DV Info Net - Manual Exposure Settings In Video Mode

Bruce's tips for systematically using manual settings in video mode.

(T2i, T3i, and 60D) First off be sure you have the camera set for manual exposure in video mode. In video mode press the menu button and find the item for Exposure, two choices: Auto and Manual. Set to Manual (you've likely already done that).

On the Canon 7D you have a dedicated "video mode" switch and the mode dial on top must be set to "MANUAL".

Then find your frame rate settings and pick what you want to use. 24p or 30p (NTSC), your choice but there may not be a real reason for going with 24p unless you need to go with a “filmout” on your project (fewer and fewer are doing this these days) or a client requires 24p delivery. TV sets and DVD players are pretty good about sorting this out anyway so I go with 30p at 1920x1080.

Leave menu mode.

Shutter speed. In PAL regions this may be best set to 1/50 (due to power line frequency of 50Hz) to prevent “banding” and flickering if artificial lights are in the scene. In NTSC countries where the line frequency is 60Hz this should be set at 1/60 (although it can be set to 1/50 if no artificial lighting is in the scene). The idea is to have the shutter speed at some fairly close multiple of the region’s power line frequency.

Both of these shutter speeds allow some degree of “motion blur” the film shutter speed of 1/48 at 24fps on film cameras used to give. Faster speeds can be used but may begin to introduce some “stroboscopic” effect or just plain begin to look “stuttery” (unless you have very little motion in the frame).

I’ve had good luck with 1/60.

Aperture: Set this for the specific Depth Of Field effect desired. Wide (larger opening) for shallow DOF and “selective focus”, narrow (small opening) for “deep” DOF and resulting wide zone of acceptable sharpness, or somewhere in between for having a subject in sharp focus and the background somewhat clear but not as sharp as the main subject.

To some extent shallow DOF is "doable" with the "kit" lens, not much at the 18mm position as shallow DOF is not as apparent in wide angle views due to the "spatial" relationships and size of objects in the frame, but at the midrange (where the maximum aperture may be around f4.5) and at the 55mm end where max will be f5.6, managing the shooting distance and distance to the backgound elements can result in some nice selective focus effect.

ND filters may be needed here to reduce the light coming through the lens so medium and larger apertures can be used. I recommend .6 (two stop reduction) and .9 (three stop reduction) but don’t go for any lower quality than Tiffen, cheaper filters may give a troublesome color shift. With these two filters “stacked” I get a five stop reduction and sometimes a very slight magenta shift, fairly easily correctable in post if needed.

Get these in 58mm thread size for the "kit" lens and for the 24mm f2.8, 28mm f1.8 primes, and if you get the EF 50mm f1.8 lens with a filter thread of 52mm all you will need is a 52mm to 58mm stepup ring. 77mm may be the best bet for larger Canon lenses with appropriate step rings for smaller lenses. I also recommend a rubber lenshood for the "kit" lens, extended will give fairly effecting shading on the lens at the midrange and telephoto end, at the 18mm position it will need to be folded back to prevent vignetting. It won't look "uber cool" but will provide effective function (plus act as a rubber "bumper" on the lens front end).

ISO: Set to AUTO but only temporarily. When you have shutter and aperture set, press lightly on the shutter release to cause your settings to read out at the bottom of the LCD (you should have the “display” set for this), take note of the ISO the camera will use and manually dial this value in.

Exposure is now “locked” and will not drift as you pan. This is the way I want it to be.

At this point you can “evaluate” your exposure three ways. Visually on the LCD but only if you are using a loupe such as the Hoodman or one of the others that also exclude all extraneous light. You also have the exposure “metering” scale at the bottom of the LCD. In all auto exposure modes the indicator will remain centered under the center “index” mark because the camera is handling exposure for you.

But in Manual mode this indicator will move as the light changes but you should keep it “somewhere near” the center index mark in most cases. Now if you set exposure for a darker effect this moving pointer will indicate some degree of underexposure, likewise it will indicate some overexposure if your go for a “higher key” lighter effect”. This built in meter is actually quite accurate.

So with a loupe you can visually “judge” exposure effect and also refer to the camera meter scale at the bottom of the screen.

Third method of evaluation is to either press the shutter and take a quick still or press record and do a very short (3 second or so) video recording. Press the playback button and check the histogram.

Here I’m going to step into an area that will cause some to “go into orbit”. Adjusting LCD brightness. You have to pay strict attention to returning it back to normal if you do this. And many feel that there is no way one can “eyeball” exposure by “monkeying” with LCD brightness.

Even with a loupe, our eyes can adjust to ambient brightness to the point we may not be able to see the LCD well. One day working in Texas sun I couldn’t see enough tonal detail on the LCD to give me much to go on. My eyes were “tuned” to the extreme brightness and to see the LCD and it’s image detail I had to set the brightness up almost all the way. Canon gives us a good tool to determine where to set this. If you have a still photo on the card this will be displayed and on the right side of the image is a “gray scale”.

Brightness should be set so that you can see each step of the gray scale distinctly, as well as make out normal detail in the image.

When done shooting in that bright environment remember (really REMEMBER) to set brightness back at mid scale or wherever is normal for you.

Working at night outdoors, I found if the image on the LCD looked good to me, it was really underexposed when I started working with it in the computer (the meter and histogram may not help you here). Again, eyes and vision had adjusted somewhat to the darker environment and setting the LCD brightness down some but so that I could still see distinctly all steps on the grayscale put me right back in the “ballpark”.

Again, REMEMBER to set the LCD brightness back to midrange or “normal” when done.

The loupe is absolutely essential here. Without one, you have to rely on the camera’s metering which will get you by in daylight and normal indoor lighting levels, but outdoors at night or in any real low/marginal lighting levels you need the loupe.

Canon has given us some incredible motion picture imaging tools in these DSLRs and the capability to apply visual judgments is there in a very real way.

Helluva essay, but stuff I've found useful.

Bruce Foreman