Gear Talk > Technical Support

Possible 7D Autofocus Issues

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MSP:
Hi,

This is my first post but I've checked out the CR many times and seen some high quality advice and insights so I'm hoping that some experienced 7D users can help me out.

My experience: I learned to shoot on a fully manual Minolta with a 50mm f1.7 over fifteen years ago and I've been shooting with a 30D for the last five years, maybe longer. I bought the 7D in mid-January 2013 and I've watched several hours of video tutorials, read some 3rd party books and read up on the AF system and custom functions to fill in any knowledge gaps from the 30D to 7D jump. In total I've taken around a thousand shots with the 7D (not a lot really, it's been a slow month with a lot of cold days...).

The problem: The 7D AF system that I've heard so many good things about has been utterly disappointing. I'm missing focus at least 75% of the time on still subjects and slow moving subjects that my 30D never struggled with. I haven't used AI Servo enough to judge whether it performs any better or worse than One Shot focus. The problem has been consistently inconsistent so I haven't been able to tweak the AFMA to compensate. I mainly use Single Point AF and Spot AF and will lock focus but then end up with blurry subjects even with good lighting and good contrast. There doesn't seem to be a consistent back or front focus, it just seems to randomly miss, often to a large degree. To be clear I'm not focusing and recomposing with a shallow DOF causing the focal plane to shift; the misses are happening even with smaller apertures. I've also had issues with AF "hunting" for several seconds when lighting is adequate (minimal focal distance and settings haven't been the issue, and it has happened with CFn III-4/Focus Search turned on and off). I've switched between full manual, shutter priority and aperture priority and the AF misses have happened regardless of what mode I'm in and what lens I'm using. The AF has been poor when shooting handheld, on a tripod and with a monopod. I mainly shoot with a 35mm f1.4L and 70-200mm f2.8L IS II but I have a 50mm f1.8 and 180mm f3.5L that have also had AF issues with the 7D (I don't count the AF hunting on the 180mm as a problem since that can happen with any body). I find it hard to believe that the lenses are the problem, they all seem fine on the 30D.

So now I can't help but wonder if I'm just lacking good technique (not impossible), if the AF on my new 7D isn't working correctly, if there's a setting I'm missing somewhere that could be the culprit or if my expectations are just too high. I can post my Custom Function settings if it's necessary but I've reviewed each and every one of them and can't imagine they're causing the AF to miss focus like it is. I've tried different combinations of shutter speeds (particularly with the 70-200mm), apertures and ISO/exposure settings and can't find any rhyme or reason as to why the focus works when it works or why it misses as it does most of the time.

One more bit worth noting is that the AF point appears in the correct place when reviewing photos, so it is registering and supposedly locking focus on that point. Also worth noting is that I can still return or exchange the camera within the next week.

Is my miss rate typical? Do I suck at focusing? Is this camera a lemon? Is the AF this inconsistent with most 7D's? Should I exchange it? Should I get a refund and go back to the 30D? Should I get a refund and drop the extra coin for a 5D Mark III?

Any advice would be appreciated. Just ask if you want and additional or more specific info. Thanks!

DCM1024:

--- Quote from: MSP on February 09, 2013, 09:20:00 PM ---
The problem: The 7D AF system that I've heard so many good things about has been utterly disappointing. I'm missing focus at least 75% of the time on still subjects and slow moving subjects that my 30D never struggled with. I haven't used AI Servo enough to judge whether it performs any better or worse than One Shot focus. The problem has been consistently inconsistent so I haven't been able to tweak the AFMA to compensate. I mainly use Single Point AF and Spot AF and will lock focus but then end up with blurry subjects even with good lighting and good

--- End quote ---

I feel your pain - my 7d gave me fits when I first got it, but it was a matter of more tweaking of settings than I was accustomed to, and mine is fine now. I still prefer the iq of the 5d, though.

The auto focus settings were the key. I have disabled zone focus and use spot with expanded points. Canon told me not to use ai servo unless you are tracking a very fast moving subject such as bif. They compared the af of the 7d to the 1d4. If you want further detail of my settings, I would be happy to share.

