I was comparing some lights tonight to check out the differences in tints. Reason being, my new FF4 arrived yesterday, with "5500k" hand written on the box. The user manual & other reviews that I've seen all say it's a 4300k tint, so I was perplexed....
I decided to do a side-by-side comparison of five lights, to try & gauge the tint of the FF 4. I took a couple of pictures of all the lights shining on the fence, which was between 4 - 7 meters away (on an angle). Probably a little too close, but it did show the differences fairly well.
From left to right;
* C8 w/MT-G2 @ 4.2A (Very floody, no real 'hot spot', neutral-warm tint)
* HD2010 w/XM-L2 U2 1A @ ~5A (Nice big hot spot, blue tint very apparent)
* Jacob A60 w/de-domed XM-L2 U21A @ ~5A (Much smaller spot, a little warmer due to the de-dome)
* Convoy L2 w/de-domed XP-G2 R5 2B @ ~5A (Very intense spot, greeny-yellow tint)
* Firefoxes FF4 @ 40w (Different profile than the LED's, but seems to be a little on the blue-ish side)

Mouse-over for slightly different angle.
With the MT-G2's tint being 5000k, it appears that the FF4 may be a little cooler, although at this distance, it's intensity may be overwhelming things.
Thoughts & Comments? Anyone heard of the FF4 being equipped with a different bulb?