Hello all

I wonder if anyone can help

I have for years shot solely on 5/4 but now also have a leaf aptus 75 digital back on an arca swiss 6/9

After years of knowing exact the perfect lens for each situation I find the new focal lengths confusing

Can anyone give me an accurate idea of what local lengths on medium format digital would provide the equivalents focal lengths as the 5/4

IE Which lens would I need to use with the aptus/Arca to get same coverage as the 72 on 5/4

I shoot architecture and design worldwide


Edmund Sumner
www.edmundsumner.co.uk

http://www.alpa.ch/index.php?path=knowledg...e&detailpage=27

Edmund,

I have found Rui Salgueiro's FOV Calculator web page to be invaluable and a lot easier to use.

http://www.mat.uc.pt/~rps/photos/angles.html

Just select the "other" format size and then change the millimeter sizes to match your digital sensor.

Also, you can add other focal length lenses in the selector bar at the top of the graphic.

Then click Submit and enjoy.

I have made numerous comparisons of film sizes, digital sensor sizes, print ratios, etc. with this web based tool.

Joe Bossuyt

Dear Edmund,

instead of taking tables, just calculate the factor: a 4x5" has a diagonal of 155mm, a 33 MPx Dalsa sensor has a diagonal of 61mm ---> the factor is 2.54.

To get the same image on a 33 MPx Dalsa sensor as on a 4x5" with a 72mm lens, you need 72/2.54 = 28mm

That's the most easy way to calculate, IMO.

Best regards,
Thierry