How much error can Micro Adjust handle?

[AJQS]

Just out of interest really, My Sigma 70-210 has always front focussed, I'm fairly certain Micro adjust would take care of it. at approx 2m focus is approx 20mm in front of where it should be. Would Micro adjust take into account that much error?

 

[Janesy B]

My 70D goes +/- 30 so that's 60mm of adjustment from end to end. If it really is that bad it might be worth sending back for calibration.

 

[LongLensPhotography]

best thing to is take the camera and start playing. If you set MA to max and get backfocus you know you'll eventually get it right; otherwise it is well and truly time to service.

and to be quite accurate MA only can do very minor focus tweak (hint in the name - micro)

 

[Janesy B]

You should be quite methodical otherwise you can be worse off than before.

 

[Canon Bob]

My 70D goes +/- 30 so that's 60mm of adjustment from end to end. If it really is that bad it might be worth sending back for calibration.

It's not mm's Bryan. (at least with Canon bodies)
Each unit of MA is 1/8th of the single sided depth of focus (~depth of field in the image plane). Wider apertures and shorter FL's will need a larger offset relative to the error seen.

Bob

 

[HoppyUK]

Just out of interest really, My Sigma 70-210 has always front focussed, I'm fairly certain Micro adjust would take care of it. at approx 2m focus is approx 20mm in front of where it should be. Would Micro adjust take into account that much error?

As Bob says, there's no easy way of translating MFA increments into actual distances because that's not how it works, but from my own experience, I think you should be able to accommodate 20mm with that lens at that distance.

 

[AJQS]

As Bob says, there's no easy way of translating MFA increments into actual distances because that's not how it works, but from my own experience, I think you should be able to accommodate 20mm with that lens at that distance.

Cheers all