Questions tagged [phase-detection]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
19
votes
1answer
2k views

Why do even high-end cameras often still include normal (non-cross-type) AF sensors?

Modern cameras often use two kinds of AF sensor: normal, and cross-type. While normal-type AF sensors notably struggle focusing on high-contrast vertical lines, cross-type sensors, though more ...
2
votes
3answers
139 views

How does autofocus micro adjustment (AFMA) really work?

One of my answers was edited to include autofocus micro adjustment (AFMA) as a camera choosing criterion. The edit linked to another answer explaining the AFMA more. My understanding of autofocus is ...
2
votes
2answers
494 views

Does on-sensor phase detection autofocus need adjustment for accuracy?

Is autofocus adjustment actually no longer required with on-imaging-sensor autofocus that's phase-detection only i.e. not relying on contrast detection? If not, why? How does lens autofocus adjustment ...
4
votes
2answers
378 views

How does on-sensor phase detection AF not impact the image?

My understanding is that some of the photosites on the sensor have additional functionality in them to measure phase, which in turn uses some of the energy that would have otherwise registered as ...
4
votes
1answer
205 views

How does auto-focus work with old cameras and new lenses?

I read the following statement in the Lens Rentals Blog about the functioning of phase detection auto focus systems.... The camera reads the phase detection sensor, looks up a huge data array ...
3
votes
2answers
649 views

Is contrast-based autofocus really better than phase-based, or is it just me?

I feel like I quite consistently get: Blurrier autofocus Lower exposure when shooting with my T5i's viewfinder than its LCD (i.e., in phase-based vs. contrast-based mode). But whenever I search ...
4
votes
1answer
3k views

What is “hybrid AF”, and how does it compare to other autofocus technologies?

I've heard of some new cameras — particularly mirrorless cameras — with a feature called "hybrid autofocus". What does this mean, and how does it relate to the traditional approaches of contrast and ...
1
vote
1answer
867 views

What is the Autofocus type in Nikon D3300?

What is the autofocus type in Nikon D3300, Is it phase detection or contrast detection ? Or both ? If both then when is phase detection used and when is contrast detection used ? I was looking in the ...
-1
votes
2answers
275 views

Will more autofocus points improve hit rate for focus on the target I want?

I got a Canon 70D a couple weeks ago from Amazon. As explained here and many other places around the internet, its autofocus system doesn't work as one might think it does. The focus "point" actually ...
6
votes
1answer
1k views

Converting cameras for infrared use: When does the filter have to be replaced, and when is simply removing it ok?

When converting a digital camera for infrared use, the general approach is to remove any filters that limit its sensitivity to the visible range of light wavelengths. Some conversions replace the ...
1
vote
0answers
199 views

What would cause an AF confirmation light to go on and off as I approach correct focus?

I'm using two cameras: Canon EOS 400D (Digital Rebel XTi) and Canon EOS 450D (EOS Rebel XSi). 450D was more heavily used than 400D. Not so long ago I noticed that 450D's autofocus system works not ...
3
votes
1answer
1k views

Do mirrorless cameras focus less or more accurately than SLRs under low light?

How do the following compare in terms of autofocus accuracy for night photography: Mirrorless cameras like the Sony NEX-5R, in hybrid autofocus mode. The NEX-5R, in contrast-only autofocus mode. A ...
1
vote
1answer
2k views

What is the purpose of Quick Mode focusing in live view?

What is the purpose of Quick Mode (found on some Canon DSLRs) focusing in live view? To me it seems like a bad blend between live view and viewfinder mode that really doesn't cut it. Of course it's a ...
4
votes
1answer
365 views

Why isn't the gain on phase-detect autofocus sensors increased in low light?

Modern phase-detect sensors can focus in pretty low light. However, the limit for low light focusing tends to be reached much before the camera can no longer capture images using a high imaging sensor ...
22
votes
6answers
40k views

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 ...
26
votes
2answers
82k views

What's the difference between cross-type autofocus points and regular ones?

What's the difference between different autofocus point types (cross vs point and such)? Cross points seem to be a "feature" — why?