Update: Laser-powered auto focus assist version 2

We don’t know if our feature from a couple of days gave [Adrian] a kick in the pants, or if he was just on target to finish is writeup this week, but he’s posted about version 2 of his laser auto focus assist project.

The original idea was to use an unfocused laser pointer dot to give his DSLR auto focus feature a kick in the pants since the built-in light doesn’t come back on when photographing moving subjects. The original version worked, but he had to operate the laser manually and the hardware was kind of spread out all over the camera.

The latest version (2.0) can be seen above, housed in a project box that mounts to the hot shoe and keeps everything together in one package. The laser operation is now automatic, coming on when the shutter trigger is depressed half way, or when the auto focus enable button is depressed. The controls on the project box include an on/off switch as well as a potentiometer which varies the intensity of the laser.

It looks like this won’t be the last version of the hardware that we see. [Adrian] covers a few outstanding problems in his post. Most notably, the laser light is still a bit too strong. At a recent live event, another photographer took issue with the fact that his images included the red splotch from [Adrian's] diy hardware.

Comments

  1. lokerin says:

    actually the red splotch would be good if you frequently are hired as the photographer for a event where there is no other photos that are supposed to be taken. dance recitals, plays and musicals

  2. b0b says:

    A red splotch on his photograph?
    Could be a hot pixel or ketchup. ;D

  3. Aki Korhonen says:

    I did an AF-assist light for my Nikon D2H a couple of years ago and I used the shutter release pin from the cable release connector. I figured out that I could get the button information from there to activate the led automatically when the button is pressed.

    The case should be the same with Canon cameras too that the lines are at somewhere around 5 volts when the shutter button isn’t pressed and they get grounded when the button is pressed half-way down and fully down.

    I added a new schematic on my old AF assist light page on my website (http://akikorhonen.org/projects.php?action=view&id=648) that I haven’t tested yet but it should work in theory. Try out on your own risk.

    1) When button isn’t pressed, the bases of T1 and T3 are high (T1 is an inverter for T2’s base) so T2 is low and the led is off.
    2) When button is pressed half-way down for focusing, the focus line pulls T1’s base low and T2 goes up and the led turns on.
    3) When button is pushed all the way down, the shutter line goes low and T3 turns off turning the led off.

    Using the flash shoe’s pin isn’t a very good idea because it gets pulled low when the shutter is fully open, the shutter line goes low immidiately with the button.

  4. Renee says:

    Had no idea people standing still in front of a laptop were hard to focus on. I thought this was suppose to be for no light fast moving objects?

  5. fartface says:

    there is TTL data coming out of the flash hot shoe to give all the information needed

  6. fartface says:
  7. steve says:

    Stupid. He should use a laser grating to create a holographic pattern as Sony did for their “Hologram AF”. Furthermore, the laser he uses is far to dangerous to use in this kind of application. This needs eyesafe uW laser. And if it shows up on other peoples photos, it’s obviously garbage.

  8. Adrian says:

    Yes, there is TTL data coming out of the flash hot shoe, but to my knowledge there is no publicly available standard on how to decode that data.

  9. Bogdan says:

    Why not use white light? White light might be less distracting on most pictures. My nikon D90 has a white AF light. You could use some narrow angle white led…

    The problem with the strong and concentrated AF lights is that the also bother the ones photographed. I know many cameras(usually compact ones) that have spots of red/green/orange lights that are very annoying when when pointed at someone’s eyes.
    My external flash does not put a concentrated spot but rather a larger grid which i find not annoying when looking at.

  10. Garbz says:

    @steve laser pointers are generally weak enough and he has dramatically defocused the beam too spreading the power over a large area. This is not dangerous.

    Also everyone’s focusing light shows up on other people’s photos. Try not to take photos while other people are focusing is always a good trick. You should see how bright the AF assist lights on many flashes really are.

    This is a neat hack.

  11. The Ideanator says:

    Why not use an IR laser? It won’t show up except on others photos, stealth AF!

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