I've collected a number of G-Claron lenses and it's been suggested to me that the elements could be interchanged and used as a casket set. So using the 210, 240 and 305s that fit into a copal 1 what focal lengths could be made? what adjustments to the aperture scales would be necessary for correct exposure? and would there be compromises in the lens performance?
http://www.largeformatphotography.in...ate-Casket-Set
as much as I know...
If, and this is a big if, dagor type G-Clarons follow the f/6.8 Boyer Beryl pattern, half of a 210/9 will be a 360/18; 240, 410; 305, 522. Combining unlike cells won't buy you much, 210 + 240 = something in between, and so on.
So what happens if you just use half a G-Claron? Anyone try that? Then you get a whole bunch of interesting focal lengths. (710 mm etc.)
Kirk, I just put the question to a 210/6.8 Beryl and a 210/9 dagor type G-Claron. I measured with very low precision and accuracy. They're about the same. A single cell's focal length is around 1.7x the complete lens' focal length.
By the way, plasmat type lenses are convertible too. Well, not that many, according to their makers, but single cells will form an image. A single cell's f/# is usually twice the complete lens', its focal length is around 1.7x (convertible Symmars, 1.75x) the complete lens'.
Don't be pikers, if you're going to play silly lens games with dagor types, play them with plasmat types too.
I have one by accident. Years ago a seller on ebay very apologetically offered a 210 rear and 240 front old style dagor type for cheap and knowing that Schneider had done that same thing years ago with the original dagor type Symmar's I thought, why not? It's a killer performer. 225mm. Covers 8X10 very nicely, and seems perhaps sharper than the others (probably just my over-active imagination). I saw no need to experiment further. A 270 and a 210 would make a 240 with smaller than standard full aperture. I've already got a 240. Who needs that. I suppose a 270 front and 240 back would make a viable 255, but ??? Not worth the trouble. the jumps are too small to bother with.
Whatever you do, put the larger light in front, smaller one in back.
Missed this
More to test!
Thank you
Originally Posted by Dan Fromm
Tin Can
Well I did try
https://www.largeformatphotography.i...=1#post1561918
Lasse Thomasson | Instagram
Also relevant I've unwittingly tried combining two focal lengths of a plasmat lens of the same type. I believe it was a 150mm up front and 100mm rear element- the result looked like a 100mm to me.
A few years ago I made a complete table of all possible lens combinations of the G-Claron lenses. 27 different lenses are possible and yes I realised a complete casket set of all focus length.
The most usefull for me is the combination of the cells of the 210mm and 150mm, in combination it is a 180mm lens with f/10.8 A perfect wide angle lens for 8x10" with around 350mm immage circle. Enough for me when using it for landscape.
It starts above on the left side, here a 360mm (355mm) in a shutter size 3. The table shows the aperture numbers of this lens.
Right of it you find the 300mm (305mm) mounted in shutter size 3. The correct aperture numbers are mentioned.
Example: 360mm f/22 is f/18.3 for the 300mm; f/16.5 for the 270mm; 14.7 for the 240mm; f/12.8 for the 210mm and f/9.2 for the 150mm
All aperture values are the ones from a shutter size 3 with 360mm. The other values are calculated.
I hope it is understandable
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