How to help the autofocus feature of an amateur camcorder

Question

I just acquired an amateur camcorder (Samsung HMX-Q10) that has only a few settings available, most of them are automatic.

I tried to shoot a video of me playing a bass guitar cover but it seems that the image is always slightly out of focus. I'm just slightly blurred but with HD image this kind of detail is really noticeable.

Shooting environment : me standing in front of the camcorder (~2-3 meters) with an instrument, in my appartment (walls mostly white), natural winter/cloudy lighting, white / bright brown background, black clothes, red guitar.

Cam specifications/settings : Full HD 1920x1080/50i, Exposure Value : 0, Shutter 1/50 of a second (there is a "low light mode" that set it to 1/25 but it adds colored artifacts).

I can't notice that the image is blurred on the camcorder small monitoring screen, but when I open the video on the computer it is more obvious (especially because the guitar brand label is blurred), so without proper feedback it is quite hard to manually set the focus.

So what can I do to help the autofocus ?
What can I change in the shooting environment to improve its accuracy ?

I'm thinking, maybe the lighting, the colors (background / clothes), some camcorder settings, another element I forgot ?

Answer 1

I reviewed the specifications for the Samsung HMX-Q10 and have to say there is not a whole lot of information e.g., optics has no mention of "Minimum Focus Distance". So we are pretty much in the dark on the near boundary of the depth of field.

(a little rant on auto-focus)

Most auto focus systems have two modes: Single AF and Full-time AF. Single AF translates into setting the focus once, focusing what ever the sensor picks up first usually in the center of the frame (there are other possible areas depending on the camera, but I'm guessing this Samsung is limited to center weighted focus). Single AF keeps the same focus area during the whole shot. Full-time AF changes focus according to what is changing in the frame. This would be good for tracking a sports event or something moving. Unfortunately the Samsung specs don't mention any of this so I am not sure if this camera has two modes, or one, or if one mode, which one Samsung made the default.

Here is how I would approach shooting your bass playing.

1) mount the camera on a tripod so the camera is steady.

2) Likely 1 meter to 2 meters will be far enough away to be in focus. I recommend that you experiment with this to see if 1 meter is better than 2 or if 2 is better than 3 meters.

3) light the set with as much light as you can as this will force the auto-exposure to 'stop-down' the iris as in a smaller aperture, which translates into more depth of field.

4) in front of the camera, dead center, put a chair or something where you will be playing, (use some gaffers tape to mark this spot off camera on the floor assuming your not going to show your feet) this will force the auto-focus to focus on the space you are going to be.

5) set the camera zoom to full wide (the wider you set the lens, the greater the depth of field).

6) press the record button, walk to your spot toss the chair or prop that was standing in for you and start your action. All the stuff that happened before you started playing your bass can be cut out in post production.

Alternately you can have a friend stand in for you on your mark before you start the camera, you could even have them give an intro then decide later to keep it or cut it and go direct to the bass playing. Also, you could have an assistant do all this camera work for you while you stay in place to start the show.

Quick review: 1) tripod to steady the camera, 2) lots of light, 3) set zoom to widest angle, 4) have your spot in focus before you start.