traviswears
Well-known member
Can't wait to see some footage!
Canon C300 MKII Announced
- Thread starter rob norton
- Start date
nyvz
Veteran
The real point about the Alexa is that dual-read works there because the individual A-D convertors are the weakest link in the DR chain - not the sensor itself. And that is perhaps more because the sensor is so good than the A-Ds are poor!It's largely because the Alexa isn't 4K that it wins in this way - it enables the individual photosites to be larger for a s35 chip size.
Most cameras on the market today are DR limited by their ADC, so it's speculation that somehow alexa is extra special in that regard. That's why adjustable analog ISO/gain exists in cameras, because simply amplifying the voltage off the sensor allows the ADC to read a different portion of the sensor's signal. It's interesting to see a camera like the c300ii announced with potentially dual gain and adjustable gain because it seems to imply they designed it to have specifically 15 stops of DR, since adjustable gain implies the sensor still has quite a bit more DR that is accessible by using different gain levels... The interesting thing is that it's possible they just added a gain pathway to the old c300 sensor to get extra DR.
Ya, I just should have found the post and linked it.I had to go back to see what I did put (
As to Alexa vs. C300 MK II, the number of pixels isn't that different - 5.7 MPX in open gate for Alexa vs. 8.8 MPX for C300. But this is where my knowledge of the electronics ends - arithmetic.
Hypothetically speaking, a $16,000 camera could add a processor intensive noise removal that is close to, in principle, to a Denoiser or Neat, but done at a higher level, with superior algorithms to boot.
ripupthehwy
Well-known member
+++1 I agree whole heartedly. Plus its aggravating when people take a professional camera outdoors and shoot against a bright sky and don't expose properly for it and go "yuck look at those blown out highlights. That camera's no good!" Use a freakin' reflector already and stop over-exposing. You know it is possible to overexpose with any camera, even a Red or Alexa. Everyone wants a sub $10k camera that looks like hollywood. It will (and is happening) closer and closer with each product release but we still live in an age where price separates the men from the boys, so to speak. Oh sorry, this was supposed to be about slow motion. yeah I don't get it that it's such a priority these days.
GaryinCalifornia
Veteran
slow mo can be used greatly in a narrative story...
Surf it Mike
Well-known member
Today it seems HFR is like the zoom in the 60's, the star filter of the 70's, big hair of the 80's & Justin Beiber in the 00's.
Its overuse is everywhere making for boring content now even more boring by being longer. Generally it's use is not creative . It also says something about what people are shooting & certainly it isn't actors. Yes it has it's place but it needs to be planned. So, when you need it , go hire a Phantom Flex 4k, at least then it will not be the new boring "120fps".
Its overuse is everywhere making for boring content now even more boring by being longer. Generally it's use is not creative . It also says something about what people are shooting & certainly it isn't actors. Yes it has it's place but it needs to be planned. So, when you need it , go hire a Phantom Flex 4k, at least then it will not be the new boring "120fps".
This is where generalisation becomes so difficult, and it wasn't my intention to make the Alexa extra special per se. But it remains that *compared to 4K s35 sensors* it does have larger photosites, and to a first approximation of the order of twice the size. Make the (probably over simplistic) assumption that a typical s35 4K sensor in itself will manage 15 stops, and the Alexa will manage 16 stops, and further assume a 14 bit A-D will mange 14 stops, then the most dual read will gain you is one stop for the s35 4K sensor but two stops for Alexa.
Further assume that dual read means more complexity, and likely higher cost and the thought may well be that it becomes valid to gain two stops, less so just to gain one.......?
I may be missing something fundamental, but whilst I can well see the point behind simultaneous dual-read, I can't for adjustable gain applied in a single read sense. It begs the question of why not simply set such to access the part of the sensor DR that gives highest ISO? You may be able to slip it down by a stop or so to access a slightly different range at an ISO of a stop or so less, but why bother doing so? It won't affect the overall DR, so is the extra effort worth it simply to avoid using an extra stop worth of ND?
