Thanks Andrew for the nice summary. This is my first post, and I'm a complete newbie to Video on DSLR. I have few questions that I hope members can answer or point me in the right direction.
[list type=decimal]
[*]It's clear from the definition that I-frame compression (also referred to as intra-frame or ALL-I) is superior to B-frame compression (inter-frame or IPB). But my question is how much better? Is it the same as RAW vs. JPEG?
[*]In your review, you mentioned "[i]D800 is doing a very bad job of downscaling to 1080p, since there’s moire on the sample videos[/i]" but you also contradict yourself by stating that non [Canon/Nikon] have uploaded full 1080p files, so it's difficult to judge - could the artifacts be from further compression for the "Web"?
[*]You mentioned the 5D has an amazing 91Mbit All-I, while I couldn't verify that, the specs mention "Variable (averaged) bit rate", so is 91Mbit the highest? [EDIT: Ok, I get it. [url=http://usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_5d_mark_iii#Specifications]635MB/s[/url] = 91.33Mbps.]
[*]D800 specs mention: [i]"Video compression: uses B-frame 1080p Full HD video at 30p in H.264/MPEG-4 AVC format with [b]unmatched moving image integrity[/b]"[/i] - I take it that's marketing fluff?
[*]The fine print in the [url=http://chsvimg.nikon.com/lineup/dslr/d800/pdf/d800_28p.pdf]D800 Brochure[/url] (page 17) says: "[i]*When video is output through HDMI interface simultaneously with recording to a CF/SD card, output image through HDMI interface will be smaller than 1,280 x 720.[/i]" - does that mean you cannot record AND output Full/Standard HD simultaneously? Do they also expect that those with an HDMI recorder will remove the CF/SD memory card from the camera before recording? I don't see how else you can start to shoot video without recording.
[*]Some websites claim that D800's uncompressed HDMI output is 8 bit, 4:2:2 - though no Nikon evidence to support that claim (yet?)
[*]How important is SMPTE timecode support (which the D800 does not support). Especially in light of software solutions (such as [url=http://www.singularsoftware.com/dualeyes.html]DualEyes[/url]) that solves(?) the sync video/audio sync problem?
[*]The 5D Mark III allows you to trim in 1s increments at the start/end of videos - wouldn't most people do that in post?
[*]You failed to mention that the 5D Mark III features a touch-sensitive rear dial - this could be a huge advantage while recording video to minimize unwanted camera movement.
[*]The 5D Mark III has a buffer capacity that allows 16,000 JPEGs to be recorded in burst. The D800 is limited to about ~100. While no one needs more than a 100, I'm sure some creatives will find a way to utilize the higher capacity.
[*]The 5D Mark III has an HDR mode which auto-aligns shots! So HDR can be shot hand-held! The camera also saves the original files (obviously) in addition to the HDR output.
[*]The D800 has a Time-lapse feature which creates a movie at the end of the sequence, but it DISCARDS the original files afterwards. However, if you shoot at Full Resolution with the built-in intervalometer, you could potentially create Time-lapse movies that are near 8K / UHDTV. (I'm not sure why Canon does not even include a simple built-in intervalometer in camera.)
[/list]
Thanks!
-hq