Many DSLR shooters make the mistake of relying on the auto-exposure function on the camera. This is a mistake. Learning how to manually set an exposure on your DSLR is not an easy art to master, but if you want to be an effective visual storyteller it's crucial that you put in the time to really figure it out. After a recent conversation with an aspiring filmmaker who's been learning this the hard way I figured it was time to finally knock this post out.
So what are the basic guidelines for shooting usable footage?
There are three basic parameters that affect the exposure - the aperture, shutter speed and ISO settings. The combination of these three settings will produce the overall look and "feel" of your footage. There are lots of great sites that explain these three in depth; for our purposes we'll keep it basic.
Shutter Speed
In a nutshell, the shutter allows light to pass through to the sensor for a specific amount of time. The longer it's open, the more light is allowed in and the brighter your image will be. In photography this setting is a very big deal requiring a lot of study.
For beginning filmmakers there's a much easier rule of thumb: the shutter speed should be exactly double your frame rate. So shooting at 24 Frames per second requires a 1/50 shutter speed; 30 Frames per second means 1/60 shutter speed
This will give your footage a nice, natural motion. You can vary this for special effects later on, but for now just start by setting your shutter speed using this rule of thumb.
Aperture
Once your shutter speed is set, the next setting you want to tackle is your aperture. The aperture is basically the size of the opening letting light into the sensor. The trick with aperture settings that's often hard for beginners to grasp is that the lower the value (f/1.4) the bigger the opening. A smaller aperture opening would be expressed in a larger number - say f/8. To get a better understanding of what I'm talking about check out the diagram to the right.
As filmmakers, setting the aperture is usually one of the primary ways we influence the image. A wide-open aperture will create a huge separation between what is in focus and what's blurry. This effect is referred to as a shallow depth-of-field, and the ability to create that shallow depth-of-field with sub-$1,000 cameras is why DSLRs have rocked the indie filmmaking world so completely.
When setting your aperture, start out by opening the lens as wide (smaller number) as possible, say f/2.8, then backing it off one number (f/4) or two in order to get a sharp image with a good depth of field. How wide your aperture will open depends entirely on your specific lens.
Adjust the camera aperture up or down depending on how blurry you want the background of your image to be. It's all about balance, so don't be afraid to fuss with this a little before you begin shooting to get what you're looking for. It's all about story, so don't be afraid to consider how important that background information is, or isn't.
ISO (or gain)
The ISO setting is basically means how much the camera's sensor is boosting the amount of light that's hitting it. This single feature is usually a major factor in how expensive your camera is: Often, the better the ISO performance, the more expensive the camera.
With ISO here's the first rule of thumb: Use as Little ISO as Possible. The more ISO you use, the more noise you introduce into your imagery, so you'll want to use the minimum necessary in order to get your shot. Ideally you'd never go over ISO 800 on a shot, but sometimes you have to. Remember, it's better to slightly under-expose than to over-expose.
So again, here are those steps -
1. Set your shutter speed to 50 or 60
2. Set your aperture for the look you want
3. Add the ISO to get the brightness up to where it needs to be
Color Profile
The last thing to consider when shooting usable DSLR footage is to really pay attention to the color profile you are shooting with. On Canons you want to shoot with a flat profile such as Technicolor or Marvels, then add a great color grade later.
The one danger to consider here is that shooting flat can often lead you to over-expose your images. If you have time, always set your exposure in Neutral then switch over to Marvels or Technicolor.
Hopefully that helps you get started creating the right look for each shot you're composing. Just keep in mind, what I've talked about here is a bare minimum starting point. Never stop learning, growing and experimenting. Just keep shooting!
Thoughts, insights, pushback? Leave a comment below and let's get a discussion going...
