Metering problem?

[rEveRie]

I set the my camera, a D200 on aperture priority.

with AF-S 70-200 VR lens, i noticed there is a slight change in exposure between f/2.8 and f/10.
Tested this against various subjects with different tones, and it is consistently giving a slight change of exposure between apertures.

Changed to a AF 35mm f/2 lens, it results the same way.
Changed to a AF-s 12-24mm f/4, it is the same.

I loaded test pictures into nikon capture and observe the histogram, indeed there is a slight shift to the right for the smaller aperture.

I shifted the exposure compensation to mimick similar exposure and it is roughly around 0.10 EV difference between apertures.

I am not sure if this is a problem or it is meant to be this way?
I didn't do such test on my D70...

can some bros advise?
thanks

[rebbot]

Originally Posted by rEveRie I set the my camera, a D200 on aperture priority. with AF-S 70-200 VR lens, i noticed there is a slight change in exposure between f/2.8 and f/10. Tested this against various subjects with different tones, and it is consistently giving a slight change of exposure between apertures. Changed to a AF 35mm f/2 lens, it results the same way. Changed to a AF-s 12-24mm f/4, it is the same. I loaded test pictures into nikon capture and observe the histogram, indeed there is a slight shift to the right for the smaller aperture. I shifted the exposure compensation to mimick similar exposure and it is roughly around 0.10 EV difference between apertures. I am not sure if this is a problem or it is meant to be this way? I didn't do such test on my D70... can some bros advise? thanks

aperture does affect exposure if I understand what you are trying to ask.

[rEveRie]

Originally Posted by rebbot aperture does affect exposure if I understand what you are trying to ask.

hahaa...
pardon me for being unclear.

what I am trying to ask is, under aperture priority, under the same metering mode,
changes in aperture would not result in exposure changes because the shutter speed changes accordingly to achieve the consistent exposure of the same scene.

[Zerstorer]

Almost all lenses have slight exposure variations/inconsistencies across apertures. It would be the same on a D70 or a D2x.

[rEveRie]

Originally Posted by Zerstorer Almost all lenses have slight exposure variations/inconsistencies across apertures. It would be the same on a D70 or a D2x.

phew... glad to hear that.
thanks.

i tested on a canon A95 point and shoot, it doesnt seem to experience this tho'.
haha. anyway, i guess it's different since the lenses is made specifically for that body.

[roti_prata]

Originally Posted by rEveRie the shutter speed changes accordingly to achieve the consistent exposure of the same scene.

the shutter speed cannot change accurately enough. for example 1/9.8 sec is required for identical exposure but the closest the camera can do is 1/10 so the pic will be slightly darker

[rEveRie]

Originally Posted by roti_prata the shutter speed cannot change accurately enough. for example 1/9.8 sec is required for identical exposure but the closest the camera can do is 1/10 so the pic will be slightly darker

yepz, I have considered this issue as well.
Do you think this is the predominant factor as compared to lens inconsistency?

I tried across faster shutter speeds and the results is the same, I understand that faster shutter speeds does not go down to exact number as well.

[Zerstorer]

Originally Posted by roti_prata the shutter speed cannot change accurately enough. for example 1/9.8 sec is required for identical exposure but the closest the camera can do is 1/10 so the pic will be slightly darker

No, shutter speeds are almost stepless. It's just the displays are rounded up to simplify matters.

[rEveRie]

just checked the images downloaded from the canon point and shoot camera, A95.
there is indeed slight shift of exposure as well.
from f/4 to f/8

same phenomena.

[espn]

Why worry so much.. just shoot first, talk later.