If I set a lens to, say, f/2 but my focus is set to its closest point, my effective f-number won't be f/2 any more but it will be higher by a factor that depends on focal length, image magnification ...
How can I determine the diameter of the image circle (i.e. the diagonal size of CCD required to fully utilise a telescope's optics) at near-infinity focus? I have looked around online and found this ...
I have got a fixed focus, 5 MP camera with 3.3mm focal length (not sure what it means) on my phone. I want to know what's the best way to take pictures with since it's missing auto-focus feature. Is ...
I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
By definition, a prime lens is a fixed lens system with a fixed focal length. Then, simple physics tells us that it should be able to focus only on one plane (at a fixed distance) in front of it. But ...
When using manual focus or back focus on D60, I sometimes zoom in the lens, set the focus, and then zoom out. Does changing the focal length (zooming out), also change the focus? In case the answer ...
Does a crop sensor affect closest focusing distance? Why does it not affect focal length in EXIF data?
Since I am considering to buy the Nikkor 105mm micro VR, I wondered if the cropped sensor does affect the closest focusing distance of 0.31m? Thinking about this, the following additional (and ...
I guess this is a total noob question, but doesn't 18-55mm mean that it can focus only up to 55mm?
I'm curious about how my "area of acceptable focus" changes when the focal length of the lens I'm using changes as I zoom (or switch lenses). In particular, I'd like to know how the front & back ...