The way I understand it is that the DR of the sensor comes about from basic physics of construction and sensor size/no of photosites. So build a s35 sensor with 4K resolution and the basic 15 stops of DR is the result, rather than specifically being designed for! The question then is can it all be accessed?
Do we know for sure that the C300 Mk2 does have a dual gain read, or is it just hope and rumour?
To clarify, then when you say "...adjustable gain implies the sensor still has quite a bit more DR that is accessible by using different gain levels... " I'm assuming you mean "simultaneous dual reading at different gain levels"? With a single read, then lowering the gain simply means it will access a different part of the sensors DR range, but without any change in overall output DR?
I assume Reid was one of the early testers and knows this part. His opinion about the Dual ISO being "in camera trickery" is just something I found amusing.
Jim Martin
DVXuser Sponsor
Canon will have their official videos at NAB I'm assuming...and after that, they probably will put them up on the Cinema EOS site......
Jim Martin
Samuel H
Major Contributor
^That
Dual ADC is a very valid method for improving the image you get from a sensor. The Alexa uses it, but so does the Pocket, so there's nothing super-special about it: you just need to have access to the patents, plus the will to implement it.
For Canon it would particularly useful because their off-sensor-ADCs design means that the read noise is relatively high. I'm not sure, but I think that by adding a secondary ADC channel with a signal that comes from an analogue amplifier, you can almost kill that read noise disadvantage, at the cost of extra circuitry, some amplification-induced noise, and the pain of re-joining the readings from the two ACD channels.
This camera must have either that or in-sensor ADCs if it's getting significantly more DR than Canon's most expensive DSLRs get in RAW stills. I think.
Dual ADC is a very valid method for improving the image you get from a sensor. The Alexa uses it, but so does the Pocket, so there's nothing super-special about it: you just need to have access to the patents, plus the will to implement it.
For Canon it would particularly useful because their off-sensor-ADCs design means that the read noise is relatively high. I'm not sure, but I think that by adding a secondary ADC channel with a signal that comes from an analogue amplifier, you can almost kill that read noise disadvantage, at the cost of extra circuitry, some amplification-induced noise, and the pain of re-joining the readings from the two ACD channels.
This camera must have either that or in-sensor ADCs if it's getting significantly more DR than Canon's most expensive DSLRs get in RAW stills. I think.
It's also possible that they found it easier to implement something like this in an APS-C sized sensor with only 8MP rather than the 20-22 MP that their stills cameras have, less than half the pixels to deal with. I wonder how the Varicam 35 does it to get their 14+ DR at 800 ASA.
Matt Gottshalk
Resident Preditor
Preach it brother!
Matt Gottshalk
Resident Preditor
alaskacameradude
Veteran
Just remember.....not everyone is shooting what YOU are shooting. Slow motion has a lot of uses for those
of us who are NOT bigshot DP's working in narrative film making (or hobbyists making our own 'Zombie film.')
For corporate and promo videos, (which makes up most of how I buy food for my kids and pay the mortgage),
it is actually very useful. I cannot think of a project in the last year, that I have not used slow motion in.
If that means I'm 'not being creative' so be it. At least I'm getting paid. And no, I don't have the time or
budget to just 'hire in a Phantom'.
of us who are NOT bigshot DP's working in narrative film making (or hobbyists making our own 'Zombie film.')
For corporate and promo videos, (which makes up most of how I buy food for my kids and pay the mortgage),
it is actually very useful. I cannot think of a project in the last year, that I have not used slow motion in.
If that means I'm 'not being creative' so be it. At least I'm getting paid. And no, I don't have the time or
budget to just 'hire in a Phantom'.
FrameFarmMedia
Veteran
Lol I used to try & find legit reasons to pull out a Kiki wipe. It came once... Just once.
Ha!!! You Toaster User, you!:laugh:
preach! haha
it can be overused for sure, and while I have no doubt there are those who have little need for it... it's a very big deal to some of us.
Nah. I think you're overrating the tier of exclusivity that being an "early tester" entails and having a fairly popular site exceeds the minimum threshold by a vast amount, as it's basically free pub at no cost.