some pics of said problem

here is my first attempt F22 av mode, -1 ev comp, 3 second exposure, iso 200



i then dialled the ev comp down to -3 ev comp and still got some highlight clipping
f.22 0.7s, iso 200



i don't know how to reduce the shutter speed further in av mode, so i used manual still f22- 0.5s, iso 100


i would love to know if there is anything i can do to make the metering system a little more accurate, maybe there are some settings i can change.

cheers Peter

sorry i meant to reply to my post on av mode exposure problems

What lens and what ISO setting did you use ?

They were all tacken with the 16-50 da*
The two on av mode were both at iso 200, but the 3rd in m mode was 100.

That is way over-exposed.

In full sun the exposure for 200 ISO should be approximately 1/200 sec at f16. This is the "sunny 16" rule and is actually very accurate.

f22 at 0.5 sec does not bear any relationship to this at all, so something is very wrong.

I would check the ISO setting and that the exposure compensation is set to zero. This is a major error, so there could be a fault. It needs checking out.

i will try to take a shot at f16 iso 100 tomorrow, it should be sunny in the s/w.
i hope it will be me not the camera.
Thanks for the help

doesn't look like the dof one would expect from f22 either...
I know this sound stupid, but with the weather sealing on that lens, it might feel like it is properly locked in when it may not be...unmount it and remount it and make sure it clicks into place so all the contacts connect up?

The sunny 16 rule gives the exposure for a subject frontally lit in full daylight. This is f16 at 1/ISO sec. In other words, for 200 ISO the exposure is f16 at 1/200 sec.

In other light you would have to compensate. Early evening light with cloud cover is a bit too vague to judge, but the images are certainly way over-exposed. The most likely reason is the exposure compensation being set to a + value, maybe even up to +3 stops. This would mean the correct exposure for the situation given would have been f22 at 1/15 sec, which gets to be more realistic.

i have just checked that don hoping you were right but it seems ok,
i have rechecked the raw data to see if i did +the ev comp not -, but i did indeed expose as i said.

i have just taken a few shots with my 50-200 da, it also overexposes at f22, if i use -3 ev, there is only some small amount of highlight cliping so i assumed that all k10's do the same.

put the thing on a tripod.
set it on manual and shoot the same scene on av and check every aperture...let us know if the exposure changes and the dof.
use a scene that has some depth and constant lighting.


I'm curious if your aperture is sticking...or your meter's out of whack...or both.

well done don you found the problem, how the hell do i fix a sticking aperture, and why is it doing it on 2 different lenses.
Peter

must be the body...take it to the store and try your lenses on a different body....somethings gonna need to go in for repair....

I had this problem with my old Tamron 70-300, which had been on the shelf doing nothing for about seven years. It took me quite a while to work out what the problem was... but not very long to ruin the lens trying to fix it!

All I can say is don't bother partially dismantling it and carefully squirting a little WD40 onto the iris assembly. Surface tension just makes things worse, and several months later it's no better.

In the end I bought a very cheap replacement, but with two lenses to replace that's going to be more painful for you. Hopefully someone will have some better advice for you. But when I started peering around inside my lense I couldn't see anything obvious in the moving parts which was causing a problem, and I really didn't want to risk a complete dismantling, because I doubted my abilities to put it all back together again successfully. That led to the unsuccessful iris experiment.

Good luck.

Andrew McP

PS Even partial dismantling can be a little tricky! Well, it was for me.

In my case it was easy to see the problem was the lens, once I'd realised that might be the problem. I could see the aperture sticking when I had it off the camera, set it to "A" and moved the lever on the mount end around.

Andrew McP

yep that's a good point, but with the same problem on two lenses..either the operator is hamfisted and did the same thing twice or the coupling in the body is damaged.....my bet is the body....