50-135mm /f2.8 with AF1.7xTC
687 posts
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Posted 11/02/2010 - 13:47
are you saying that focus is fast becauyse the TC bypasses the SDM focussing and therefore uses the in-camera AF motor?
does it make it much faster than the lens on its own?
what TC is this you're talking about, is it the Pentax version?
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
does it make it much faster than the lens on its own?
what TC is this you're talking about, is it the Pentax version?
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
Link
Posted 11/02/2010 - 13:53
SDM is off as the Pentax AFTC is screw drive. Lens is pre-focused manually to "some where near" and the AF TC does the rest. K7 was indicating f4 due to two stop loss.
Zoom is still OK to use.
Regards
cameradextrous _ Motorcycles etc. link
Zoom is still OK to use.
Regards
cameradextrous _ Motorcycles etc. link
Last Edited by K10D on 11/02/2010 - 13:54
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Posted 11/02/2010 - 13:56
right, but you don't have to 'pre-focused manually to "some where near" ' - right?
I mean, does the screw drive not work normally? does the AF hunt more than the usual?
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
I mean, does the screw drive not work normally? does the AF hunt more than the usual?
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
Link
Posted 11/02/2010 - 14:22
nathanever82 wrote:
right, but you don't have to 'pre-focused manually to "some where near" ' - right?
I mean, does the screw drive not work normally? does the AF hunt more than the usual?
right, but you don't have to 'pre-focused manually to "some where near" ' - right?
I mean, does the screw drive not work normally? does the AF hunt more than the usual?
Only just started to use this TC and the pre-manual focus is only as near as slightly recognisable subject, the TC then snaps it into focus. It does not hunt.
I will do some more shots at smaller apertures tomorrow to see how the IQ is. The extra reach of the 1.7x is very useful.
Regards
cameradextrous _ Motorcycles etc. link
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Posted 11/02/2010 - 14:37
Very interesting, i would have thought that the AF would be able to cope with the full focus range.
But good to know!
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
But good to know!
'Between the lights there is always a shadow'
www.nathanservi.com & PPG
Link
Posted 11/02/2010 - 16:53
#2 I like!! Very nice
K20D,24-90 3.5-5.6,50-135 2.8 + GRIP. SAVING FOR 60-250 F4
FUJI S6500 + FUJI Z33WP
Konrad
K20D,24-90 3.5-5.6,50-135 2.8 + GRIP. SAVING FOR 60-250 F4
FUJI S6500 + FUJI Z33WP
Konrad
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Posted 12/02/2010 - 08:48
I'd always assumed that AF teleconverters worked by (the user) setting the lens to infinity, then the TC doing all the work itself. Interesting to know - not that I'm ever likely to find a Pentax AFTC for sale!
Last Edited by MrCynical on 12/02/2010 - 08:49
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K10D
Plus Member
Very shallow DOF. I like this combination.
C&C welcome
Regards
cameradextrous _ Motorcycles etc. link