[Adrian Onsen] keeps making improvements on his auto-focus assist hack for DSLR cameras. The module seen above is version 3.0, which makes a few changes to the previous hardware and also presents a much more finished look.
With version 2 [Adrian] was using a defocused laser to illuminate dark subjects so the DSLR auto-focus could be used. It worked, but wasn’t really ideal. This time around he’s swapped out the laser diode for an autofocus assist lamp salvaged from a Canon 550EX he picked up ‘as is’ on eBay. It is mounted on the front of his project enclosure, using two alkaline batteries for power. It sounds like [Adrian] is struggling a bit with his circuit design. He want’s to make it work with either alkaline or rechargeable AA batteries (just two, down the from four AAAs used in version 2) but so far the rechargeable are a no-go. They power the circuit, but must not put out enough light for the sensor to work.
Future plans include getting rid of the external cords by adding a hot shoe connector.
“Want’s” – really?
my built in AF assist on my D7000 works wonders but the SB-600 i use on that and the nikon D3X works wonders
but i have never known any one who needed an AF assist light who did not use a flash
for the shear amount of cables alone id see this as to much hassle than its worth
It’s common for available light shooters to use the Canon ST-E2 in the hotshoe as a focus assist light. It’s so the camera can lock the focus better in low light.
An AF assist light like this, with a hot-shoe added on to allow connecting other devices, would be amazing for those who use external strobes on remotes in less than ideal lighting circumstances. On some shoots I end up bringing along a flashlight to lock focus because my Alien Bees are too far back for the modeling light to throw enough light.
Use one of the 3 to 5v boost circuits that have been featured here numerous times.
or even better – a single cell LED driver and run it from 1x aa/aaa – Find one with a shutdown pin and you’re done.
400d firmware hack allows flash to be used for AF like this. Flashes till it gets focus.
couldnt you use a small ultrasonic rangefinder and some math to focus? Ive always wondered about that, or perhaps a laser rangefinder instead?
There is no way for the camera to take the data.
Not to discourage hacking attempts, but that’s a $400 lens on there. For a fraction of that price you can get either an ST-E2 knockoff or the capable 270EX flash.
Who shoots available light and uses autofocus?
Install a focus screen and call it done instead of always getting fuzzy photos with the inferior autofocus.
A lot of people do. Good autofocus is usually more accurate than doing it by hand and eye.
Remember your pentaprisms (on f screen) get dark too and then you can’t focus for shit. Same problem AF has but even sooner.
Manual focus is too slooooooow.. especially for venue shooting. He probably has some manual lenses for all you know.
I don’t get all the extra wires. Or why he ditched the defocused laser – laser pointer gives instant AF without beaming the whole area with red light.
There’s an AF pin that goes high on the hotshoe of the Canon camera when the shutter is half pressed (which is what triggers the AF light on Canon flashes) – couldn’t he tie into that without butchering a broken Canon flash? Especially since he’s using an Ebay ETTL foot with the pins on it?
http://forums.dpreview.com/forums/readflat.asp?forum=1041&thread=35983456