EOS R6 Mark II requires multiple shutter presses to focus in low light

[LifelessLewis]

Hey, I have a Canon R6 Mark ii with an RF 24-105 L f/4. I am using spot autofocus with no tracking in one shot mode. Sometimes in low lighting it will fail focus on something with slightly low contrast. However, if I half press the shutter a few more times it will eventually focus, showing that it can manage it at the point I'm trying to focus on.

I have ensured that the Lens drive when AF impossible is set to continue focus search. However it's like it doesn't actually search the full focus range to even try, just decides that it can't focus without actually trying. Is there a way to force it to search the full focus range before deciding that it's out of focus?

Thanks.

[Waddizzle]

“ It's not just one specific thing. I was just testing it out on a wooden unit in my house. There's some detail/contrast on the panel I was trying to focus on. “

I don’t know what a “wooden unit” might be. I don’t know what lens or focal length you’re using.  I don’t know the an approximate distance to the subject.

What I do know is this. Trying to focus in low light can be difficult.  Trying to focus on a low contrast object can be difficult.

Using Spot AF can be a problem, especially when shooting handheld.  It doesn’t work well on small subjects without IS in the lens.  I only use Spot AF on a tripod, does not mean I always use it when using a tripod. 

[Waddizzle]

“ What shooting mode are you using?  Try this test.  The next time that happens, try taking the photo again using Intelligent Auto mode, the Green [A+] mode.  “

???  You’re not answering the questions.  Try to help someone to help you!

[deebatman316]

Is the AF Assist Beam turned on if it is the camera body will emit an orange light from the camera body. Is there a speedlite (external flash) mounted if so what model. Please provide the FULL NAME of the speedlite being used. If its a Canon Speedlite it will automatically switch to Intermittent Flash Firing to assist the camera's AF system. But the AF Assist Beam must be enabled on the speedlite and enabled in the camera's menu. Also the camera must be set to One Shot AF. If its set to Servo AF the AF Assist Beam won't be projected by the Speedlite or camera body.

[deebatman316]

If its all the same color the camera won't lock focus. The camera needs contrast to focus there isn't contrast.

[p4pictures]

The AF system needs contrast to work. Low contrast subjects in low light are most challenging for AF. Dual pixel AF has left / right photo diodes in each pixel, these work best with vertical lines of contrast. 

If you are handholding the camera it is possible that each time you press the shutter again you move a fraction and the camera then finds enough contrast to focus on. I found that if I aim at a blank painted wall the camera mostly fails to focus and the AF point shows in red. If I move slightly so that more contrast is found the camera focuses as expected. If the lens is focused manually to be very out of focus then it is hard for the camera to find any contrast to focus with, and the AF point goes red. 

The lens drive when AF impossible is more useful when using servo AF. Here if the subject is lost the lens stops or continues to search as expected. Using ONE SHOT AF is literally one shot, if the focus is not found then the camera stops looking. You may find that SERVO AF is actually better at trying to continually focus. 

I note that you said no tracking was used, does this mean you set the subject to detect to none, and switched off Whole Area Tracking Servo AF? The latter setting only applies when SERVO AF is used, not ONE SHOT. 

[jrhoffman75]

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@LifelessLewis wrote:

Can you elaborate a bit more please? You're saying that I turn on the camera in one shot at mode, point and something, half press the shutter and it won't focus. And that it's supposed to do that?

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It won't focus if the subject doesn’t have enough contrast. 

[LifelessLewis]

So, yes I am handholding it, so I suppose micro movements mean i might end up pointing at an area with slightly more contrast. The wood grain I'm trying to focus on is running vertically.

Yes tracking was off (although i know most of those settings are irrelevant for one shot). However I did also try in SERVO AF and it still stopped trying to achieve focus. Until i engaged the af a few more times then it eventually would.

[LifelessLewis]

I think you might be missing some of my replies. I stated that I shoot in manual (I have not had time to try the auto mode, although I don't want to have to use auto for something to work). Also I specified the lens in the main post. RF 24-105 f4 L. BY wooden unit, I mean a cabinet, the door of a cupboard on the cabinet to be specific.

Like I say, the spot AF is generally fine, it's just that it doesn't sometimes even try to find focus through the full focus range, when if it tried, it would.

[LifelessLewis]

So Yes I was trying with the orange AF assist, however the lens blocks it from the center of the frame... and it didn't even light up half of the time even when it failed to achieve focus.

I haven't yet tried it with a speedlight. Perhaps I will test that out. I can't recall the model off the top of my head but it is a canon branded one.

Thanks,

[deebatman316]

What you're trying to focus on has NOT ENOUGH CONTRAST as my collogues have pointed out. If everything is the same color and no subject separation the camera won't lock. I've run into the same problem doing low light wedding photography. One example is all of the bridesmaids wearing the same dress. This situation in low light will make it difficult for the camera to lock focus without an AF Assist Beam. Note AF Assist Beam projection by a speedlite is by Intermittent Flash Firing. It is also dependent on the ambient lighting which type of AF Assist Beam is projected.