[ma318]

ma318- I will give that a try tommorow.

When doing the control test, I also suggest that you test it at different apertures. Try it at f2.8, f5.6, and f11 for example.

I had an older lens that was giving me overexposure whenever it was stopped down. The more it was stopped down, the more overexposed. It turns out, the aperture spring was worn out and lost its tension so that the aperture blades were not closing fast enough. So the lens aperture was actually bigger than what the camera intended when the camera stopped the lens down.

This may or may not be the cause of your problem. But it is a possibility.

I notice you used f2.8 (max lens aperture) for photo #1 and #2 so this can not be the cause of the problem. The issue for these two may simply be getting a better handle on how to use spot metering.

Erratic exposure problem at smaller aperture may be caused by the above described issue though. The control testing will rule it out or in.

---

Last edited by ma318; 01-15-2010 at 11:25 PM.

[montman]

ma318
That article was tremendously helpful. It seems this is mainly caused by my misunderstanding on how metering works. Just like you said, I am complaining of underexposure when a lot of sky is present in the picture and that article clarified why it is doing that. I have not experienced this problem with my other lenses but that is probably because I don’t use them in this type of environment (bright skies). Thank you all this has been very helpful. I think this resolves my problem, I will have take my other lenses out there in the bright skies but I think I am going to get the same results.

[ma318]

ma318
That article was tremendously helpful. It seems this is mainly caused by my misunderstanding on how metering works. Just like you said, I am complaining of underexposure when a lot of sky is present in the picture and that article clarified why it is doing that. I have not experienced this problem with my other lenses but that is probably because I don’t use them in this type of environment (bright skies). Thank you all this has been very helpful. I think this resolves my problem, I will have take my other lenses out there in the bright skies but I think I am going to get the same results.

That's great. Just like you, I did not know how spot metering work and was using it incorrectly until I read that article.

[Ash]

Glad to see you working some of this out - and there's nothing functionally with your lens.