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I have been experiencing a lot of back focus with my Sigma 35mm f1.4 lens on a 5DIII.
Up close, at any aperture, focus was always perfect. Sharp too.
Give it 10ft between you and the subject, at any aperture (even f5.6+) and it horrendously backfocused. Often 20ft + of back focus.
Went out with a mate this lunch time, with both our 5DIII's and both our S35's and had a play.
Conclusion... Mine IS backfocusing horrendously as I thought, and its not anything I am doing wrong (technique etc).
Stupidly!!!!! I had never checked the Micro Adjust... and it was set to +10 (backwards direction) which may explain a lot!
Brought this back to 0, and it now front focused!
Ended up on +6 which (according to the camera LCD) seems the sweet spot.
Now, my question.
The difference between +10 and +6 isnt much... but in my photos this is making an ENORMOUS difference... we are talking about 20-30ft+ of focus adjustment this has made?!
This seems excessive to say the least... but I cant deny the results.
Photos before MA adjustment - 100% were OOF on the subject (me, holding a black work PIT pass over a light coloured shirt - high contrast) and sharp on a building 40ft behind me.
Photos after MA adjustment - 100% were in-focus on me (using same black/white contrast as above) and OOF on the building behind me.
So... could a MA of this small an adjustment really make such an enormous difference?!
Interested to hear other's thoughts
Up close, at any aperture, focus was always perfect. Sharp too.
Give it 10ft between you and the subject, at any aperture (even f5.6+) and it horrendously backfocused. Often 20ft + of back focus.
Went out with a mate this lunch time, with both our 5DIII's and both our S35's and had a play.
Conclusion... Mine IS backfocusing horrendously as I thought, and its not anything I am doing wrong (technique etc).
Stupidly!!!!! I had never checked the Micro Adjust... and it was set to +10 (backwards direction) which may explain a lot!
Brought this back to 0, and it now front focused!
Ended up on +6 which (according to the camera LCD) seems the sweet spot.
Now, my question.
The difference between +10 and +6 isnt much... but in my photos this is making an ENORMOUS difference... we are talking about 20-30ft+ of focus adjustment this has made?!
This seems excessive to say the least... but I cant deny the results.
Photos before MA adjustment - 100% were OOF on the subject (me, holding a black work PIT pass over a light coloured shirt - high contrast) and sharp on a building 40ft behind me.
Photos after MA adjustment - 100% were in-focus on me (using same black/white contrast as above) and OOF on the building behind me.
So... could a MA of this small an adjustment really make such an enormous difference?!
Interested to hear other's thoughts
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