Mt Spokane Photography:
You mention that it has issues with still subjects?
 
Puut the camera on a tripod and take images of a flat wall about 15 ft away with a 50mm focal length.
 
Thak 10 shots moving the focus to infinity before each shot.  Make sure your shutter speed is at least 1/100 of a second, and set the aperture to wide open.
Variance in critical AF is normal, but 8 or 9 should have sharp focus.
That should show you that the focus is ok, or that it is bad.  The worst thing is when its erratic and every other shot is off.  That can be the camera or the lens, or a combination of the two.
Many of us went from a 8 or 10 mp camera to the 7D and started viewing images at 100%, and were appalled.  It takes more care and twice the shutter speed to get the sharp image you are used to seeing at 100%.  Once you get it down, then your images will be sharp, but its still a challange when you view them at 100%.
Now, just imagine those D800 users when they went from their 12mp D700 to the D800.  They had to learn to be very careful, and even then, viewing at 100% can be frustrating. I was one of them, but I went from a 5D MK II and 7D to the D800.  After a couple of thousand images, I got really tired of the long time it took to post process images and sold it, so I now have a 5D MK III.
 
Here is one of my first batch of images with the D800.  It was a struggle!

 
100% crop ---Frustrating and Fuzzy!!

 
By the second event, things were better. Same camera and lens, more experienced photographer :)

 
100% crop  Much better, but getting the apparent sharpness of a 30D at 100% requires ultra careful shooting, and thats not me!

 
 

CharlieB:
I bought a 7D in the fall of 2012.

I went NUTS with its focus - which also varied by lens quite a bit.

My own problem - all lenses were giving problems, some more than others. 

After about 2500 shots of testing, I was able to determine that ONE lens terrible, and would not focus consistently at all on the 7D.  It thereafter gave problems on my 5Dii.  When I did a AFMA on the lens, it was best at 0 correction... why... I can't understand it.

The camera was sent to Canon - and they replaced the AF sensor, mirror-box... and CD card "socket" in the body.

The body was returned to me... in about two weeks time... and has been totally reliable and consistent with all my lenses.

I've got... 5 Canon EF primes, and 4 Canon EF zooms.  Fixing auto focus... errors... I'm glad they fixed 'em up!

MSP:
Thank you all for the quick responses.

@DCM1024 - I almost always use Single-Point AF or Spot AF in One-Shot mode. I occasionally switch to AI Servo but I expect more misses with a moving subject so I'm focusing on One-Shot AF issues here (no pun intended). Besides the AF modes, are there any specific settings that you've found significantly alter your AF hit/miss percentages with still subjects? I've gone through all of the camera's settings including the Custom Functions and don't see anything that would result in the AF inconsistencies I'm experiencing.

@Mt Spokane - I've definitely had some blurry shots that I can attribute to camera shake and/or shutter speeds that are too low but I think I can differentiate those from AF misses fairly well. There's definitely a bit of an adjustment with the 10MP jump that requires better technique but after doing the test you recommended I'm leaning towards returning/exchanging the camera. Results are below.

@CharlieB - I'm glad you got your camera working well. Your problem sounds a lot like what I'm struggling with. I haven't found that any specific lens is worse than the others, they're all inconsistent.

Here are the results of my tests (w/35mm @f1.4, Shutter >1/100,  ~15 feet from the wall on a solid tripod using a shutter release cable):

Test 1:

Tack sharp: 1/10
Fairly sharp: 1/10
Slightly OOF: 2/10
Significantly OOF: 6/10

Test 2:

Tack sharp: 1/10
Fairly sharp: 4/10
Slightly OOF: 4/10
Significantly OOF: 1/10

Test 3:

Tack sharp: 0/10
Fairly sharp: 4/10
Slightly OOF: 2/10
Significantly OOF: 4/10

In total around 11/30 images were in focus, without being extremely critical. I would only consider 2/30 images tack sharp. Some the images that are OOF aren't even in the neighborhood of the focal point. A 37% AF hit rate while shooting on a tripod with a shutter release cable isn't acceptable to me for a $1000 body.

Thoughts?

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