CTO Filter

[lunaticitizen]

I bought this color filter from B&H because I wanted to bring down the temperature of my Nissin i60A flash to 2900K for our Christmas picture.
https://www.bhphotovideo.com/c/produ..._RoscoSun.html

However, I just found out that my i60A's color temperature is 6850K.


And when I applied the filter, it only brought down the color temperature to 3400K.


Should I have applied another piece of filter on the flash head? Ideally it should be 2700K.

[revi]

Unless you have other relevant light sources in the picture or use camera jpegs,
is there any particular reason to worry about the exact colour temperature?
Your flash may "drown" any ambient lamps.

If you really need to get that temp down to 2700K, perhaps add another 1/4 CTO?
If that 2700K comes from the ambient bulbs, I'm not sure how reliable that value is.
(for starters, LED light is not black body radiation)

[lunaticitizen]

Unless you have other relevant light sources in the picture or use camera jpegs,
is there any particular reason to worry about the exact colour temperature?
Your flash may "drown" any ambient lamps.

If you really need to get that temp down to 2700K, perhaps add another 1/4 CTO?
If that 2700K comes from the ambient bulbs, I'm not sure how reliable that value is.
(for starters, LED light is not black body radiation)

Sorry, not enough information from my part.

Yes I did have other relevant light sources that I included such as my floor lamp, table lamp, and the LED lights of the Christmas tree. I purposely chose high-CRI LED bulbs for the lamps and they're 2700K according to their spec sheet . I just looked up "black-body radiation" on Wikipedia! Interesting.

My flash was, I guess, not the main light; it meant to illuminate our faces, only.

When we took the picture, I had the feeling that the flash light on our faces was too white, hence my little test above.

Btw when I took the picture, I fixed the WB on the camera to 2700K. Not sure if that was the right way.

[DanK]

Leo,

I'm not an expert on flash photography, but I think I can confidently say that yes, setting WB to a fixed 2700 was a mistake, guaranteeing that WB would be too cold on the faces.

My own flash work is mostly candids, where I have no control over lighting. Occasional events as well, but I have no control there either. I haven't used gels in so long that I realized today that I don't know whether I still have any.

My most common starting settings are AWB, ETTL, manual at 1/60 or a little more, f/4 or a little narrower, ISO 400. In most indoor settings, the exposure set via E-TTL will create a reasonable balance between flash and ambient light, avoiding harsh fall-off. of course, you can adjust if the mix is wrong.

When I have control, the ambient light is 3000K. In my own home, I use Soraa bulbs in some rooms, which are as far as I can tell the among most color-accurate LEDs available to consumers in the US, so I'm confident that the ambient lighting is at least close to 3000K. (I did test it, long ago.) If I'm not mistaken, my flash is 6000K at full power, but like most, it changes somewhat if the power level is dropped.

With these settings, as Remco says, flash dominates. Yes, there can be some variation within an image in white balance, but usually not that I can see. There will be shots where the overall WB is off (usually, too warm, not to cold), but since I shoot raw, it's usually simple to fix that with the eyedropper tool in LR.

So my guess is that with the filter you bought, you might just need a slight warming of WB in post.

I hope this helps. Someone with more expertise with flash can correct me if I went off the rails anywhere.

Dan