Sam Eilertsen here. Since BTV just bought a Canon T2i, one of the so-called HDSLRs (still cameras that shoot HD video), I figured I’d share some of my research and experience with shooting video on a DSLR.

Why use a DSLR to shoot video? First of all they are cheap, even with a decent lens and an external sound recorder they will come out similar in price to “prosumer” video camcorders. Second, they are by far the cheapest cameras with a sensor size similar to that of 35mm film, which allows you to get a much shallower depth-of-field than is possible with a camera with a smaller chip. Finally, they have a much higher sensitivity than most video cameras, allowing them to be used in lower light situations.

However, along with all of these advantages come some serious drawbacks. When you are taking a camera that is designed to shoot 18MP still images a few times per second and you are making it shoot 2MP video 24 at frames per second there are going to be problems. Below I’ve outlined the major issues and how to deal with them.

Tip 1: Respect your camera’s dynamic range

When last November I got the chance to chat with Doug Liman and asked his thought about shooting DSLR, this was his main complaint. You just aren’t going to get anywhere near as much latitude as film, and that’s that. If you aren’t familiar with dynamic rage, basically, it’s the range of brightness you can capture between black and white. I haven’t found a good source of hard numbers, but there is a huge difference in DR between a DSLR and a high-end video camera (RED, Alexa, the Sony F3) or film. The result of this is that you won’t be able to shoot a scene with a large difference between the darkest area and the lightest area without losing detail in either the highlights or the shadows.

To make up for this, you need a lot of fill light. Even if you are going for a high-contrast look, you need to light somewhat flat so you don’t lose your shadows completely. Don’t shoot outdoors on a sunny day without lots of lights or bounce cards. Using a diffusion filter in front of the lens can help with this somewhat (and also helps with moire), but you really just don’t want to push it.

Tip 2: Install the Marvels picture style

DSLRs already have inferior dynamic range, but the Canon standard picture style makes it much worse. In order to make a vibrant, contrasty image right out of the camera, the standard style will actually throw away some of the shadow detail the sensor managed to capture. By using a custom picture style, you can flatten your image out a bit, capturing more information. The raw footage may not look quite as nice, but you will be able to manipulate it much more when you color correct. You can always throw away information you don’t want, but you can never recover information that’s been lost, so it’s much better to shoot flat.

You can download version 3.4 of the Marvels custom picture style here. It’s installed on BTV’s T2i in slot 3, and the other two are older Marvel styles. Instructions for installing styles can be found here. You need the EOS utility, which comes on the camera CD. If you don’t have your camera CD, installing it is a bit tricky, you can download the software from Canon but you have to trick it into thinking its already installed. Fortunately, there’s a fairly simple hack.

Tip 3: Watch your exposure

When I first shot film, I was terrified of the light meter. Not being able to actually how see the shot was going to look seemed terribly dangerous. However, after I got the hang of it my shots all came out just about perfect. And as soon as I went back to digital, I instantly missed the light meter. With little LCD screens its just really hard to spot underexposure, you don’t see it until you look at it on a computer monitor in a controlled environment and then it looks totally dull.

Unless you’ve installed the Magic Lantern hack (currently in stable build only for the 5DmkII), your DSLR isn’t going to give you a histogram to check exposure, or even the zebra stripes available on most video camera to indicate overexposure. If you can, just use a light meter or connect your camera to an external waveform monitor, but you can get a poor-man’s meter by snapping a still image and looking at the histogram. If there’s a big empty space at the top of your histogram, you are underexposing.

Tip 4: Stick to ISO400, carry NDs

Digital camera manufacturers (other than RED) don’t really like telling you the rating of their digital sensor, but most people rate the Canon DSLRs at around ISO320 or 400. This means you will always get the best results at this rating. As most people know, raising the ISO increases noise, and this is most noticeable (unfortunately) in a high-contrast scene like a night scene. What is less known is that lowering the ISO below the rating is also problematic. It’s difficult to wrap your head around, but lowering the ISO, which you do to avoid overexposure in a bright environment, actually LOWERS the dynamic range of your highlights, making clipping more likely. A detailed explanation of this can be found here. But, basically, lowering your ISO much below 400 sacrifices highlight protection, which is something you don’t ever want to do.

Instead, for situations where you need to lower your exposure (like shooting outdoors), carry neutral density (ND) filters, either screw-on filters for your lenses or mattebox filters. You can buy decent screw-on filters pretty cheaply and get step-down rings for sharing them between lenses.

