Coping with changing illumination

[Ozpeter]

Looking at the outcome of a 25 minute GH1 project, the chief problem that I'm aware of is the obvious and abrupt changes in aperture that happen when using Creative Motion Picture mode, shutter priority. Not only does the illumination obviously change during shots but this in turn causes momentary blockiness in the picture due to the abrupt change of the whole scene. No way is the aperture stepless! Sometimes something not unlike aperture hunting can be seen to be happening.

I realise that real men only use full manual mode, which would avoid the problem, but how then do you cope with the changes in illumination? An example is panning slowly to follow someone walking along a path, with the background content changing (and the angle to the sun also changing of course).

Presumably one sets an aperture value which will cope with the average illumination but may lead to some underexposure and overexposure during the shot, and you just lump it? Or choose a different shot?

I'm using the kit lens only (plus a variable ND filter, which I guess one could deftly adjust during the shot, but I'm not that optimistic I could make a good job of that).

I'd be grateful for any advice.

 

[sirk]

You let the illumination change without changing camera settings in one cut. I think thats a pretty aesthetic way to use light. After a cut you can always adjust the camera to the light conditions, but I can't remember having seen anything like a variable aperture in a movie or something....

 

[thisisapocalypse]

Looking at the outcome of a 25 minute GH1 project, the chief problem that I'm aware of is the obvious and abrupt changes in aperture that happen when using Creative Motion Picture mode, shutter priority. Not only does the illumination obviously change during shots but this in turn causes momentary blockiness in the picture due to the abrupt change of the whole scene. No way is the aperture stepless! Sometimes something not unlike aperture hunting can be seen to be happening.

I realise that real men only use full manual mode, which would avoid the problem, but how then do you cope with the changes in illumination? An example is panning slowly to follow someone walking along a path, with the background content changing (and the angle to the sun also changing of course).

Presumably one sets an aperture value which will cope with the average illumination but may lead to some underexposure and overexposure during the shot, and you just lump it? Or choose a different shot?

I'm using the kit lens only (plus a variable ND filter, which I guess one could deftly adjust during the shot, but I'm not that optimistic I could make a good job of that).

I'd be grateful for any advice.

This is another reason why location scouting is so important if you have this sort of shot. If you search around you should hopefully be able to find locations where this sort of shot can be accomplished maintaining a constant aperture and getting consistently good exposure - different locations, different times of day are all factors here. If you just try to do it *anywhere* at *any* time you might get lucky now and then, but probably not often enough. Take a light meter with you when you scout.

 

[ydgmdlu]

Professional cinematographers split the difference (for aperture value).

 

[dvbrother]

Professional cinematographers split the difference (for aperture value).

Professional cinematographers with a budget also have the option of using lights to fill in the dark areas or hoisting large overhead silks to cut the brightness of certain areas. A cheap solution to add light in sunny exteriors is to use a reflector. It's essentially a big square mirror mounted on a stand. You reflect the sun into the shadow areas to bring them up. It works.

 

[Martti Ekstrand]

but I can't remember having seen anything like a variable aperture in a movie or something....

That's done all the time but executed in a manner not to be noticeable by rehearsing. Which is why cine lenses have aperture rings without click stops unlike still lenses. A Fader ND can be used in a similar fashion on a HDSLR.