Alexa sxt why they can and we can’t?

SJX

SJX

Veteran


I think everybody heard of alexa sxt with fake 4k like amira?
Alexa is 6 megapixel sensor. F35 is 12 megapixel sensor. Arri can up resolution in camera and all applaud. If we up resolution in post people say we liars. But F35 probably look better because sensor is better and double resolution. But why do in camera arri? To fool producers? In post is better probably. But you are called liar. In camera is ok. If arri do it is ok. Make me sick.
 
I think they made it pretty clear that they are uprezzing, and they do it in camera because that's what theri consumers asked for to simple the workflow. And the internet is pretty loud from people who do write more than they read.
 
Upressing the 'pure' signal before any compression is surely the best way to do it.

So arri have it right and the F35 is not open to its full theoretical capability?

S
 
I feel one could get VERY good results from the 12-bit DPX output of the F35 uprezzed to 4K. I know some (viddo I believe) even thought of some sort of algorithm that could theoretically remap all the pixels back to their respective photosites in the sensor, which you could then re-transcode the video whatever you wanted. It was a bit beyond me but seemed very cool. I would love if CD made a feature on the O7Q that took that 12-bit raw dpx and up-rezzed to 4k prores or something, but they'll never do it. That would just be for the clients that want the illusion of 4k heh.

I just shot some stuff that will be intercut with Alexa Arriraw and I think it came out quite nicely - I was using sharper more modern glass and I'm sure what I shot will look sharper than the Alexa stuff

but again at the end of the day its all whatever.
 
Yeah maybe someone can reverse engineer the 4:4:4 RGB into quasi-raw based on how the rgb photosites are actually arranged. Until then you'll never get more than 2k luma resolution from the camera. There's a pretty big difference between uprezzing 2k to 4k and 3.2k to 4k... 2mp vs 6mp!
 
morgan_moore said:
Upressing the 'pure' signal before any compression is surely the best way to do it.

So arri have it right and the F35 is not open to its full theoretical capability?
S
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ARRI, obviously, won't give out their secret sauce, aka the upscale algorithm.

I'd also assume that the camera itself - given its price tag - packs a lot of processing power, far beyond to what can be found in a 4K TV purchased by a consumer at Best Buy. What this does remind me of is the digital audio processing that took the old jazz and rock recording and then tried to create a stereo out of mono, with a superior signal-to-noise ratio to boot. In the hands of a top pro, the remastered recordings sounded far superior to their own originals ... but getting them to the current standards is still a forlorn hope. The gap is just too big.

The difference between 2.8K and 4K, however, may be somewhat bridgeable.
 
SJX I agree that the price difference between the two cameras, and the arriraw feature being one of the main reasons, is incredible. I have turned a few Alexa users to the F35, which at first F35 is usually spoken of as "outdated". The biggest factor ruling the F35 from shooting a lot of future projects is the 1080P limitation, even though we all seem to agree, at 12-bit uncompressed HD from the 6k sensor, it's pretty damn good and ready to upscale to 4k.

What the Alexa is doing that the F35 can't, and the reason 4k upscaling is shunned over the method of the Alexa, is that it is able to take the sensor data and record it before it enters a 1080p pipeline. The F35 will always be limited by it's 1080P pipe, taking 6k, down to HD and back up to 4k is not 4k. The Alexa has true 2.7k and this for whatever reason, to the people who pay the money, this fact keeps the Alexa at the top of the cinema camera food chain even to this day.

I am 100% that there are F35 bodies with fully working 2k firmwares sitting on some forgotten shelf in the sony factory. The F35 is completely capable of 2k, 2.7k, maybe even a raw 6k output, that would miraculously put it back in the game as a dragon killer. But the truth is, that Sony decided to let this camera go in trade for the F65, F55 and F5, without Sony releasing the secret code of this camera, we are limited to what is was, and no one has the time or money to open it up and figure out the secret switch, no disrespect to the very smart people we have had working on this camera over the past 2 years. Just don't hold your breath for a raw output from the F35, we are limited to what it is right now. Although I would also argue that a 6k raw output would be nearly pointless besides a selling point to producers. The reason the F35 has 6k is the down-sample to 1080p perfectly.

