Unacceptable Focus Issue...Please Help

kevingeary · April 17, 2011

This happened to an entire series of shots that I took today. It's been happening consistently on each shoot I do at some point. This is a 100% crop:

I originally thought it might be a focus/recompose problem so I started manually choosing the focus point that was resting over the eyes during composition.

This is totally RAW out of the camera...obviously the focus is totally missed. Like I said...this was on a series of pictures, not just one.

50mm 1.4 at f2 and 1/1000.

This is unacceptable. Is this a lens problem, camera problem, or technique problem???

Here's the full shot web sized:

Again, this is RAW, but totally unacceptable.

Surfdog · April 17, 2011

What camera? What ISO? Is this a new camera, or one you have been using for a while? Did this problem just suddenly come up?

I had similar problems with a new Nikon D80 a few years back. Defective sensor.

anonymouscuban · April 17, 2011

Is there any part of the image that is in focus? Like something in the foreground? Looks like the stump by her left foot may be but not sure.

kevingeary · April 17, 2011

Surfdog wrote: »

What camera? What ISO? Is this a new camera, or one you have been using for a while? Did this problem just suddenly come up?

I had similar problems with a new Nikon D80 a few years back. Defective sensor.

Sorry. Canon 7D.

ISO 100. Shot at 1/1000th at f2.

It's something that just happens with me. I'm beginning to think it's a technique issue.

pixelatem · April 18, 2011

to me, it looks like the stomp in front of her is in focus.
if this is a sigma, or any third party lens there might be a problem with micro adjustment of the sensor.
a friend of mine had the same issue on his sigma 1.4, so he micro adjusted the sensor on his d700.
possibly this can happen to any lens, not just third party.

Bryce Wilson · April 18, 2011

I too think it looks as the stump in the foreground is crisp and in focus.

Have you tried to focus on the desired plane manually with the same lens?

cmason · April 18, 2011

Open in Digital Photo Pro to confirm the focus point. At f2, the depth is incredibly shallow, and something as simple as 'focus and recompose' could cause this. Did you focus and recompose?

Hackbone · April 18, 2011

You have about .91 feet in focus with that setup. So where ever your camera focused that is your depth of field. So you need to make sure where your camera is focusing where you intended. I have the most problems with focusing in an outdoor setting. That tends to fool the camera the most.

Here is a neat site for depth of field. http://www.dofmaster.com/dofjs.html

zoomer · April 18, 2011

Are they all like this or just this one. With short depth of field it is not uncommon for a few to "miss".
Check for front or back focus if this is a consistent problem.

At this distance focus recompose should not be the problem.

kevingeary · April 18, 2011

A lot of them were like this.

I was manually moving the autofocus point so focus-recompose was as minimal as possible.

I too think the stump was in better focus...but HOW...I placed the focus point manually over the eye and focused and took the shot. How does a stump at her feet get in focus when I'm requesting her eye to be in focus?

jpc · April 18, 2011

Any time this has happened to me, it was because I had inadvertently selected a focus point other then the center. I would bet you had the bottom right focus point selected. You just didn't realize it.

rwells · April 18, 2011

I suspect a technique issue is at play here.

Take test shots from a tripod, or the camera sitting on something flat.

Does it focus every shot just fine? If so, then you more than likely have a "holding the camera" technique issue.

People often will inadvertently have some part of their support hand touching the lens focus ring, and accidentally moving it. Since most lenses allow manual focus after auto-focus has locked, this will throw the focus off.

Pick your camera up like you normally do to take a shot, both in portrait and landscape orientation. Don't do anything outside your normal grip/hold.

Now, just freeze... Where are your hands exactly? What are they touching?

Give these "test" a try and you might be surprised what you find out.

Hope that helps...

divamum · April 18, 2011

What focus mode is your 7d set to (ie single point, zone, auto af etc)? For the best hit rate with shallow DOF, it really needs to be single point so you can be 100% sure of controlling it; I think that's what you mean you were doing, but just in case.... In some circumstances, spot-focus is helpful too (not spot-metering, but spot focus. I have it linked to the DOF preview button on my 7d so it's always right under my fingertips when I need it).

What mode were you in? I believe the 7d defaults back to zone/all points if you're in the auto modes (I never use mine that way and don't have the manual to hand, so somebody correct me if I"m wrong). So... even if you were set to single point focus in Manual or Av, if you were (for instance) using Program, it might not have worked that way.

Also, do you have it set so it keeps the orientation of the focus point when you switch from landscape to portrait? If so, that might have been how you wound up with the focus point in the wrong place for a set of shots when you changed your orientation.

Take Randy's advice seriously - I found that he was exactly right when I was having some focus issues at one point! My hand was catching the MF ring without my realising it.

Next, as others have suggested, some more scientific testing is in order to try to isolate where the problem is, so test it on a tripod at varying DOF's (I usually test wide open, 4.0, 5.6 and 8.0 as reasonable markers within the band of settings I'm likely to use) and have a look at those shots to see if you can glean any more information.

Lastly, it is entirely possible that either the lens or the camera has an issue. Does it only happen with this lens? If so, try MFAF and see if you can compensate for any front- or back-focusing issues there might be. Conversely, does it happen with ALL of your lenses? Then it could be the camera. Try doing a hard reset on the 7d (details here)

HTH!

kevingeary · April 18, 2011

divamum wrote: »

What focus mode is your 7d set to (ie single point, zone, auto af etc)? For the best hit rate with shallow DOF, it really needs to be single point so you can be 100% sure of controlling it; I think that's what you mean you were doing, but just in case.... In some circumstances, spot-focus is helpful too (not spot-metering, but spot focus. I have it linked to the DOF preview button on my 7d so it's always right under my fingertips when I need it).

