Focusproblems

L

leif_ivan

Member
We have just produced what Sveriges Television (BBC in Sweden) calls Webisodes and to be honest we are not completely satisfied. Certain shots are not 100% in focus even though it looked allright in the viewfinder and the little monitor. At least in a quick glance during a fast production.

The red lines that appear when you are in focus helps. But without testing it, we don't really feel comfortable with it.

I guess this is less of an issue when using AF of course. But generally you don't want to work automatio when shooting in for instance a controlled drama. But you want to use the shallow depth of field, and then we get these problems...

Are we missing somehting? Can you magnify the EVF or the small monitor for instance?
 
Big sensor = shallow depth of field = very critical focus :) Especially wide open. It comes as a bit of a shock that there's no 1:1 on the camera (Jan... I understand why no 1 SENSOR pixel to one pixel on the screen- optical low pass filter- but I don't understand why no 1 OUTPUT pixel to one pixel on the screen).

A 1:1 external monitor, either a zoom in on a small unit or a full size unit you can get close to, is the only way we've found to confirm critical focus. Focus in red in the EVF (with EVF set to monochrome) helps so long as you have a sharp edge to check- catchlights in the eye work, for example. But sometimes there's just no sharp edges exactly in the plane of focus you want, and for that viewing the image 1:1 is the only way to fly.

The AF100 works best in a "fully rigged" configuration, I believe, with the camera itself buried under huge lenses, lens supports, rail systems, monitors, external recorder, cables, etc. It is truly for cine style shooting in very controlled situations, not run & gun/ENG/documentary.

That said, maybe the 14-140 lens with video style autofocus would help?

Cheers, Hywel.
 
I don't know if this is the situation, but some lens adapters are not machined to strict tolerances. We ran into focus issues using a couple of cheap adapters, which cleared up when we replaced them with higher quality lens adapters.

Good luck!

Dave
 
My suggestion is to practice with the Focus in red, you can confirm it with the focus bar. Start with the peaking off, but graduate to peaking turned off. With the peaking off, and you see the red, it will be in focus, without question.

Best

Jan
 
You must log in or register to reply here.
Back
Top