Is rolling shutter truly progressive?

[Anaconda_]

I was taught at college that interlaced footage was invented as a stopgap until they found a way to record digital video as whole frames like film does. Now we all shoot progressive, but since that's most common at this level with a rolling shutter, is it really much better than interlaced?

For example, if you're filming a model and there's also a photographer there, you can clearly see their flashes rolling down the frame, especially so in slow motion shots. I would think that interlacing would handle those situations at least 85% better, which made me wonder; did we really make progress with progressive acquisition on RS sensors? Is global shutter the only 'real' progressive frame? Does it matter?

[DBounce]

  On 6/17/2019 at 11:14 AM, Anaconda_ said:

I was taught at college that interlaced footage was invented as a stopgap until they found a way to record digital video as whole frames like film does. Now we all shoot progressive, but since that's most common at this level with a rolling shutter, is it really much better than interlaced?

For example, if you're filming a model and there's also a photographer there, you can clearly see their flashes rolling down the frame, especially so in slow motion shots. I would think that interlacing would handle those situations at least 85% better, which made me wonder; did we really make progress with progressive acquisition on RS sensors? Is global shutter the only 'real' progressive frame? Does it matter?

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Film has rolling shutter, as explained here. It's just fast. I do notice a difference in global shutter. For me it's more about motion cadence... which I feel looks better on GS.

[hmcindie]

  On 6/17/2019 at 11:14 AM, Anaconda_ said:

I was taught at college that interlaced footage was invented as a stopgap until they found a way to record digital video as whole frames like film does. Now we all shoot progressive, but since that's most common at this level with a rolling shutter, is it really much better than interlaced?

For example, if you're filming a model and there's also a photographer there, you can clearly see their flashes rolling down the frame, especially so in slow motion shots. I would think that interlacing would handle those situations at least 85% better, which made me wonder; did we really make progress with progressive acquisition on RS sensors? Is global shutter the only 'real' progressive frame? Does it matter?

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Rolling or global shutter has nothing to do with interlacing. You can have interlaced material with either, it's just a way of encoding more framerate into the same bandwidth. So 25p -> 50i in PAL. 

Most of the cameras used in the days of interlacing were using global shutter CCD's.

Interlacing would not help in anyway for rolling shutter as the RS is independent of how the frames are encoded and is usually 1/60 atleast.

  On 6/17/2019 at 12:30 PM, DBounce said:

For me it's more about motion cadence... which I feel looks better on GS.

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That goddamn RS wobble is horrific.

[Anaconda_]

  On 6/17/2019 at 1:22 PM, hmcindie said:

You can have interlaced material with either, it's just a way of encoding more framerate into the same bandwidth. So 25p -> 50i in PAL. 

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I get that, I was just wondering if trading the interlaced standard for RS was really worth it. Both give artifacts like jello for, or bad moire on lines etc. but interlaced footage from days of old seems to have a more global shutter feel in some cases (ie. camera flashes, propellers etc.)

  On 6/17/2019 at 1:22 PM, hmcindie said:

Most of the cameras used in the days of interlacing were using global shutter CCD's

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And that's why. Does anyone know if Blackmagic's Production Camera has a GS? As I know that can shoot interlaced, while their other cameras don't. 

[BTM_Pix]

  On 6/17/2019 at 1:55 PM, Anaconda_ said:

Does anyone know if Blackmagic's Production Camera has a GS? As I know that can shoot interlaced, while their other cameras don't. 

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Yes it does.

Some fast panning tests with it here 

 

[UncleBobsPhotography]

  On 6/17/2019 at 1:22 PM, hmcindie said:

Interlacing would not help in anyway for rolling shutter as the RS is independent of how the frames are encoded and is usually 1/60 atleast.

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Wouldn't 50i only read half the lines on the sensor for each interlaced frame? If so, that can be done at twice the speed of reading every line.

[Mokara]

  On 6/17/2019 at 4:44 PM, UncleBobsPhotography said:

Wouldn't 50i only read half the lines on the sensor for each interlaced frame? If so, that can be done at twice the speed of reading every line.

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Depends on the camera. Old Canon consumer cameras for example shot everything as 60i, then reconstituted 30p or 24p in camera from that (fake progressive footage, my old HF-S10 does that for example). In later cameras the interlaced footage may be reconstituted in a similar way, but in reverse.