All Questions
5
questions
5
votes
2
answers
2k
views
Why do zooms have small apertures even around 50mm?
A 50mm f/1.8 prime from one of the major manufacturers can easily be found for $200 or less, but zooms that include 50mm in their range always seem to have much smaller apertures even at 50mm until ...
15
votes
3
answers
2k
views
How do zoom lenses restrict their widest aperture at the telephoto end?
Does the aperture ring lock the apertures beyond, say 5.6 at length lens's telephoto end?
Does the lens introduce an obstacle to the aperture ring so the lens can't be opened anymore beyond the ...
2
votes
1
answer
969
views
Why don't all zoom lenses have variable f-numbers? [duplicate]
As I understand it, the f-number is a ratio between the focal length and the aperture diameter. A zoom lens can change focal length, but shouldn't the maximum aperture be a fixed size? If so, that ...
22
votes
2
answers
5k
views
Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?
Why does a camera's maximum (allowed) aperture get smaller when you increase its zoom?
46
votes
7
answers
14k
views
How do constant aperture zoom lenses work?
Cheaper zoom lenses usually are faster at the wide end and slower at the long end (for example, the $150 Canon EF-S 18-55mm f/3.5-5.6). More expensive constant-aperture zoom lenses have the same ...