Rolling Shutter VS FPS confusion

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Currantos Senior Member • Posts: 1,276
Rolling Shutter VS FPS confusion

So I am a little confused.

Silent shooting/electronic shutter is supposed to have worse/worst rolling shutter effect than mechanical. So the recommendation is to avoid it for fast moving objects.

For fast moving objects the recommendation is to use highest possible FPS to catch that best moment in an action sequence. Electronic shutter allows for higher FPS so one would switch to that.

? Conflict?

So which is it? Avoid it due to rolling shutter or use it to get the FPS?

Natural light situation?

Continuous stage/regular lights?

Advice on shooting athletes or a dance performance on stage? I want high FPS but I don't want rolling shutter. Looking for advice from mirrorless users that can choose from full mechanical, full electronic or EFCS which to use when.

Lee Jay Forum Pro • Posts: 56,269
Re: Rolling Shutter VS FPS confusion

Currantos wrote:

So I am a little confused.

Silent shooting/electronic shutter is supposed to have worse/worst rolling shutter effect than mechanical. So the recommendation is to avoid it for fast moving objects.

For fast moving objects the recommendation is to use highest possible FPS to catch that best moment in an action sequence. Electronic shutter allows for higher FPS so one would switch to that.

? Conflict?

No.  Both are correct.

So which is it? Avoid it due to rolling shutter or use it to get the FPS?

Rolling shutter can cause skewed parts in the image when those parts are moving across the frame.

Missing the right moment can make the shot useless.

Advice on shooting athletes or a dance performance on stage? I want high FPS but I don't want rolling shutter.

Then use a flash-dominated exposure (but without risk to the performers, so you have to be careful here) or a fast mechanical shutter (unless you have a global electronic shutter).

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Lee Jay

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OP Currantos Senior Member • Posts: 1,276
Re: Rolling Shutter VS FPS confusion

Thank you.

On stage can't use flash, and usually with dancers flash is not possible, unless it is "staged shots". What I mean is live performance where they have to be naturally lit. Is it ok to use electronic shutter or only with A9 Sony? Others too slow?

Same thing with athletes, I am not going to be able to use flash in a stadium or on a field track where I am shooting with a 200/300mm lens from the sidelines.

No experience here with MILC so maybe I am not explaining properly.

Lee Jay Forum Pro • Posts: 56,269
Re: Rolling Shutter VS FPS confusion

Currantos wrote:

Thank you.

On stage can't use flash, and usually with dancers flash is not possible, unless it is "staged shots". What I mean is live performance where they have to be naturally lit. Is it ok to use electronic shutter or only with A9 Sony? Others too slow?

I don't know.  My mechanical shutter transits the full frame in 1/400th of a second.  I don't know what the fastest progressive shutters in consumer cameras do.

Same thing with athletes, I am not going to be able to use flash in a stadium or on a field track where I am shooting with a 200/300mm lens from the sidelines.

No experience here with MILC so maybe I am not explaining properly.

No, you explained it right.  I gave you the reasons why each can be objectionable.

I've found very few (but not zero) instances where 1/400th was not fast enough to avoid noticeable skew, but those were in things way faster than dancers and runners.  I'm guessing e-shutters are more typically in the 1/60th to 1/120th range, but I don't really know.

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Rambow Contributing Member • Posts: 813
Not that complicated

The mechanical shutters are fast enough for athletes/indoor events etc. Even basic cameras can do 1/4000 exposures.

I can't imagine reaching the fastest shutter speed either, since usually this means cranking up the iso to uncomfortable levels.

Electronic shutters were developed for stuff like very high burst speeds, where mechanical shutters struggle.

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Chris R-UK Forum Pro • Posts: 20,789
Re: Rolling Shutter VS FPS confusion

With an electronic shutter, rolling shutter effects occur most frequently when you are panning the camera across a background with vertical lines in it.  Examples are racing cars or birds in flight in front of a building.  The vertical lines appear slanted.

In athletics, it will be a problem if you are panning to follow runners in, say, a 100m race, but it won't be a problem if you have the camera set up to catch them crossing the finishing line.  It also wouldn't be a problem if you are shooting a field event like the pole vault.

It shouldn't be a problem shooting dancers unless you are panning to follow them moving fast across the stage.  I suspect that more normally you won't be panning much.

In my experience, very high fps rates are only necessary when you are shooting high speed action and trying to capture a precise moment, for example the winner in a 100m race just reaching the tape, a baseball batter with the ball just hitting the bat, a headed goal in soccer or an eagle taking a fish out of the water.

