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Hi again,
I bought a Schneider 121mm lens and I will use it on an 8x10 camera. This will be 100 degrees of field of view (diagonal), theorically equivalent to a 18mm lens on a 35mm format.
Does someone use a viewfinder for this lens ?
I was thinking of buying a Sea&Sea viewfinder, any toughts ?
Thanks !
Hi EricQuote:
Originally Posted by Eric Constantineau
I assume you have the 121mm Schneider Super Angulon? if so I am fairly sure that it doesn't cover 8X10, I have a later 120mm Super Angulon which only just covers 8X10 and needs a centre filter as there is approx. 3 stops difference between the centre and edge, sorry if this is bad news but hopefully it may save you some hassle.
Good luck.
According the the www.schneideroptics.com website, the 121mm SA and the 120mm SA have the same image circle. (288.4 for 121 and 288 for 120.) So, if the 120mm covers, the same should be true for the 121mm.
In fact, Ansel Adams claimed in his book that the 121mm would cover 8x10 on axis.
The Schneider specs are, of course, quite conservative. They claim, for example, that the image circle of my 47mm Super Angulon is 123mm, but I have used it with some movements on 6x12 without complete vignetting. But there is considerable partial vignetting. Center filts may do more harm than good--they darken the center to reduce the gradation into the corners but they also mechanically vignette slightly when the lens is used outside its spec.
A 121 on 8x10 is probably a bit wider in effect than an 18 on 35mm, because of the difference in shape of the format. Just comparing the width, it's probably closer to 17. In height, it's more like a 14. I think I would be tempted to experiment with a Cosina/Voigtlaender viewfinder for their 15mm lens on the Bessa rangefinders. I have a Sea-and-Sea viewfinder for the Nikonos and it's--okay. That might work for you. The Nikon viewfinder for the Nikonos 15mm underwater lens has a curved port and can only be used under water, but the Sea-and-Sea finder for their "16mm" supplemental lens has a flat port and will work on land.
Come to think of it, I have used that Sea-and-Sea finder on a Fed rangefinder when I had adapted an 18mm Canon FD lens to the Leica Thread Mount. That was mostly an experiment to see if it could be done, though, and I don't recall over the ensuing decade or so how accurate the finder was. With those rangefinders, one had to be a bit loose with the edges.
But to solve the same problem I bought a Maxwell screen for my 4x5 camera so that I could see the corners with my 65mm lens right on the ground glass. A viewfinder will tell me where a camera is pointed but not whether it's in focus, and managing focus with 8x10 will require inspecting the corners, I would think.
Rick "who might have to retask that S&S finder for a large-format project some day" Denney
Hey thanks !
I think I' just try the sea and sea, nothing has to be perfect to have fun :-)
Thanks for sharing your experiences
Eric
I finally bought a Voigtlander 15mm and it fits perfectly.
Just for the record, if the Sea and Sea is like the Nikonos u/w finders, they're corrected for use in water -- using them on land gives a blurry image, and the angle of view is different because of the varying indices of refraction of water and air.
Quote:
Originally Posted by Eric Constantineau
No, the Sea and Sea finder for their 16mm supplemental lens (which attaches to the Nikonos's 35mm standard lens) has a flat port and works fine out of the water. I have not checked the coverage in dry air, but it might be close enough. 16mm is 16mm. It's the water that refracts differently, narrowing the coverage of a 16mm lens, but in air it should behave like any other 16mm lens.Quote:
Originally Posted by John Schneider
(The supplemental lens, however, does not work in air--it requires a wet interface between it and the Nikonos lens.)
The Nikon 15mm finder for the Nikonos has a curved port and only works underwater, as you say.
The key is the flat port, or front surface, which is required for a lens intended for underwater use to focus in air.
Rick "who replaced a leaking Sea and Sea 16mm finder with a Nikon 15mm finder" Denney
121mm covers 8x10, at least mine did. You'll want to use gel filters.
Voitlander makes a zoom wide angle viewer, but it's pricey. Contax has a 16mm. Maybe a door peephole with a little bit of black tape would do the job.
Leica makes an 18mm finder: http://www.bhphotovideo.com/c/produc...er_M_18_f.html
It'll cost more than you paid for your lens, but it is available.