Does F stop value change? (adapting larger format lens)

austrokiwi1 · Post by **austrokiwi1** » Tue Mar 15, 2016 10:51 pm

I am just testing my assumptions. I use a Mamiya 645 80mm macro on my sony A7rm2. Its rated F4 by the manufacturer. does the effective aperture change on the full frame sensor camera?

I have always assumed the answer is no.

rjlittlefield · Post by **rjlittlefield** » Wed Mar 16, 2016 1:15 am

The effective aperture of a lens does not change when you use it on a different size sensor.

In going from the Mamiya 645 to a full frame sensor, all you're really doing is cropping from 6x4.5 cm down to 3.6x2.4 cm.

--Rik

austrokiwi1 · Post by **austrokiwi1** » Wed Mar 16, 2016 4:22 am

Thanks that is exactly what I thought. I believe it was a couple of weeks ago I read some photo blog that said the F value did change. At the time I thought it was less-than-intelligent. However over time the statement niggled away in my subconscious soI thought I would confirm my understanding. The blog was much in the same line as some "boy wonder" on you tube claiming that the A7 range of cameras was the best because by switching to APSc capture the focal length of the lens would change. It horrified me that some might believe him... he obviously didn't understand that crop factor only applied to the field of view. I tried to find both blogs again... I couldn't

ChrisR · Post by **ChrisR** » Wed Mar 16, 2016 4:54 am

I doesn't matter that he's wrong. If he says it loud enough he'll get elected.
Oh sorry, wrong forum.

austrokiwi1 · Post by **austrokiwi1** » Wed Mar 16, 2016 5:51 am

ChrisR wrote:I doesn't matter that he's wrong. If he says it loud enough he'll get elected.
Oh sorry, wrong forum.

the tears are rolling down my face!!!!