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View Full Version : 240mm for 8x10: Docter Germinar W vs. Fujinon A



Phong
7-Jan-2006, 06:59
I am a little confused by something Kerry Thalmann wrote; on the one hand, this page on Kerry's website (http://www.thalmann.com/Ebay/240mm_Germinar_W.html) indicates that the Fujinon A and the Docter Germinar have similar coverage. On the other hand, according to one of Kerry's post on this forum (http://largeformatphotography.info/lfforum/topic/502306.html) , the Docter lens has larger coverage. Kerry and others, could you clarify ? Thanks much in advance. By the way, how much does the Docter lens weigh in a Copal #1 shutter ?

Arne Croell
7-Jan-2006, 08:05
Phong, both lenses have an official coverage of 70° as stated by their respective manufacturers. However, often the useable coverage of a lens can be larger for practical use, especially when stopped down. How much, really depends on your personal criteria. The most common example are the G-Clarons, with an official coverage of 64° and a useable one of 80° stopped down well. Whereas the Germinar-W is in the G-Claron camp (but multicoated), with coverage up to 80° stopped down, the Fujinon apparently breaks down pretty quickly (according to Kerry and others, I haven't tested it at the extremes). If MTF curves for both lenses were available (they are not), we would likely see that for the Fujinon all the curves will drop close to zero pretty quickly after the 70° mark, whereas for the Germinar-W there would be a more gradual falloff at least for the coarse to medium detail curves (3-10lp/mm).

Joerg Krusche
7-Jan-2006, 09:32
Phong, if you search on APUG for "germinar-w" you may find a note from "Donsta" who had the Fujinon A 9/240 and then bought the 9/240 Germinar-W from Kerry Thalmann. He then decided to sell the Fujinon because the Germinar offered him greater coverage on 8x10.

Best

Joerg

Jeff Liao
7-Jan-2006, 09:44
Dear Arne,

by any chance do you know the coverage of Apo-Germinar W 8/240 at infinity?
anyone ever do the test?

thanks alot

JEff

Joerg Krusche
7-Jan-2006, 13:06
Jeff,

the Apo Germinar W 8/240 due to a somewhat smaller picture angle acc. to manufacturer specs has less coverage the Germinar-W 9/240 .

Best

Joerg

Jeff Liao
7-Jan-2006, 13:42
from Arne's chart of Docter Germinar

Apo Germinar W 8/240 has 72 degree of angle coverage.

Apo Germinar W 8/240 should have bigger image circle than Germinar-W 9/240.

there is no reason why make then twice size of old lens and only have same image circle..

thanks

Joerg Krusche
7-Jan-2006, 15:07
Jeff,

I correct myself, Arne's chart is ok, Carl Zeiss specifies 73 degrees at f=16. The Apo Germinar W 8/240 with 8 all air spaced multicoated elements was technological overkill, perhaps the best repro lens in it' s application range ever made, .. but very heavy, too heavy.

Hope this helps.

Joerg

Arne Croell
7-Jan-2006, 15:23
Jeff, the Apo-Germinar W has 73°coverage, so nominally that is a little more than the Germinar-W. However, the mount vignettes if you go considerably beyond this value, so the image circle cannot be extended much farther than specified, even when stopping down to really small apertures. Thus the Germinar-W has more coverage in practice at small apertures, with the Germinar-W being 5-6 times lighter than the Apo-Germinar W. As Joerg stated, the Apo-Germinar W was probably one of the best corrected WA lens for process lens applications (the MTF curves at 1:1 are considerably higher than those of the G-Claron, especially in the corners) ever available, but at the cost of weight, size, and money.

Kerry L. Thalmann
7-Jan-2006, 16:51
Phong,

Joerg and Arne have done their usual excellent job answering most of your questions. Based on tests by Jim Galli and others, the usable coverage of the 240mm Germinar-W is right around 80 degrees when stopped to about f45. Jim reported 410mm (equal to 81 degrees) of usable coverage at f64. So, if you are willing to stop down a bit (f32 -f45), you can get a usable image circle in the 380 - 400mm range - which allows for substantial movements on 8x10. Even at f16, the manufacturer's rated coverage (70 degrees = 336mm IC) is enough to cover 8x10 with very limited movements.

As Arne stated, performance of the Fujinon A series drops off very rapidly beyond the manufacturer's spec (the same 70 degrees and 336mm). Based on my experience, you can't really gain much, if any, usable coverage by stopping down further (maybe a few millimeters, but not nearly as much as the Germinar-W or G Claron). Don't ge me wrong, the 240mm Fujinon A is a great lens - quite amazing actually given the small size and Copal No. 0 shutter. For 4x5 or 5x7 use, the performance of the 240mm Fujinon A and the 240mm Germinar-W are very comparable. However, for 8x10 use, I'd take the 240mm Germinar-W every time. The extra coverage makes it a much more usable lens for 8x10. The 240mm Fujinon A makes a great lens for 4x5 and 5x7 use and, in a pinch, it can be used on 8x10 with minimal movements. The 240mm Germinar-W makes a great everyday 8x10 lens.

Concerning the weight, in barrel, the 240mm Germinar-W weighs 230g. I have my 240mm Germinar-W mounted in a Copal Press No. 1 shutter and it weighs 279.54g. In a standard Copal No. 1 shutter, it weighs 325.33g. For comparison, my 240mm Fujinon A in Copal No. 0 weighs 243.36g. So, the Fujinon is a bit lighter (mostly due to the lighter Copal 0 shutter), but the 240mm Germinar-W is still very compact and lightweight for a lens that covers 8x10 with generous movements.

Kerry

Kerry L. Thalmann
7-Jan-2006, 16:56
Apo Germinar W 8/240 has 72 degree of angle coverage.

Apo Germinar W 8/240 should have bigger image circle than Germinar-W 9/240.

there is no reason why make then twice size of old lens and only have same image circle.

Jeff,

I think you may have that backwards. The 240mm Germinar-W is actually the newer design. It was the last new large format product line developed by Docter Optics prior to Berhard Docter's unfortunate passing.

For general photographic use, the much smaller, lighter Germinar-W is a more practical solution than the older, bigger, more expensive APO Germinar-W.

Kerry

Jeff Liao
7-Jan-2006, 17:30
thanks you guys..

I was wondering if APO Germinar-W 240mm can cover 20x24" at infinity.

from the number, guess it won't



thanks again

jeff

Phong
7-Jan-2006, 21:26
Joerg, Arne, Kerry, et al., thank you for the great information. I guess I will have the Docter lens shutter mounted, and sell the Fujinon A. Looks like the Docter lens will serve me well in both 4x5 and 8x10 formats. This is great news.

Jim Galli
7-Jan-2006, 23:21
Bottom line is, I sold the Fuji, good as it is, kept the Germinar-W, and it ain't for sale. I never did use the f9A on 8X10. I always seem to grab the G-Claron for 810 until the Germinar came along. Even now it is second fiddle to a mis-matched 225mm G-Claron dagor type that seems to never let me down.

Arne Croell
8-Jan-2006, 13:02
Jeff, for a 240mm on 20x24" you need close to 120° coverage. Only a super wide angle construction like a Super-Angulon XL or one of the old exotic SWA's (Hypergon etc.) will be able to give you that.