I should note that you also don’t want to compensate for a bright scene by closing down your aperture too much, first of all because then you lose the shallow focus look that makes DSLRs nice, and second because once you get down to f/16 and lower, you actually lose resolution due to diffraction (which I can’t really explain without a lot of physics).

Tip 5: Mind the Moire

One huge problem with DSLRs is moire. Moire refers to the weird stripped patterns you get when you point a camera at a brick wall or a finely stripped shirt. This is the result of aliasing, which is an inevitable result of finite sampling and an issue with all digital capturing systems including cameras. However, with most digital cameras you have something called an OLPF (optical low-pass filter) which prevents aliasing to some degree. DSLRs have an OLPF, but it is designed for taking still images at very high resolution (18MP or more). The way the camera downsamples for the much smaller HD video format, the OLPF is much less effective and the camera is exposed to all kinds of aliasing problems.

In order to avoid this, you must avoid ever shooting fine, repeating detail from far away. Banish stripes from your sets. No striped shirts, cups, wallpaper, what have you. Avoid brick walls or even fences in the distance.

Unfortunately, chroma (color-specific) moire can show up even in things like hair or skin. If this is a noticeable issue, consider blurring your color channels a little (the eye is more sensitive to luminance so its not easy to notice), or using one of the moire removal plug-ins available online. But moire is very difficult to remove completely, so try to just avoid it.

Tip 6: Lock it Down

DSLR’s suffer from a serious problem called rolling shutter. This phenomenon results from the way CMOS image sensors work: rather than capturing an entire frame at once, they scan pixels line by line. This means if the frame moves during the shot, the captured image is skewed because the camera has moved between when the top line is read and when the bottom line is read. Many cameras, even the very high-end RED and Alexas, suffer from this issue, but because they are designed for taking stills DSLRs scan slowly and thus this is a very serious problem.

In order to prevent it from being noticeable, avoid fast pans, and don’t ever try to shoot handheld. Handheld shooting was already the biggest cliche in the indie film world before rolling shutter made it so much worse. Just don’t do it. Even a shoulder mount is hairy. You should be fine on a steadicam because the motion is steady and controlled (as long as you know how to use it!)

Tip 7: Control  Your Focus

Shallow depth-of-field looks great — until you end up with blurry shots. You need to be very, very careful about focus. An external monitor will help, as will using a tape measure, but at the very least use the zoom assist feature for focusing. This is not that hard, but the problem is as soon as your actor moves a little bit they will go out of focus.

If even small movements by your actors cause focus issues, try to add more light and raise the f-stop. You can look at depth-of-field charts to see exactly how much room they have. For big movements, you need to follow focus, which is NOT EASY. In Hollywood there are people who spend their whole career pulling focus. Choreograph everything carefully, get good measurements, have an assistant pull for you if possible.

One thing to note about stills lenses is they have a tendency to “breathe” when you pull focus, meaning they zoom just a little bit. This is an unfortunate issue and if you want to pull focus with stills glass you are just going to have to deal with it.

Thanks to DSLRs, shallow focus and rack focus have become one of the biggest cliches in the entertainment industry. Think before you rack focus! Are you doing it to tell the story or because you think it looks cool? A good rack focus is mildly impressive, a bad one is downright irritating. Save yourself the headache and take your lens down a couple stops!

Tip 8: Don’t mess with H.264

A huge problem with DSLRs and other low-end tapeless cameras is that they record using the H.264 codec. This is a very heavily compressed format that sacrifices a ton of information. Once this information is lost in the encode, there is no way to get it back. Practically, this is often manifest by blocking in areas of uniform color, like highlights and shadows. This seriously hampers your latitude is post, because with too much color correction you will start to see the compression artifacts.

Some people claim that you can actually recover quality by transcoding to a low-compressed format like ProRes. This is utter BS. You should transcode your footage to ProRes for Final Cut editing because Final Cut does not like H.264, and transcoding will prevent you from losing more information when you render, as well as giving you a little more latitude by upsampling the bit depth. However, this does not recover any information, it only prevents you from losing more information by editing. This step is not necessary in Premiere, which will edit H.264 just fine and upsample on the fly.

So, basically, don’t expect to manipulate it too much. You can, and should color grade your footage to make it look right, but dramatic adjustments will break it, which is all the more reason to make sure you expose properly. If you need to do complicated grading or effects work, a DSLR is probably the wrong choice.

A Step Back…

With all these drawbacks, isn’t that EX1 looking pretty attractive? Well, maybe until you actually compare footage. Problems aside, DSLRs shoot MUCH better video than any camera of their price, and better than many cameras many times their price. As long as you understand their flaws and know how to minimize them, they can look really, really nice.

Happy shooting!
Sam