View Full Version : How do you keep sharp focus when using stabilizers(Glaidcam etc.) ?
June 23rd, 2009, 08:10 PM
I like to hear the different methods you guys use to keep sharp focus when you are using stabilizers (Glidecam, Steadicam ....).
I shoot with the Canon A1 and when I shoot 60i auto-focus is not too bad, but I have been shooting 30f and I just don't trust the auto-focus (especially inside), but can't find the right method to get sharp focus without touching the camera .
* Do you use auto-foucs outside and inside(In low lights) ?
* Do you focus on the subject manually and keep the same distance when moving ?
* If you use manual focus how do you use it when moving closer to your subject without touching your camera ?
* In low light (inside) auto-focus is not the right choice (I think) what to you use ?
I have seen many clips in this forum using stabilizers and beautiful sharp in focus images and would love to hear your techniques on that.
Any guidance would be much appreciated!
June 23rd, 2009, 09:08 PM
I usually shoot my footage with the glidecam on full wide on my Sony Z7 and it works great with manual focus.
June 23rd, 2009, 09:41 PM
Assuming you aren't having someone "riding shotgun" with a wireless follow focus, the least risky way of doing this is shooting "wide" as much as possible with a low shutter rate, boost the gain to 3 to 6dB and choke down the aperture as much as possible to increase depth of field.
June 23rd, 2009, 11:02 PM
FOr non focus pulled moving camera shots in general, stopping down the aperture extends the depth of field. Then making sure you focus at the outset and stay the same relative distance to the subject will keep them in focus... Staying wider will hide any minute loss of focus as well (and help you keep frame a bit more easily).
June 24th, 2009, 02:39 PM
All of the above.
Plus, I get as close to the subject as I plan to in my move and focus there. When your close thats when you see if the focus is off. But from further away its not so easy to make out if the focus is off.
I only use auto if im caught off guard and need to quickly get in there. Auto is normally no good as it will focus as whats in the very centre and you might not be able to keep your subject directly centred.
Evening or in low light auto is useless anyway, let alone when moving.
June 24th, 2009, 08:27 PM
Thank you all for the replies.
with a low shutter rate, boost the gain to 3 to 6dB and choke down the aperture as much as possible to increase depth of field.
Andrew, are you referring to a low-light condition ?
June 25th, 2009, 07:20 AM
The reason Andrew suggested low shutter and a gain boost is to compensate for the loss of light when you are using a high aperture. If you are shooting in bright sunlight you probably would not need to do this, but even in a moderately lit room you will have a problem with high aperture. I would think a little grain is worth what you are gaining in focus though.
June 25th, 2009, 02:30 PM
The reason Andrew suggested low shutter and a gain boost is to compensate for the loss of light when you are using a high aperture.
The problem with high aperture is you lose picture quality, I always keep my aperture no higher then f5.6 with some exceptions.
June 25th, 2009, 07:06 PM
I rarely use higher than 5.6 myself, but that is because I shoot mainly indoors with no on cam lighting. However, high aperture should not decrease picture quality in any way, it should simply make more of the frame in focus.
June 25th, 2009, 09:43 PM
Mark interpreted me correctly. I simply wanted to mention all the tools at your disposal and you can "flavor to taste" depending on what is presented. I made a point of mentioning gain as it is often ruled out when sometimes its benefits out weigh the negatives.