K10D Stop down metering exposure problem

I've jsut been experimenting with my k10 and a 50mm M lens.

In manual mode, you can turn the shutter preview switch (around the on/off switch) to do the same thing, i.e. the exposcomp 'lines' are displayed and the front wheel is used to set shutter speed.

In Av mode, the preview does nothing but knock of the viewfinder display, the green button doesn't seem to do much as the viewfinder changes iso and shutter speed automatically depending on light levels, so you focus, set apereture on the lense and the rest is auto.

I've tried the green button, the DOF preview and metering from that, and various other tricks. The K10D just doesn't like stop-down metering.

I can use match-needle type metering or plain manual if an A lens is set to A, but somehow stopping down doesn't quite work.

I works with the D, and I see no reason it shouldn't work on the K10D. I've used two different focusing screens, same result.

I don't particularly want to buy new 200mm and 45-125 range zooms~

How truly unfortunate but a sincere thanks anyway for that test and your reply Arthur. Hopefully Pentax will get this sorted out well before I can afford a K10D. As you know, there is much chatter about this everywhere on the Web so I am sure Pentax is all over it. In the meantime that does little for you and your fine manual lenses Arthur.

I'm sorry justgetoutandride I must be dense but after reading your reply several times I just don't understand your answer in relation to my post. What I was trying to ask was; if you are experiencing exposure errors, does setting the shutter speed manually using the DOF preview button and the Tv wheel work any better than using the green button?

I don't know if you realize AJ that you will not get good results using an M lens with the camera set to Av mode unless you want to shoot with the lens wide open.

Interesting opinions about abandoning M lenses now that some have upgraded to the K10D. That is valid if you value the camera body more than the lens but I for one will not be upgrading if the K10D makes my lovely M primes useless. But hey, that's me. I'm different.

Anxiously awaiting for a flurry of M lenses on Ebay

Drew

I'm new to all this so take anything I say with a pinch of salt. I have a 50mm M lens I was trying with the k10, after reading this thread I experimented to see how to best use it. My expereince is that using it in manual mode, with the DoF/preview switch and the front wheel allows you to change the exposure 'on the fly'. This seems to me to be the best way to use a manual lens on the k10.

I put in the difference between manual and Av for comparison. Sorry if i confused you, i don't always know what I'm talking about either.

This is true.

But have you also done this with an A lens, first in non-A mode as above, and then cross checked the exposure/aperture combination that the camera says is correctly exposed, with the exposure it chooses for the same aperture (selected with the rear e-dial) with the lens in A mode? All with the camera in Manual.

My experience is that they are not the same.

And if they're different, they can't both be right.

Are they widely apart or just a half stop or so?

Was the camera on a tripod with a constant light source as the target and exactly the same field of view?

I only ask because the slightest change in position with an average scene can cause differences in the exposure indicated. To be a proper test needs a description of the method used, just like we did in Physics back in school!

No, 'cos I don't have one. only recently got the k10 and kit lenses and the 50mm M from my son.

Sorry.

Examples please. Or is this just a hollow-sounding, arm waving comment from a whinger who bangs on and on and on and on....?

Yes. I suspect that you, and the others who claim to have a problem, are doing something silly.

G

Well I suppose it's understandable that if you've prejudged me as a whinger, you aren't that interested in reading the example I've posted, but let me draw your attention to it.

https://www.pentaxuser.com/forum/viewtopic.php?t=3867

Post number 6.

I'd be the first to accept that I might be doing something wrong, and the most pleased if it turned out to be so.

Just a thought. Is the eyepiece covered or uncovered when you're doing these tests? i.e. could it be ambient light coming in through the viewfinder that's confusing the meter?

If you've got the camera tripod mounted, I'm just thinking you may be looking through the finder some of the time, and not at other times...

Dan

It's a valid thought.

But from my first post on this thread:

I'll run the tests again I think. I'm starting to doubt my own name....

But I'll happily eat a Desperate Dan-sized slice of humble pie if this all turns out to be finger trouble...

Fair enough - hadn't re-read the whole thread...

Dan

I got told off by George for using my Weston Master V meter; he said there was a very good 'Spot Meter' built into the K10D but if the Weston WORKS and the Pentax meter DOESN'T on Manual then (when I get the replacement ! ) I will continue to use the Pentax with Weston V and Invercone same as for my Rollei or my Zenith and Pentax SV!

There is no reason at all why you shouldn't continue using your Weston + invercone. The difference lies in the measurement of incident light (Weston + cone) versus reflected light (any and all in camera measurement systems). Accurate incident light meter readings will always prevail (IMHO) over any camera system including Pentax, Canon, Nikon, Leice, 'blad et al.

The Weston measures the light falling on the subject. The camera's meter measures the light coming through the lens. I know which I prefer to use.

G