Sunset in Kruger

by MrFrench

submit your photo

Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Tag Info

New answers tagged


My understanding is that for the brain to percieve a photograph with the same perspective as it gets from the eye the focal length should be the same as the the diagonal on the image (film of sensor). This is about 43mm on "full frame" and 28mm on APS-C. Photographs taken with wide angle lenses tend to add depth to features, longer focal length tend to ...


The focal length of a modern zoom lens isn't something that is nice and easy to work with a lens equation to get the answer. From hyperphysics on the true zoom telephoto lens, the lens can be thought of as a few different elements: The problem is, these elements keep moving around: which makes the entire system a bit more complex to calculate for. ...


What f stands for in the f-stop values f stands for the focal length of the lens. An f/1.8 lens has the entrance pupil diameter of D = f/1.8. An 85 mm lens at f/1.8 aperture will have the entrance pupil diameter of 85/1.8=47.2 mm. A 24 mm lens will have the pupil diameter of 24/1.8=13.3 mm. Since the amount of light passing through the lens is proportional ...


They are referring to the amount of clearance between the lens rear element and the sensor. The C mount flange focal distance is 17.52mm so both of these lenses have rear elements that stick into the camera body. This fact is most relevant to SLR cameras that have a mirror which moves out of the way when a photo is taken, a lens that sticks into the camera ...


From what I know back focal length depend of the optical construction of the lens. And it is important for mirror cameras. For example you can't mount EF-S lens on fullframe camera because last element will interfere with the mirror (which is bigger than APC cameras). P.S. Above abbreviations and explanation are related to Canon cameras and lens, but IMHO ...


It seems your question has been asked earlier but seperately.. Here, this will tell you how to find the focal length. And this might help in finding sensor size. Hope this helps.


The ratio of subject width to distance corresponds to the ratio of sensor (or film) width to focal length. Thus, for portrait orientation, you may estimate the focal length as follows: horizontal: 24 mm · 5.0 m / 0.8 m = 150 mm vertical: 36 mm · 5.0 m / 1.2 m = 150 mm


I have noticed that most of the parfocal lenses have zoom ratios of 3:1. Maybe this holds the answer: in my study of photography, lenses that have a zoom ratio of 3:1, 2:1, and 1:1 have better quality compared to higher lens ratios, because they produce less chromatic aberration. In my opinion, parfocal lenses have are better since their aberration is less ...

Top 50 recent answers are included