I was wandering what might be the correlated
color temperature of my flash, a Nikon SB-910
Speedlight. So I tried to measure it with
Argyll (-a -f -T) and my new i1pro3. The room
was dark and not much around that could reflect
light. The flash was at 1/4 power.
In several measurements, I get values around
6800°K. The instrument pointed directly to the
flash in 50cm distance. In another attempt I
enlarged to distance to 130cm; then I got
values around 6350. Can distance actually be a
factor in this?
I could bet to have seen that photo flash light
should have a color temperature around 5400 to
5600°K. So I searched the manual, but couldn't
find a number. Using an online search engine, I
got reports from people having measured the
SB-900 getting numbers like 5400 but also lower
like 5200, saying that the CCT depends on the
power setting (which I tried but could not
reproduce). And none is saying that it might
depend on distance.
At last I used the flash to illuminate a
graycard, took the shot and opened the image in
darktable. There I got values very similar to
those of my Argyll spotread measurements.
As argyll and darktable seem to agree, I don't
think something is wrong with the i1. But the
difference is more than 1000°K. Can anyone
explain what I'm doing wrong?
BTW. Is there a way to use illumread with a