Multiplier not Autofocussing


swarf

Link Posted 31/08/2018 - 10:26
I have a Kenko P-AF 1.4x MC4 multiplier that has developed a bizarre problem when paired with my DA*16-50. It simply will not auto-focus - the camera display rapidly 'flickers' between MF & AF but the lens will not autofocus. I have tried cleaning the contacts on both the lens and the multiplier but the problem still occurs.

However, when I use it with any other of my fast lenses it works fine, i.e. it auto-focuses in whichever mode I have selected.

Any suggestions/thoughts?

Phil
K-5iiS; K-r; ME Super; ME; DA* 16-50 f2.8; DA 18-135 WR; DA 55-300 WR; HD DA 15mm F4 ED AL Limited; FA 50mm f1.4; A50mm f1.7; DAL 18-55mm; M40mm f2.8; + assorted non-Pentax lenses

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Mike-P

Link Posted 31/08/2018 - 12:07
I have never got any teleconverter, bar the Pentax 1.4x WR, to autofocus reliably with SDM on Pentax bodies. I have the Kenko 1.5x and although it has the required contacts for SDM it hunts back and forward and rarely locks focus.

Interestingly it used to work a lot better until Pentax issued a firmware update (some time ago) when they released their own 1.4x WR converter.
No equipment list here but thanks for taking an interest. My Flickr

swarf

Link Posted 31/08/2018 - 13:14
Mike-P wrote:
I have never got any teleconverter, bar the Pentax 1.4x WR, to autofocus reliably with SDM on Pentax bodies.

Mike

Thanks for pointing me in the right direction. I've tried it with a couple of slower screw drive lenses and it works fine.

it's just not happy on the SDM ones.

Phil
K-5iiS; K-r; ME Super; ME; DA* 16-50 f2.8; DA 18-135 WR; DA 55-300 WR; HD DA 15mm F4 ED AL Limited; FA 50mm f1.4; A50mm f1.7; DAL 18-55mm; M40mm f2.8; + assorted non-Pentax lenses

My Flikr Page link

Mike-P

Link Posted 31/08/2018 - 14:51
Yes, doesn't work well with Sigma HSM either.
No equipment list here but thanks for taking an interest. My Flickr

davidwozhere

Link Posted 02/09/2018 - 01:01
They won't play with the PLM 55-300 either.
Both the *istDS and the K5 are incurably addicted to old glass

My page on Photocrowd - link
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