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.

[LifelessLewis]

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.

Let's say I just use manual focus And set it so that the wooden panel is almost in focus, then use auto focus it will work, however if I used manual focus to set it as out of focus as I can, then try to auto focus it won't even get close because it doesn't search the full focus range.

Also, I'm shooting in manual.

Hope I'm making sense.

[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!

[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.

[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.

[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. 

[LifelessLewis]

I understand all that, But thanks for the details and screenshots, will use a speedlight and see what I get.
I'm just most confused why It doesn't even try though, think about this for a moment. If the lens is as out of focus it can get, then obviously there's no contrast for it to detect, even if the subject at least has some contrast. In my mind (and this is where I may be thinking wildly incorrectly) it should at least scan the focus range to attempt to find focus, if it did that, then once it got near focus I know that it would pick up enough contrast to actually be able to lock focus.

Forgetting everything else, does what I'm saying there actually make sense? Because to me, it logically should do. My old 6D and 6D mkii and very other DSLR all did this, I know where are fundamental differences but still.

[deebatman316]

It does try. In One Shot it will try and focus then stop. Then try again to acquire focus. It doesn't constantly keep trying and not stop like Servo AF. "In my mind (and this is where I may be thinking wildly incorrectly) it should at least scan the focus range to attempt to find focus, if it did that, then once it got near focus I know that it would pick up enough contrast to actually be able to lock focus." Doesn't work that way even if you try and manually focus close to where in focus is. If its still lack of contrast it still won't lock focus even if its close. The camera still see lack of contrast. DSLRs work the same way no contrast even if close to focus still not going to lock focus without an AF Assist Beam. "I know that it would pick up enough contrast to actually be able to lock focus." If the lighting situation is the same that doesn't change how the AF system works. What Canon branded Speedlite do you own. How do you know its not scanning through the entire focus range. RF lenses don't have a focus distance scale on the lens like EF lenses.

[LifelessLewis]

Ok, so I know it's not trying the full focus range, because I can physically see it not really try to change focus through the viewfinder. As in I can't see it change focus much, it doesn't change through the full focus distance from near to far in order to try and find the contrast to lock onto.

So it will just change to a red square and stop trying, however if I engage the AF again it might get a little closer, then after an arbitrary amount of tries it will eventually find enough contrast to actually try and manage to lock onto.
I'm not with the camera at the moment, But I think I even tried it with servo and it just came up with the red square too, again without trying to focus through the range of nearest to farthest to try. I think my flash is a 430ex, might be a 430exii but I'm not with it to be sure.

I will try to find time to get it on a tripod and take a recording of what I see happening if I can find time during the bustle of Christmas.

Thanks.