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Dragon vs Alexa

Marc Hutchings

Marc Hutchings

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Hi

hoping someone can clear this up - I often hear people talking about the Alexa's superior dynamic range but on their specs im seeing 14 stops vs red dragons 16.5 stops. Can someone clear this up for me? I understand the Alexa has better colour reproduction but I've been told how the Alexa holds more range in the highlights several times now would like to know what the deal is.

I also found this old chart that rates the dragon at 13.5 stops
http://news.doddleme.com/wp-content/uploads/2014/08/Screen-Shot-2014-08-05-at-3.18.52-PM.png

cheers

Marc
 
16.5+ stops is RED's own rating. ARRI rates their sensor at 14(+?) stops. DR is a floating target in some ways.

RED can probably prove their claim technically, but some 3rd party tests might discard a few of the stops due to noise being over a certain subjective threshold.

As someone interested in RED—and looking to become an owner—but still not invested and burdened by bias, I think that starting with Dragon and going forward you're in a good position with RED, all things considered.
 
meh so is there a general opinion to how they score on average in these tests? alexa on average has x amount of stops red x - how do people discuss the cameras with no accurate or accepted test seems crazy.
 
With these cameras its not about specs anymore. Its about, lets say, "looks", or film stocks. Obviously one provides more resolution and frame rates options, but awards have been given to films shot on both platforms. I would say these are the two manufacturers that are leading in the cinema/ high end imaging world. Then its a matter of preference of how they look.

Most of the current Arri vs Red arguments end up in perception: the reliable, decades old full of heritage and pedigree Arri with their classic approach to cameras, including form factor, ergonomics, etc, vs Red's new generation, cutting edge approach. Both systems produce great images. A decent DP can produce- if talented- award winning images with them with not much hassle and with enough Dynamic Range that equals or surpass film. The rest? Can be done in post.
 
It's not so much about DR it's about how they are used. Alexa tends to roll the highlights very smooth into overexposure while still having clean blacks that keep details. Red is much harder in that regard. From my own tests I would say that they are both 16,5 stop cameras, but Alexa works with the highlights and shadows so that the effective range is 14 stops but looking much better since everything above doesn't get crushed either in highlights or shadows. With Red you need to be more careful and you might want to do your own highlight/shadow rolloff pre-lut when grading.
 
Marc Hutchings said:
meh so is there a general opinion to how they score on average in these tests? alexa on average has x amount of stops red x - how do people discuss the cameras with no accurate or accepted test seems crazy.
Click to expand...

Well I think these tests are pretty accurate. However many people spent a lot of money on Red cameras and are not ready to hear and accept that some other models could be better in a few domains. I can totally understand that. Switching from Red Dragon to Varicam I noticed immediately that it's better in both colors and DR though, so the best and most accurate test is probably to test them yourself.
 
Christoffer Glans said:
It's not so much about DR it's about how they are used. Alexa tends to roll the highlights very smooth into overexposure while still having clean blacks that keep details. Red is much harder in that regard. From my own tests I would say that they are both 16,5 stop cameras, but Alexa works with the highlights and shadows so that the effective range is 14 stops but looking much better since everything above doesn't get crushed either in highlights or shadows. With Red you need to be more careful and you might want to do your own highlight/shadow rolloff pre-lut when grading.
Click to expand...

Hi,

Which method you use to create highlight / shadow roll off LUT? A you examples of images with and without LUT corrections?

Thank!
 
Raphaël_FR said:
Hi,

Which method you use to create highlight / shadow roll off LUT? A you examples of images with and without LUT corrections?

Thank!
Click to expand...

I just do a custom LUT in Resolve and apply it as a pre-LUT or initial node-LUT. Just shoot something that has the entire range of DR and create your own to your liking, that would work best.
Otherwise I'm just doing a rolloff while grading, that works too.
 
Arri likes to publish usable DR
Red likes to publish technically achievable DR

Dragon usable DR is slightly below 14 stops.
 
Christoffer Glans said:
It's not so much about DR it's about how they are used. Alexa tends to roll the highlights very smooth into overexposure while still having clean blacks that keep details.
Click to expand...

