Hard Clipping

So it seems there was a “calibration” problem with some of the first Blackmagic Design Pocket Cinema Cameras shipped. Many users have reported a kind of hard clipping, often described as ORBS or BLOOMING.

It’s worth looking at exactly what this is and why it happens.

The problem is that once you describe something as an “orb” then you can start to see orbs in almost any footage including those from cameras that aren’t Blackmagic Cinema Cameras.

Orbs can be created through any number of factors and are greatly affected by sensor size, lenses, exposure, where you set focus and what kind of lights or “orb” sources you’re shooting.  So lets’ say orbs are normal.  You get them whenever you have a small point source like the bare filament of a bulb at a distance or a small glint from the sun off a car.  It could also be lights at a great distance that are out of focus.  They are usually super white or beyond clipping.  Once out of focus they become even more “orby”

Once the sensor clips then it renders that detail white.

Specular highlights and small sources with extreme overexposure can cause a kind of hard clipping with the Blackmgaic pocket cinema camera, as opposed to “orbs”.

It barely was present in my own early footage and it seems to have been much worse in the production versions of the camera.

BMD have come up with a fix in the space of a couple of weeks.  I’ve got both an uncalibrated production camera and a calibrated production camera so I thought I’d shoot them side by side with a bit of a highlight orb torture test.

One thing I’ve found amazing is that once you start looking for “orbs” you start seeing them everywhere !  Various forums have been rife with “orb spotting” and many of them have really just been regular clipping on small point sources.

As I mentioned, it’s normal to have a kind of orb with a hot point source of light when you clip or overexpose certain objects. Look at my iPhone photo below in the same setup I’ve tested with below.

This is why I’ve never been comfortable with calling it ORBS or BLOOMING because it doesn’t really accurately describe the fault and creates a false impression of a problem. To my eyes, it’s a “HARD” or HARSH” clipping that occurs on overexposed or super white point sources of light.  So we’re looking for HARD clipping and HARD clipping that eats into foreground images, not ORBS.

Here’s a shot I took with my iPhone.  Would you call this an ORB fault ?  I wouldn’t.

2013-09-11 19.39.11

So here’s what I did to try and create the effect.

I got a mirror ball and pointed a 100w dedo at it.  Right beside it in-shot is another 150w bare dedo bulb.

In the foreground I placed two plants, with the middle ground slight obscuring the 150W dedo in the deeper BG.

I wanted to set up a few “orb” scenarios and look at both re-creating the effect and also showing that there is a more “normal” kind of clipping orb.  Again look at the image below, taken with my iPhone.  Note the clipped “orb” highlight in the mirror ball.

2013-09-11 18.01.42

Pocket

So below is an edited version of what I shot.  You can download the original ProRes files here.

I’ve shown both the un-calibrated camera and a calibrated camera.  You’ll notice that it’s very difficult to pick much of a difference on the mirror ball’s occasional hits from the dedo.  Where you’ll see the hard clipping most in the first clip with the 150W dedo that’s in shot and you’ll notice it actually has a hard and ugly edge and kind of “eats” into the foreground flower.

In the calibrated camera, you notice that the 150 lamp is still clipped or blown out.  You could even say it’s an orb too, but there is detail in near clipping, and you can also make out more of the flare.  There’s also none of the circular hard edged clipping that eats into the flower in foreground you see in the previous example.  I also did some small blow ups and a large scale up as well so you can really look at the hard clipping close.

You should also note, that the black sun effect is also now gone from the image in the “calibrated” camera.  The next firmware release should incorporate this.

Finally, just because I hadn’t had the Zeiss CP2 50mm Macro on before, I did a quick grade on the footage showing off some lovely close detail.

Direct link is here

 

And some final proof.

2013-09-11 18.00.46

2013-09-11 18.01.07

About johnbrawley

Director Of Photography striving to create compelling images
This entry was posted in Black Magic Cinema Camera, Equipment and tagged , , , , , , . Bookmark the permalink.

10 Responses to Hard Clipping

  1. Ron Coker says:

    The 1.4.2 Firmware really trims this hiccup. It’s a tremendous little camera.

    Thanks for sharing.

  2. Pingback: John Brawley explains why Orbs exist on the Blackmagic Pocket Camera, and how it has been fixed | wolfcrow

  3. Your hard work and dedication to craft are commendable! Thank you sir!

  4. Pingback: Hard Clipping | Filmmaking, Photography and Sou...

  5. Pingback: Hard Clipping | VideoDrome | Scoop.it

  6. Thanks for this. Are you happy with the View Factor cage? Is that the hotrod PL adapter also?

    • johnbrawley says:

      Hi Cort.

      Yes it’s the HotRod adaptor on the Viewfactor. They’re designed to go together.

      The viewfactor is a great addition and a no brainier for the price. I’m just hoping for an EVF mount and elegant ext battery system now.

      JB

  7. Pingback: Blackmagic Design Cinema Cameras: Production Workflow Roundup | Premiumbeat.com

  8. Fred says:

    Your attention to detail is pretty impressive. I had to watch your video twice to notice the difference. I was curious to see what Blackmagic Design had to say about this..

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