What mode were you in? I believe the 7d defaults back to zone/all points if you're in the auto modes (I never use mine that way and don't have the manual to hand, so somebody correct me if I"m wrong). So... even if you were set to single point focus in Manual or Av, if you were (for instance) using Program, it might not have worked that way.

Also, do you have it set so it keeps the orientation of the focus point when you switch from landscape to portrait? If so, that might have been how you wound up with the focus point in the wrong place for a set of shots when you changed your orientation.

Take Randy's advice seriously - I found that he was exactly right when I was having some focus issues at one point! My hand was catching the MF ring without my realising it.

Next, as others have suggested, some more scientific testing is in order to try to isolate where the problem is, so test it on a tripod at varying DOF's (I usually test wide open, 4.0, 5.6 and 8.0 as reasonable markers within the band of settings I'm likely to use) and have a look at those shots to see if you can glean any more information.

Lastly, it is entirely possible that either the lens or the camera has an issue. Does it only happen with this lens? If so, try MFAF and see if you can compensate for any front- or back-focusing issues there might be. Conversely, does it happen with ALL of your lenses? Then it could be the camera. Try doing a hard reset on the 7d (details here)

HTH!

I'm positive of where the focus point was on every shot because on the 7D it remains in the viewfinder and does not disappear.

I have it on spot focus, single point.

I was not touching the manual focus ring.

I wasn't, however, taking care not to move much or shake during the pictures as I assumed 1/1000th was fast enough for slight movements to not effect IQ???

I really need a grip on the camera for portrait shots so I can hold the camera more comfortably, though.

I'm going to get a tripod (don't have one!! lol) so I can do some testing.

aj986s · April 18, 2011

kevingeary wrote: »

I'm positive of where the focus point was on every shot because on the 7D it remains in the viewfinder and does not disappear.

I have it on spot focus, single point.

I was not touching the manual focus ring.

I wasn't, however, taking care not to move much or shake during the pictures as I assumed 1/1000th was fast enough for slight movements to not effect IQ???

I really need a grip on the camera for portrait shots so I can hold the camera more comfortably, though.

I'm going to get a tripod (don't have one!! lol) so I can do some testing.

If the photos are still on the memory card, you should be able to review them in the camera and see the red marks confirming the focus points. I think you can also review using Canon's PC software, which I never use....

lanaer · April 18, 2011

It could be a calibration issue.

SLRs use dedicated sensors for AF, that use light reflected off the mirror, but the image is captured on the sensor. If the sensor, mirror, and AF sensors are not the correct differences from each other, then the sensor could be in a different focal plane than the AF sensors.

At least, that's what I gathered from an article over on Luminous Landscape. This isn't an issue I've had to deal with personally.

Hope that helps.

RacinRandy · April 18, 2011

kevingeary wrote: »

I'm going to get a tripod (don't have one!! lol) so I can do some testing.

FWIW. I have a 7D and had a similar problem with a longer lens.
I found;
A) A slight haze on the filter I was using, Cleaned and reinstalled and was better.

without the filter on it was still just off a touch, A micro adjustment in the camera brought it back in line.

Without a tripod, set the camera/lens on a table. Measure to a subject and set your focus, Fire, check the frame. then you can make adjustments accordingly. Also, on a bright backlit scene like this the 7D has a bard time "seeing" into the shade for focusing, not sure why.
Granted I shoot mostly cars moving in many directions at the same time but i do have to get the winners circle shots right every time too.

puzzledpaul · April 18, 2011

In addition to above ... whilst not for a 7D, a couple of things in my Canon manual - 'For when AF fails' ...
Low Contrast subjects
Extremely backlit ditto

I experience similar issues under such (but worse) conditions when shooting low across water.

pp

divamum · April 18, 2011

Definitely open in Canon's Zoom Browser software so you can see where the camera thought the focus point was (even if that isn't where you put it!) - very useful info in this kind of situation.

kevingeary · April 18, 2011

divamum wrote: »

Definitely open in Canon's Zoom Browser software so you can see where the camera thought the focus point was (even if that isn't where you put it!) - very useful info in this kind of situation.

I've enabled the feature that shows me in camera when i review pictures where the focus point was.

jeffreaux2 · April 18, 2011

Looks like a challenging shot for autofocus. Her face ( if thats where you focused) is all in shadow and low contrast. A focus target held in front of her face would have been a good idea....or an STE2 or Shoe Mounted Flash for focus assist.

Randy's comments are spot on.

divamum · April 18, 2011

kevingeary wrote: »

I've enabled the feature that shows me in camera when i review pictures where the focus point was.

Ok, I didn't even know I could do that (the 7d's features continue to offer suprises even after a year of use!) - what is that feature/setting? Would be super useful for me when I'm reviewing shots on the LCD!!

kevingeary · April 19, 2011

divamum wrote: »

Ok, I didn't even know I could do that (the 7d's features continue to offer suprises even after a year of use!) - what is that feature/setting? Would be super useful for me when I'm reviewing shots on the LCD!!

6th menu from the left "AF Point Disp. = Enable"

Unacceptable Focus Issue...Please Help

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