AutoFocus, LensAlign
Auto Focus Woes
14/05/09 09:49 Filed in: Education
AUTO FOCUS WOES
Do you have a Canon 50D, 5DMkII, 1D/Ds MkIII, Nikon D300, D700, D3, D3x, Sony A900 or Pentax K20. If you do, then this article will be of most interest to you. If not read on as there is a link to an article about Focus-Recompose-Shoot that we can all learn from if you use that technique with Auto-Focus.
If you have one of the new generation cameras listed, you have a feature called MicroAdjustment (or something of the same meaning depending on manufacturer)
This takes into account error tolerances in lens/sensor combinations, sometimes acceptable on their own but when combined could result in a back or front focussing nightmare.
If you shoot wide open with a fast lens, usually 2.8 or faster but can even be seen at f4 at longish focal lenghts, then it is critical that, for example, the eye that you think you have focussed on, should in fact turn out to be sharp in the image. If it’s not there are a couple of variables, such as camera shake, Focus-Recompose-Shoot error (check out this link) or front or back focussing errors.
There is now a commercial solution. I have purchased the Lens Align Lite product from the US (see a review here on Luminous Landscape site)
I have calibrated my 5 lenses, not one reading a zero on the scale, even the primes were out a little. The zooms required more correction but within the scale of the microadjustment available on the 5DMkII.
Result: my confidence has returned with auto-focussed results as expected.
There are a couple of good example images on this blog, and BTW, this guy’s stuff is worth bookmarking, especially his flash tutorials.
Contact me to arrange to have your lenses and camera calibrated for a small fee.
David Magahy
Do you have a Canon 50D, 5DMkII, 1D/Ds MkIII, Nikon D300, D700, D3, D3x, Sony A900 or Pentax K20. If you do, then this article will be of most interest to you. If not read on as there is a link to an article about Focus-Recompose-Shoot that we can all learn from if you use that technique with Auto-Focus.
If you have one of the new generation cameras listed, you have a feature called MicroAdjustment (or something of the same meaning depending on manufacturer)
This takes into account error tolerances in lens/sensor combinations, sometimes acceptable on their own but when combined could result in a back or front focussing nightmare.
If you shoot wide open with a fast lens, usually 2.8 or faster but can even be seen at f4 at longish focal lenghts, then it is critical that, for example, the eye that you think you have focussed on, should in fact turn out to be sharp in the image. If it’s not there are a couple of variables, such as camera shake, Focus-Recompose-Shoot error (check out this link) or front or back focussing errors.
There is now a commercial solution. I have purchased the Lens Align Lite product from the US (see a review here on Luminous Landscape site)
I have calibrated my 5 lenses, not one reading a zero on the scale, even the primes were out a little. The zooms required more correction but within the scale of the microadjustment available on the 5DMkII.
Result: my confidence has returned with auto-focussed results as expected.
There are a couple of good example images on this blog, and BTW, this guy’s stuff is worth bookmarking, especially his flash tutorials.
Contact me to arrange to have your lenses and camera calibrated for a small fee.
David Magahy
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