Review: Blackmagic Design Video Assist

In use, the unit feels solidly built, and the screen is very bright. The difference in size and clarity between the Video Assist and the typical camcorder or DSLR LCD panel is very significant. Not only is the screen brighter, allowing for a more accurate preview; the 5" diagonal size is also much more useful for framing and focus, with the histogram and large volume meters welcome additions.

If you have multiple watchers behind the camera (either before or after the shot), the Video Assist specs call for a viewing angle of 135%, and if anything, it looks wider than that, with the visible quality dropping off very little when viewed from the side. This is a unit you’ll feel comfortable passing around to multiple stakeholders at a shoot.

Recording

ProRes and DNxHD are very high-data rate formats, so be sure to purchase media approved by Blackmagic for use with this device. When I tested with unapproved cards, I invariably dropped frames during capture, but once I started using approved cards, this problem disappeared.

Once I ironed out these issues, I turned my focus to whether capturing in ProRes produces a higher-quality source video than the native capture format of your DSLR or camcorder. To test this, I shot under multiple conditions, captured in AVCHD and ProRes, and compared the results.

For a typical, well-lit, shoot-it-and-ship-it kind of project, you’ll see minimal difference between H.264 and ProRes. You’ll still likely want to use the Video Assist as a monitor, but you may not want to mess with ProRes. You’ll see this in the video embedded below, which shows H.264 on the left, and ProRes on the right.

On the other hand, when shooting in low light, H.264 will start to show small macroblocks, which won’t appear in your ProRes version. It's not night and day, but if you're shooting for the Queen (or a client who thinks she’s the queen) you definitely want to capture in ProRes.

The most interesting use case is when you're shooting video that you want to color grade, or video that contains challenging scenes from an exposure perspective. The inspiration for these tests came from a Vimeo video that compares the 12-bit RAW capture performance of the Blackmagic Cinema Camera to 8-bit H.264-based capture formats.

In the video, the author found the difference profound as you can see around the 7:00 minute mark. In our case, ProRes is 10-bit, not 12-bit, while AVCHD-H.264 is 8-bit. When you're shooting under challenging exposing exposure conditions, those two bits can make a significant difference.

You can see how much difference capturing in a 10-bit codec can make in Figure 2 (below), which I deliberately overexposed and captured in both H.264 and ProRes. Then I adjusted highlights, whites, and blacks in Premiere Pro to see how much detail I could pull back into the picture. As you can see on the left, when you blow out the whites with H.264, the detail is gone. While ProRes on the right won't win any Academy Awards for cinematography, there’s a lot of more retained information to work with.

Figure 2. ProRes retains more information than H.264 when a portion of the video is blown out. Click the image to see it at full size.

I tested in low light with my AVCHD camcorder, and didn't see the same ability to pull detail back into the shot, most likely because the image was riddled with noise, even though gain was disabled. Again, faint compression-related macroblocks were visible in the AVCHD footage, but not the ProRes video, which swings the needle in ProRes’ favor, particularly if you’re shooting with a large-sensor device that produces cleaner video in low light.
One Note of Caution

In my research on the Video Assist, I came upon a design review by Allen Tepper of ProVideo Coalition that complained about the lack of pulldown removal (reverse telecine) from an HDMI source. Specifically, Tepper stated, “most consumer and even professional HDMI cameras do not output pure progressive over HDMI. Most HDMI cameras unfortunately output 29.97p-over–59.94i and 25p-over–50i (aka 29.97PsF and 25PsF) with a 2:2 pulldown, and unfortunately output 23.976p-over–59.94i telecine with a 2:3 (aka 3:2) pulldown. There are few exceptions to that.”

I checked Video Assist’s ProRes files in MediaInfo, which did show them as interlaced, despite the camera being set to 30p progressive. However, I didn't see any of the typical interlaced slicing artifacts, so I’m not sure if and when this would cause a problem. I asked my Blackmagic Design technical contact about Tepper’s comments and he responded, “As for the lack of pulldown removal, I’m not sure if any modern-day recorders do pull-down removal on the fly. I can’t think of any modern camera that would require it. If that process is needed, [the bundled] DaVinci Resolve can certainly handle it and the Teranex 2D, 3D and Teranex express can do 3:2 pulldown of video from legacy devices.”

While I didn't see any issues in my captured footage that would dissuade me from buying and using the Video Assist product, if you're finicky about these types of issues, you should read Tepper’s article and draw your own conclusions. From my perspective, as a relatively inexpensive monitor, the Video Assist is a great replacement for the LCD panel on your camcorder or DSLR. While I wouldn't record all my events in ProRes, I can think of several more challenging DSLR-based projects in the past where the ability to capture in ProRes would almost certainly have made a noticeable difference.