cropping crop factor field of view

[blackest]

The Leica Q is a full frame camera with a fixed 28mm lens

they did something quite clever they set it up so you can crop to a field of view of 35mm or 50mm.

naturally this loses some pixels and reminded me of a few arguments.

 

argument no1 is that a lens doesnt change if it is on aps-c or full frame the difference is crop because of the different sizes of the sensors.

 

so a 50mm full frame lens on aps-c has the fov of a 75mm lens recorded on the sensor,

 

and if you cropped the fullframe image to the size of the aps-c image they would be the same.

 

So I was wondering if we could have a crop box to size to a fov of a longer lens.

so if I have a photo taken on 28mm i could put a crop box on top that when applied made it look like it was a 50mm lens took the shot.

 

we know that a 28mm with a 1.5 crop factor has fov of 42mm

and with a 2.0 crop 56mm

 

so for 50mm fov  50/28 = crop factor needed

 

if you use 1 / crop factor  1/1.5 = 66.67% and 1/2 = 50% so the cropbox would want to be 2/3rds of the side length for a 1.5 crop and 1/2 for a 2x crop.

 

is there anyway we could crop by a percentage of the original image size?

 

or even be able to calculate what lens should have been used in order to avoid cropping :)

 

just a thought :)

 

[pruus]

Perhaps this article is what gives you more information: http://av.jpn.support.panasonic.com/support/global/cs/dsc/knowhow/knowhow12.html