Inconsistent focus with 70D

[paulbpilot]

I'm struggling with gettng consisten focus results with my 70D. I can take two shots, one auto-focused right atfter the other, restablishing focus for each, and get very different focus results.

The setup:

Mode: AV

Lens: New Canon 70-20 mm 2.8 IS USM, zoomed to max

ISO: Auto

Style: Standard or Auto

Single Shot

Single point focus

Shooting across my back yard, approx 75 ft at woodend fence that contains lots of grain, and high contrast weathering. I can take on shot, handheld, refocus on another object, come back to the exact same spot on the fence, re-foucs and shot. One pic will be tack sharp on close inspection (fine grain in the wood is crisp) the other will have all the wood grain blured out with no definition. What the heck is going on?

[Yorptunes]

I have a new 70D and went out shot some test frames at about 75 feet using my canon 70-200 1:2.8.  I shot on AV with auto focus through the viewfinder.  My lens was set to 2.5 mm oo, with stabalizer mode on 1, stabalizer on.  

My test frames came out identical.  I up loaded them to my MAC Pro using a 42 incc monitor.  I could not see any difference.  

I am sure you doubled checked all your settings, if so I have no idea why your not getting considtent auto focus.  

John

[Yorptunes]

On second thought try using a tripod and see if there is any improvement.

[paulbpilot]

Definately looks like focus and not camera shake. I was shooting in broad daylight at 2.8. Didn't note shutter speed, but it woulda be fast. What's puzzles me, is that the only vaiable in the equation is the focus on a new object inbetween the shots. I never moved, changed a setting, or anything. It's strange for sure.

[ebiggs1]

Paul, "...  is that the only vaiable in the equation is ..." and you!

Even at high shutter speeds you can get movement just not as likelky.

[paulbpilot]

If focus. Not movement.

[Maria]

Makes me wonder more about my issues with my new 70d .... Would sort of explain why some back to back shots are in focus and some not... Or in my case 'sharp' - I can't tell if which...

[paulbpilot]

Yep. At first I thought it might be the Tamron lens I'm using, because they don't yet say it's fully 70D compatible. Still testing. But a new Canon 70-200 2.8 IS II should be spot on.

[SGFFX]

Are you manually setting an AF point? If so, try putting that AF point on the same spot every time.
Another thought: did the light change between shots? There may have only been seconds between shots but maybe the sun went behind a cloud and there was less contrast for AF to use.

Lastly, I have a 6D and was seeing inconsistent focusing. I shoot in RAW and I have turned off High ISO Noise Reduction (this is one parameter that is applied even in RAW). This made a big difference in correcting "softness" in the focus.

Note that even when shooting in RAW what you see on the LCD is jpg. So any optional "enhancements" are applied to the LCD image and will not be applied to the RAW image file. In other words what you see on the LCD in not necessarily what you will see in the image file. If you turn off all of the corrective/enhancement settings then RAW and what you see an the LCD should be very similar. This last suggestion only matters if you shoot RAW.

[ScottyP]

I'm with SGFFX. Are you using just the center AF point, or are you letting the camera pick whatever points it feels like?

Try something other than the fence. Try an actual object/target that stands out away from the background. A fence sounds like it would kind of BE the background, and it could be hard to get the camera to grab just one part of it without a clearer subject in the foreground.