Focusing problem

I recently purchased a 5D Mark III and did a commercial job of some moving bicycles. I only ever use the centre focusing point, but after reviewing some of the images, the centre of the photograph wasn't sharp, but the far left of the image was sharp.

 

I assumed that I had I had accidentally switched focusing points, but took some portraits of my daughter on the move today and the problem has appeared again on some shots. Lens for bicycle photos was an old Canon 28-70 2.8 L and the portrait shots were on a newly purchased 2nd hand Canon 135 f2 L.

 

Does anyone know of an error that could cause this?

I assumed that I had I had accidentally switched focusing points,

 

I'm assuming you checked which focal point is active, and that only a single point was activated. The 5DIII has can be customized to change how the focal points were selected, so it isn't hard to make a mistake when the camera is unfamiliar to you.

 

The fact that this happened with two lenses pretty much rules out a lens problem. It also makes it very unlikely that back- or front-focusing is a problem, unless there is something wrong with the camera. Normally, that shows up in specific combinations of body and lense.

What focus mode were you using?

I had the same with my motorcycles last week, but i was in 1 shot. So the moment i picket up the cycles, and focused was not the same as when i fully pressed the shutter and made the shot. Should have used ai-servo. (see the Jaguar, the back wheel is sharp)

You should be in AI Servo mode for moving subjects.

Thanks for the replies. I used centre point focus, one shot with low speed continuous shooting and this slow moving bike . The image below is with the 28-70L, the logo and text on the red box is burred, but the round red and white sign to the left is pin sharp. I've found some more complicated focusing settings, the AF Selection Modes on page 75 of the manual. On page 72 there is the centre point with one box, then there's pin point focusing with two boxes. Would any of these two boxes make a difference?

 

Either it's a user fault or the camera, it's hard to know. This camera doesn't confirm which focusing point was selected at the moment of capture, whereas my old Eos3 lit up red when it chose its focusing point.

 

Which AF settings are people using for everyday shooting of people?

 

 

 

 

Edited May 15, 2017 by Gary Holliday

This is the 'portrait' taken at f4.5 with the 135 f2 L. The girl is playing a ball game so not much time to take the shot.

 

Centre focusing in the middle of the shot. Either the purple hair band has been picked up by the AF, or maybe the long strand of hair in front of the face has thrown the AF? The end of that long strand looks sharper, surely both eyes should have been sharp?

 

 

 

 

 

Gary, are you reading what we tell you? Use AI Servo for moving subjects and One Shot for stationary subjects. There's nothing wrong with your camera.

 

For little girls, focus on the eye, not the purple headband. Even if she's moving, she's slow enough for you to keep the AF point on the eye. For action shots, I'll use an f-stop in the f/8 range, to get a little DOF. If you want a portrait shot, with max bokeh and a wide open lens, it's best to stop the subject. When you choose razor thin DOF, you have to hit AF perfectly.

Right. f2 and 135L is a recipe for out of focus close up pics of a moving head shot anyway, unless you can always lock on to the eye, expect a high error rate - take a lot and then you increase your chances.

dcstep, I used one shot for the stationary shot of the girl and focused on the eyes, not the purple headband.

 

Robin, the aperture was f4.5 for the little girl, not great DOF I know, but the focusing point should have picked up the bridge of the nose on this occasion and kept the eyes in focus. Maybe this is an issue of shutter lag, something I've not experienced before having working with film cameras all my life?

 

As for the bike shot, a single shot should be fine for a slow moving bike, but it still doesn't explain why the round sign is in focus rather than the big red box. I'll check the exif data to see what the shutter speed was. Maybe it's lack of speed or shutter lag rather than dodgy focusing.

Have you done MFA with your large aperture lenses? As you've just gotten the camera I would guess not. The 135/2 is (so I've been told) subject to occasional focus shift, and there's no way to know why the first owner decided to get rid of it. Were I you, I would set up a tripod, and MFA all your lenses. Doing so may reveal more about your lenses than you want to know, but at least you'll know it ;)

 

As far as the bike image goes, I would guess the red box is slightly OOF because of subject movement. The front tire certainly is. IDK what your shutter speed is, but the paving stones directly under the chain are in focus, as well as the sign (on the near side of the box), so the facing side of the box is bracketed by two objects (in front and behind it) which appear to be in sharp focus. Clearly the camera focused correctly. There is no necessity for using AI Servo once you've got the camera squared away, and are used to it, for slow to medium speed moving subjects. However, while you are learning the camera, you may be better served (w/ a higher keeper rate) by using AI Servo for moving objects.

 

As far as the focus confirmation light... the 5D3 does give you a bright red focus confirmation on that focus point... in dim light. In daylight all you get is the circle/triangles... which is utterly retarded as it's out of your direct line of sight, so you find yourself glancing down to confirm... yeah, whoever made that idiotic design decision was NOT a photographer - especially as it can't be overridden by a C.Fn.

Most of my lenses need some AFMA and that's one of the first things I check with new gear. Typically AFMA is in the +-2 to 5 range. Even +-2 makes a visible difference with large aperture lenses.

Any good resources on how to check this lens?

Any good resources on how to check this lens?

 

It's ok, I found it:

 

Canon DLC: Article: Canon EOS AF Microadjustment Guidebook

Just an update; I sent my lenses and body in for calibration and body matching. The CMOS on the new 5D body had a fault and the older f2.8 28-70L USM is not compatible with the digital body. It wouldn't focus on the same spot, hence the dodgy bike photo. The lens requires a repair and the part is not available. Should work fine with it's original EOS 3.

 

So this craftsman is happy to blame his tools.

Edited October 3, 2017 by Gary Holliday

Don't understand why the the 28-70 L is not compatible. I don't have a 5D but do own a 6D and a very old 28-80 f2.8-4 L and don't have any problems with focusing. Let us know what you find out.

I can only repeat the brief explanation from the Canon repair tech; that the old 28-70L 2.8 would not likely have an issue with my EOS 3 film camera, newer digitals...yes.