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uphid
March 9th, 2010, 04:34 PM
I've noticed some oddities about the autofocus when using a D300 in full-screen photo booth mode; and I wanted to see if anyone has had the same experience. It appears to lock focus before starting the live view; and doesn't seem to refocus before taking the picture. This gets me sometimes, as I start up the booth "empty", then people sit down. Any thoughts, experiences, or suggestions from the field?

On a followup to a previous post: I have replaced my Acer Aspire One with a mid range Dell. The difference in performance (and stability) is amazing.
Chris Breeze
March 10th, 2010, 08:26 AM
AF is not used when taking pictures when live view is active. Nikon cameras support AF with live view but it works by contrast detection which is slow and is only suitable for static subjects (as opposed to the much faster phase detection AF used for normal shooting).
The best thing to do is to set the camera to manual focus and pre-focus to the correct distance.
uphid
March 10th, 2010, 02:13 PM
That was my suspicion... If the subjects moved after the initial lock, things would be out of focus. Probably best to do a single "timer" shot, then lock out the focus manually.

Chris: The program is working great for us. The booth is still a new addition, but it's getting really popular.
uphid
March 10th, 2010, 07:15 PM
Chris:

I'm looking at building a second booth... Is there a better camera for live-view autofocus than a D300? I'll buy a Canon if it's preferred.
Chris Breeze
March 11th, 2010, 09:42 AM
The live view AF from a Canon or a Nikon DSLR is too slow to be suitable for moving subjects. The latest Canon models (e.g. Rebel T2i/EOS 550D and EOS 7D) support "Quick mode" AF from live view which drops the mirror down, focuses using the camera's phase detection AF system and then takes the picture before flipping the mirror back to display live view images again.

One drawback with using AF is the camera will only take a picture if it can focus. This means that if the camera can't focus the photobooth shooting sequence will fail.

I think the best compromise is to use manual focus and pre-focus at the mid point where the guests will be standing. Using a wide angle lens will help to increase the depth of field as will having plenty of light and selecting a small aperture.
uphid
March 11th, 2010, 12:57 PM
Makes sense...

I'm currently running at f/ 6.3, but perhaps it's time to move a few stops. I've really happy with the results, as have my couples who rented the booth.

That shortcut key for "quick reprint" was a wonderful improvement, btw.