simonSE15
Established
hi all
I was looking to devise a maths activity to do with photography and was thinking about doing it on focal length.
I got the idea from here:
http://www.mrmartinweb.com/photomath.html
It's the formula I'm interested in: f-stop =focal length / diameter.
In theory easy enough to understand but a quick look at my Zuiko 24mm/2.8, 50mm/1.4 and 85mm/f2 suggest that aperture diameter of 85mm is not wider than the 50mm at same f-stop (e.g both at f4 85mm diameter is smaller).
Why is this?
thanks,
Simon.
I was looking to devise a maths activity to do with photography and was thinking about doing it on focal length.
I got the idea from here:
http://www.mrmartinweb.com/photomath.html
It's the formula I'm interested in: f-stop =focal length / diameter.
In theory easy enough to understand but a quick look at my Zuiko 24mm/2.8, 50mm/1.4 and 85mm/f2 suggest that aperture diameter of 85mm is not wider than the 50mm at same f-stop (e.g both at f4 85mm diameter is smaller).
Why is this?
thanks,
Simon.
ferider
Veteran
Maybe because you look at the aperture through front or back elements that distort the real dimensions ?
Best,
Roland.
Best,
Roland.
simonSE15
Established
ok now I feel really stupid 
ferider
Veteran
Don't - it was a good and non-obvious question, IMO.
Some great photos on your flickr site.
Cheers,
Roland.
Some great photos on your flickr site.
Cheers,
Roland.
Harold Gough
Established
You will find lots of such discussion here, but much will mainly be relevant only to close-ups/macro.
http://www.photomacrography.net/forum/index.php
http://www.photomacrography.net/forum/index.php