photovdz
Well-known
even if most of us use 24x36 only, i would love to find a conversion table where it would be possible to compare lenses focal length for various film sizes. It would be usefull when you use old cameras with dim or faded finders for instance.
Of course the table must take into account the image ratio to give an accurate comparaison.
The main 3 images ratios are : square, 4:3, 2:3, but some 1:2 or more exist
Usually the diagonal of the film size is considered "natural" focal length (43mm for 24x36) but we are all used to see 50mm instead.
Does an calculation chart or excel file exist somewhere ? my mathematical abilities are limited but all suggestion would be useful
Stephan
Of course the table must take into account the image ratio to give an accurate comparaison.
The main 3 images ratios are : square, 4:3, 2:3, but some 1:2 or more exist
Usually the diagonal of the film size is considered "natural" focal length (43mm for 24x36) but we are all used to see 50mm instead.
Does an calculation chart or excel file exist somewhere ? my mathematical abilities are limited but all suggestion would be useful
Stephan
photovdz
Well-known
yes it is... even if it could be improved by using a ratio variation.... I'll work on it, but I don't have the maths with me ;-)
Thanks a lot...
Stephan
Thanks a lot...
Stephan
Matthew Allen
Well-known
Pherdinand
the snow must go on
It is really simple. Diameter A per diameter B equals focal length A per focal length B, this is the formula to use. A and B are two different formats.
Diameter can be the diagonal of the frame, but it can be width or height of the frame if you prefer that.
Example: the equation 36mm per 85mm (i.e. 135 format frame width per 6x9 format frame width) equals x per 90mm gives you the "corresponding" 135-format focal length of a 6x9 90mm lens to give the same horizontal field of view.
Diameter can be the diagonal of the frame, but it can be width or height of the frame if you prefer that.
Example: the equation 36mm per 85mm (i.e. 135 format frame width per 6x9 format frame width) equals x per 90mm gives you the "corresponding" 135-format focal length of a 6x9 90mm lens to give the same horizontal field of view.
JRG
Well-known
Does this help?
Does this help?
It's a chart that matches some popular focal lengths in the 35mm world with lenses available for 6x6 cameras. It takes into account three aspect ratios that you can get by cropping either a 35mm negative or a 6x6 negative: 1:1, 1:1.25, 1:1.5.
I've got a much higher quality rendition of the chart as a PDF file; this jpeg is a very low resolution version. If the chart is helpful, PM me, and I'll email you a copy of the PDF version.
Does this help?
It's a chart that matches some popular focal lengths in the 35mm world with lenses available for 6x6 cameras. It takes into account three aspect ratios that you can get by cropping either a 35mm negative or a 6x6 negative: 1:1, 1:1.25, 1:1.5.
I've got a much higher quality rendition of the chart as a PDF file; this jpeg is a very low resolution version. If the chart is helpful, PM me, and I'll email you a copy of the PDF version.
Solinar
Analog Preferred
The above table has an important attribute. It shows a measure of the film gate rather than the usual 6x9, 6 x 6, and 6 x 4.5 ratio.
6x9 which isn't shown can get squirrelly. For example some 6x9 cameras capture less width than 54 x 82, which gets closer to a 6x8.
6x9 which isn't shown can get squirrelly. For example some 6x9 cameras capture less width than 54 x 82, which gets closer to a 6x8.
JRG
Well-known
I built the chart for myself when I was pondering a Hasselblad purchase, and wanted a simple way to compare focal lengths with 35mm cameras. It wouldn't be hard to expand the chart to include 6x7 and 6x9 formats.
But I'm unfamiliar with the precise film gate size of popular 6x7 and 6x9 systems. Give me some standard target sizes, and I can make the chart bigger.
photovdz
Well-known
other usefull format :
18x24 (mm) pen f
24x24 (mm) robot
4x4 need to verify the exact gate size...
6x7 idem
6x9 = 55x 85
18x24 (mm) pen f
24x24 (mm) robot
4x4 need to verify the exact gate size...
6x7 idem
6x9 = 55x 85