Inconsistent AF with my EOS 600D in low light; which body upgrade do you suggest?

Hello all,

I'm fairly new here. Well, at least I haven't posted anything before. So excuse me if my question or issue is a common one. Anyway, here goes...

I regularly shoot at seminars and speaker events. Primarily the drinks before and after the main event, but also the stage parts. There is very low light then. With the drinks, there isn't a problem, really. I can use my external flash and photos come out nicely. It's the stage parts where I'm having trouble. I can't use my flash there, understandably. And usually I'm too far off to at least use the IR focusing assistant of my external flash.

I shoot with a Canon EOS 600D and usually use my EF 50mm f/1.4 USM for portraits during the drinks and my EF 70-200mm f/4L IS USM for stage shots. The issue I'm having is that the AF performance of my 600D is pretty lousy in low light. I don't know if this is common, or that it's a flaw in my unit. It's tack sharp when there's enough light, but especially during the stage parts of those events, it's very hard for me to get any good shots.

Now, my real question is, whether or not this can be helped with a new body. I am seriously considering upgrading to a 70D. I am also willing to wait for a 7D mark II, though, but only if its introduction isn't too far off. A full frame body is out of the question for me, due to their high prices. While the 6D is within my price range, I don't believe its AF system is that much superior to that of the 600D. I could be wrong, though.

I will be upgrading my body in the near future anyway, as I'm feeling more and more limited by my 600D, the longer I use it. High ISO performance is quite bad, the (genuine Canon) batteries drain quite quickly, it's not weather sealed, the viewfinder is pretty small and only shows 95% of the image, the image buffer is quite small, it doesn't have micro adjustments, it has no option for recording GPS coordinates, the shutter sounds extremely clanky (a real hindrance when shooting in certain circumstances), plus it just feels like a toy.

Which body will serve me best? Will the 70D give me all I want, or would it be best to wait for the fabled 7D mark II? What are your opinions on this all?

Are you sure it really is the AF performance or simply because the ISO has been pushed very high?

Like you said the light is poor at the stage part and 70-200f4 isn't particularly fast.

Also what AF are you using?

Any samples to share? I am not convinced that it really is the AF problem.

The 6D is a low light focussing beast. For events like you describe, I would choose my 6D over my 70D every time.

kin2son wrote in post #16761974
Are you sure it really is the AF performance or simply because the ISO has been pushed very high?

Like you said the light is poor at the stage part and 70-200f4 isn't particularly fast.

Also what AF are you using?

Any samples to share? I am not convinced that it really is the AF problem.

I limit the ISO value to 1600, as image quality gets pretty badly when I try to go any higher. In RAW PP I can retrieve some sharpness, but I can't perform magic on my photos. Here are two examples: shot #1 (1/60, f/2.8, 50mm, ISO 1000) and shot #2 (1/50, f/4, 200mm, ISO 1600). The speakers in these two shots were standing still at the time I pressed the shutter, so apart from the moving hands, the lack of sharpness is not due to motion blur. This lack of sharpness is a common thing in my shots, even at very fast shutter speeds. It really is due to bad AF, I'm afraid.

By the way, I only use my center AF point. Which is the cross-type one. I don't trust my camera with any of the other points. Especially in low light.

neacail wrote in post #16761996
The 6D is a low light focussing beast. For events like you describe, I would choose my 6D over my 70D every time.

Interesting. And yet the 6D only has 11 focusing points, of which only one is cross-type. Isn't that a severe limitation? I mainly shoot with my center point anyway, but would gladly start using all points if the AF system is more advanced and reliable.

Normally the center point is the best performer in low light. If that can't do it, then nothing can.
You can try live view, magnified view and manual focusing as an alternative. If that way of working is fast enough for you.

As said above, the low light performance of the center point in the 6D is the best in the current Canon lineup. Specificationwise, it beats the 1DX too, but only for low light performance with the center point. The rest of the AF system in the 6D is much more standard specification, though.

The EF 70-200 mm f/4L IS USM is about as good as anything, AF wise, so not much more to get there.

apersson850 wrote in post #16762006
Normally the center point is the best performer in low light. If that can't do it, then nothing can.
You can try live view, magnified view and manual focusing as an alternative. If that way of working is fast enough for you.

