Has anyone with a K-5II or K-5IIS retested SDM lenses with a TC?

Started Feb 1, 2013 | Discussions thread
brandrx Forum Pro • Posts: 28,337
Re: Thanks for your reply.


Hi ,

This is part of my "Teleconverter question" thread,

The camera is the K01 and I'm testing the Kenko 1.5 teleplus DG teleconverter with the FA50 1.4 lens. The speed is OK when the change of focus is near,but when going from 2 mts to infinity it advances with a speed so slow it grumbles barely audibly, taking up to 5 secs to lock,the accuracy was so poor you see the lens barrel stopping in a different place with each AF,(at infinity). I also tried the Tamron 17-50mm 2.8, the image quality was OK ish but repeatable accuracy was poor. No real problems on the K5 with PDAF, fast and accurate with OK ish image quality.

I see the same thing with my FA77mm LTD. The only conclusion I can come to is that some lenses just don't work very well with CDAF.

Apart from the film days with MF ,I've had little to do with teleconverters and heard of the difficulties of finding appropriate converters for AF screwdrive or SDM, so I was rather disappointed with the results. All in all it shows me that Contrast Detect AF is not without it's problems in spite of the belief that it can't be wrong because it's the sensor that detects the AF. We live and learn!

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Ron - 'We don't have time to go take pics this afternoon Carl.'
Carl - 'What do you mean? It will only take 1/1000s.'
'Keep your eyes looking forward. However, glance back now and then to see where you've come from. It will put a smile on your face.' ~ brandrx

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