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Ursa 4.6k Black Shade Calibration | My Findings

January 27, 2017

 

       With the release of Blackmagic's latest firmware version 4.2 for the Ursa Mini 4.6k it had some big implications for heavy Ursa users like myself as far as helping with the noisy images with most underexposed or dark lit scenes which was freaking terrible because as a music video director those are often very common shots when shooting in let's say a nightclub or dark alleyway. Now I knew getting into the Ursa game that it was not a low light camera and required light for the sensor to shine. but what about the background when your limited on equipment and have to roll as is? Sure shooting at ISO 200 would solve that problem but we don't always have enough lighting gear depending on the budget.

 

Luckily I've been hearing great things about this update so before installing it and running the black shade calibration I decided to do some tests for myself and everyone to get a better understanding of what this means for us dark lighting junkies.. Let's take a look.

Before & After Black Shade Calibration

False Color W/ Lens Cap on

 

 Wow. Pretty clear and dry that it removed a ton noise. Now that's great and dandy but how will this affect my images. That's all I really care about. So I dug deeper and filmed some test before and after the upgrade to see how much of a difference it actually makes in my footage.

The Tests

 

I filmed an old photography camera I had laying around on my shelf of ancient technology in what I would like to call a "low light situation" in my case this is an ideal test as a lot of music videos demand this type of high contrast look. I made sure most of the camera was slightly underexposed while leaving the key parts decently well lit as seen here by my false color readings. 

 

For those of you who don't use false color very often, The green and grey areas of the image are correctly exposed while the pink usually means black and the blue has a little more detail left.

 

 I took the same shot at different ISO levels trying my best to match the same exposure by adjusting my aperture. I really only wanted to see the extremes of this so I tested ISO 200 and 1600 before and after black shade calibration to see if the update was really as powerful as i've been hearing. For the sake of time the rest of this post I will be referring to black shade calibration as BSC . These tests were done in 4.6k Lossless Raw format with a rehoused sigma 18-35 f1.8.

 

ISO 200 pre-BSC.

At ISO 200 the sensor does a decent job crushing the blacks in camera leaving behind little noise. But as you can see by the scopes in Davinci Resolve the blue channel is somewhat lifted above the rest. Yes this is a bluer image due to the lighting but that still seems a little high to me. Still not bad. Let's add a basic LUT and some Noise Reduction in Davinci Resolve to see how this will look since that's what we'd be doing with an image like this in the real world.

I like to use Kholi Hicks's "Comet Color LUTs" (Purchase Here) and for the sake of this example I used "B Side - Contrast". As far as my noise reduction I might have over done it a bit but I set my Temporal to 10 and my Spatial to 10 as well. Still this is a great image (to me). Really captures that dark ambience and contrast look i've been going for without much noise in raw and practically none after a quick grade.

 

 

Now let's take a look at ISO 1600 pre-BSC.

 

 Yeah, there is just nothing pretty about that. Let's just call it like it is and say that is freaking fugly. As you can see the sensor pushed a ton of blue into the shadows of the image and just overall made it pretty unusable from any kind of professional standpoint. I've seen this in Shane Hulburt's tests where he would underexpose and try to lift. It would always come out with this nasty blue in the shadows and blacks of the image.

 

I wanted to know if this was able to be cleaned up a bit in a last ditch effort to try and get something usable out of this. So I added the LUT and the same noise reduction in Resolve to see if it was passable or not.

 In my personal opinion absolutely not would I ever hand this off to a client. When taking a closer look you can see just how bad this really is.

Lens Cap Test

I also took some clips with the lens cap on to see the varying levels of noise within different ISO levels Pre-BSC.

Below are the Parade scopes from the photo above showing ISO from 200-1600

 

With the lens cap on the proof was in the pudding. The sensor clearly was raising the blue channel into the blacks and shadows of my image.

So after all that ugliness realizing that iso 200-400 was really my only option for night time scenes if I wanted a clean image without having to do a bunch of work in post I went ahead and updated to the new firmware V4.2 and ran the BSC from the settings menu. I let the camera run for about 15 minutes before doing the calibration and than repeated my tests.

 

POST BSC

Lens Cap Test

 One of the first things I noticed was a color shift from blue to red. But a lot less noise or at least way cleaner noise. The blue channel never seems to go nearly as high on the scopes as it did Pre BSC. This is a huge, amazing & almost low light game changer for me. But these are just scopes. That's great and all, but I obviously needed to see how it would look in my actual image with the lens cap off.

 

ISO 200 POST-BSC.

 Relatively clean but ISO 200 normally is. But for the sake of it i'll add the LUT and NR.

 Looking back between the two, I feel I see the difference that the blacks are just blacker Post-BSC. Either way It's a beautiful image at ISO 200. But take a look for yourselves to see if you can tell the difference. I'm fully aware that the true power of this test lies in the 1600 ISO results. So lets dive in to that.

 

ISO 1600 POST-BSC.

 

Now there is still a lot of noise in this image but guys come on. We're all aware this is not a low light camera. That being said, let's take a look at what the BSC actually did. I feel it did a nice job not pushing a crap load of blues into shadows. Looking at the scopes it's all mostly pretty even. And overall I feel it's totally workable. Not Preferable. But workable. This really shows me that they fixed a huge problem that was driving me insane. Let's add the LUT and NR and see how we're looking.

 

 

 I'd say this ISO 1600 image after graded is completely usable in most settings. Definitely a huge difference between before BSC and after. Just to drive that home I'm going to do a comparison photo.

 

 The last and final test I wanted to do, which would be the biggest advantage out of this (for me), was to see if I could make an ISO 800 image POST - BSC look as good as an ISO 200 image PRE - BSC.

 

 

Final Thoughts

 

The BSC is an unbelievably amazing update that was badly needed for this camera. I'm almost stunned by the results and the difference it makes. As a music video director this is a complete game changer for me. I feel that after doing a BSC during each shoot before starting or changing rooms (as pointed out to me by Brandon Cooper from the BM user forums) I can now make ISO 800 images look as clean and as noiseless as ISO 200 images before the update. It's a must! Thank you to Blackmagic Design for staying on top of the issues and focusing on what the consumer needs!

 

 

 

 

 

 

 

 

 

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