Sunday, November 29, 2009

Adobe Badges


IMG_3159
Originally uploaded by Ric Charlton
I was sorting through some 'old' pictures to upload to Flickr and stumbled across this one.

I'd forgotten I'd taken this and, I think, it's rather good :-)

Monday, November 23, 2009

Noise versus ISO for Canon EOS 1Ds

Gary recently pointed me towards a forum post discussing noise on a EOS 40D at different ISO settings. The forum post can be seen here.

This whole 'faking' of ISO settings - basically using a full stop lower ISO setting and boosting the EV in camera which caused problems.

It seems that the 5D also suffers from this, although the effect is seen at different points through the ISO range. This got me thinking... does my 1Ds do the same thing? An experiment was required!

After a few practices, I settled on the following conditions:




  1. Camera set to Manual


  2. No lens - just the body cap


  3. Eye-piece cover shut


  4. Exposure time set to 30 seconds (this exagerated the noise at very low ISO)


I then took a shot at each ISO setting (from 50 to 1250) and measured the mean luminance in Photoshop CS4. That produced the following graph (which didn't show a lot because I didn't have enough noise!).





I re-measured the luminance after increasing the EV on each shot by 20. This made for some noisy shots at high ISO (as you would expect!). The following graph was produced which showed the differences a little clearer.





So... what does this prove? IMHO, the 1Ds does not suffer from the faking of ISO settings in the same way as the 5D and 40D were described. Although the graphs do not clearly show this, ISO 160 did produce slightly less noise than both those ISOs below and those above it - the difference was only 0.06 on the +20 EV shot mind ;-)