Personally, I rarely go above 8-10 fps for my wildlife photography.  Even events like whale breaches don't require a high fps rate because they last 2-3 seconds and there isn' a "decisive" moment in the breach when you have to get the shot.  Dolphins leaping do require a very high fps rate because everything happens much faster.
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OP Currantos Senior Member • Posts: 1,276
Re: Not that complicated

1. did you read my post? I can't see how your reply relates to what I asked.

2. Can't use mechanical in the middle of a dance performance when I am sitting in the audience and there are 30 people around me quietly watching. Directors don't allow mechanical shutter during LIVE performances.

3. electronic shutter will have rolling shutter effects. Great for fast FPS and then will have jello effect on the arm or leg of a dancer. Ruined image.

We are talking 1/250-1/2000 of a shutter speed for most dance/athletes, I don't need 1/4000 on stage or with wrestlers/mma. Maybe boxers need faster.

OP Currantos Senior Member • Posts: 1,276
Re: Rolling Shutter VS FPS confusion

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak. In dance there are tons and tons of "decisive moments' that often last less than a second easily, with smaller jumps and movements they can be just a flicker, not even a full "run jump suspend in air land" type sequence. Just a hop or skip out of nowhere can be all they give you.

I definitely missed tons and tons of shots and need faster shutter.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

Chris R-UK Forum Pro • Posts: 20,789
Re: Rolling Shutter VS FPS confusion

Currantos wrote:

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak. In dance there are tons and tons of "decisive moments' that often last less than a second easily, with smaller jumps and movements they can be just a flicker, not even a full "run jump suspend in air land" type sequence. Just a hop or skip out of nowhere can be all they give you.

I definitely missed tons and tons of shots and need faster shutter.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

Do you need to pan significantly during a burst?  If you don't, then an rolling shutter shouldn't be a problem.

Do you need continuous focus or can you prefocus?  If you can , then like may enable you to use the Pre-Capture facility that many cameras have.  That would enable you shoot at 50-60 fps and to start shooting whenever you think a jump is about to happen.

Are you looking to record an entire performance or just looking for outstanding shots?  If the latter, then you can shoot a burst whenever a jump looks likely and just accept a low hit rate.

I think that the Sony A9 is probably the camera with the lowest rolling shutter effect at the present time.

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Chris R

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Lee Jay Forum Pro • Posts: 56,269
Re: Rolling Shutter VS FPS confusion

Chris R-UK wrote:

Currantos wrote:

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak. In dance there are tons and tons of "decisive moments' that often last less than a second easily, with smaller jumps and movements they can be just a flicker, not even a full "run jump suspend in air land" type sequence. Just a hop or skip out of nowhere can be all they give you.

I definitely missed tons and tons of shots and need faster shutter.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

Do you need to pan significantly during a burst? If you don't, then an rolling shutter shouldn't be a problem.

That just isn't true. If the subject or a portion of the subject is moving, that's an issue too - no panning required and no background subjects need be in the frame.

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Lee Jay

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sybersitizen Forum Pro • Posts: 17,818
Re: Not that complicated

Currantos wrote:

On stage can't use flash, and usually with dancers flash is not possible, unless it is "staged shots". What I mean is live performance where they have to be naturally lit.

So flash is out.

2. Can't use mechanical in the middle of a dance performance when I am sitting in the audience and there are 30 people around me quietly watching. Directors don't allow mechanical shutter during LIVE performances.

So a noisy mechanical shutter is out. That still leaves almost silent mechanical leaf shutter cameras.

3. electronic shutter will have rolling shutter effects. Great for fast FPS and then will have jello effect on the arm or leg of a dancer. Ruined image.

So you would like a very fast electronic shutter. The readout speed of the Sony A9 is about 1/150s ...

... high FPS is absolutely necessary

... with a burst rate of 20fps. That should be okay for your purposes.

If your choice of gear doesn't provide those options, you'll just have to compromise on something.

Seems to me the most logical compromise is to use silent shutter so you don't get chastised and banned from the theater. If objectionable rolling shutter effects actually appear in some of the results, perhaps mild ones can be mitigated in PP.

beatboxa Senior Member • Posts: 7,259
Re: Rolling Shutter VS FPS confusion

Currantos wrote:

So I am a little confused.

Silent shooting/electronic shutter is supposed to have worse/worst rolling shutter effect than mechanical. So the recommendation is to avoid it for fast moving objects.

For fast moving objects the recommendation is to use highest possible FPS to catch that best moment in an action sequence. Electronic shutter allows for higher FPS so one would switch to that.

? Conflict?

So which is it? Avoid it due to rolling shutter or use it to get the FPS?

Natural light situation?

Continuous stage/regular lights?

Advice on shooting athletes or a dance performance on stage? I want high FPS but I don't want rolling shutter. Looking for advice from mirrorless users that can choose from full mechanical, full electronic or EFCS which to use when.

