Nice cameras..... I want one of each.
I would, however. like to say a bit more on your final comment ("it's either compressed or not").... especially for those who may not be well versed in "the nuts and bolts of video".
When we talk about audio, I often phrase the options that way ("either it's compressed or it's not"). When you get a digital audio file, it starts out in some format, with some "original" sample rate, and you then have the choice of keeping it in "full original quality" or reducing the quality by compressing it. If we choose to preserve the full best quality, we will have several options, all of which we term "lossless", and all of which preserve the original content exactly - and so are actually equivalent. However, if we decide that we're willing to accept a slight loss in quality, we have a lot more options, and there is a lot more nuance between those options. Various lossy compression formats sound better or worse on different types of music, may introduce more or less of different
types of quality loss, and most of them offer you the option of trading off and deciding how much quality you're willing to sacrifice to achieve smaller files. (Spotify uses Ogg Vorbis compression, Apple uses AAC, and most other people use MP3. All of those are perceptual lossy CODECs, and arbitrarily "equivalent", but each is in fact slightly different.) However, as far as I'm concerned, since the storage requirements of even the highest resolution audio files you can purchase aren't exorbitant, I still feel reasonable in saying "either compress it or leave it alone - and I prefer to leave it alone".
There is, however, a fundamental difference with consumer video (and even most professional video). That difference is that the "full quality uncompressed" option
DOES NOT EXIST. There is no choice between "compressed and uncompressed" because you do not have access to uncompressed video. Regular Blu-Ray discs are compressed; streaming video is compressed (usually a lot more); and video files you rip or download are compressed (usually the most of all). Other than in the form of very short sample clips, uncompressed video files are not available to consumers. (As an example, a certain computer rendered movie is 45 minutes long, and takes up about 9 gB in "good quality MPG Blu-Ray format"; it is about 92 gB in full 4k h.264 format; and it's 425 gB in CinePro format (which is a professional high-quality format). That works out to needing more than three full 4k UHD discs to store that one 45 minute video. And CinePro is
STILL COMPRESSED... although it is compressed
LESS than a standard 4k UHD disc would be.
My point here is that, with video, you do
NOT have the choice between "compressed or not" - but you do still often have a choice between "which compression" and "how much compression".
And this can get tricky...
For example, a standard HD video (call it 2k if you like) is compressed using h.264 compression... which does a pretty good job of trading off between size and quality (yes, you get to pick how much of each to trade for).
In terms of pure data, a 4k video has four times as many pixels as an HD video... so, with "equivalent" compression, it would be four times the size.
However, 4k UHD discs use h.265 instead of h.264, and h.265 is generally agreed to be able to deliver "the same quality" in about half the file size (it delivers "better compression" than the older h.264).
Because of this, a 4k disc can be "only" twice the size of the equivalent HD disc (the 4k disc can store four times as much screen area as the HD disc, at the same quality, in only twice the storage space).
Furthermore, because of the way h.265 does its thing, most people I know agree that the flaws in video compressed using h.265 tend to be "less obvious and less annoying".
(That's a nice way of saying that, even though we can measure things like "detail" and "accuracy", the "equivalent" flaws in h.265 don't look as unpleasant as the similar flaws in h.264.
So, in other words, if you use h.265, you can make a video really small and it will still look pretty good... even more than you would expect from the numbers.)
The other thing is that, even with discs, but especially with streaming video, there is this thing called bandwidth.... which simply means "how many bytes of data per second can you use to send your video".
This limitation is usually a combination of the server at your streaming service, your Internet connection, and even how quickly your computer can process all those pixels.
I've taken this long way around to try to explain why there are actually a far wider variety of choices involved - and they may not always be of the form you think.
FOR EXAMPLE, let's say that
YOUR NetFlix connection has a bandwidth of 25 mBPS available to use... and we wish to use it to deliver the "best possible picture".
They could use it to send a minimally compressed HD (2k) video picture.
Or they could use it to send a much more heavily compressed 4k video.
The 4k video will have more pixels that could contain better detail, but it will also almost certainly also have more unpleasant artifacts.
But, we could use "the 4k connection" and send a 2k video through it.... so, we could use the better h.265 compression used by 4k video, but sacrifice resolution for a "cleaner picture" with less artifacts.
We could also then take advantage of the 4k color space - and use it with 2k video.
Many broadcast pros have suggested that "a 2k picture with low compression does in fact look better than a 4k picture with high compression".
Many have also suggested that "a 2k picture with a really wide color gamut - like HDR - looks better than a 4k picture with a more limited color gamut".
And, to make matters even more complex, some people just plain think sharpness is more important than color accuracy, while others think the exact opposite.
And, of course, a lot depends on how the movie itself was produced and processed... and whether the subject matter benefits more from better sharpness or better color.
(I saw Deadpool in both standard Blu-Ray and 4k - and the improvement with the 4k version was minimal at best - but Transformers, even in streamed 4k, was impressive.)
And, of course, that's also going to depend on your TV and your other equipment (on some TVs, upsampled HD is really hard to tell from native 4k if the original HD Blu-Ray is really high quality to begin with).
To put that into perspective.... as well as why it matters....
The companies who sell products
ALWAYS do their best to "promote their strengths".
So, for example, NetFlix is going to make a major point that they're offering 4k.
However, some people I've spoken to, with average Internet connections, find that an "HD" picture looks better than a "4k picture"
ON NETFLIX, IN THEIR HOUSE, ON THEIR SET.
(It just may be that, with the bandwidth that they have available, their choice is between "a
BAD 4k picture" and "a great HD picture" - in which case the HD picture may just be the better choice.)
My overall point is that while "compressed 4k
CAN look better than compressed 2k" - and often does - that isn't necessarily a given for everyone with our current technology.
(And there are an awful lot of variables involved - many of which we have little or no control over.)
And, no, you should
NOT assume that Apple TV has made the same choices there as NetFlix, or your local cable company, or your favorite streaming service.
200 large for an Ari? More for the Helium? Look at ROI first and the size of movie theater screens. Nothing but the BEST will do for those viewing conditions. A camera like that pays for itself within minutes of being taken out of the case.
Many if not all of the Alexa 65's used on Thor Ragnarok were rented for the duration of the shoot. My movie friends tell me that's because the camera technology changes too frequently to buy plus the directors and cinematographers have their favourite cameras so they tend to change with every movie as well. Hence renting is very common.
I mentioned it a couple of posts ago, I have a cable connection at 100 - 130 mbps. What I am comparing is not 4K on a disk from an Oppo 203 to 4K from an ATV4K, that would be just plain silly. But comparing compressed 1080P via the ATV4 to compressed 2160P via the ATV4K, the later is noticeably superior with or without HDR. Not that I have choice, not everything that I watch is available on disc.
To put it simply, "compressed" 4K looks better than "compressed" 2K and since they are the only 2 choices that's all that really matters.
Cheers
Gary