Canon Flash Colour Temperatures with Various Gels

Since I have a free saturday since long time ago, I just did some "research" on the color temperature of my Canon 580ex-II and 430ex.

Since I don't have the professional equipment for that, I relied on shooting raw with Canon 5D (on the excellent 100mm Canon Macro) and measuring the temerature of a grey card via Lightroom (and no averaging of many shots). So, take these numbers with a grain of salt.

Variation of temperature of the 580ex-II

1/1 power: 6500K

1/4 power: 6850K

1/16 power: 6900K (Averaged from 2 shots)

1/64 power: 6950K

Variation of temperature of the 430ex

1/1 power: 6500K

1/4 power: 6800K

1/16 power: 6700K

1/64 power: 6700K

So, the 430ex and the 580ex-II are copareable -- *phew* -- so, I did the CTOs and CTBs only on the 580 ...

Temperature with CTO on 1/16 power (580ex-II)

1/4 CTO: 5600K

1/2 CTO: 4450K

3/4 CTO: 3650K

1/1 CTO: 3350K

Temperature with CTB on 1/16 power (580ex-II)

1/4 CTB: 9000K

1/2 CTB: 13500K

I havent found these numbers on the net yet, so perheps this might help some of you.

And, like you can see, to balance a hotshoe flash with a studiostrome (normally 5500K), you'll need the 1/4 CTO on the speedlight.

Addition: The golden reflector for the (small) elinchrom beatyidish brings the strobetemperature to 4400K.