K-mount lenses with K10D

Excellent advice.

However, it was as a result of trying things out for myself - having read the manual on how to use pre-A lenses - that I started that thread in the first place.

If I'm doing something wrong, and the camera's fine after all, don't you think I'd dearly love to know?

What I do is:

- Enable Aperture Ring
- Set camera to manual
- select desired aperture on M-series lens
- press green button, noting that lens stops down and shutter speed is set
- take picture

Can you see anything wrong with this procedure?

What exposure mode are you using? I believe that K and M lenses don't support matrix metering.

Is the light constant between exposure reading and taking the picture?

Is the subject one that might cause exposure problems? Water, snow, strong back-lighting etc.?

Have you done a side by side test with a prime lens of identical focal length and at the same aperture? When I compare my K 50mm 1.2 with my F 50mm 1.4 (handheld) I get exposure variations of between zero and half a stop. With the 400mm (I have nothing to compare it with) exposure is always within reasonable limits.

G

I've tried spot and centre-weighted as well.

Well the picture was taken less than a couple of seconds after the exposure reading each time, and the camera was on a tripod. AFAICT the lighting wasn't changing significantly - one was indoors under natural light, the other was, as I said, a garden scene, sky uniform and cloudy.

I wouldn't have thought so. One was a bush in the garden (leaves, twigs etc) and the other was a row of books on a shelf.

I'm not trying to compare different lenses here, I know they can be a bit different.

I'm just noticing that for a given lens the metered exposure at a number of different apertures result in wildly different amounts of light ending up at the sensor - some of the shots metered this way are very over- or under- exposed.

But I have tried a couple of A lenses in both A-mode and manual. The exposures were significantly different in A-mode and non-A, for a given selected aperture (in A-mode, aperture selected on the camera, obviously).

The manual says that for exposure using the aperture ring, either with a pre-A lens or an A lens set other than to A, centre weighted metering is automatically set. Regardless of what we set the meter to.

Why not try the experiment using a grey card, controlled lighting and the stop down round the shutter release. And a tripod of course.

Eliminate any variables you can think of and the experiment will be more valid.

Being new to forums and such activities, I would simply like to thank all those who participated - it has been a great help.