[opiecat]

[quote name='woodsfortysix' timestamp='1290904258' post='4505']

I also just ran the same series of tests with my D700 and added the Nikon 28-300 lens. The exposure results for the Tamron were identical with the D700. The 28-300 exposure results were close to the Nikon 70-300VR at 70 and 300.



I know this is not a very scientific test, but it appears that my Tamron is underexposing in aperture mode, but exposes correctly in shutter mode if there is "headroom" to adjust the aperture.



Appears that if I shoot in shutter mode, I will be okay...



Comments / suggestions...



Thanks,

[/quote]



i have the same findings with my tamron 70-300 on my d7000. it seems to underexpose by about .5 to 1EV.

i compared the same scene from the same location using both 16-85 and 70-300 both at the 70mm setting.

the tamron would show a faster shutter speed (Av mode) than the 16-85 and would result in underexposure.



what i also noticed was that the camera's metering seems to be more sensitive to the tamron when pointing the camera to a different area of particular scene.



i'm going to try Tv mode.



has anyone talked to tamron about this yet?