Hi all!
We've been trough extension tubes, light loss and TTL metering already. BUT (you knew
there was a but following, didn't you) I received weird results.
I was using EOS 300 (Rebel 2000) with EF 50 f/1.8 and EF 28-135 IS with Kenko
extension tubes (12, 20, 36 mm).
I think I can safely state that there is light loss involved when using extension
tubes. So I'll go from there.
I printed my target (18% grey) and metered of it. The light source was neon light (so
there is no variation in luminance). I used partial metering.
Now, the confused part. Without extension tubes, I get 1/60 @ f/4.
When I put 12, 20 or 36 mm tube on it, I still get 1/60@ f/4. Confusing.
I then switched to 28-135.
I got 1/90 @ f/4 without the tube. Notice the difference?
1/45 @ f/4 with 36 mm tube.
1/60 @ f/4 with 20 and 12 mm tube.
Maybe there are subtle variations in light reaching the sensor so the measurements are
off a bit, but I should be getting around two f stops of light loss with 36mm tube,
right? Where is it?
Gerard, you used extension tubes if I remember correctly, what's your experience with
28-135 IS and ext. tubes?
TTL should compensate automatically, right?
Kindest regards,
Miha.
*
****
*******
***********************************************************
* For list instructions, including unsubscribe, see:
* http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************
