Canon focus issue

[StephenM44]

I went to a wedding last weekend and only had my 100mm F2.8L IS USM. Camera is 5dii.

In the Church the lighting was challenging, bright light behind the alter through the stained glass windows but I still managed to get some nice shots. Outside the church it was a bit cloudy but again some great shots, really good focus, incredible detail and a high percentage of keepers, as you'd expect from the lens.

But at the reception in a marquee it was very difficult to get the auto focus to work well, most shots were poorly focused - they looked ok in the viewfinder but processing at home showed the majority to be very slightly off, most shots were soft which is unusual. They'll be OK if not printed too big but I know they're not right.

Is it possible the light in the marquee upset the AF ? It was a strange hazy, creamy light which I've not tried taking photos in before. Has anybody else experienced this sort of issue ?

[LongQ]

Have you made any assessment of the EXIF information to see if it throws up any clues?

[flat-planedCrank]

Don't recall ever having problems with AF in a marquee - but it might be one of those occasions where your eyes might actually be 'seeing' more light than was actually available?

IMO it's not unusual to be able to see reasonably clearly yet have the camera AF struggle - even when using fast lenses. I don't doubt that 'sports AF' cameras will be better in this regard...


As LongQ said, maybe post some shots (and 100% crops) with EXIF?

[RobDickinson]

Always better to post example pics with exif so we know more of what the environment was like.

But frankly the 5d2 in low light especially with off centre focus points, is crap.

[flat-planedCrank]

RobDickinson said:

But frankly the 5d2 in low light especially with off centre focus points, is crap.

Ah yeah ^

Must say I'd stay away from the non-centre points for normal use (even more so if you're asking it to track movement)

[StephenM44]

This was taken at F2.8, 1/60th and at about 20 feet from the baby.



Edit to add, that's a bit small . . . I'll see if I can find a better example.

[LongQ]

StephenM44 said:

This was taken at F2.8, 1/60th and at about 20 feet from the baby.



Edit to add, that's a bit small . . . I'll see if I can find a better example.

Hmm. FY the general consensus on here is that Thumbsnap may be a little 'compromised' for attempts to present examples of images with quality issues, whether real issues or not.

[RobDickinson]

theres also a lot of questions on how you focus?

I use back button af-on focusing and AI servo even for static shots, if focus is dubious I tap the focus button a couple of times which gives it a chance to zone in properly.

[checkmate91]

Me too, just gotten into back button focus. Also I spent nearly a year with my camera set on af=live mode rather than quick mode. That last point made a H U G E difference in af speed and precision, especially in low light. My bad but I'm glad I worked it through...

[flat-planedCrank]

Another back-button-AF-servo-for-everything vote here

[Seight_Returns]

I'm a back button focus convert too - and also got into the habit of leaving the camera in AI-SERVO for static shots too - I wasn't happy with the sharpness of a lot of my shots to the point that a perfectly good 15-85 almost got consigned to Ebay - have now switched back to using One-Shot for static and am getting noticeably better results.

I've set the DOF button to toggle between AI Servo and One Shot so I can switch from static to moving subjects easily.

[Crafty_]

Could it be shake? even on full frame 100mm @ 1/60th is pushing it a bit is it not ?