View Full Version : focal distance

16-Dec-2008, 02:44

Does anybody nows where i Can get some data for Sironar S Lenses.
Just to get all the distances right. and choose the Right F-stop!!!
I now there are technical data charts, but where on this internet...
(Sironar S 210, Sironar S 135, and a 75 N lens)

Can any body help me

Clive Gray
16-Dec-2008, 03:39
I'm not sure if you mean you have the technical charts but are looking foe more ? or you just want to find them online ?

If the later is the case Sinar lenses for large format PDF (http://www.sinar.ch/file_uploads/bibliothek/k_87_UserInstructions/155_0_sinarlensesforlargeformatphotography.pdf) and the Rodenstock data tables (http://www.prograf.ru/rodenstock/largeformat_en.html)

The Rodenstock link is more comprehensive and certainly covers the lenses you mention, all Sinaron models are Sinar branded Rodenstocks.

Bob Salomon
16-Dec-2008, 04:24
Or you can ask me 800 735 4373

Bjorn Nilsson
16-Dec-2008, 04:32
I think that you don't really know "how to put the questions". When it comes to Large Format Photo lenses, most of them are about the same. (Yes, the lenses you mention are among the very best ones, but the same basic principles still apply.) There is a section in http://lfphoto.info on the basics of lenses. Do check there.
Among the basics are: The bellows draw for infinity is about the same as the focal length. (I.e. about 210, 135 and 75mm respectively, in your case.) The usable "image circle" is most often quoted for infinity. "Image circle" is simply the diameter of the sharp image at a given aperture opening (usually f/22) and indicates how much (or little) you can move the lens off axis vs. the film plane.
A double bellows draw gives you a 1:1 rendition. This will also double the usable image circle.
The "sweet spot" when it comes to apertures is around the middle of the aperture scale. (f/16 - f/22.)


Ken Lee
16-Dec-2008, 08:00
Are you looking for a depth of field calculator ?

Brian Ellis
16-Dec-2008, 08:51
I can't tell exactly what it is you're looking for (focal length, hyperfocal distance, right f stop?) but Rodenstock's U.S. distributor, HP Marketing, will send you a brochure or data sheet if you call or write but last I saw neither they nor Rodenstock published anything on the internet (that was a couple years ago, you might check both web sites to see if this has changed). Paul Butzi has downloaded some of this information on his web site. www.paulbutzi.com/articles/large format