Nanoflash and rolling shutter?

[Simon Bailey]

I was just wondering if rolling shutter might be reduced with the use of a nanoflash?

Someone told me the rolling shutter issue found on cameras with CMOS sensors, was due to record speeds? Doesnt really sound right to me but just wondered if the nanoflash had any effect on rolling shutter?

Cheers,

Simon

[Piotr Wozniacki]

No way, Simon.

The "rolling shutter" term applies to the way data is collected from the CMOS sensors (imagers), as opposed to the traditional CCD.

NanoFlash uses the same source (the camera sensor(s)) as the camera's own codex/storage media. Where it shines is using much better codex - but any "rolling shutter" phenomena will still be there.

Personally, I never found the rolling shutter to be a problem with my EX1.

[Simon Bailey]

I'm using an EX1 too and agree its not much of a problem but it only shows up for me with a high shutter speed and using the smoothcam filter to stabilise it in FCP.

I'm trying the Foundry Rolling Shutter plugin but so far haven't gotten the settings right for the EX1. Very surprised The Foundry haven't published settings for all popular cameras.

Cheers,

Simon

[Piotr Wozniacki]

Simon,

This discussion is irrelevant to the nanoFlash, and hence to this forum - but I can tell you that the rolling shutter "problem" can be split into two phenomena:

- partially overexposed frames from photographers' flashes (typical for "red carpet" events)
- vertical contours being skewed with fast motion.

For the EX cameras, the latest ClipBrowser version can effectively repair the former; the latter only really becomes visible with high shutter speeds (as you've already mentioned). I'm afraid this can only be avoided by slowing the pans you are doing - especially in the progressive mode.

Last but not least: I have tried many different NLE plugins, and NONE can really take care of the skew - what's more, they all introduce their own "yello look" problems.

But as I said - this has nothing to do with what Convergent Design is offering with their excellent products.

[Tim Kolb]

The CMOS sensor "fills" vertically as it creates the image. Anything that moves across the sensor at a speed faster than that "fill" rate is progressively imaged further and further over in its horizontal progress.

I've had a few manifestations in my automotive work...usually the car is quite close and passing quite fast...and the effect isn't really perceivable to anyone who doesn't pause the footage.

I'm not saying that it isn't a concern...just that it doesn't seem to happen under any but somewhat extreme conditions for me.

The point about the Nano having no ability to change this is accurate. Once the camera sensor creates the image, anything that records it will record the same thing. The Nano is most useful for raising the data rate of the recorded footage and increasing image quality over the native format inside most cameras.

[Simon Bailey]

Thanks guys.

I suspected that would be the case. Either way I still think I need the nanoflash as I grade quite a lot and need more dynamic range for sunsets and skin tones.

I downloaded a few of the EX1/3 samples from the site but would like to find more samples with a more challenging scene like a sunset, or snow would be interesting.

The guys at Convergent Design might want to look at a cover with dust protection and perhaps some rubber armour?

Cheers,

Simon

[Gints Klimanis]

I would guess that the Nanoflash's higher bitrates would code "rolling shutter" artifacts more accurately. Short bursts of light (camera flashes, police rotating lights) and the rotational effect stress video encoders with new information that will cause the rest of the scene to degrade. If this can be demonstrated, Convergent has another selling point.

" While we cannot repair footage marred by rolling shutter artifacts, we can prevent it from looking worse."

[Piotr Wozniacki]

Gints,

"Short bursts of light (camera flashes, police rotating lights) and the rotational effect that stress video encoders" are indeed much better handled by the nanoFlash codex (due to their color resolution and high bit rates), however they are not exclusively CMOS artefacts!