I want a better autofocus system for low light. Low light auto focus is my biggest bane.

I use a 5D so the options are AF on a flash like the 430 or 580. I happen to use the Pocket Wizard TT1 so I don't have a flash on my camera. I could mount a 580 on top of the TT1 but the TT1's top bracket is so weak it breaks, plus the whole mountain of gear is pretty awkward even before my TT1's bracket broke.

I have tried the ST-E2 on top of the TT1 which is lighter weight and smaller profile than the 580 but I've had issues with the my ST-E2 and don't feel like forking out $200+ dollars for simple auto focus and I don't find the auto focus assist that good when it does work.

What I'd actually love is something like an autofocus laser. I've tried with pen light laser and it works way better than either the auto focus on the 580 or the ST-E2 but it's almost impossible to use a laser in one hand and camera in the other. Plus if I put a pattern diffuser over the laser I have a hard time seeing where it's landing event though it still works well for autofocus.

I've debating with the idea of getting some sort of mounting bracket that I can put into the tt1 hot shoe to mount the laser. Even with such a mount there is no clear way to fire the laser.

I've checked all the hotshoe pins for activity when autofocusing, but can't detect anything. I believe instead of a typical circuit connection, the autofocus is sending a bunch of bits that fire autofocus assist on the flash unit.

I am surprised this isn't more of an issue. I've seen people wish that PocketWizard added an auto focus assist to the TT1, which would be awesome, but I'm surprised there aren't some DIY kits out there, or even available gear to help focusing better.

  • Is there a question in there somewhere? :)
    – mattdm
    Jul 5, 2011 at 23:22
  • Not to mention the wall of text... Jul 5, 2011 at 23:27

4 Answers 4


How about something like the 220EX or one of its current equivalents (I don't know the model numbers of these)? I used one of those at need when I had a 5D; you should be able to pick one up cheaply these days. That said, the AF on the 5D is one of the things I don't miss from that camera; the 1Ds2 I replaced it with eats it alive in that respect.

  • good to know that there are Canon setups that work. Not sure I'll be buying a 1D any time soon, but I might rent one for a day to test it out and then dream about buying one if it works. Thanks Jul 6, 2011 at 17:21
  • One of the links in the answer suggested 160E or 200E flashes which look to be on Ebay for about $20. I think I'll pick one up and try to cannibalise it by taking off the flash part , just using the focus assist and possibly hooking up a laser pointer to it as well. Jul 6, 2011 at 18:21

As far as DIY goes...

With minimal electronics skill, it appears that it can be done by interfacing a hacked up cheap laser to a particular pin (looking down, camera pointed away from you, the top left pin for Canon) via Op Amps. Then the laser would be tied to the autofocus assist.

Sites that detail this further are here and here.

  • I think an LED would be a better idea than a laser. While a camera with a borg laser effect would be funny I'm guessing blinding your subjects accidentally wouldn't be. Jul 6, 2011 at 3:32
  • Awsome!! Those links are perfect :) I did quite a few google searches on the 5D pins and autofocus as well as testing them myself with just a volt/amp meter but couldn't find anything. Thanks for the links. that's perfect. Jul 6, 2011 at 17:23
  • @Rob The penlight lasers I'm using aren't any brighter than they autofocus assist on the 580 and when used with a pattern diffuser like cross hatches the are even less noticeable than the typical autofocus lights but seem to allow quicker faster more accurate focusing. Jul 6, 2011 at 17:27
  • Apparently targeting something with a laser while operating something targetable on a tripod could end up very tragically misunderstood.... Sep 29, 2019 at 18:59

I was just considering hacking something together along these lines, because I came across a product that seemed helpful (but, of course, overpriced). I figured I could replicate its use DIY-style, because it's only physically connected to the camera -- not electronically.

Here's a a video of that product, the PinPoint by DeluxGear.


A cheap laser pointer that had tips that make a pretty pattern rather than a dot would present a target to focus on in a similar way to the assist lamp, for about a buck. You need to control it manually though. Hack the switch to make a momentary button in a convenient location as you hold the camera, and mount the laser to a "shoe" plate (or scrap of thin material cut in that shape, if it holds in the shoe well enough without adding a strip of tape)

I think this is even more doable now (re the "buck" price) with the toy laser keychain multifunction trinkets flooding in from China (ali express, 97 cents).

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