While I know what you mean, I don't buy the whole "rolling in and rolling out" when it comes to DR discussions. DR is the value between the extremes—what happens in between doesn't matter.

The car industry has a standard test for measuring fuel consumption on average. I don't know solid that test is, but something similar could be developed for cameras. A DR test based off of 'linear light' with a predetermined curve to boost the shadows added and the a software that spit out a number based on SnR. Same for all. Admittedly I'd like to see this...


..but at the end of the day... what would that give us? With today's cameras it's a number that is becoming increasingly unimportant. Not because DR is unimportant, but because cameras are so good nowadays.
 
Christoffer Glans said:
I just do a custom LUT in Resolve and apply it as a pre-LUT or initial node-LUT. Just shoot something that has the entire range of DR and create your own to your liking, that would work best.
Otherwise I'm just doing a rolloff while grading, that works too.
Click to expand...

thank,
And with what tools Resolve you doing this?
I do not really understand and am looking for a tutorial or explanation to learn to make this correction..

R
 
Any camera with more than 13 stops is good enough to work with. Just know the limit of you camera.
Weapon body with Dragon sensor have 14-15stops. It is significantly better than the same sensor on a DSMC1 body, and to my taste than Alexa.
I don't like green skins out of the box like on Alexa. But of course, it can be tweaked as with any Reds. And I'm more than happy to work on a Arri camera.

Professionnal cameras are professional cameras, Arri, Red, Sony, Panasonic have good picture out of the box.
There are no bad pictures with them, except the one you can make.
 
yea its not so much that im worried about Red vs Alexa, Red in my opinion is by far the most useful camera for vfx with the resolution and frame rates, it was more that I would like to expand my knowledge when the whole conversation about Alexa having better dynamic range comes up at work as it so often does!
 
Marc Hutchings said:
yea its not so much that im worried about Red vs Alexa, Red in my opinion is by far the most useful camera for vfx with the resolution and frame rates, it was more that I would like to expand my knowledge when the whole conversation about Alexa having better dynamic range comes up at work as it so often does!
Click to expand...

Yes, this is the reason I'm using Red as well, far more control and capabilities for creative problems. Alexa has a good image... pretty much the only thing. Red, with HDRx, greater resolution, simple RAW workflow all within a lightweight small body that is modular. The choice is obvious in my opinion.
 
If you're asking about the Alexa, you're probably not shooting documentary work. If so, you'd most likely ask about the Amira. Sure, they share the same sensor. But I'm just trying to put into context that if asking about the Alexa you are most likely shooting scripted narrative of commercial...and probably with some sort of a budget. After all, those rental fees can add up. :)

Under that assumption, you'd rarely, if ever, really light a scene at 14 stops. You'd most likely have a budget for G&E. Even if shooting outside, you'd be able to lift your shadows. A 12x12' silk and a 1K plasma on a put put is not a very complicated nor expensive set up. Of course this is a generalization. Still, most productions with budgets for G&E, DR limits wouldn't be a huge deal. So pick whatever camera is gonna provide the other things you need: color, resolution, frame rates, compression settings, form factor, etc.

So, in the scenario you're shooting on the Alexa or the Red and can't control light in your scene for whatever reason, then you'd likely want the best DR possible. My opinion mirrors some that have already been expressed. It's a relative game based on what you're willing to accept as an image. Alexa likely has a larger DR than advertised, but they use that to slowly compress the highlight roll-off to mimmick the way film does. It also manages to keep some good fidelity in the shadows at 13 stops. Or you can steal some stops from above middle grey and allocate them to below middle grey and rate the camera at 400ISO, cleaning the blacks even further...which is where I see the Alexa being a clean 14 stops of DR. The dragon sensor on dsmc1 has a reputation of performing best under a lot of light. Or to say, it's not a great lowlight sensor. It also does not roll off as gently as the Alexa. To be fair, I've only shot on dragon sensors a hand full of times, and never in a scenario where I couldn't control light sufficiently so I never ran into their DR limits.

Still, the dragons rent for cheaper than the Alexa.
 
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