CAMERA TIPS: Exposure

Posted by Chris Thomson

​Let’s talk all about those buttons and wheels on the camera. Probably one of the most important ones is the levels of audio, but I’ll go into that on a separate post. With regards to the image you’re going to get, (I’m working on the assumption that you know the bare bones basics like how to get your subject in focus already) the thing you need to perfect is exposure. 

Now the two things you need to consider here is your aperture and your shutter speed. Getting a good relationship between the two is critical, but you need to know what effects each one has on your image. Your aperture creates/reduces depth by reducing/increasing the area of focus in relation to distance away from the sensor, and this helps to outline your subject and attract the viewer to the subject in focus. One thing to remember is to make it look real, the human eye can see at about f2.1 when it’s dark and around f8.3 when it’s bright, and up to 1/200 of a second shutter speed. Of course, there are a number of factors here that effect how a human eye sees things like age, ambient light and a whole lot more.
So, what does it all mean? Well if you have a very bright scene and you want to have a shallow depth of field to enhance your subject, the first quick fix is increase your shutter speed, but if you end up going up to 1/2000 shutter speed, your image is not going to look real. You want to stick around 1/50 to 1/200 for best results. That’s where your neutral density filters come in to play. Think of them as sunglasses for your camera, they allow you to preserve shutter speed to create the motion blur and keep that depth of field - so there’s one solution.
Now let’s talk about the other end of the spectrum, you’ve got a dark scene, you opened your iris as far as your lens can go, and you’ve gone as slow as you can with your shutter speed without creating too much motion blur, but your scene is still too dark. Yes, you can use ISO, but think of this as nothing more than an amplifier. A photography friend of mine once explained this to me in my earlier video days; he made me think of it as the volume knob for your stereo. Yeah you can turn the volume up and up, but at some point, you’re going to get distortion, and it’s not going to sound good. ISO is like that for your picture, and that distortion is referred to as noise, and appears as specks and dots and general untidiness predominantly in the darker areas of your picture. So one thing to have at the front of you mind while shooting in low light is that while ISO can be helpful, it can also affect your video for the worse. It is the digital sensitivity level of your sensor, and making your sensor too sensitive, will mean you’ll pick up unwanted noise.
So, what do you do if you start getting too much noise? Light your subjects. Lighting really is one of the key elements to quality videography, and is really important to get right. I’ll dive into this in depth in a future article.
Remember exposure is all about capturing light, and you have 3 variables to play with:

1. Shutter speed. This is how long the sensor is exposed to light. Shooting at 1/100 instead of 1/200 lets in twice as much light.
2. Aperture. This is how big a hole you are opening. Opening 1 stop by doubling the opening (1.414x the diameter), will let in twice as much light.
3. Sensitivity. This is how much light the sensor needs to produce an exposure.

ISO is a measure of no.3. Doubling the ISO means the sensor only needs half as much light to produce the same result.
Nail your exposure, and you’re one step closer to creating a great video.
For the perfect example of correct exposures, check out the following video. It's our 2017 Showreel, but we've selected it because very single shot that we chose to showcase in it features perfect exposure.