Please help us all understand Alexa's high points.

[Sebastian Gross]

Sebastian, can you direct me to samples of smearing highlight MX footage ?

Rivai

well unfortunately i have to say no (we we're not alllowed
take away the test footage we created during a seminar mentioned as follows.)
but i can tell you this:
during a german seminar called hands on hd (which is unmatched throughout europe, a strong suggestion.)
we tested the sensors with arri's new OECF (opto electronic conversion function), which is not on the market yet. it takes adaptive filters into consideration leading to the fact that ususal test charts are rather inaccurate when it comes to DR (one reason being that you cannot measure stray light as precise as you'd have to, if you want to know more read this). so they found a way to measure all t-stops in one frame (in a light sealed environment) and get the noise level measured in an instant, spitting out a very precise curve.
we testet both cameras ( with no prejudice ) and a F35 and then we put the material in the nucoda grading system.

alexa: between 12.9 and 14 T-stops
f35: 11.5 T-stops
red-mx, build 30.5: about 10.3, black shaded

during grading the RED-mx shifted (the color) red (?!) drastically towards pink even with adequate LUT's applied while F35 and alexa stayed very stable in terms of reproducing colors correctly.

for i am not a colorist but being sourrounded by a few professionals during te seminar the alexa seems to be a colorists wet dream.

 

[Sebastian Gross]

and what an epic can do is not carved into stone by just announcing it. :coolgleamA:

..that has nothing to do with how much we all want to see its birth.
(well after it got rubbed dry)

especially the DR will be put to countless tests.. :coolgleamA:

 

[RivaiC]

... to my understanding, film is chemical and has "infinite resolution", theoretically speaking, it is the scanning process putting the limits ...

a 4K scan is considered to be a high quality scan of the negative, which theoretically speaking, could be higher ...

It is measured 4K spatial resolution and you can scan it to any resolution you want even it's beyond 4K, but that doesnt mean you have more than 4K spatial resolution. If it's infinite, you dont need 65mm, And the current state of RED resolution, it even beats Alexa, set aside Epic.

And that doesnt change the fact that Alexa has far less resolution than film due its mastering at 1920 x 1080. How can someone said Alexa has resolution close to film ? The posting by Jim clearly shows the result. Logically speaking even without seeing a result, everyone should know 1920 x 1080 is not even close to film

Dynamic range is unknown for sure, but i have no doubt in RED.

 

[Marc Wielage]

Prores is a mess, when it comes to gamma and video levels. It is such a mess, that D-Vision had to hire a PhD, just to figure out how reliably do a simple roundtrip for FilmMaster (yes, it's coming, despite FilmMaster running on Windows). Same goes for FilmLight with Kompressor. I wonder how Resolve deals with this problem. So, Prores is not that easy to do...

That's not my experience. I did a ProRes 4:4:4 project in the spring, over at Post Group/Hollywood, and we had zero problems with the format. And that was just conventional daVinci 2K color-correction, all corrected in Rec709 color space from a DVS Clipster. Worked fine -- zero issues. I had a very mild LUT on the front end, and we were able to time the whole project in five days, which is very typical. The ProRes part was the easiest aspect of the entire project.

I would have preferred not to use uncompressed RAW files, but this was a client decision, and we worked with what they had. The end result (going to HDCam SR) was fine.

... to my understanding, film is chemical and has "infinite resolution", theoretically speaking, it is the scanning process putting the limits ... a 4K scan is considered to be a high quality scan of the negative, which theoretically speaking, could be higher ...

I was told several times by the color scientists at Kodak/Hollywood when I worked there in the early 2000s that they believed their current negatives (like 5217) could achieve 6K. But they admitted that the moment you go to IP -> IN -> release print, the effective resolution drops like a rock. I'm not convinced you can get honest 2K out of a chemically-timed 35mm print in a run-of-the-mill theater. And as I recall, the last movie to win the Best Cinematography Oscar used an HD camera (and not a very recent one). Archer, not arrows.

But so much of the talk about resolution is a numbers game. I'm much more concerned about exposure range, reliability, how well the camera handles heat, data storage, and other practical concerns. I'm not going to expect the Alexa to handle 14 real-world stops, but if it's better than the D21, I'll be impressed, given its size and price.

It may not be ideal in terms of pricing, but I'm glad that there are alternatives out there (on both ends of the price spectrum) and that several manufacturers -- including Red -- keep setting the bar higher. As far as I'm concerned, that's good for DPs, good for post, and good for filmmakers in general.

 

[Robert Niessner]

it is simpy amazing what "she" sees in the dark. we watched an alexa shot (on a proper 2K beamer in a proper viewing environment) of a basment that was just lit by an open door and even this door was covered by a wall.
then they drenched a rubber ball in burning liquid and let it bounce down the basement stairs and it literally lit up the basement so you could see the structure on the walls of what seemed to be an unlit room.
then there was a closeUp-shot of roses with a nice purple-white gradient and all i can say is that its brilliance made our eyes water.

Sebastian, I guess you were talking about those shots, right?

Click for full res.


Click for full res.


Click for full res.


(All images copyright by Arri, posted here for demonstration purposes only.)

 

[David Wyatt]

got me on this one. to set it straight:

alexa: 23.760mm x13.365 mm
red: 24.4mm x 13.7mm

s.

I think you were right the first time ;-)

The Red's 24.4mm x 13.7mm you mention is the entire sensor, whereas the actual 16:9 area recorded is 22.12mm x 12.44mm. I'm not too up on the Alexa but I assume the 23.76mm x 13.365mm figure is the actual 16:9 area recorded, in which case it is actually a slightly larger 16:9 recorded area than the Red One. The Epic on the other hand will supposedly record a 16:9 image measuring 25.92 x 14.58 mm which would indeed be bigger than the Alexa's.

 

[Erich Ocean]

Those Alexa grabs are just stunningly beautiful. EPIC can't come soon enough, I want that look in 5K @120fps!!!

 

[RivaiC]

Sebastian, I guess you were talking about those shots, right?

Click for full res.


Click for full res.


Click for full res.
(All images copyright by Arri, posted here for demonstration purposes only.)

WHat is the data specs ? ISO, Lens, Exposure ? Any touch up in post or it's RAW ?

 

[Charles Angus]

Here's a reason to choose Alexa over RED ONE MX:

Shorter rolling shutter.

Other than that - branding and (based on past experience with Arri) great build quality and reliability.

That's most of it.

 

[Lucas Wilson]

<moderator hat on>

Come on guys... this has been discussed over and over again. This is Reduser. This started out as an interesting thread with some good information and is devolving into cameraA vs. cameraB. Gonna cut it now. The discussions about ProRes and film resolution are pretty cool - and can happen easily in other threads if anyone cares to launch one!

There are plenty of places on the web to discuss other camera wonderfulness... it's like whistling at another girl in front of your wife. Expect to get smacked.

Lucas

<moderator hat off>