Yes there's some EV compensation and different setting in each shot. So these are not really a comparision of the 2 lenses. It's a metering issue and not a lens issue anyway.
If each shot is setup basically identically and there were drastic differences then I could see a problem:
True test for an outdoor nature shot would be:
Camera on tripod with all settings left untouched.
Both lenses set as the same focal length (one at 45mm the other at 50mm)
Shoot the exact same subject with the horizon in the same spot. Make the lens change and Test shots as close together in time as physically possible to avoid light changes.
Same f stop, shutter speed etc. 0 Ev
To look at these 2 shots and the settings in the EXIF data as well as the FOV of the shots both are exactly what I'd expect.
You used multi-segment metering and in the shot from the 16-45mm the tree line is much smaller in the shot and the metering system did a good job of balancing the sky and water which are the dominant features of the picture. It didn't try to meter the tree line as much since it's a smaller % of the shot. What the tree line correct then switch to spot or center weighted metering.
The second shot is the opposite. the tree line is large and the water is even larger with almost no sky. So the metering left the sky alone and balanced the metering for the water and tree line. As the tree line id basically dead center it did that section best.
All that being said these are very tough shots for the metering system. But there are some ways around it. 1) shot closer crops with the bright vs dark areas kept to a minimum.
2) shoot multi exposures on a single frame when there is no movement in the shot. there's another thread on right now dscussing that:
https://www.pentaxforums.com/forums/general-pentax-photography/13261-barts-te...st-loving.html
3) Learn how to do HDR's for some of these technically difficult shots.
4) Use center weighted or spot metering more.
All that being said the shot from the 16-45 is the better shot. Once you have downloaded this shot you can easily adjust the levels to get the brightness you want. An underexposed shot is much easier to adjust than an overexposed one.The 16-45 shot exposed the water and sky accurately and you can enhance the shot a bit to bring out the colour in that shot.
Attachment 5296
This is a basic adjustment of the levels of that first shot.
Last edited by Peter Zack; 12-16-2007 at 08:52 AM.