Even if there was an F35 6k RAW option, how much better of an image would you get over the 12-bit 444 HD one? The whole issue revolves around being able to sell this camera against modern cameras and it simply won't come back that way because once a camera is old, you are not going to convince gear-heads it is somehow better (or even comparable) than what is brand new.
 
Ugh....

The F35 can not, will not and will never be more than 1080P. The finest 1080P you'll ever see, but 1080P.

I think ALEXA's engineers didn't want to make the Alexa "4K"... they just got told to do it by the marketing people. Why they haven't made a proper 4K chip yet (ignoring Alexa 65) I don't know.

The ALEXA's "4K" though is derived from Open gate mode I believe, so it starts at about 3.4K/3.2K if memory serves.

They basically did it because people who like ALEXA were being told they couldn't use it because "it isn't 4K" by people who don't really understand these things. So ARRI fought ignorance with stupidity and have allowed DPs to carry on using their favourite camera, safe in the knowledge that it is the same as it ever was...
 
the size of the sensor and compresison and CCD and CMOS are all factors beyond the resolution it's delivered at, right?
 
fill factor, sensor noise, sensitivity, and amount of oversampling also play a role in how well a scaling algorithm performs. more 'data points' lead to better scaling.
 
JMtheDP said:
Ugh....

The F35 can not, will not and will never be more than 1080P. The finest 1080P you'll ever see, but 1080P.

I think ALEXA's engineers didn't want to make the Alexa "4K"... they just got told to do it by the marketing people. Why they haven't made a proper 4K chip yet (ignoring Alexa 65) I don't know.

The ALEXA's "4K" though is derived from Open gate mode I believe, so it starts at about 3.4K/3.2K if memory serves.

They basically did it because people who like ALEXA were being told they couldn't use it because "it isn't 4K" by people who don't really understand these things. So ARRI fought ignorance with stupidity and have allowed DPs to carry on using their favourite camera, safe in the knowledge that it is the same as it ever was...
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Fantastic answer.
 
JMtheDP said:
Ugh....

The F35 can not, will not and will never be more than 1080P. The finest 1080P you'll ever see, but 1080P.

I think ALEXA's engineers didn't want to make the Alexa "4K"... they just got told to do it by the marketing people. Why they haven't made a proper 4K chip yet (ignoring Alexa 65) I don't know.

The ALEXA's "4K" though is derived from Open gate mode I believe, so it starts at about 3.4K/3.2K if memory serves.

They basically did it because people who like ALEXA were being told they couldn't use it because "it isn't 4K" by people who don't really understand these things. So ARRI fought ignorance with stupidity and have allowed DPs to carry on using their favourite camera, safe in the knowledge that it is the same as it ever was...
Click to expand...


The reality is a bit different though and not that easy. Unless one believes in numbers on a paper. If you go by the numbers for example the Sony F65, which is the F35 replacement should crush the F35 in every single way. In real life this is not the case at all.

It's important to be able to separate marketing perception from reality too. The current market would have you believe the F35 is totally obsolete and surpassed, while the reality is there is not a single camera, at any price range, which totally surpasses a F35 yet. There just isn't. Note that I said totally.

I stopped paying serious attention to numbers long ago. I now look at the image. It either looks good or it doesn't.

As to the topic at hand, I just wrote a full blog article on it. But it ended up too long for a forum post. Things are not as straight forward when comparing the upscalling from the Alexa to a possible upscalling from the F35. There are many factors to be considered and it's not as easy as "the F35 is only a HD camera and the Alexa is more." Specially given that this remark about the F35 is only half true. Depending if you consider a F55 a 4K camera or a F65 a RBG camera. It's just more complicated and because of the complexity it often gets shortened , simplified or just ignored.

Again it either looks good or it doesn't and I have seen F35 material upscalled to 4K side by side with current 4K cameras and it holds it own just fine.
 
Aaveum said:
The reality is a bit different though and not that easy. Unless one believes in numbers on a paper. If you go by the numbers for example the Sony F65, which is the F35 replacement should crush the F35 in every single way. In real life this is not the case at all.

It's important to be able to separate marketing perception from reality too. The current market would have you believe the F35 is totally obsolete and surpassed, while the reality is there is not a single camera, at any price range, which totally surpasses a F35 yet. There just isn't. Note that I said totally.

I stopped paying serious attention to numbers long ago. I now look at the image. It either looks good or it doesn't.

As to the topic at hand, I just wrote a full blog article on it. But it ended up too long for a forum post. Things are not as straight forward when comparing the upscalling from the Alexa to a possible upscalling from the F35. There are many factors to be considered and it's not as easy as "the F35 is only a HD camera and the Alexa is more." Specially given that this remark about the F35 is only half true. Depending if you consider a F55 a 4K camera or a F65 a RBG camera. It's just more complicated and because of the complexity it often gets shortened , simplified or just ignored.

Again it either looks good or it doesn't and I have seen F35 material upscalled to 4K side by side with current 4K cameras and it holds it own just fine.
Click to expand...

I agree - I trust the image, not some data sheets. I just did a resolution test - sony f35 vs red one - it holds its own
 
Aaveum said:
The reality is a bit different though and not that easy. Unless one believes in numbers on a paper. If you go by the numbers for example the Sony F65, which is the F35 replacement should crush the F35 in every single way. In real life this is not the case at all.

It's important to be able to separate marketing perception from reality too. The current market would have you believe the F35 is totally obsolete and surpassed, while the reality is there is not a single camera, at any price range, which totally surpasses a F35 yet. There just isn't. Note that I said totally.

I stopped paying serious attention to numbers long ago. I now look at the image. It either looks good or it doesn't.

As to the topic at hand, I just wrote a full blog article on it. But it ended up too long for a forum post. Things are not as straight forward when comparing the upscalling from the Alexa to a possible upscalling from the F35. There are many factors to be considered and it's not as easy as "the F35 is only a HD camera and the Alexa is more." Specially given that this remark about the F35 is only half true. Depending if you consider a F55 a 4K camera or a F65 a RBG camera. It's just more complicated and because of the complexity it often gets shortened , simplified or just ignored.

Again it either looks good or it doesn't and I have seen F35 material upscalled to 4K side by side with current 4K cameras and it holds it own just fine.
Click to expand...

Qft!
 
Yes, the F35 has 12.4 megapixels in photosites, six per each RGB pixel at 1080. Six - not three. Half of those photosites are used in dynamic range processing and image sharpness, edge detection, etc... but they never get to a place in the camera where you can record them. Even in RGB 4:4:4 12 bit, you're only recording 6.2MP of RGB data.

At the end of the day, the F35 was designed for 1080p. It may upscale very well, and using custom algorithms could certainly help, but as has been said, it's a fight against ignorance.

I can't help thinking that soon we'll be drowning in high pixel perfection. 8k. 16k. why not 32k? Just wait, in twenty years, the hip youngsters will want a retro lo-fi "Vaseline over the lens" 1080p look.
 
Ed, can you tell me how you did that Red vs F35 resolution test? What are we looking at in that? A 1080p file from both cameras zoomed in, or Red's 4K file and the F35's 1080 file separate?

I'm at the NAB show and find it kind of funny how Red is resorting to "8K!" to sell their cameras now when I am not able to see clear differences. Not to mention the FF sensor, which seems to confuse a LOT of people about what that means (and does not mean!!)
 
I am certainly never going to put the F35 down, however the issue we all face is the camera can be as good or bad as you want, it is the perception of people hiring you or it that decide whether something is or isn't rentable.

I shoot around half of my F65 work with the camera in 1080P mode. In truth image quality was actually not a deciding factor at all in my upgrade decision.

i do not consider the F5,55,RED ONE,BM4K or many other cameras to be proper 4k cameras. Sadly marketing people run far too many things and you will see a million people talking about the merits of 4k vs 5k but hardly any discussing 12 vs 16 bit ad converters.

the good news is, without this situation, F35s would not be the price they are.
 
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