Camera testing and comparisons

[Peter Moretti]

Thank you once again for your time and un-paid effort. I apologize for any technical misconceptions I may have. Someone please point them out to me if I have them.

Please understand Geoff that I speaking with utmost respect, as I always do when talking to artists. I hope everyone can forgo any preconceptions of "fan-boy" tone, if there are any.



Saying this doesn't delete the weight your words carry Geoff. CML is a powerful megaphone; and having started it it is inconceivable you wouldn't have an idea of how many, and how much, people listen to you. Many with little technical know-how, as you pointed out and included in your target audience.

I haven't looked at the files yet. I am waiting for the R3Ds. But with different people agreeing that at least a few more Red One M-X frames should have been posted by the standards with which Alexa frames were posted, I can't see why you wouldn't kindly take a quick look and comment. I am inclined to believe them because those claims are closer to earlier DR measurements. The frames from your comparison which were posted on this thread seem to make it clear the same standards were not utilized, which only suggest they were not compared when choosing to stop at the top end --and do not suggest any conspiracy theories. I believe you are trying to be un-biased, and I am certainly not questioning your intentions. I think you most likely haven't found the time between uploading all other camera tests and a very busy work schedule to take a look at this and comment.

I apologize for my lack of patience if it feels that way, but your subsequent posts seem to indicate you don't intend to go back to upload the missing frames.

I want to get to the bottom of the DR difference. I thought it was settled, but I am shocked now by what your test suggests through the absence of so many frames. I more than willing to accept any DR ratio between Red One M-X and Alexa, so I hope you can find the time to let us know if there is something people are missing that supports the absence of those frames, then I will be able to look at your comparison and accept it as complete and the most current.

Robert,

I too would like to see the extreme images for all the cameras and all workflows. I think one of the reasons why they aren't there is that they are not necessary to read the results.

If I understand this test properly, the upper dynamic range is reached just before when the center chip and the chip to its immediate right become indistinguishable. For the Log images, Red would be plus four and the Alexa plus six.

The lower dynamic range is reached just before when the center chip and the chip to its immediate left become indistinguishable. So for Red Log, that would be minus six, and for Alexa Log minus seven.

Now I feel like I made a some close calls in evaluating the images that all tipped the way of the Alexa , so I'd probably say that its total Log DR advantage according to this test is more like 2.5 instead of 3.0 stops. (But the Alex images are amazingly clean at the bottom, so perhaps 3.0 is fair. Even possibly 3.5 b/c it looks like you could squeeze out another half stop.)

For the Canon, the numbers would be plus two and minus 4.5.

This is testing the DR of the entire workflow, so it is possible that more DR can be extracted from either cameras' footage. And as was suggested by Jim, the Alexa may be using a contrast filter in front of its OLPF. So the Red would offer you the option of adding one in front of its lens, which is somewhat misleading in its benefit but still may add up to a half a stop (according to David Mullen).

I hope I've interpreted Geoff's charts correctly. And while I would LOVE :001_tt1: :hurray: :thumbup1: arty: :thumbup: for all the images to be filled in, it is possible to draw conclusions from how the test is currently being presented.


P.S. Like Geoff said, anyone can do this test for themselves. So any of us with a Red can replicate the methodology and see how much DR we come up with. Really, Geoff has done his job, IMVHO. If we don't like it, it's now up to us to show that the Red fares better than is indicated (which is still very, very good).

 

[Jannard]

We feel compelled to do the DR tests again when we are present. We have no idea what was done in these tests and certainly get different results. We have acknowledged that the Alexa is a great DR performer but the RED ONE MX does better than these tests suggest. We'll post with all specific details of how the tests were done, firmware build, post methodology, etc. so people can duplicate the test results.

Jim