Rolling Shutter VS FPS confusion

Started 2 months ago | Discussions thread
sybersitizen Forum Pro • Posts: 17,738
Re: Rolling Shutter VS FPS confusion

Dem Bell wrote:

sybersitizen wrote:

Dem Bell wrote:

If you use a camera with a high FPS rating, say 20+, you will struggle to spot any jello effect in your shots of dancers.

The frame rate is not an indication of the electronic shutter sensor readout speed.

Well, it is if you have to wait for the previous frame to finish before starting a new frame.

I knew someone would take exception to that, which is why I already revised it to this:

The frame rate and the electronic shutter readout speed are two different factors.

Yes, of course the frame rate represents a limit as to how slow the actual readout can be.

For example, in Fuji land (model, readout time, FPS):

X-T100, 1/6 sec, 3 FPS

X-T1, 1/15 sec, 8 FPS

X-T2, 1/25 sec, 14 FPS

X-T3, 1/40 sec, 20 FPS

There is a pattern, right? If the readout time is 1/100 sec no manufacturer would advertise their camera as 10 FPS, when they could probably do about 50 FPS. I suppose if the first electronic curtain is not required for the whole sensor, then it is possible to read the sensor line by line, clear each line immediately and start reading next frame achieving phenomenal FPS with slow read out times. Does any manufacturer do that?

The first can be relatively fast while the second remains relatively slow, and the second is what makes the Jello. For example, 1/30s readout speed is definitely Jello territory in many situations even though it might allow 20 exposures in a second.

I don't actually know what sensor readout speed is required to mostly avoid rolling shutter issues with human dancers. That's the factor that ought to be clarified.

Agreed.

Good.

Are there many CMOS sensors that can do much better than 1/40 sec?

The question is not how many there are. The question is what the OP, or anyone else, considers the minimum readout speed needed to mostly avoid rolling shutter issues with human dancers. When there's an answer to that, cameras that meet that requirement can be identified. I have a camera with a sensor readout of 1/80s at 20fps with continuous hybrid AF (or 60fps with single AF), but the OP isn't necessarily going to want that one for his work.

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