yeah well, you get 4:4:4 during the edit, and that can be useful. The catch is that all 'consumer' codecs are also 4:2:0, so you will be throwing the extra chroma data away again when you render to your 1080p delivery format. The only time it is really preserved for a viewer is if they're watching a 4k video which is downscaled live to 1080p.

@apefos

We have topic in flame about all this, use it, please.

Otherwise some of the claims are not very accurate as idea to calculate different sensors crop factors by diagonal.

@apefos Aren't you forgetting to calculate the full-frame's diagonal from a 16x9 crop of the sensor?

I do agree with using the diagonal to calculate crop, though, as lenses are spherical and thus the diagonal is the most accurate measure of how close to the edge of the image circle the sensor is "seeing".

Edit: by my calculations (and I am by no means a math whiz, so correct me if I'm wrong), with a FF sensor's diagonal being 41.3mm (when cropped to 16:9 for video), the crop factors are the following:

-GH2 16x9 1080p: 1.91x

-GH3/4 16x9 1080p: 2.08x

-GH4 17x9 C4K: 2.375x

-GH4 16x9 UHD: 2.49x

@aldolega I believe both of us are correct. both of us are comparing the diagonal.

You used a 16:9 full frame video camera to compare to others, I used a 3:2 still camera to compare to others because i would like to perceive what you said: "the most accurate measure of how close to the edge of the image circle the sensor is "seeing"".

the advantage os using the diagonal is that it is the most accurate to compare different aspect ratios considering how far the image gets close to the image circle limits.

this way a 16:9 full frame camera will have a 1.047x crop factor when compared to a 3:2 full frame still camera.

also there are people who prefer to use the horizontal dimension to compare the crop factor or the field of view, so the crop factors are different in their calculations. I prefer to use the diagonal because it gives me more perceiving of how much vignetting or edge aberrations I will get, and a better understanding of the lens focal lenght in each camera considering the image circle.

@ revitdazio 5. I use that same card and tried it last night at 200Mbps and it was fine. I think it said around 42 min. remaining when I started. 6. I have the Think Tank Streetwalker Pro backpack, and really like it http://www.thinktankphoto.com/products/streetwalker-pro-backpack.aspx?code=CC-368. I do all my shooting with my camera mounted on a spotting scope, and both fit really well in that pack. There is also a larger one secifically designed to carry your camera gear and a laptop: http://www.thinktankphoto.com/products/streetwalker-harddrive-backpack.aspx?code=CC-368

Had my first day out with GH4 so now need to understand proper workflow/down-scaling with 4K when the final export will be 1080p. I’ve read this entire post but am still confused. I have a 4 year old iMac computer, plan to get a new top of the line by the end of year but meanwhile even editing HD is very sluggish so I feel my best option is to down-scale first and then drop into a 1080p timeline. Is there anything wrong with transcoding the 4K into ProRes 422HQ with 5DtoRGB and selecting the “Source” option. Is this a good way to down-scale/transcode the 4K to 1080p? And would there be a difference in quality with this method compared to dropping the 4K directly into the NLE onto a 1080p timeline (assuming my computer could handle it)? Are both these methods down-scaling and which would do the better job - 5DtoRGB or the NLE (FCPX in my case)? And am I correct in assuming that dropping the 4K into my NLE onto a 1080p timeline would tax the computer much more than the ProResHQ? Also would there be a visible improvement in ProRes4444 over 422HQ? Two frame grabs are included below - one from the original 4K clip and the other from the transcoded ProResHQ clip - may not be the exact frame but the ship was not moving so should be good comparison with lots of detail.

By the way, Firecoresoft Video Converter yields much smaller files than 5DtoRGB when converting 4K to ProResHQ and the difference in clarity can easily be seen! With 4K transcodes using 5DtoRGB, I can barely see a difference if any between the 4K clips and the ProResHQ transcodes and by selecting “Source”, the frame rate is not converted which is useful for slow motion when shooting at higher frame rates. Any help and/or comments are appreciated. Look forward to posting 4K-1080p sample video once edited and graded.

@aldolega

So if the crop factor is GH4 16x9 UHD: 2.49x does this mean that my 50mm F/1.4 turns into a 125mm F/3.5 lens??? Thats a big bummer ;-(. So what will the crop factor be with the Metabones adapter then? Lets say I use my 35mm 1.4 with a Metabones adapter as an example.

I don't care that a consumer delivery is 4:2:0... What's important before that fact is the color we have to work with during the edit.

If the consumer codec was all that mattered, we wouldn't care about 200mb data rates either.

A DR comparison between GH4 (on the left ) and BMC 4K on (the right).

I'm glad to see that GH4 has not only better DR than BMC 4K but also better colors.

The BMC colors look like crap, but this is my personal opinion. Yes, I also saw the black spot issue on clipped whites.

@Eno The BMC was consistently darker. The GH4's green tones were quite different with a lighter green tone. Detail on both looked close. Would be interesting to see a color grade with the intention to match as close as possible the two cameras. I recently received comments on Vimeo from my GH2 Moon T7 vs BMPCC comparison that Blackmagic camera's image is superior to any DSLR including all the GH series. I suppose each of us have our own personal views and tastes and that is what makes it all so interesting! Personally I like using the GH cameras which are so much easier than Blackmagic. I own a BMPCC, hacked GH2, Gh3 and now GH4 while looking forward to the Sony A7s for low light and still photos. I will surely be using the GH4 more than the BMPCC but yet want to also challenge myself in learning how to better grade the Blackmagic footage as it does require more color grading skill.