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Cinema and DSLR Comparison: Canon EOS C300 vs. 5D Mark III

By Ron Dawson

It's challenging to compare Canon's EOS C300 (the first in its line of cinema cameras) with the EOS 5D Mark III (the long-awaited update to the 5D Mark II). When it comes to video quality and features, the C300 handily wins. But that doesn't mean buying or renting this camera over the 5D Mark III is a slam dunk. Having now used both cameras in the field, I want to highlight some key differences that will be worth considering, especially when you take into account the street price for the C300 is about $16,000 vs. $3,500 for the 5D Mark III.

This is by no means an exhaustive comparison. The point of this article is just to point out some specific concerns about each camera.

A New Line of Cinema Cameras
The C300 was announced November 2011 and is the first in Canon's line of cinema cameras. Since then they have also released the C500 and the 1DX, which will be a 4K camera. The C300 is a full-blown cinema camera but with a weight and form factor similar to a Hasselblad. It has many of the features that traditional filmmakers and video producers like me missed once we started shooting with DSLRs. Things like peaking (the ability to set the viewfinder to show areas of greatest focus), professional XLR audio inputs, zebra lines (live display of highlights), and professional grade BNC outputs for use with high quality monitors (vs. the cheapo, but works-in-a-pinch HDMI outputs you get on DSLRs).


On the set of a music video with a 5D Mark III connected to a SmallHD monitor via HDMI cable, the cable broke later during filming.

The C300 has a Super 35mm chip, which is equivalent to a 1.5X crop factor (vs. the 5D Mark III's full-frame sensor). There's an EF-mount model for taking Canon EF lenses, and a PL-mount model for using more traditional cinema lenses. Currently there is no adaptor if you want to have both options on one camera.


Here’s the Canon EOS C300 on set of our documentary shoot, loaded with a Zeiss CP.2 Cinema lens with EF mount (Note: the CP.2s are specially made cinema lenses with EF mounts. Definitely worth renting or owning if it fits your budget).

C300 Tips
I highly recommend at least renting the C300 and trying it out. If you make a living with video production (or are adding it to your repertoire of services), it’s well worth getting a feel for this camera and understanding how it works. You can even play around with the menu online ahead of time using this menu simulator. Even if you opt for the less expensive 5D Mark III, when your budget permits, you may want to rent a higher-end cinema camera. When doing so, here are some key tips to keep in mind. 

  • Slow motion: Slow motion is usually achieved by shooting at a higher frame rate then converting the footage to the playback frame rate (i.e. shoot something at 60 frames per second, then convert the footage to 24 fps to get 40-percent slow motion). With the C300, use the Slow & Fast Motion feature to do that in-camera.
  • Shutter speed: Filmmakers like to consider shutter angles vs. speed. A shutter angle of 180 degrees (1/(2 x frame rate)) will give you the “correct” level of motion blur. At 24 fps, a shutter speed of 1/48 would be 180 degrees. The C300 allows you to set your camera to read shutter angles or shutter speed. 
  • Canon Log: This is a custom profile on the C300 that gives the footage a “flat” look, allowing for more flexibility in editing for color grading and color correction. It also will give you 12 latitudes of dynamic range! It’s kind of hard to find. Under the Custom Picture setting it’s the one labeled C8.
  • Transcoding: If you shoot video with DSLRs, you may be used to transcoding your footage. This is where you convert the raw H.264 footage to a codec that is easier to work with depending on your editing system. The C300 shoots in Canon’s MXF codec. You’ll need to install the Canon’s plugin to convert the footage to a format a program like Apple’s Final Cut Pro or Adobe Premiere Pro can use. Note: you cannot use a program like MPEG Streamclip or Apple’s Compressor to transcode raw C300 footage. 



The file structure of clips from the C300.

Canon Finally Upgrades the 5D Mark II
The 5D Mark III has many functions DSLR filmmakers have wanted for a long time. Some of the most notable improvements include: much clearer imagery at high ISOs (shoot at ISO 3200 all day if you want), onboard audio monitoring with level control (although personally, I still believe the compressed audio on a DSLR is not worth using unless you either have no choice or are using it sparingly), “slow motion” filming at 60 fps (but still only at 720p resolution), and you can now record continuously for up to 30 minutes (vs. the 12 minute clips on the 5D MkII).

Another huge plus is the reduced aliasing and moïre over the 5D Mark II (an issue that is non-existent with the C300). It was so refreshing not having to deal with moïre when shooting with both of these cameras.

One of the things you’ll notice about the 5D Mark III when selecting which frame rate and mode to shoot in is the choice for All-I (intra-frame) and IPB (inter-frame) recording. With All-I recording, compression is achieved by the camera considering each frame by itself. With IPB, the camera compares frames before and after to determine which aspects of the image to leave alone because they are so similar. All-I (interframe) will give you a higher quality image with larger file sizes. Theoretically, it should also be easier on your computer processing power because there’s none of that back-and-forth frame comparison going on. I shot in All-I for the music video on which I used the 5D Mark III, so I didn’t compare the two. Canon claims the quality difference is minimal. If you’re concerned about drive space, consider IPB.

Do a Google search on All-I vs. IPB and you will get a number of people saying All-I is better, and then you’ll get some saying IPB is the way to go. (You’ll also probably get a headache reading all the “Pixel-peeping” debates.) As usual with this kind of topic, it comes down to the project you’re shooting and the resources at your disposal. There isn’t always a definitive right or wrong choice. Do your own tests and see what works best for you.


Click to enlarge and view an All-I vs. IPB comparison showing blue and green channels. Image ©

A big disappointment to many filmmakers is the fact that slow motion at 60 fps can still only be done at 720p vs. 1080p. Also, there is still a little bit of the rolling shutter “jello” effect. It’s better than the 5D MkII, but still there (the C300 has no jello effect).

Overall, I would say the 5D Mark III is definitely a great investment, even if it is not as huge an improvement over the Mark II as many filmmakers and I would want. My guess is that’s because Canon would prefer you to purchase/rent one of the cinema cameras (which is worth doing at least once). In any case, I would say it’s time to put that old 5D Mark II on eBay.