BHS Portrait - 600mm (1 img)

Started Apr 26, 2013 | Discussions thread
OP brandrx Forum Pro • Posts: 28,337

SanMat wrote:

Terrific.  Great portrait shot.  Face detail, eye detail, horn detail.

Thanks Pete.

Surprised that it's listed as f/4.0 (wouldn't it have to be at least f/5.6 with that converter - or is there something you can do with the contacts?)

It reads as f4 but exposes as if it is f5.6.

There is no Pentax mount autofocusing teleconverter that passes the corrected focal length or aperture to the camera. The Pentax-F 1.7X AF Adapter requires that you enter an SR focal length when you turn on the camera. The 1.7X AFA will also pass the corrected aperture for many lenses to the camera. However, not all lenses. Many of the Sigma lenses when trying to use with the 1.7X AFA will pass incorrect aperture to the camera, usually it is something that is more wide open than the lens is listed at. Example: A Sigma 500/4.5 when used with the 1.7X AFA will pass f2.8 when the lens is wide open. You can correct this by taping certain pins but not worth the effort IMO.



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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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