Linked Questions

2 votes
3 answers

Why don't any cameras use time-of-flight systems (like ZCam) for autofocus (and allow extra raw creativity with z-data)?

After reading Why don't DSLRs use laser rangefinders for autofocus? This question come in my head : Why camera don't use z-cam for autofocus (and allow extra raw creativity with z-data) There is ...
0 votes
3 answers

Is it normal to see focus inconsistency frame-to-frame with an f/1.4 lens?

I have the Nikon Sigma 85mm 1.4 and I've noticed some inconsistency with focus. I setup a tripod, and a lens calibration card in an attempt to micro adjust the focus. However, what I noticed was that ...
1 vote
1 answer

How do smartphone cameras know they are in focus?

I just wanna begin by saying that I have no real knowledge of cameras, so this might be a stupid question. But how do smartphone cameras know they are in focus? I would assume that if you told a ...
19 votes
5 answers

Why can't my SLR autofocus on certain parts of a scene?

I had my Nikon D7000 on single-point auto focus and it just would not focus on the spots I wanted. I have marked the spots that could not be focused on with red circles, and the parts that could be ...
0 votes
1 answer

Nikon lens asp vs asc [duplicate]

I am new to DSLR camera and just purchased a Nikon D3400. Is autofocus determined by the lens or the camera? I'm using the 18-55 kit lens and the 70-300 ASP Lens.
22 votes
2 answers

How does focus work on mobile phone cameras?

How does focusing work on mobile phone cameras? Aren't their optics simple enough to not have any moving parts whatsoever? If so, how come most smartphones have an auto-focus, and with various ...
5 votes
1 answer

Why is DSLR autofocus much faster than Mirrorless autofocus?

When DSLRs are not using Live View they autofocus much faster than Mirrorless cameras. Why is that? Why can't Mirrorless cameras use the same autofocus mechanism that DSLRs use?
0 votes
2 answers

Fungus cleaning from a Nikon superzoom

Happened to be a proud owner of Nikon Coolpix P600 till I discovered that ugly fungus on its lens! Contacted the Nikon India service centre at Kolkata and they said that there is no option of cleaning ...
10 votes
6 answers

Why is the main sensor not used instead of the separate AF sensor to focus a DSLR?

From this answer I understand that the reflex mirror of a DSLR is actually not reflecting all the light, but it passes a certain amount on to the AF sensor. So if the reflex mirror can pass light, ...
23 votes
6 answers

What is the practical difference between phase-detect and contrast-based autofocus?

What are the main differences in field use between phase detect AF and contrast based AF? I understand the technical differences, but I am not sure what the implications from a photographer ...
3 votes
3 answers

Why is AF slow in Live View on DSLRs?

Why is AF so slow in Live View on SLRs ? On compacts, the AF works very smoothly and quickly.