A focus on focus

Traditionally Voxvision have produced corporate and educational videos for such applications as training health and safety and website show reels, filmed and edited as a collection of scenes as in film and television style shooting. Occasionally we have been asked to video live events which although not our speciality we have at times undertaken dependant on the logistics of the event as this type of videography usually requires multiple cameras and a small crew to get it right.

We have videoed small conferences and podium presentations in the past and using our previous Canon XL2 SD video camera this has never been an issue as we have set it on autofocus and when appropriate zoomed in and out to make the picture more interesting remembering that this is a single camera set up and the event is live. But now we have invested in new technology and are using an HD camera more suited to cinematography. So what? I hear you ask , well here is the difference. No automatic zoom button and limited (slow) autofocus.

We recently undertook to video six presentations live on an exhibition stand at the NEC and I thought that I would have a practice at home prior to the event, changing from close up to mid shot, using the lens barrel to zoom and manual focus. I anticipated that I would have a few problems but to my surprise carrying out test shots at home following the basic rules of focus as used by seasoned cinema-graphic shooters I was pleased as to how effective it was. I zoomed the lens out to it’s maximum and focussed on an object slightly behind my subject. The panasonic AF101a has an electronic viewfinder detail facility (EVFDTL) which highlights the object in focus making it easy to ensure that it is pin sharp. Then I readjusted the zoom to frame my subject in close up. Low and behold when I then zoomed out for a mid shot they were still in focus

Sharon close up still

 

Sharon Mid shot

To facilitate easy movement of the lens barrel for zooming I attached a gear ring to the lens from my follow focus kit and used the protruding tightening screw as a lever to smoothly turn it. I did this because it was a live event and I would be amongst the audience in close proximity and wanted to keep things simple and not have to take or use my matte box rig which does have a zoom lever attachment. I found the zoom action using the gear ring relatively smooth and it could be facilitated using one finger which was easier than turning the barrel by hand.

On the days of the filming I used the above principle and for the majority of the shoot sharp focus was maintained. I analysed the few occasions where focus had gone soft and came to the following conclusions.

1/ My 14-140 Lumix lens is manual/autofocus without a selection switch  on the lens itself, and when the camera is switched off it does not hold the previous manual focus settings.

2/ Occasionally in my haste to get the job done in a live environment I forgot to FULLY zoom out before focussing on the farthest point thus shortening the depth of field.

Professionals out there used to live event filming with follow focus will be saying ‘But any fool knows this’. But for my part in some eight years of professional filming I have used a camera (Canon XL2) that has great auto focus and excellent built in Zoom facility with a relatively wide depth of field and I have always tended to play safe , use auto focus then switch over to manual to lock the shot (I consider myself an arty not a techy).

My conclusions drawn from this exercise were that I should have really been using this technique years ago. The end results would have been the same but by now it would be second nature. I hope that this something of a confession of laziness in the past helps new shooters get to grips with something that very often we take for granted -focus

Bob Sanderson M.M.Inst V. ALAM

Voxvision Video Productions Ltd

http://www.voxvisionvideoproductions.co.uk

bob@voxvisionvideoproductions.co.uk

01384 374767

07815 933597

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