Questions tagged [phase-detection]

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confusion about the principle of on-sensor PDAF technique

There are a lot of pictures over the internet illustrating the principle of phase detection autofocus, such as this one The simplest way to ...
Jogging Song's user avatar
2 votes
1 answer

Can a lens affect relative performance of autofocus points?

I am comparing the autofocus performance of my Nikon D800 with two lenses, A Sigma 150-600 C (post sigma-dock calibration) A Nikkor 50mm 1.8G (post AF fine tune). Both lenses focus well with the ...
user363165's user avatar
-2 votes
2 answers

Is there any test data available that characterizes performance of Canon's "AI Servo AutoFocus"?

After trying numerous recommendations for setting Canon's AI Servo AF, I am getting only the rare in-focus picture of small birds in flight in their native environment. Based on this I have formed an ...
Seamus's user avatar
  • 177
19 votes
1 answer

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 ...
Jules's user avatar
  • 658
2 votes
3 answers

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 ...
juhist's user avatar
  • 6,598
3 votes
2 answers

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 ...
user avatar
4 votes
2 answers

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 ...
PhaseDetective's user avatar
4 votes
1 answer

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 ...
Scorb's user avatar
  • 1,048
3 votes
2 answers

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 ...
user541686's user avatar
4 votes
1 answer

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 ...
mattdm's user avatar
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1 vote
1 answer

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 ...
New one's user avatar
  • 143
-1 votes
2 answers

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 ...
MrMerrick's user avatar
  • 111
6 votes
1 answer

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 ...
jstarek's user avatar
  • 494
4 votes
1 answer

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 ...
Kartick Vaddadi's user avatar
1 vote
1 answer

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 ...
Hugo's user avatar
  • 8,288
4 votes
1 answer

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 ...
Chinmay Kanchi's user avatar
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 ...
subsub's user avatar
  • 965
25 votes
2 answers

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?
rfusca's user avatar
  • 26.5k