K-01 and K5-II Contrast AF problems

Started May 5, 2013 | Discussions thread
brandrx Forum Pro • Posts: 28,337
Re: K-01 and K5-II Contrast AF problems

MightyMike wrote:

I've been saying this for months... CDAF isn't the second coming of focusing systems, some lenses just don't work

Sigma 18-125mm F3.5-5.6, Sigma 75-200mm F3.8, Sigma 17-70mm F2.8-4.0, and others, the common issue is it gets worse at the tele end.

The issues is likely spherical aberrations, all lenses have this to some extent, this causes softening of the image if its really bad and allows for 3 points of focus, of course 2 of those points aren't accurate and one is best focus. What happens is the stupid CDAF system doesn't know which best focus to stop at and just lands on one. there may be a way the CDAF system can be programmed to go past the first point of focus to the best point of focus and this may be occurring in first party lenses.

So for all those people who are singing the praises of CDAF being the most accurate system out their, look again, with some lenses and in low light its a dud! its useless!

I agree with Mike when it comes to CDAF with some lenses. However, I did find that my new Sigma 18-250mm HSM Macro seems to be working fine with my K-01. I just now stepped outside and took a few quick shots using the K-01 + Sigma 18-250mm HSM Macro and with the lens at 250mm. I shot at subjects at different distances and all seemed to be in focus.

The K-01 with manual focusing and focus peaking is a dream come true IMO.


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