Sounds like something's misaligned. I had that problem with the Vivitar
Series 1, the aperture lever was mildly bent enough to stick when the
lens was stopped down more than half way. Not focal length related but
having disassembled a couple of broken FA zooms I can see how it could be.
On 6/14/2014 6:08 PM, Bruce Walker wrote:
A clue! Thanks. Aperture lever itself seems fine, but it only works
more or less normally from 50 down to somewhere between 35mm and 28mm.
Then as I zoom it wider I hear a metallic springy noise from inside
and the aperture goes wide and stays stuck open. Ie the return spring
doesn't close it unless I force it manually by manipulating the
aperture lever.
Definitely something borked inside that lens.
Just great. Got a big shoot on Tuesday. Oh well, forces me to use
another lens and do different stuff than I had planned. Might spur
creativity. :-P
On Sat, Jun 14, 2014 at 5:49 PM, Zos Xavius <[email protected]> wrote:
Doesn't the aperture lever toggle the aperture on the 16-50 like all
pentax lenses? Does it feel stiff? Is it bent at all?
On Sat, Jun 14, 2014 at 4:08 PM, Bruce Walker <[email protected]> wrote:
I think I know the answer to this, but what the hell.
I'm testing a lighting setup today. K-3 on M, remote triggered flashes
for light. Settings are around 1/125th, ISO 200, f:11.
So I zoom in on my test object, ~35mm, shoot, exposure is perfect. I
pull the zoom out, 16mm, shoot, exposure is _wildly_ off. Lightroom
suggests at least 4-5 stops overexposed, but it's madly clipped. WTF?
This is repeatable. But every once in a while, like after
power-cycling K-3, the exposure is right.
Long story short: cleaned the contacts of both K-3 and 16-50, nothing.
Swapped an 18-55 in and bingo! 100% perfect exposure at all zooms.
So it looks like the DA* 16-50 is failing to stop down for the shutter
under some circumstances, like very wide zoom. Has anyone else
experienced this? Is it something that one can fix, eg by giving it a
good smack? :-)
Thanks!
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-bmw
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