7D focus issues

Apologies if (that) I'm late to the game and will find similar threads on the issue I'm having. I was just hoping to get a quick confirmation that the issue I'm having is a well-known one.

I bought a 7d just a few weeks ago to use as a secondary camera for weddings. In the last couple of weeks I've been playing with custom functions and AF setup and feel like I have a fairly decent understanding of the camera.

Here's my issue. If I'm in low light and shooting at f/2, AF is inconsistent, meaning if I focus on a target, shoot, then half press again to focus, shoot again etc., well, the AF is improperly shifting (generally front focusing) throughout the sequence leaving me with anywhere between 30-50% miss rate.

Note that I'm using a contrast rich target, I'm placing the focus point (I've tried point and spot) precisely on that target, and the camera is reporting that it is easily finding focus--but up to half the time it isn't.

Thus far I've only looked at my 50mm in depth. It doesn't seem to be doing the same thing for my 70-200 but at F/4 perhaps it just isn't so obvious.

Overall my experience with this particular 7d is that it's just not as trustworthy as my 5d classic--which when reports having caught focus, actually nails it 90% of the time.

Does this seem familiar to anyone ?

Note: I'm on the latest firmware and I've tried the hard reset.

Are you using spot focus, manual AF point, AF point expansion, or zone? Are in in one-shot or AI Servo.

Info here on the difference between modes:
http://www.learn.usa.c​anon.com …D_AF_Modes_Quic​kGuide.pdf

Let me guess, you're shooting in One-Shot or, even worse, AI Focus. You're shooting handheld with a razor-thin depth of field. You carefully line up the shot, half-press the shutter to focus then you do a final tweak to the composition - moving slightly forwards or backwards to get the framing correct. Then you shoot and look at the result at 100%.

Try doing some test shots, with the camera on a tripod using a remote release. If that works consistently then you know that it's a case of PEBV.

I'm using a manual AF point - centre point as well as centre 'spot'; I'm shooting in one-shot mode, and I'm not moving the camera at all between shots. I'm not re-composing. The shots that are off (there are always a couple) are off by a non trivial amount and are all front focused.

I should also make something clear here: I'm a full time professional photographer with an understanding of my gear and how it should perform that is as solid as anyone around here. I'm not new to the dslr; I'm experiencing something that I've never ever experienced with, again, my far older 5d classic.

Tripod shots are moot. If I perform the same test handheld (how I actually use my camera) with my 5d all shots are in focus.

Micro Adjustment?

If all of the shots were off, micro adjustment might be the answer. It's because some are bang on and the very next shot is massively front focused that would render MA unhelpful. If I adjust MA to 'fix' the front focused shots, then the ones that are actually bang on will be rear focused.

I'll post a few shots later today to give a better sense of what I'm getting.

cory1848 wrote in post #16919484
Micro Adjustment?

Christopher Steven b wrote in post #16919472
Tripod shots are moot.

They are the only way to be certain it's a fault with the camera.

hollis_f wrote in post #16919532
They are the only way to be certain it's a fault with the camera.

I agree, take the hand holding variable out of the equation.

As to whether any 7Ds have had problems, sure, and we hear about them, send it in, since you are convinced that the camera has a problem. Using a tripod is a proven way to test the AF, but if you are convinced you don't need to ask here, some bodies have had AF problems, although since there are many happy users here, well, you'll get questions. Send it in and get answers!

Okay--I'll do the tripod test.

hollis_f wrote in post #16919532
They are the only way to be certain it's a fault with the camera.

There are suggestions for a tripod test in this link:

https://photography-on-the.net/forum/showthre​ad.php?t=857871

Thanks, Tony.

tonylong wrote in post #16919610
There are suggestions for a tripod test in this link:

https://photography-on-the.net/forum/showthre​ad.php?t=857871

And try using a normal single AF point and not using "spot af".
This is just my impression, but I seem to feel that the majority of 7D and 5D3 related AF problem threads start with " I am shooting with spot AF"

CyberDyneSystems wrote in post #16919747
And try using a normal single AF point and not using "spot af".
This is just my impression, but I seem to feel that the majority of 7D and 5D3 related AF problem threads start with " I am shooting with spot AF"

I agree spot AF is only is useful mostly for static subjects where the area within the focus point has good contrast and in good light. That is my experience with it. Single AF and AF point with expansion are the only 2 options I really use.

@Jake, butterfly2937: I am only talking about shooting a static subject that is contrasty. This problem occurs with spot AF and point AF.