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DIY AF Assist Light for D2H

Sometimes it would be handy to have an autofocus assist light on the camera, but D2H doesn"t have one (there is one on the SB-600 I'm using but it isn"t always attached the camera). This idea has been on my mind for some time now and now I finally decided to do it.

Pinout for the 10-pin connector can be found here.

d2h_af_light_photos.jpg af_assist_light.jpg

I had this one unused cable release lying around (haven"t been using it because of the bad connector, I have a better one that I'm using instead) and it was a good candidate for donating a connector. I cut the cover away and soldered all the parts together by "free forming". I then squeezed some hot glue between the parts and put some heat shrink tube over the whole thing to secure all the parts.

The circuit uses a normal PNP-transistor circuit to switch on the white led. The AF pin is normally high (+5V) and it connects to ground when the trigger is pushed half way down so that is why a PNP-transistor is used (current flows to the led when the base is low). I used the 1N4148 (D1 diode) to drop the voltage down a little bit (~0.7V) before the transistor because the voltage on the pin 2 is around 6V.

One thing I noticed tho is that the light stays on while the picture is taken and affects the light metering a bit. The next version I'm going to do will have a better connector and a push button to put the light on when needed (it will be in a quite good place and it's easy to operate with left hand's thumb).

Below is a short video of the light in action:

Update, 2011-06-03

An updated schematic that should activate the led when the button is pushed half-way down and turn it off when the button is pressed fully down for a photo: