webrunner5

I think you are trying to defy mathematics and physics. It takes twice as much data to move up to the next bit. Easy peezy. Sort of rocket science, but not. And you are not going to achieve 14 stops using 32 steps , he calls it code value, in your 6 bit example.

And that task is not easy to achieve. There is a reason a Arri Alexa XT cost 60k and a G85 cost 800 bucks. Show me an example of a camera that has 14bit that can only do 6 stops of DR unless you are shooting in a coal mine. I can make any example you want under less that ideal conditions, and that is why normal scientific DR, bit rate is tested at, ideal conditions, not some extreme example.

Alister is not making a test of every possible thing that could happen, he is addressing a simple Physics fact. Map all you want, that is not how standards are calculated or correlated.

This would not be my top leaned skill, but I would not like to be shown to be wrong, or the nuns in school would blush in embarrassment..

Well it looks like I have been very wrong about AF if these videos are to be believed. I am amazed they have been able to boost it that much.

Some real voodoo science going on here! I may Have to get one. 

I pulled this off of http://www.xdcam-user.com/  Alister makes a valid point here on the limit of DR with the output in lesser bit compared to the high end stuff. No wonder they look so much better.

I know this is talking about Sony cameras, FS5, FS7 but it applies to all cameras. Higher data bits count!

"cameras, cinematography, Technology

Not all raw is created equal. Log may be better

February 11, 2017 Leave a comment

This keeps cropping up time and time again.

Unfortunately every now and again a new term or buzzword comes along that gets taken as a holy grail term. Two that come to mind right now are log and raw. Neither log, nor raw, are magic bullet solutions that guarantee the best performance. Used incorrectly or inappropriately both can result in inferior results. In addition there are many flavours of log and raw each with very different performance ranges.

A particular point in case is the 12 bit raw available from several of Sony’s mid range large sensor cameras, the FS700, FS7 and FS5.

Raw can be either log or linear. This particular flavour of raw is encoded using linear data.  If it is linear then each successively brighter stop of exposure should be recorded with twice as many code values or shades as the previous stop. This accurately replicates the change in the light in the scene you are shooting.  If you make the scene twice as bright, you need to record it with twice as much data. Every time you go up a stop in exposure you are doubling the light in the scene. 12 bit linear raw is actually very rare, especially from a camera with a high dynamic range. To my knowledge, Sony are the only company that offer 14 stops of dynamic range using 12 bit linear data.

There’s actually a very good reason for this: Strictly speaking, it’s impossible! Here’s why: For each stop we go up in exposure we need twice as many code values. With 12 bit data there are a maximum of 4096 code values, this is not enough to record 14 stops.

If stop 1 uses 1 code value, stop 2 will use 2, stop 3 will use 4, stop 4 will use 8 and so on.

STOP:  CODE VALUES:  TOTAL CODE VALUES REQUIRED.

+1          1                                   1
+2          2                                   3
+3          4                                   8
+4          8                                   16
+5          16                                32
+6          32                                64
+7          64                                128
+8          128                             256 Middle Grey
+9          256                             512
+10       512                             1,024
+11       1,024                          2,048
+12       2,048                         4,096
+13       4,096                         8,192
+14       8,192                         16,384

As you can see from the above if we only have 12 bit data and as a result 4096 code values to play with, we can only record an absolute maximum of 12 stops of dynamic range using linear data. To get even 12 stops we must record the first couple of stops with an extremely small amount of tonal information. This is why most 14 stop raw cameras use 16 bit data for linear or use log encoded raw data for 12 bit, where each stop above middle grey (around stop +8) is recorded with the same amount of data.

So how are Sony doing it on the FS5, FS7 etc? I suspect (I’m pretty damn certain in fact) that Sony use something called floating point math. In essence what they do is take the linear data coming off the sensor and round the values recorded to the nearest 4 or 8. So, stop +14 is now only recorded with 2,048 values, stop +13 with 512 values etc. This is fine for the brighter stops where there are hundreds or even thousands of values, it has no significant impact on the brighter parts of the final image. But in the darker parts of the image it does have an impact as for example stop +5 which starts off with 16 values ends up only being recorded with 4 values and each stop below this only has 1 or two discreet levels. This results in blocky and often noisy looking shadow areas – a common complaint with 12 bit linear raw. I don’t know for a fact that this is what they are doing. But if you look at what they need to do, the options available and you look at the end results for 12 bit raw, this certainly appears to be the case.

Meanwhile a camera like the FS7 which can record 10 bit log will retain the full data range in the shadows because if you use log encoding, the brighter stops are each recorded with the same amount of data. With S-Log2 and 10 bit XAVC-I the FS7 uses approx 650 code values to record the 6 brightest stops in it’s capture range reserving approx 250 code values for the 8 darkest stops. Compare this to the linear example above and in fact what you will see is that 10 bit S-Log2 has as much data as you would expect to find in a straight 16 bit linear recording below middle grey (S-Log 3 actually reserves slightly more data for the shadows). BUT that’s for 16 bit. Sony’s 12 bit raw is squeezing 14 stops into what should be an impossibly small number of code values, so in practice what I have found  is that 10 bit S-log has noticeably more data in the shadows than 12 bit raw.

In the highlights 12 bit linear raw will have more data than 10 bit S-log2 and S-Log3 and this is borne out in practice where a brightly exposed raw image will give amazing results with beautiful highlights and mid range. But if your 12 bit raw is dark or underexposed it is not going to perform as well as you might expect. For dark and low key scenes 10 bit S-Log is most likely going to give a noticeably better image. (Note: 8 bit S-log2/3 as you would have from an FS5 in UHD only has a quarter of the data that 10 bit has. The FS5 records the first 8 stops in  8 bit S-log 2 with approx 64 code values, S-Log3 is only marginally better at approx 80 code values. 12 bit linear outperforms 8 bit log across the entire range).

Sony’s F5 and F55 cameras record to the R5 and R7 recorders using 16 bit linear data. 16 bit data is enough for 14 stops. But I believe that Sony still use floating point math for 16 bit recording. This time instead of using the floating point math to make room for an otherwise impossible dynamic range they use it to take a little bit of data from the brightest stop to give extra code values in the shadows. When you have 16,384 code values to play with you can afford to do that. This then adds a lot of extra tonal values and shades to the shadows compared to 10 bit log and as a result 16 bit linear raw will outperform 10 bit log across the entire exposure range by a fairly large margin.

So there you have it.  I know it’s hugely confusing sometimes. Not all types of raw are created equal. It’s really important to understand this stuff if you’re buying a camera. Just because it has raw it doesn’t necessarily mean an automatic improvement in image quality in every shooting situation. Log can be just as good or possibly even better in some situations, raw better in others. There are reasons why cameras like the F5/R5 cost more than a FS5/Shogun/Odyssey."

Just now, fuzzynormal said:

Well, we don't know how violently the lens was panning when those shots were taken.  Looks well within normal motion blur probability to my eye.

Why are we looking at stills anyway?  The c100 is a video camera.  The OP should upload the actual clip.

Very good advice LoL.

Could be a shutter speed problem, but that would be a damn extreme example of it from your information on the specs.

More GH5 video tests from Personal View.

http://www.personal-view.com/talks/discussion/13179/gh5-panasonic-camera-from-anticipation-to-love-or-hate/p45

Looks like some kind of 6k video is coming in the summer. Test of the GH5 in link, not a full one but some info. Seems they liked the AF.

http://www.redsharknews.com/production/item/4366-panasonic-gh5-review-the-first-full-hands-on-report

Can you tell us anything about the camera setting?

Wow the first video is Scary good! Way out of my price range, or skill set for that matter.

Yeah Black Magic stuff can be habit forming! Best bang for the buck. But I do wish they would come out with Version 2 on all of them and solve the quirks on them. I mean no camera is flawless, but BM is new to the game, came up with some crazy cheap stuff, with no way to really fix the warts on them. Time to get quality in the bodies also, and in some cases better form factor. BMCC comes to mind.

A lot of monitors, including the one I have, only have 2 options at what resolution it can scale. It is either full resolution or half. And half doesn't cut it.  But yeah you can modify text size but you loose full screen sometimes. You could end up not getting what you paid the big bucks for. If your younger it works out OK.

Wow 200GBP is not going to buy a quality mechanical Glidecam that I know of, not even a used original one which still are the best ones. hijodeibn is right, unless you strip it all the way down and use the 40mm pancake lens they are pretty heavy. And no electronic Gimbal is going to work for less than 600 US dollars even used.

You are right there is 50 knockoffs and 20 original concepts on Amazon. Hell if I know which one to suggest. Stabilazition is a damn expensive thing to buy. I mean you are looking at a Ronin for the top end stuff. I have 2 Came TV Gimbals and neither one would hold a C100.

Well you should have a certain style to add to the overall look, and hopefully know the cameras being used. Not going to be as good as the operators, but knowledgeable about their strength and weakness. Be a leader, or things go down hill quick. Hopefully you get paid because you have a needed skill, you are good at it, and you are quick to see what the writer, producer has in mind. And be better than the last guy he had or he would still have him or her LoL.

You are the person that makes it happen, the scrape goat if not. Ain't for the weak at heart. Best have some damn thick skin. Operators will throw you under the bus if they smell blood!! And every grip you have will bother the shit out of you.   Other than that it is a very rewarding job.

Basiclly you have to be honest about your skills with the head person, and just make shit happen. Nobody knows it all. Could be a ton of FX on it, not many people great at shooting that. Green Screen you have to have a hell of a imagination to do that well. And give women actors a Lot of Pee breaks. They will love you for it.

7 hours ago, Herbert Massey said:

 

I like the look of this video.  Damn good job.

7 hours ago, dbp said:

 

Neither the Gh5, or the GH4 did much for me on this video at all. Looks like a Sony VG-20!  And I had a VG-20, and a VG-30, loved the concept, Hated the output! Yikes.

Well one thing sometimes you MIGHT want to shoot with a large DoF. Ergo get shit All in focus. Means maybe f11 at night, horror film in a dungeon, one flickering far away candle, you know the creepy guy with a sinister shadow on the wall thingy, creeping toward a screaming ass hot young Blonde.

I don't think having a camera that sucks in low light fits that need. Plus I am too old to carry lights. And No room for my beer.

Trouble with 4k monitors is the text is small as hell. I am old LoL, so I went with a 30" 2k IPS screen and am happy I did.

Because if it is sort of good there it will be great at say even 6400. You do realize people shoot video in sporting events, horror films at night, bedroom scenes, run and gun, broke people that can't afford lighting, plane wrecks in farm fields at night, etc, etc.

I had my house broken into when I was in Florida last month. No surveillance camera, but if I did I bet I had one that was good at 100,000 ISO!! And I was glad as hell I had most of my video stuff with me in Florida.

I don't see m4/3 Ever being worth a crap in low light. When you use the comparameter? it is still rather dishearting how little Any camera has gained with great Low Light ability in the last say 6 years. 1 stop if we are lucky in that amount of time. Sony A7s is the only one that is sort of great in low light. And real life that is 25,600 at the top without biting your lip. Sure more if you HAVE too, but you sure as hell don't Want to. Most cameras are still 6,400 tops, 12,800 is Oh Shit stuff. Ain't happening on a m4/3 camera video wise.

I don't think it has to do as much with DR as we all think. Kodak states "Vision3, the last film stock they produced, has a maximum dynamic range of 13 stops." The Zacuto test pegged this figure at 14.5 stops. I’d rather believe Kodak, they’ve been doing this for a hundred years.

So basically a BMPCC has the same DR with Raw. Heck Arri and Red cameras are well above 14 stops and they don't look like film to me. I would say a Arri XL is the closest, they ought to be for 60 grand for a basic package!

It to me is the gradients, no banding, no jagged edges, butter smoothness, pure blacks, pure whites, etc that make it happen. Sure it has to be exposed right, but that craft has been honed to perfection for years.

Am I going to start shooting film, hell no, but i am going to "waste my time" doing Raw on a Black Magic Camera or a Canon camera. Why not, I want that smile back again!

Now if I am trying to make a living doing it, I am going with a C300 mkII or a Red, Sony FS7. Fast turn a rounds and great output. Well not film great, but sure as hell great enough to put bread on the table.

1 minute ago, Christina Ava said:

thanks but the GH4 is not a full frame camera, so you wouldn't see the vignette with a 100mm..

Yeah but the SB makes is into a s35 sensor. That is not far off from a FF aspect ratio. Maybe not wide open.

Well this is a video using a Canon 50 1.4 on a GH4 with a MB XL speed booster. Looks fine using that. But that ends up really s35mm not FF though. I don't see why it would not work.

5 hours ago, jonpais said:

I was watching Birdman the other night and couldn't stop thinking to myself, 'if only it had been shot on film!' If only Andy Warhol, Robert Motherwell and David Hockney hadn't used acrylics...

I am really starting to worry about you lately LoL. It's those damn Fuji cameras isn't it??

10 hours ago, fuzzynormal said:

Agree to disagree. Raw ain't the "filmlook" panacea many people like to think it is. 

Its great, and I shoot it from time to time too, but it's not a priority for me.

And 12 stops of DR is better than what I was used to growing up on 70's cinema screened at the drive-in. It's not like those films were awesome image-wise. 

Salvaging some highlights is nice and all, but blown out sky on a bad print never stopped me from enjoying a Sergio Leone or Sydney Lumet film. 

In fact, a good exercise last year was watching "Hateful 8". The novelty was fun. Even under the best controlled conditions of what they were doing, I was thinking, "yep, this is a film projection and it's crusty."

after a few minutes of the narrative, it really didn't matter. 

Also watched the last Mission Impossible, shot on film, (digital projection) and thought, "Wow, that's grainy and rough."

For me, a lot of the "film look" is the analog flaws of it all. The blessing and curse. Of course, that's just me though. Your mileage may vary. 

 Going to a Drive-In movie theater and think your going to see a movie as art well.... Like I said above, watching those old Gun Smoke re runs in B&W was just, well it was mesmerizing. I could not get enough of it. And hell it was on a 720p 32" LCD TV. It was buttery smooth, NO crushed blacks, but black as hell, just almost art. A Stupid weekly TV show! Man the people that produced, shot that show had to feel good about what they were doing. They were artists. And they made hundreds of them, thousands maybe.

There is not a digital camera in the world that can look like that. I took some of my video gear with me down to Florida, and what I shot sucked compared to that damn Gun Smoke. My brother in law ruined it for me LoL. I am going to buy another BMPCC or a BMCC and give it a whirl again. Only camera I have had that made me smile with the output. A pain in the ass camera a bit, but hell it's worth it. I don't make a living doing video. Who cares. But I wish they were a camcorder body shape. I sure do miss my old ENG cameras for something you just turn it on, sling it on your shoulder, and hell you are good to go, every control at hand. Damn good stuff.

Yeah pissing away data on some goofy crop is hard to justify unless you are making a unlimited budget film.

1 hour ago, jonpais said:

I don't see any reason to come down so harshly on DPR like a pack of bloodthirsty packhounds. We've already seen much worse, at least I have - and more is yet to come. Correct me if I'm wrong, but I thought DPR was a gear review site, not a production studio, so it's not fair to compare their work to that of Griffin Hammond. 'Wobbly!', 'Fail!', 'Shaky!', 'Atrocious color!' Actually, I can count the number of camera reviewers who actually know how to shoot on one hand.

DPR is pretty much tops on camera reviews, but I am surprised they have not hired a full time know everything video guy. I know they are grooming Barney for the role, and I like him, but he is admittedly new at it. With video now a very important part of camera reviews I am confused why they don't up the ante with more talent. Probably something to do with Richard Butler. Seems too old school for my liking anymore. But I guess you have to have a stern Headmistress!