AF Sensitivity Test Target

[Ted B.47613]

My D30, with a Canon 28-135 IS, at full wide, will focus on patch 16 from about 2', with a calibrated monitor, subdued flourescent lighting.

At full zoom, I had trouble hand holding the center square on the vertical line between black and white.

 

[Julian Loke83476]

My D30, with a Canon 28-135 IS, at full wide, will focus on patch
16 from about 2', with a calibrated monitor, subdued flourescent
lighting.
At full zoom, I had trouble hand holding the center square on the
vertical line between black and white.

Hi Bogey,

Your monitor might be calibrated, but it would help to compare other results if you could also report the meter reading over the:
WHITE / PATCH / BLACK

You can use my EV (Exposure value) calculator to convert from shutter speed, aperture, and ASA settings to EV readings.

I also note that the EF 28-135 IS USM is f/5.6 at its longest focal length, and the max aperture of f/5.6 will reduce light reaching the AF sensor on your D30 by 5 stops.

 

[Julian Loke83476]

And it seems that the D60 meter is biased by about 2EV ...

Simple: the further you get from a source of light, the dimmer it
is. To match image sizes with the same lens on the D60 you have to
go further away.
EOS IX and Rebel should have been different. (The IX is APS format?)

And so the D30 / D60 is also "APS" format.

The best way to meter consistently is to jam the lens as close as physically possible to the screen so that the part being metered fills the entire frame. Use Centre-weighted metering to overcome the effect of any hotspots or reflections.

Metering WHITE should be the same between different cameras (spec is usually + - 0.5EV).

 

[Ted B.47613]

It took me a while before I understood what you meant with the EV info. I normally stay away from formulas when at all possible! When I get home tonight, I will use a tripod and do the whole test with the 28-135, Sigma 15-30, and Tamron 90mm macro and post complete results this time.

My D30, with a Canon 28-135 IS, at full wide, will focus on patch
16 from about 2', with a calibrated monitor, subdued flourescent
lighting.
At full zoom, I had trouble hand holding the center square on the
vertical line between black and white.

Hi Bogey,

Your monitor might be calibrated, but it would help to compare
other results if you could also report the meter reading over the:
WHITE / PATCH / BLACK

You can use my EV (Exposure value) calculator to convert from
shutter speed, aperture, and ASA settings to EV readings.

I also note that the EF 28-135 IS USM is f/5.6 at its longest focal
length, and the max aperture of f/5.6 will reduce light reaching
the AF sensor on your D30 by 5 stops.

 

[Julian Loke83476]

It took me a while before I understood what you meant with the EV
info. I normally stay away from formulas when at all possible!
When I get home tonight, I will use a tripod and do the whole test
with the 28-135, Sigma 15-30, and Tamron 90mm macro and post
complete results this time.

Thank you for your continued interest. If you are not sure how to use the calculator to get an EV value, just post the ISO setting, the shutter speed, and the aperture for your specified lens/camera combination. I can do the conversion for you.

It would also help if you had any other autofocus camera (particularly an EOS one) so that you could establish a ranking between the cameras.

More information about EV:
http://www.dpreview.com/learn/Glossary/Exposure/Exposure_01.htm
http://www.chem.helsinki.fi/~toomas/photo/ev.html