Linked Questions

0
votes
1answer
48 views

Nikon D5100 struggling to autofocus on screen, but fine through viewfinder? [duplicate]

hope you can help me and my frustrating issue I have a D5100 with a Sigma 18-250mm f/3.5-6.3 dc os lens which will AF no problem at all when I'm looking through the viewfinder but when I change to ...
18
votes
5answers
2k views

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 ...
13
votes
4answers
2k views

Why doesn't auto-focus work with an all-white subject (like a wall)?

I am trying to compose a shot using my Nikon D60 and 18-55mm lens towards a white wall in a auto-focus mode. It looks like I am not able to take the photo. I feel the camera is not able to find any ...
7
votes
3answers
3k views

Does autofocus work better with f/2.8 lenses vs f/4 or slower?

I read following in a web site (http://realphototips.wordpress.com/tag/ai-servo/) Lenses with maximum apertures of f2.8 allow the camera to use all high precision sensors. In low light or other ...
5
votes
5answers
2k views

Why does the autofocus capability depend on the aperture rather than the amount of light available?

In many DSLR manuals one can read something to the effect of: Maximum Lens Aperture: f/3.2 - f/5.6 With all AF points, cross-type AF sensitive to both vertical and horizontal lines is ...
6
votes
2answers
5k views

Why is on sensor PDAF drastically slower than traditional PDAF?

Why is on sensor PDAF drastically slower than traditional PDAF? I assume the technology is the same, doesn't matter if the module is on the sensor or located behind a mirror. But the performance is ...
7
votes
2answers
5k views

How do I diagnose the source of focus problem in a camera?

Probably a novice question, but how do I correctly diagnose from a photo for what reason that camera wasn't able to focus properly? It can be any 1 of the following Unsteady hand Lens issue Metering ...
4
votes
3answers
9k views

Why is my camera focusing fine in liveview but getting it wrong with the viewfinder?

When I first got my Yongnuo 50mm f/1.8 it would not focus through the viewfinder. It will always miss (95% of times). Yet it worked fine in liveview. And now, recently, I started noticing the same ...
3
votes
2answers
1k views

What could be causing focus problems in low light?

I am not a professional photographer but shoot outdoor and indoor pictures, weddings, and portraits as a hobby. I use a Nikon D750 with a 70-200mm 2.8 VR lens and a 35mm 1.8 ED lens. I have been ...
3
votes
1answer
920 views

Pictures of surfers start in focus then go out of focus?

I was recently shooting some surfers after a session with my 7D and Tamron 18-270mm F/3.5-6.3 Di II VC PZD. I started shooting while he was in focus, then as he got to the main part of the maneuver ...
5
votes
2answers
529 views

One camera unable to focus in low light, different camera, same brand model, has no problem

With a Canon T3i mounted in a camera/flash tower, the camera cannot focus in low ambient light with dark complected subjects. All the settings are preset as this is being used in a drivers license ...
0
votes
2answers
3k views

My viewfinder won't autofocus but live view focuses well

I have a Canon EOS Rebel T5 camera and I've been running into an issue lately that I do not know how to solve. The autofocus while using viewfinder does not work at all; I could not even take a photo....
4
votes
1answer
366 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 ...
2
votes
2answers
365 views

How can I effectively use the focus points (of Canon DSLR), to get accurate focus on a small subject?

I'm shooting birds with my Canon 1200D and 55-250mm lens. I know this is not ideal lens and focal length for bird photography. But I am new to this field and before investing on expensive equipment, ...
0
votes
1answer
721 views

Canon 600D Autofocus not working when using view finder but working in live-view

My Canon 600D's autofocus is not working at all when using the view finder. When I use it in live-view mode the autofocus works fine. I tried to google but could not find anything concrete. Any ...

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