Jakelutz wrote:This is a legitimate question I think most of us want to know.
This is an issue that comes up a lot.
Yes, it's possible to see FPN on the camera, but it's _usually_ something that can be avoided or reduced depending on how you process your footage.
Here's a recent thread that kind of started the same as this one and then the OP ended up getting to this point.
viewtopic.php?f=2&t=57403&p=348229#p348193You'll find some very low lights shots I did recently on multiple ursa bodies that look great and have very little in the way of FPN.
So what would be really useful is if you can post some original files as examples and how you're grading / processing and we can maybe see if there's something we can do to make it look better ?
Jakelutz wrote:I'd like to start a discussion on the process of removing FPN. I've been doing tons of research but Blackmagic are very hush hush when it comes to how they process their images.
What EXACTLY did you want to know ? I also presume you have done the "sensor calibration" function ?
Jakelutz wrote:As FPN is an inherent CMOS problem it's hard to fix but Red, Arri, Sony and Panasonic have it figured out so what's taking Blackmagic so long to implement a fix and is there any glimmer of hope to a future solution?
Well let's start here. An AC colleague of mine tells me he just did a series for Netflix on RED (not yet aired). He complained about a lot of problems with the cameras they had but one that came up for him was FPN. To calibrate on the camera it's a very lengthy calibration process and that you need to do it several times for many different potential operating temperatures. In other words if the ambient temperature range varied more than about 10 degrees C they had to have a different temperature calibration. You have 5 memories in the camera available and he found it wasn't enough because it ALSO was supposed to use the same settings when working off speed, but that function didn't seem to work. Their solution was to shoot HFR with a 360Deg shutter.
Does that sound like they have it figured out ? I'm not sure it does to me. More like managed.
Arri. Well they do indeed have it very well sorted but in the right conditions it also will show up there.
https://www.arri.com/forum/viewtopic.php?t=267&p=682Sony have another process they call APR, which you have to do every day, every time you turn the camera on in the morning. If you don't and skip it (which I've done) you also get nice stuck pixels instead.
I haven't worked with the Varicam for a while so I haven't seen what Panny are doing these days, but I imagine it's like sony, that a black balance sorts it once you're at operating temperature.
I think that maybe the problem is is that BMD firstly give you everything from the sensor. What they maybe should do is truncate the bottom end and just clip it and have a bit less dynamic range and be done with it.
The second issue is that BMD's log is especially flat. You look at a low con subject in BMD film on any LCD monitor and you'll see noise and FPN that end up disappearing in a normalised grade.
Now, you may well have an abnormal camera too. So post some shots !
Jakelutz wrote:Yeah the 4.6k can create beautiful images but there are a good 4 stops of decent latitude going to waste. This camera would be truly perfect if it weren't for that FPN.
If you think you're losing 4 stops to FPN then I'd say there's something extremely wrong with your camera.
Jakelutz wrote:I'd love for a BM employee to give us some info on this infamous FPN issue.
You may get someone to respond, but I doubt it
JB