what is motion cadence?

[zlfan]

alexa has no global shutter, yet has better motion cadence, say, than f35, or komodo?

what is motion cadence, then? 

probably my om-1 in 6k 120p burst mode has better motion cadence than alexa in slow mo mode, as om-1 treats each frame as a single photo?

 

[Andrew Reid]

Motion cadence for me, is matching the target frame rate with the sensor and shutter speed-sensor interplay.

It is also about rolling shutter vs global shutter as that plays into the look of motion.

The less distortion or jello the better.

I wish people would SHOW things again. Where are all the tests on the a9 III with global shutter showing what it's like in video mode at 24p vs the a1 II?

I miss the Vimeo days of being able to compare with meaningful shots rather than the standard YouTube guff of a candle for low light, ridiculous whip pans for rolling shutter that nobody ever does in proper cinema, a model staring blankly at the camera for skin tones and a crazy underexposed shot with the shadows lifted until everything looks flat and dirty with no tonality - yeah that's a dynamic range test, sure.

The best motion cadence I've ever shot was on the Digital Bolex with the CCD sensor.

I think some of the faster sensor readouts are losing something important.

They all look like 60p in their 24p modes.

For 60p and 120p motion cadence has less meaning. Since there's no motion blur subtleties that need taking care of.

[zlfan]

"The best motion cadence I've ever shot was on the Digital Bolex with the CCD sensor."

 

i wish i have a digital bolex. 

[zlfan]

"I think some of the faster sensor readouts are losing something important.

They all look like 60p in their 24p modes."

 

probably this is why people complain about the clinical images of the latest crop of cinema cameras, the high res, plus the lack of motion blurs. 

probably it is better to have 24p mode only in a camera. nowadays, high frame rate modes and 24p mode are in the same camera, not good for 24p optimization. 

f35 has only 24p, its 60p is rarely used. probably this is why f35 is so good at motion cadence other than its global shutter. 

 

[Andrew Reid]

The later Sony CineAlta F55 (CMOS) also had a global shutter and can be had for dirt cheap these days, as low as $1k

Perhaps that's the key.

To expose the entire sensor at once.

[Clark Nikolai]

5 hours ago, zlfan said:

"The best motion cadence I've ever shot was on the Digital Bolex with the CCD sensor."

i wish i have a digital bolex. 

I have one and it really is a good camera when it comes to the image quality. I love the image it makes. It's brought my own filmmaking to another level. It's not a run and gun camera though. More of like using a 16mm film camera. Nothing automatic. Manual everything. The dream of an all-in-one isn't quite true with it though. You need to rig it out with an EVF. (Although I don't have and have never used the shark fin shaped viewer with the mirror so maybe that's okay.)

 I used to see them come up on eBay a few times a year but now they rarely do. And people are asking US$11000 with accessories. (I also notice that nobody is bidding on them at that price and the listing ends without any bids, then gets relisted.) I occasionally see them listed for about US$5000 but they don't last long at that price. They're a good camera, worth $5000 but not worth $10000. I think that it's no longer such a unique camera image-wise and you can get a close enough image with a used Alexa or Blackmagic Production camera 4K and be making your movies. (Still if one came up and you could afford it, get it.)

If you're handy you could make your own using the same sensor. Check out this project:

https://github.com/lafauxbolex

https://www.youtube.com/@LaFauxBolexDigitalCinemaCamera/videos

 

[KnightsFan]

I've been thinking about global shutter for a specific project, after being unsatisfied with test shoots using my S5. There are several to choose from now, but you're totally right that it's surprisingly difficult to find quality reviews or comparisons, particularly older models like the F55 in a modern context. If I move forward with it, I'll probably end up with a Komodo--but I've struggled to find direct comparisons between the Komodo, F55, Ursa Mini 4K, and A9III, not to mention comparisons with IMX410 cameras that I'm already familiar with.

[kye]

Motion cadence will be impacted by every step in the image pipeline from the sensor onwards.  

The way to think about this analytically is anything that influences the quality or quantity of the motion blur within each image will impact the motion-cadence, or anything that lets the contents of any frame influence the surrounding frames.

So it will be influenced to some degree or other by:

• shutter speed
• sensor modes (RS, etc)
• in-camera NR
• in-camera compression (codec, especially bitrate and IPB vs ALL-I, etc)
• processing in the NLE (NR, sharpening, colour grading, noise, etc)
• NLE export compression (codec, especially bitrate and IPB vs ALL-I, etc)
• streaming platform processing (NR, sharpening, colour grading, noise, etc)
• streaming platform compression (codec, especially bitrate and IPB vs ALL-I, etc)
• viewing device refresh rate vs video FPS mis-matches
• viewing device motion smoothing settings
• ambient viewing conditions and screen view angle etc

I think of there being three dimensions within video.  
There are individual-pixel things that impact each part of the frame in isolation, like temp, tint, exposure, contrast, saturation, etc.
There are spatial things where one part of the frame influences other parts of the frame, like softening, sharpening, halation, bloom, NR, etc.
There are temporal things where parts of one frame are influenced by the content of other nearby frames, like temporal NR, grain algorithm, etc.

We talk a huge amount about the first category, we talk anecdotally about the second one but no-one is really tackling it as a whole, and the third one is rarely even discussed.

[QuickHitRecord]

Ah, my favorite topic (and it comes up every couple of years). Hopefully we can have this discussion without the usual accusations.

I've done a lot of personal experimentation in this area because most cameras looked off to me. Where I've landed is that I don't think that global shutter or CCD sensors is a surefire recipe for pleasing motion. I spent a lot of time and money figuring that one out.

My list of favorite motion capture cameras is a motley crew and includes the Red One MX (but oddly, not the DSMC1 line), the EOS-M in 1:1 crop, and believe it or not, the hacked GH1.

[kye]

A primer on the fundamentals might be useful as a refresher too...