Fujinon SW 125 f/8 for 8x10?greenspun.com : LUSENET : Large format photography : One Thread
Does the Fujinon SW 125/8 cover 8x10? Badger Graphic lists its image circle as 280mm, but I have often read that these numbers are conservative estimates. I would use it for architecture and therefore need some room for movement.
Is there a general rule for how much bigger than the format the image circle should be to avoid loss of sharpness at the edges of the image?
-- Tony Karnezis (firstname.lastname@example.org), October 23, 2001
In teresting how these questions pop up when a lens or camera coems up for auction on eBay
. I saw the eBay posting where he said the lens covers 8x10 and that set off alarm bells in my head so I sent him an email and got back the following response:
"I have a Wista Reterick 5x7 with an 8x10 back. The lens to film distance with the 8x10 extension is too great to be able to focus with the extension, but I tried to use it with the lens stoped down greatly. It did notdocus, but it covered, so I am selling it. It might need a center grad to make it work better, n 8x10, but I have been told that it covers it with no problem, but no movements.My description is not by first hand experience. I used it on a 6x24 camera and it was fine."
"Steve Simmons writes in his book that this lens covers 8x10 but there is no room for movements."
As to the former statement covers to me generally means focused. As to the later statement , I took a quick look in "the View Camera (1992 revised) and so no specific mentionof this lens.
On a more general note my experience with Fujinon lenses is that their specifications for image circle are NOT as conservative as Schneider's (hat) is a statement generalized from those lense I have used and does not specifically relae to this lens). Even if they were as conservative as Schneider's teh fact that the Schneider 110 with a published image circle of 288º JUST covers the required 312º required for 8x10 makes it hard for me to imagine a lens with a published image circle of 280º covering.
-- Ted Harris (email@example.com), October 23, 2001.
Thanks, Ted. I guess you saw the auction. Thanks for all the info. The ad itself was not really the point of my question but rather the amount of coverage one needs. I wonder how unsharp lenses become toward the edge of their image circles. I have 90/135/210 Caltars. I've never needed much movement for landscape of course but don't want to unwisely push the limits of a lens and degrade image quality without knowing it until after the fact.
-- Tony Karnezis (firstname.lastname@example.org), October 23, 2001.
You need a minimum 312º image circle to cover 8x10 with NO MOVEMENTS. So if published specs are close you can always try and find out. For example, I sometimes use my 210 mm APO Symmar on 8x10 (published specs say 305º image circle). That spec is much less conservative than the one on the 110 Super symmar; even without movements I can see a teeeeeny bit of vignetting at the bottom corners. OTOH it (and the 110 Super Symmar) is completely sharp with no noticable image falloff that I have been able to see right out to the edges. A lens, no matter what its focal length, will not necessarily have any image falloff in terms of sharpness at the edges. Lens design is a lot of tradeoffs though and many designs tradeoff some edge sharpness for whta the designers consider other, more important characteristics (without going into a long discoures on variuos types of aberation).
-- Ted Harris (email@example.com), October 25, 2001.
"I would use it for architecture and therefore need some room for movement."
Tony, the shortest modern lenses that would fit the bill in this respect (for 8x10) are the Nikon 150SW and the Schneider 150XL. (150mm is about as wide as I'd want to use for architecture anyway unless I wanted really exaggerated perspective effects; a 110-120 is wiiiide on 8x10.)
Both the Nikon 120SW (which I've used, on a Hobo) and the Schneider 110XL (which I haven't) apparently can cover 8x10, but it's "barely" at best and would leave no room at all for movements. Re: the ebay seller, unless someone actually has focused a given lens, at infinity, at f16 or f22, using the actual film format in question, without vignetting, and will vouch for that, I wouldn't gamble on it.
-- Micah (firstname.lastname@example.org), October 26, 2001.
Ted - you shouldn't have gone through the trouble of placing all of those "º's" - they should have been "mm's". How can an image "circle" be less than 360º? :-)
-- Wayne DeWitt (email@example.com), October 26, 2001.
Duhhhhh .... ah well happens sometimes when braincells are dead in the night.
-- Ted Harris (firstname.lastname@example.org), October 26, 2001.
Ted - beating a dead horse here, but... I was looking for a photo in Simmons's book and came across the reference to the Fuji 125mm and the Schneider 120mm on page 35 (unrevised 1987).
-- Wayne DeWitt (email@example.com), October 27, 2001.