Now, one thing about the fact that the DSLR is also a high quality stills camera that you have to deal with when filming are the ISO settings. ISO settings control how sensitive your camera is to light, the lower the ISO setting number the less sensitive to light the camera is, the higher the number the more sensitive it is – but the higher the number the more grainy or noisy the image becomes.
One incredible feature about DSLR cameras that seems to be overlooked by a lot of low budget filmmakers is that with a switch of a button we have an incredibly high quality stills camera too. So how does this have a bearing on film work? Well here’s a couple of ways…
If you can’t afford a stills photographer and you want high quality stills for promotional purposes, you can take your own with the DSLR, saving you the hassle of having to carry around another camera.
Also, if you’re like us and tend to do most of your own special effects work –as it’s one way to keep the budget down, you’ve no doubt been out shooting and seen something that would potentially be good material for say a Matte shot (where part of the set or shot is created digitally and superimposed/blended into a live action shot in post-production), like a great sky or distant mountains. Before we had the DLSR, we’d have to carry a dedicated stills camera to be able to capture these images as high quality stills, not any more.
According to Shane Hurlburt, the DP on Terminator Salvation and DSLR pioneer, the “cleanest” ISO settings to use are 160, 320, 640, 800 and 1250. This was the result of extensive testing carried out using the Canon 5D mark 2 and the Canon 7D.
Philip Bloom, another top Hollywood DP and DSLR pioneer, also conducted a series of ISO tests on the above cameras and he too found these settings were also the cleanest.
There are some interesting discussions on this subject – but Hurlburt and Bloom both know their stuff when it comes to DSLR cinematography, so we’d say stick to what these guys recommend.
Hurlburt visuals produce an interesting newsletter – this one covers ISO settings…
Unfortunately on the Canon Rebel T2i/550D, which is the camera we use, you’re stuck with multiples of 100 – 100, 200, 400, 600, 800 all the way up to 6400 – but Hurlburt says, “ anything above 1600 and the image falls apart”.
As a rule, we try to keep the ISO settings as low as possible. But this, of course, depends on the situation we’re in when filming as there are times when you have to use a higher setting to compensate for less light – and these cameras need light. For example, a heavily overcast day, a night scene or an action scene where we’d want a much wider latitude of focus, and therefore be shooting with the iris partially closed up (when you want a greater depth of field, with a nice blurry background, you shoot with the iris as wide open as possible, we’d recommend ND filters or variable ND filter to control the light in this situation – we’ll look at recommended accessories in a later post).
Again, when it comes to ISO settings it’s a matter of testing and more testing.