I tried that. And it works. Well, kind of. It's very slow, though. The hybrid live view AF of the 70D would be a huge benefit here, but I'll take AF through the viewfinder any day.

That's what I thought, yes. While I could have gone for the f/2.8 II version, my budget did not allow it then. It still doesn't, by the way.

Bengt77 wrote in post #16762002
Interesting. And yet the 6D only has 11 focusing points, of which only one is cross-type. Isn't that a severe limitation? I mainly shoot with my center point anyway, but would gladly start using all points if the AF system is more advanced and reliable.

I am mainly a centre point shooter: even with my 70D. It is pretty rare that I'll use any other point. With the number of pixels available now, I just crop in post if I want to change the composition of something. Now, I am historically a landscape shooter, and have been for nearly three decades. I may be a "Jurassic" in my approach at times. But, it works for me.

My 70D is a perfectly capable camera, but the low light focusing abilities of the 6D are astounding to me. It will focus in low light where my 70D fails. I have actively set out to make the 6D fail in low light, and it has been difficult to present it with a reasonable situation where it failed. I write "reasonable" as it did fail when I tried to photograph something in a very dark closet.

Bengt77 wrote in post #16762002
I limit the ISO value to 1600, as image quality gets pretty badly when I try to go any higher. In RAW PP I can retrieve some sharpness, but I can't perform magic on my photos. Here are two examples: shot #1 (1/60, f/2.8, 50mm, ISO 1000) and shot #2 (1/50, f/4, 200mm, ISO 1600). The speakers in these two shots were standing still at the time I pressed the shutter, so apart from the moving hands, the lack of sharpness is not due to motion blur. This lack of sharpness is a common thing in my shots, even at very fast shutter speeds. It really is due to bad AF, I'm afraid.

By the way, I only use my center AF point. Which is the cross-type one. I don't trust my camera with any of the other points. Especially in low light.

Shot #1 I can't seem to see any point of focus, shot #2 the speaker's suit pocket looks like the point of focus. So my question is did you use center point and recompose? If you use center point where did you aim, or did you crop in post?

Did you shoot #1 with the 50mm prime? If you did then 1/60 was too slow at 50mm on a crop 600D. The motion blur might not be from the speaker but from you.

Shot #2 I assumed you use the zoom which has IS but you miss the focus.

kin2son wrote in post #16762020
Shot #1 I can't seem to see any point of focus, shot #2 the speaker's suit pocket looks like the point of focus. So my question is did you use center point and recompose? If you use center point where did you aim, or did you crop in post?

I cropped both shots in post. The focus is in the centre.

This might be the case, but I am perfectly capable of taking tack sharp shots at 1/60 with the 50mm prime. Here is an example: shot #3. Here I did recompose. Which, as long as you aren't too close to your subject, doesn't affect the focus all that much. At least, that is my experience. This shot was taken in better light and with an external flash. Which greatly increases the performance of my camera's AF system. But it's still 1/60. And sharp. (It's resized somewhat by imgur, by the way; it really is tack sharp.)

Possible, yes. Then again, I can try and focus all I want in low light and my camera will miss focus nearly all the time. Very frustrating.

Some time ago, I sent my 600D and 50mm prime to Canon, as that combination missed focus a lot of times. Even in bright daylight and at smaller apertures. They applied a micro adjustment. I assume this adjustment – even on the 600D, which doesn't allow user appliable micro adjustments – only has effect when my 50mm prime is mounted. This was done before I got my 70-200mm telezoom. They also adjusted the contrast detection in my 600D at that same time.

neacail wrote in post #16762012
My 70D is a perfectly capable camera, but the low light focusing abilities of the 6D are astounding to me. It will focus in low light where my 70D fails. I have actively set out to make the 6D fail in low light, and it has been difficult to present it with a reasonable situation where it failed. I write "reasonable" as it did fail when I tried to photograph something in a very dark closet.

Wow! Very, very interesting. Now I'm definitely tempted to wait and see what the 7D mark II will have to offer, when – and if – it is released.