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I keep hearing people say their lenses are 'front focusing'...what is this? How would I know if one of my lenses was doing it?
What is front focus?
- Thread starter curiousanderson
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Front/Back focusing is where a lens focuses in front or behind the intended focus point, which depending on aperture can render the intended focus point out of focus.
There are tests you can do to see if this is happening http://focustestchart.com/focus10.pdf and some cameras have a micro adjustment function where you can counter the affect and effectively calibrate lenses to the body.
Alternatively, manufacturers will offer a similar service if you're having this problem.
There are tests you can do to see if this is happening http://focustestchart.com/focus10.pdf and some cameras have a micro adjustment function where you can counter the affect and effectively calibrate lenses to the body.
Alternatively, manufacturers will offer a similar service if you're having this problem.
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Brilliant, thanks Russ.
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No problem Andy 
Didn't notice you're a fellow 7D owner. The 7D has got micro adjustment which would allow you to compensate for front/back focusing issues.
I checked my lenses (15-85 & 100-400L) and they were pretty much spot on
It's one of those thing where in theory every lens should leave the factory 100% spot on but some aren't quite as spot on as others.
In "real life" the only time you may notice a small amount of back/front focusing is in close ups using a lens wide open so macro and close-up head shots would be the most likely candidate unless there's a big problem but then it'd probably be obvious to you already
Didn't notice you're a fellow 7D owner. The 7D has got micro adjustment which would allow you to compensate for front/back focusing issues.
I checked my lenses (15-85 & 100-400L) and they were pretty much spot on
It's one of those thing where in theory every lens should leave the factory 100% spot on but some aren't quite as spot on as others.
In "real life" the only time you may notice a small amount of back/front focusing is in close ups using a lens wide open so macro and close-up head shots would be the most likely candidate unless there's a big problem but then it'd probably be obvious to you already