View Full Version : image circle
Daniele Minetto
27-Apr-2006, 11:17
What is the image circle to cover 8 x 20"?
Richard Ide
27-Apr-2006, 11:27
Hi Daniele
You need an image circle of 550mm absolute minimum which gives no movements at all.
Richard
The "absolute" minimum is closer to 547 mm maybe even less as the 8x20 format is probably not exactly 8x20. The old Pythagoras again??
Capocheny
27-Apr-2006, 20:45
Well, while we're at it... what about for:
4x5,
5x7,
and 8x10? :)
Thanks in advance.
Cheers
Oren Grad
27-Apr-2006, 21:29
Henry -
Here are the numbers presented by Schneider in their literature:
4"x5": 153.7mm</br>
5"x7": 208.7mm</br>
8"x10": 312.5mm
In practice there are slight variations depending on the exact design of the film holder.
Cheers...
Capocheny
28-Apr-2006, 01:24
Greetings Oren,
Thanks for the info... :)
Cheers
Matt_6555
28-Apr-2006, 03:50
What about 11x14
Exactly the same as 14 x 11
Oren Grad
28-Apr-2006, 08:24
I think 11x14 is somewhere around 435mm. I'll try to remember to measure one of my negatives next time I'm down in the darkroom...
figures quoted for 4x5 are usually infinity focus at f22. Smaller apertures usually give bigger useable image circle and focussing closer also gives greater image circle.
Formula for diagonal of film area is √(width^2 + height^2)
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