Fresnel lens for 8x10 Toyo M Field Cameragreenspun.com : LUSENET : Large format photography : One Thread
When using my Toyo M 8x10 with a wide angle lens, the corners of the ground glass get rather dark. I would like to add a Fresnel lens. There seems to be a slot in the frame behind the groundglass (looking towards the bellows) which could be meant for placing a Fresnel. Toyo does not sell any such article. I also own a Tachihara 8x10 which has a Fresnel lens placed in front of the groundglass. Are these Fresnel lenses of standard size and can I place the Tachihara lens in front of the Toyo groundglass without infringing on the focusing ability of the camera? What do the 8x10 gurus of this community have to say about this?
-- Emil Ems (email@example.com), November 16, 1998
I am far far far far far from a guru, BUT Ron Wisner has quite a bit to say on the subject and his opinions can be see on the View Camera Magazine web page in the on-line articles. His p.o.v seems valid but runs counter to Leslie Strobels dissertation in his tome. Ron does sell a Fresnel for his 8 x 10's 2 kinds - one which is removable, the approach he advocates, and one which is permanent. Zone VI/Calumet sell Fresnels for their cameras as well and Steve Shuart in PA makes part of his living by making and selling ground galss & Frresnel replacements - he's in Shutterbug. In other words, most but not all GG's and Fresnels are interchangeable- at least on the older cameras. So call Steve and tell him what you got and get his opinion.
Ron's major point is that the ground glass is designed to sit in exactly precisely the same plane as the film in the holder, so all will be sharp. If this is the case and you place a Fresnel that has a focal length of it's own in by removing the GG, placing the Fresnel in (oriented in the correct way) and then replace the GG on top, you have moved the plane of focus by the thickness and focal length of the Fresnel. My half-assed but inexpensive and so far effective solution to this debate has beeen to find a "PAGE MAGNIFIER" or similar inexpensive Fresnel of adequate dimensions and cut it to fit and place it INSIDE the camera back, taping it against the ground glass, without removing the groundglass from its position as installed. That way the ground glass is not disturbed in it's alignment and I get the benefits of greater illumination I desire. Is this a good idea? I don't know, but it seems to work for me although I make only contact prints at this point. I'm sure there are errors in this and that others could correct them...
-- Sean yates (firstname.lastname@example.org), November 16, 1998.
I too stumbled on the half-assed cheapo plastic page magnifier, purchased at the local book store for a few bucks and cut to fit with a pair of sizzors. I've used it on the outside of the ground glass groves down, and I've used it inside the camera with groves up against the frost. Either way, the results look focused to me, but I am far from an expert.
-- David Clark (email@example.com), November 25, 1998.