the SB900 gel reporting feature is interesting, but I am not sure if its worth it or just a marketing gimmick, I looked over the web but could not find pictures illustrating this feature, any photos guys?
The gels are unique to the SB-900 and bend at a right angle below the flash output to a "reader" pointed down, just below the flash head. Information from the gel is read by the flash which then sends information to the computer in the camera and sets its white balance to match the gel.
It is pretty slick. From a user perspective it is a simple matter of placing the gel over the bounce head, bending at the crease, being sure the index hole matches the index pin (only can be installed 1 direction). Then snap on the clear gel cover.
Flash, and your WB is automatically set on the camera to match the gel you chose! Extremely useful if you are shooting in a room with tungsten or fluorescent lighting; all light will render the same color.
This is the only Nikon flash that can read the gel, determine what color it is, display that gel number on the backlit flash LCD, and set the camera WB without the operator doing anything more than inserting the gel! Remove the gel and plastic cover and WB is immediately restored, and the gel description disappears from the flash LCD.
Nikon even included a pocket in the SB-900 carry case for the gel holder, the plastic gel cover, the bounce flash diffuser, the 1/4"-20 threaded stand, and of course, the SB-900 itself. They even provided a sewn-in belt loop. If I sound impressed, you guessed correctly. The SB-900 is the easiest to set-up, most thought out, and most powerful flash I have ever had the pleasure of using. It is well worth the cost of admission IMHO!
From the way it sounds its beyond amazing because the colours will not always look flash cold and the user will need a degree in photoshop to adjust the WB, but Nikon doesnt advertise this properly, I would love to see the gels in action?
These made for SB-900 gels have a small (chip?) speck on them which is read by the "reader". It works. I put on a Tungsten gel (quickly discovered it only goes on 1 way. Hole must line up with index pin). Snapped on the thin clear gel cover. Turned the flash on and along with the picture of the flash head was the gel # correctly identifying the color. Surely enough, the D3 color balance adjusted to this color automatically.
The diffuser for bounce head is made to either fit over this clear cover, or to fit without it. That is cool, too. the filter use does not impair the use of the flash diffuser.
I need to defer to others for before / after samples. My work assignment has me working away from my gear for a couple weeks. I did not save the test shot I took last week. I described how to install and uninstall it in detail. Hopefully that will prove helpful.
This gel filter over the flash allows the flash to match (assuming you use the correct gel filter) the same ambient light source, other wise, the flash would come off as a day light source while other light source, such as tungsten light source. In addition, the camera's WB is changed to match the gel filter light providing balance between ambient light, SB-900 light and camera WB. Very nice tool.