150 G-Claron info needed

[Darryl Baird]

I'm continuing to expand the stock of lenses I'm using for 8x10, mostly on the wider end. I'd pretty much decided I could afford a 210 Fuji (older style with 352mm of coverage), but as I looked at an old brochure on the G-Claron line of lenses I was struck (pretty hard) by Schneider's claim of 385mm of coverage for a 150 at f/22 :eek: !!!

I've seen folks post that Schneider under-reports coverage and this is certainly true for their more contemporary literature on this line of lenses, and the brochure (http://www.cameraeccentric.com/html/info/schneiderb/p8.html) was old (1986) and posted at Cameraeccentric, but 385mm image circle is huge.

Anybody have any info to share about using this lens on 8x10, stopped down and the coverage they can verify?

Also, I've read it fits directly into a #0 shutter ... Copal, Seiko, etc. True or false?

[Jim Galli]

I'm continuing to expand the stock of lenses I'm using for 8x10, mostly on the wider end. I'd pretty much decided I could afford a 210 Fuji (older style with 352mm of coverage), but as I looked at an old brochure on the G-Claron line of lenses I was struck (pretty hard) by Schneider's claim of 385mm of coverage for a 150 at f/22 :eek: !!!

I've seen folks post that Schneider under-reports coverage and this is certainly true for their more contemporary literature on this line of lenses, and the brochure (http://www.cameraeccentric.com/html/info/schneiderb/p8.html) was old (1986) and posted at Cameraeccentric, but 385mm image circle is huge.

Anybody have any info to share about using this lens on 8x10, stopped down and the coverage they can verify?

Also, I've read it fits directly into a #0 shutter ... Copal, Seiko, etc. True or false?

One tiny caveat: It covers that at 1:1 :D For normal shooting it covers 5X7 barely.

[Ole Tjugen]

1986 is not old in LF lenses; 1896 is.

All the -Claron lenses are repro lenses of one sort or another, and are optimised for 1:1 or close to that. All (official) image circle claims for repro lenses are stated for 1:1.

But yes, it fits in a #0 shutter.

[Darryl Baird]

:rolleyes: Still laughing at myself... I knew if the specs were true, they'd be written about EVERYWHERE, in large and bold type and would sell at huge premiums (more than already) like the Fuji A lenses, but then it answered my questions and helped me to get some closure on my thinking (and buying).

onward through the fog...

[lee\c]

I used to have a Fujinon W 150mm/6.3 that covered 5x7 and I never ran out of room. Nice tiny little lens. I have used the G-Claron
210 on my 8x10 and it covered without movements as I recall. Been a few years, I since retired the 210mm to my Durst 138s for enlarging 5x7 negs.
lee\c

[Brian Ellis]

You might look at the 210 G Claron. It covers 8x10 when stopped down to about f16 and the useful coverage continues to increase the more you stop down. I've had a couple of them that I used with 8x10 and had plenty of room for movements when stopped down to my usual (for 8x10) f32 and smaller.

[lee\c]

Brian is right about the coverage of the 210 G Claron and stopping down past f16. I forgot to include that info. It has been a few years since I used mine on the 8x10.

lee\c

[Emmanuel BIGLER]

The G-clarons are listed for 64° of angle. So this is the only spec to know in addition to the focal length ;-)
So for the 150 in infinity-focus position you get something like 190 mm i.e. focal_length x 0.62 x 2 (0.62 = TAN(32°))
Twice this figure for 1:1 ratio yields ~ 380 mm close to the actual spec of 385 mm in the brochure.

[Jim Galli]

The G-clarons are listed for 64° of angle. So this is the only spec to know in addition to the focal length ;-)
So for the 150 in infinity-focus position you get something like 190 mm i.e. focal_length x 0.62 x 2 (0.62 = TAN(32°))
Twice this figure for 1:1 ratio yields ~ 380 mm close to the actual spec of 385 mm in the brochure.

That 64° spec was to hold the modulation transfer function specs to a tolerance that graphic arts printers required. It really sees 82° at smaller apertures with sharpness well within tolerance of most LF photogs far into the corners at that angle. We have a different requirement than the original user it was built for.

[Darryl Baird]

well, I know I can't do the math to answer all my questions, it's easier to buy the lens and conduct testing. My only problem is time, so I bought one in a barrel and will drop into a #0 shutter and have a go. I'm already working on a project, it's summer when I have time to do this stuff, and I'm super curious anyway. (I would like to know what are the image circle(s) focused at between 6-10 feet, at several given f stops; I can't imagine being good enough in math to figure that out :D ) I'll use my eyes.

stay tuned

[Pete Roody]

It covers 5x7, not 8x10.

[Darryl Baird]

I have (copies of) two different versions of G-Claron brochures. In the most recent I have, it lists an image circle of 284 at f/22 at 1:2 reproduction (distance?). My question is, how far from the (focused) lens is something at a ratio of 1:2?

I'm headed to the basement to look for a couple of books that might have the answer, but just in case... you guys with the bigger brains might have an answer. ;)

[Pete Watkins]

I have a late 150 G-Claron that I bought new from Robert White about 7 years ago and I love it. Yes, it's f9 but on holiday last year with my beautiful B&J 4x5/5x7 I used only the 150 and my 203 f7.7 Ektar and I had a great time with very satisfactory negs. Go for a late one and you won't regret it.
Pete.

[Emmanuel BIGLER]

From Jim :
That 64° spec was to hold the modulation transfer function specs to a tolerance that graphic arts printers required.

Agreed ! But the guys in the Old World have alwys been very conservative, not like in the US where they are all revolutionaries ;)

Not kidding : Same conservatism for the official specs of the apo-ronar, listed @48° but useable as a standard focal length ~ 53 degrees.

From Darryl :
My question is, how far from the (focused) lens is something at a ratio of 1:2?

Simple ! No maths required ;)

let M = magnification ratio = (image size) / (object size ) = 1:2 = 1/2 = 0.5

here, focal_length = 150 mm

lens-to-subject distance is (focal-length) x (1 + 1/M) ; for M = 1/2, we get 150 x 3 = 450 mm

bellows extension beyond the focal plane : ext = M x f = 150 /2 = 75 mm

total bellows length (for most quasi-symmetrical lenses including G-clarons)
D = (1+M) x focal_length = 150 x (1.5) = 225 mm

Useable image circle in macro, approx, : C =~ C_infinity x (1+M)

C_infinity = 2 x (focal_length) x TAN (Angle/2)

example C_infinity = 190 mm, C (@ M=1/2 ) = 190 x 1.5 =~ approx 285 mm