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10-13-2016, 02:44 PM   #1
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How do you determine if auto focus is working?

How do you determine if auto focus is working?

Lately when I am taking pictures (outside, bright light, non moving objects, mainly of people), it does not seem to be that sharp.

This is just in automatic mode using the 18-135 lens.

10-13-2016, 03:01 PM   #2
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QuoteOriginally posted by lgbalfa Quote
How do you determine if auto focus is working?
There are some threads about this. Usually you need a focusing chart and tripod (or some other stable base), then you switch to manual focus mode to defocus the lens, then switch to AF and see if it finds the intended mark. You can find some focus calibration blog posts and threads, and you can probably find some free focusing charts as well. Use Av mode, low ISO, wide open aperture, try various zoom settings. You should use AF.S single centre point, as well as Live view focusing (just to compare, as live view AF is different from the normal AF). You should also use 2sec timer or a remote trigger when you do this, so you don't have camera or tripod shake in the shot.

QuoteOriginally posted by lgbalfa Quote
Lately when I am taking pictures (outside, bright light, non moving objects, mainly of people), it does not seem to be that sharp.
I would prefer you post some sample photos with full exif data. The reason is that unsharp photos are normal for beginners (sorry, don't know your photographic history). These do not necessarily indicate faulty equipment, or even AF problems. It can be low shutter speed, not waiting for SR to activate, bad handholding/triggering technique, improper autofocus or DoF expectations, and so on.
It is rare that a camera or lens would develop AF problems over time, but it can happen, particularly with certain lenses that have SDM focusing. There are some threads about SDM failure and how to diagnose it.
10-13-2016, 03:19 PM   #3
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There should be some red dots lighting up showing where the focus is at.

Check "15. Superimpose AF Area" in the custom menu to make sure that the indicator lights are not turned off.

Check to make sure that the switch is on AF.S for single focus or AF.C. for continuous focus.

Check to see what type of AF selection you are using: 11 point, 5 point, selection, or single point.

Hopefully this helps.
10-13-2016, 04:03 PM   #4
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QuoteOriginally posted by lgbalfa Quote
How do you determine if auto focus is working?

Lately when I am taking pictures (outside, bright light, non moving objects, mainly of people), it does not seem to be that sharp.

This is just in automatic mode using the 18-135 lens.
I think it's best if you post a typical example, Igbalfa, with its EXIF data intact.

10-13-2016, 07:50 PM   #5
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A suggestion. Tripod, richly textured 3d surface (a bush?) mark your focus point (tape or tie a ribbon) and shoot wide open then stop 2 stops down and repeat. The do the exact same thing with LiveView. Spin the lens focus ring between shots.
11-24-2016, 04:45 PM   #6
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I've set my focus with a focusing chart and things are working OK except in Live View where it fails to lock into focus. I can focus on the same subject if I turn the LV off. Is there a fix for this? I know some cameras can be adjusted internally.
???
11-24-2016, 04:57 PM   #7
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QuoteOriginally posted by Oricman Quote
I've set my focus with a focusing chart and things are working OK except in Live View where it fails to lock into focus. I can focus on the same subject if I turn the LV off. Is there a fix for this? I know some cameras can be adjusted internally.
???
Light the chart very well, Oricman.
11-24-2016, 05:24 PM   #8
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QuoteOriginally posted by clackers Quote
Light the chart very well, Oricman.
??? I've set the focusing with the chart and the lens works OK. It's only in LV that it fails to focus.

11-24-2016, 06:46 PM   #9
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QuoteOriginally posted by Oricman Quote
??? I've set the focusing with the chart and the lens works OK. It's only in LV that it fails to focus.
Because you're switching from a method that works well at low contrast levels (PDAF) to one that doesn't (CDAF).

There has to be enough light so that the chart's patterns are as black as possible and the background white, instead of shades of gray.

11-26-2016, 08:05 AM   #10
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I couldn't see how this would make much of a difference but gave it a try today and it did seem to improve things. I took shots with and without LV. (The LV seemed to induce 3 shutter failures - maybe a power issue there?)
After resetting the AF the camera did seem to focus alright in LV. So I did a couple of test shots (without LV), then went on to LV and tried to focus on my music stand (nice white sheet with black lines and something over the top so nice and contrasty.) and it wouldn't lock into focus - it kept giving my the red square. Took LV off and focused ion the same area - no problems. Put LV on and it focused each time giving the green square.
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