F-stop and behaviour of aperture with change in focal length in a zoom lens
52368
Does the diameter of the aperture increase with increases in the focal length with constant F-number(F-stops)?
20086
Why is the amount of light a lens lets in called the 'lens speed'?
8552
Which focal-length lens is usually used for portrait photography, and why?
11996
How do I find the right size of filters for a lens?
135149
How do camera body motors compare to in-lens motors for focusing?
113839
How can I visualize or simulate the effect of different focal lengths?
101960
Why are crop lenses indicated with focal lengths they don't have?
91202
Why is the aperture ring removed from new Nikon lenses?
79654
What is the effect of the number of cross-type focus points on sharp focus?
94271
What is the reference plane used when the minimum focus distance is measured?
30241
How do different aperture and shutter settings affect a photo with the same overall exposure?
35335
What is the relationship between focal length and shutter speed?
67192
Cycle Normal Pass in Camera Space
34009
How do I calculate the number of stops between two shutter speeds?
6544
How do zoom lenses restrict their widest aperture at the telephoto end?
129613
Why does illuminance stay the same for a given f-stop even when focal length changes?
47999
How do you find out the "sweet spot" of a lens?