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ic-r, I'm a firm believer in using enlarging lenses at least twenty percent longer than the film's diagonal and I think fifty percent is probably optimal provided the lenses are used within their optimum magnification range. At least this was my personal experience thirty-five years ago with EL Nikkors and Rodagons of the time. I just don't have enough room in my little building to facilitate the print size I want and use lenses longer than "normal".:)
In answer to post #29
Let
k = negative-to-print distance
f = focal length
n = negative dimension (length, width, or any other dimension of interest in the negative)
p = projected dimension of n
p = ([(k + sqrt(k^2 – 4kf) )/2f] – 1)n
Example: k = 4270mm, f = 135mm, n = 56mm
P = ([4270 + sqrt(4270^2 – 4*4270*135)/2*135] – 1)*56mm = 1657mm = 65”
It’s not pretty, but that’s the way it is.
The calculation is much simpler if you use the lens-to-print distance.
In that case we’d let
u = lens-to-print distance
p = [u/f – 1]n
Example:
u = 4130mm
p = [4130/135 – 1]*56mm = 1657mm = 65”
I assume you talked to Stephen Gandy at Cameraquest. Just wait for him to get back to you. But if he
has already sold that 300G, there are some decent bargains out there on the 305 Apo Nikkors. They'll
be around a stop slower, but are probably going to be superior in several respects to any ordinary enlarging lenses. The formal specs for these are a bit misleading because they were composed with the printing industry in mind (copy cameras) and not enlarger use.
Yes, it was Stephen Gandy.
We-e-e-e-llll darn... I called Stephen Gandy today and he can't find the 300 Rodagon-G nor the 300 EL Nikkor.
Sorry to hear that. The viewing brightness would have been easier with a G-Claron than with an Apo Nikkor, but the optimum printing f-stop similar - around f/11.
Up again...
First, I've decided to lengthen the building ten feet. This will net me about twenty-four feet of internal work space which is more than long enough for my purposes. It's also a better fit for most automobiles so this is a logical decision.
If I can't find affordable Rodagon-G's I guess I'll have to try normal taking lenses. Maybe they'll work well at high magnification. I'll find out once I have the building lengthened and set up a darkroom.
Any more advice is greatly appreciated... or if you have a nice 150mm or 300mm Rodagon-G you want to sell on the cheap then please let me know before I spend all my money on booze and ladies!!:D
A little more research and trying to drill information into my thick skull... It appears that a standard Componon-S or similar will work fine for 8x10" at 12-16x magnification but I'll need a Rodagon-G or similar for enlarging 6x12cm to 25-30x. Gee whiz... it may be cheaper to shoot 8x10" all the time.:)
I ran across some references to Fax-Nikkor and Agfa Repromaster lenses. Anyone have info on those?
RE 300mm Componon-S: All I can find is anecdotal opinion regarding magnification range. Schneider claims 2-20x for the entire line. If this is accurate then very large prints at 12-16x are well within their specs and prints should be very sharp center-to-corner. Any more data available?
As far as my Schneider Literature indicates, they never made a "HM" high magnification lens in the 300mm focal length (unlike Rodenstock). So 2 to 20x is it.
My 300mm is a Rodenstock (non-G) and my 360mm is a Componon (non-S) so I cannot give you any first-hand information about the 300mm Componon-S. My guess is that it will be just fine for your purposes. (B&W enlarging , right?)
Do you have a lens yet? Here is a Componon-S 300mm for $100: http://www.largeformatphotography.in...ighlight=300mm
The only reason I have not bought that lens is that I already have four lenses for 8x10 enlarging and they pretty much do the same thing.