As per the title, what sort of image circle would one need for a 5x8" camera? 230 mm with no movements?
I guess a focal length of 240 mm would be a "normal" lens?
As per the title, what sort of image circle would one need for a 5x8" camera? 230 mm with no movements?
I guess a focal length of 240 mm would be a "normal" lens?
Last edited by Jimi; 30-Oct-2017 at 04:15. Reason: clarification
Just calculate the hypotenuse of a 5x8" triangle -- simple algebra.
It's all greek to me, that mathematics stuff, but yes, I figured it all out with your eminent help.Originally Posted by xkaes
Thanks.
Square each dimension. Add the results together. Find the square root of the sum. 9.4 inches or 239mm.
Keith Pitman
My calculations added up to that same sum, 239 mm.
You need 239.6mm to just cover the format, not 230.
240mm would be a normal lens, but in LF the normal concept is more vague than usual...
This is because with near subjects you give bellows extension to focus, then it happens like with an slide projector and the image gets bigger and magnification is like with a longuer lens.
So for landscape a 240mm can be the normal lens for 5x8", but for close portraits it is more normal a 210mm, this is it is more close to the human vision angle of view.
Yup, the Pythagorean theorem. In mathematics, it is a fundamental relation in Euclidean geometry among the three sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. Little did they know that they would be helping photographers more than TWO MILLENIA later!
Keep in mind that the actual image size will be slightly smaller than the film size due to the edges covered up by the film holder. So if you have a film holder, just measure the distance from one corner to the opposite corner. That way, you can avoid the math and get a more accurate measurement.
Say was Pythagorus a Greek? I think he was.
But not algebra, just good old arithmetic- oops we don't need that, or shoe laces or how to tell time by a clock,
or cameras or books or even reading. cuz we got digital and velcro and video on the internet
Oh Missus Wafleschnieder, why do we have to learn this, we'll never need it in real life?
HUMPHFFF Darn kids
Well, it's actually sqrt ((5-.25)^2 + (8-.25)^2) = 9.09" or 230.9mm. If you want the bare minimum, you have to use the actual image dimensions and not the film dimensions.
But there's no point (IMHO of course) in a view camera without movements. So the minimum useful image circle is going to be something above 231mm. I'd want at least 240mm, and probably more like 250mm to be happy.
Normal lens for a 5x8 camera is probably something around 240mm. The old Fujinon 240A would be good (razor sharp, bunches of coverage), but it's only an f/9 lens and therefore a bit "dark" and hard to focus. If you want something slightly wider for a normal lens, there's bunches of 210mm lenses out there, just about all of them would cover 231mm, and many of them are f/5.6 which can make for easier focusing.
About the widest lens I found that would work with 5x8 format was the old Wollensak Velostigmat wide angle series III 6.25" (159mm) f/9.5. There was IIRC also an f/12 version. I'm thinking the ones sold in Rapax shutters were typically single coated lenses as well. Reputed to be very good. I never got my hands on one however, even after years of looking. Oh well... one of the reasons I stuck with 5x4 and never went to 8x5.
Bruce Watson
YIKES, there are lots of lenses shorter than 159mm that have an image circle over 250mm, but the OP was for a normal lens. There are lots of "mid-200mm" lenses with way more coverage than 230mm. Fuji made several with ICs up to 400mm.
Last edited by xkaes; 30-Oct-2017 at 18:58.
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