websites/Forums" under Forums on this website? If you could post a link as to where to look that would be wonderful!

Dan Fromm
7-Nov-2017, 16:18
Is "Websites/Forums" under Forums on this website? If you could post a link as to where to look that would be wonderful!

I'm sorry, we've confused each other. I was referring to the list mentioned in the first post in this http://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses discussion. Go there, click the link in the first post. This will take you to a pdf with a mountain of bookmarks on its left. Click the bookmark "Web sites/Forums:"

I've checked the list. It has a bookmark "Searching in web sites:" It will do too.

I noticed that the bookmarks don't show when I read the list with a browser, e.g., MS Edge or Firefox. To get most benefit from the list, download it and open it with a pdf reader or tell your browser to open it with a pdf reader.

DannyTreacy
8-Nov-2017, 01:12
I'm sorry, we've confused each other. I was referring to the list mentioned in the first post in this http://www.largeformatphotography.info/forum/showthread.php?138978-Where-to-look-for-information-on-LF-(mainly)-lenses discussion. Go there, click the link in the first post. This will take you to a pdf with a mountain of bookmarks on its left. Click the bookmark "Web sites/Forums:"

I've checked the list. It has a bookmark "Searching in web sites:" It will do too.

I noticed that the bookmarks don't show when I read the list with a browser, e.g., MS Edge or Firefox. To get most benefit from the list, download it and open it with a pdf reader or tell your browser to open it with a pdf reader.

Sorry Dan but all you've illustrated in the posts since you rather patronisingly advised me to search the threads is that this forum's thread searches are useless, a fact that I was already aware of.

I really don't see the problem in asking a simple question on my own thread and getting a simple response which is what you gave.

The funny thing is that I'm a member of many other photography forums, Diy forums, shooting and hunting forums and vehicle forums and I've never been able to work out what is it about this large format photography forum that attracts such belligerent pedants, perhaps I should search the threads for an answer, if it worked.

xkaes
8-Nov-2017, 06:07
Remember, LF helps those who help themselves.

Well said. 99% of us are grateful for any help/direction we get on this Forum. We should not be put off by the 1% that expect spoon-feeding -- for free!