Can I tell iSight to not autofocus?

December 8, 2005 7:27 AM

Is there anyway to set an Apple iSight's focus to infinity rather than the default autofocus?

I use my iSight as a webcam that points out of a window. Frequently the camera will get locked into an autofocus loop where it constantly tries to focus. Sometimes unplugging the firewire, and or quitting and restarting EvoCam (which I use for the webcam) will help, but I would really like to set the focus length to "infinity." Nothing on Apple's site indicates this can be done, but I wonder if it can be done via some peference setting or the command line. I am using OS X (10.4.3), and believe I am up-to-date on iSight's updater software as well.

posted by terrapin to computers & internet (9 comments total)

I think you're out of luck. The QuickTime sequence grabber API doesn't seem to expose that much functionality. You might be able to talk to the device directly and control it (Apple has a "Programming the iSight" document online that goes into a lot of detail about the internals of the iSight) but I don't think any current software configures that.
posted by schwa at 8:24 AM on December 8, 2005

There are rumors that the app iVeZeen will allow you to use the iSight with autofocus; not owning an iSight, I can't say if that's right.
posted by delfuego at 8:32 AM on December 8, 2005

Apple's "Programming the iSight" document doesn't seem to mention anything about controlling the autofocus state.
posted by odinsdream at 8:42 AM on December 8, 2005

iVeZeen does in fact allow one to control the focus of the iSight, but it doesn't seen to have a webcam/FTP feature.

Seems to me if one application can do this, that it should be able to be configured somehow. But I do not have the skills to do it. If anyone else does, I will be eternally grateful.

in the meantime, I'll beg EvoCam to implement it.
posted by terrapin at 8:55 AM on December 8, 2005

iGlasses seems to have the ability to control the focus - I'm not near my iSight right now...but there's a free demo, and it's only $8 to buy.
posted by filmgeek at 11:31 AM on December 8, 2005

I had just found iGlasses when I decided to recheck this thread. But I didn't install it until after I saw filmgeek's suggestion. So far, so good. Will have to wait until the hours of the day that I have the most difficulty to know if it really works, but if it does I will spend the $8 gladly!

In addition to control over the focus, one can control the brightness, gain, temperature, hue, etc. This is a great product so far.

I'll report back soon. Thanks again, folks!
posted by terrapin at 12:41 PM on December 8, 2005

EvoCam developers got back to me and showed me the very non-intuitive way the focus can be adjusted in their software. So while I didn't necessarily need iGlasses (hehe) I still prefer the control it provides over EvoCam's method.
posted by terrapin at 5:20 AM on December 9, 2005

terrapin; could you share what you learned from the evocam developers?
posted by odinsdream at 7:35 AM on December 9, 2005

Sure, odinsdream. Copied and pasted from the email:

To adjust focus manually, do this:

1) Choose 'Options > Video Input'
2) Click on the Adjustments tab
3) Click on the Mechanics tab (this is a secondary tab inside the Adjustments tab)
4) Change the popup menu from 'Auto' to 'Manual'
5) Adjust the slider until you have the correct focus
6) Click OK
posted by terrapin at 5:46 AM on December 10, 2005