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.
Crop factors must be calculated using the diagonal of the sensor.
The full frame film camera sensor is 36x24mm and has a diagonal of 43,26mm It uses all the image circle from the full frame lenses.
The GH2 multi aspect sensor for 16:9 video is 18.8x10.6mm and has a diagonal of 21.6mm wich is half diagonal of full frame film cameras So the GH2 crop factor for video is 2x and not 1.86x (43.26 / 21.6)
Considering the GH3 and GH4 uses all the horizontal pixels of the sensor to capture 1080p video:
The GH3 and GH4 sensor for 16:9 video is 17.3x9.7mm and has a diagonal of 19.85mm So the GH3 and GH4 in 1080p has a crop factor of 2.18x (43.26 / 19.85)
Considering the GH4 sensor is 4608 pixels in horizontal and C4k is 4096 pixels in horizontal and UHD is 3840 pixels in horizontal:
The GH4 in C4k mode uses an area of 15.38x8.11mm of the sensor and has a diagonal of 17.39mm So the GH4 in C4k mode has a crop factor of 2.49x (43.26 / 17.39) The GH4 in UHD mode uses an area of 14.42x8.11mm of the sensor and has a diagonal of 16.54mm So the GH4 in UHD mode has a crop factor of 2.616x (43.26 / 16.54)
This is all without focal reducer.
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.
Hi everyone, here's a video I shot in Yosemite. Please Enjoy!
@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
Hi, Our production company just received the GH4 from the local dealer (Foto Hans Keuzekamp, the Netherlands). Here are some sample videos we made.
@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.
Hello, Excuse-me to be a little rough, but why there is alway the same music with every sample of video? It's not possible to heard something real and in relation to what is showed? I will start a topic: stop the copyright free music, use your ears, you microphone, your recorder, your taste, your vision! (please apologize for my poor english due to anger…) Jacques Hoepffner
@ 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.
I use Final Cut Pro 7 and I use "Log and Transfer"for my sony a6000 avchd footage. I don't know if you use this or not. It will transfer all of the footage from your mounted sd card in your camera and transcode it into Final Cut in whatever codec/compression you have selected for your sequence.
@bleach551 - thanks for the tip about "Log and Transfer" - don't think that FCPX has this command but 5DtoRGB works great and I like having the ProResHQ transcoded files for editing while keeping the original camera files as backup.
Would still like to hear feedback from someone who like me has compared GH4 4K files with their 5DtoRGB ProResHQ transcodes for editing in a 1080p timeline. Seems like there is a very slight difference in the exposures between the clips and perhaps the skies varied ever so slightly but damn I could probably not tell them apart without looking at their identiyt! For me, until corrected with a better method, editing the 4K as transcoded ProResHQ via 5DtoRGB should seem ideal when working on a slow computer and when final output will be 1080p.
@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.
First test @4k
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