The reason you are confused is that you are trying to use a single variable to make a decision, when this is not a single-variable problem.

The key is to balance rolling shutter (to pick a shutter type & speed it where it is minimal or not problematic) with the highest FPS available. And there are even more variables, such as viewfinder lag in various modes.  And available light & exposure.

Every camera and setup will be different. On very fast reading shutters, electronic shutter might be ok. On slower shutters, EFCS. On some cameras, full mechanical to improve EVF.

Chris R-UK Forum Pro • Posts: 20,789
Re: Rolling Shutter VS FPS confusion

Lee Jay wrote:

Chris R-UK wrote:

Currantos wrote:

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak. In dance there are tons and tons of "decisive moments' that often last less than a second easily, with smaller jumps and movements they can be just a flicker, not even a full "run jump suspend in air land" type sequence. Just a hop or skip out of nowhere can be all they give you.

I definitely missed tons and tons of shots and need faster shutter.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

Do you need to pan significantly during a burst? If you don't, then an rolling shutter shouldn't be a problem.

That just isn't true. If the subject or a portion of the subject is moving, that's an issue too - no panning required and no background subjects need be in the frame.

That is correct, aircraft propellers or a hummingbird's wing being examples.  But is it going to be a significant problem when shooting dance?

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Chris R

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Lee Jay Forum Pro • Posts: 56,269
Re: Rolling Shutter VS FPS confusion

Chris R-UK wrote:

Lee Jay wrote:

Chris R-UK wrote:

Currantos wrote:

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak. In dance there are tons and tons of "decisive moments' that often last less than a second easily, with smaller jumps and movements they can be just a flicker, not even a full "run jump suspend in air land" type sequence. Just a hop or skip out of nowhere can be all they give you.

I definitely missed tons and tons of shots and need faster shutter.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

Do you need to pan significantly during a burst? If you don't, then an rolling shutter shouldn't be a problem.

That just isn't true. If the subject or a portion of the subject is moving, that's an issue too - no panning required and no background subjects need be in the frame.

That is correct, aircraft propellers or a hummingbird's wing being examples. But is it going to be a significant problem when shooting dance?

It can be, if the electronic rolling shutter is slow and the dancers are fast, but in my experience I haven't seen it as a big issue.  But that's with a 1/400th mechanical shutter traverse.

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Lee Jay

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Dem Bell Regular Member • Posts: 343
Re: Rolling Shutter VS FPS confusion
1

Currantos wrote:

dancers need to be caught at the peak of the jump so high FPS is absolutely necessary, timing is very difficult. A microsecond before or after and they come out of a pose and both arms and legs are now "out of place" and scattered in space rather than "tucked in" so to speak.

If a microsecond makes a difference, then you need a 1,000,000 FPS camera. Culling might be a chore...

Seriously though, if the mechanical shutter is not an option because of the noise it makes, the only option you have is to use the electronic shutter and pick the shots that are not affected by the jello effect.

Hopefully will experiment one day and see, for now I don't have access to electronic shutter, just in the planning stages.

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. Keep in mind that there is another problem with the ES - it produces banding under some artificial light (some LED, fluorescent). If the light is flickering, you will be restricted to shoot at a relatively low shutter speed (of 1/120 sec or 1/60 sec in the US) to avoid this banding, but it can be done.

sybersitizen Forum Pro • Posts: 17,818
Re: Rolling Shutter VS FPS confusion

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 and the electronic shutter readout speed are two different factors. 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 thought 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.

Erik Kaffehr
Erik Kaffehr Veteran Member • Posts: 4,652
Re: Rolling Shutter VS FPS confusion
2

Currantos wrote:

So I am a little confused.

Silent shooting/electronic shutter is supposed to have worse/worst rolling shutter effect than mechanical. So the recommendation is to avoid it for fast moving objects.

For fast moving objects the recommendation is to use highest possible FPS to catch that best moment in an action sequence. Electronic shutter allows for higher FPS so one would switch to that.

? Conflict?

So which is it? Avoid it due to rolling shutter or use it to get the FPS?

Natural light situation?

Continuous stage/regular lights?

Advice on shooting athletes or a dance performance on stage? I want high FPS but I don't want rolling shutter. Looking for advice from mirrorless users that can choose from full mechanical, full electronic or EFCS which to use when.

Hi,

Rolling shutter is coming from the focal plane exposed at different time at top and bottom of the image.

At short exposures, faster than the X-sync time, the image is not exposed at the same time, but through a slit that moves across the frame, that movement is the cause of the rolling shutter.

With modern cameras we often have three options:

  • The old mechanical shutter. Shutter speed is closely related to X-sync time. So, with 1/300s X-sync speed the shutter moves across the frame in 3 ms, or so. 
  • Resetting a CMOS sensor is very fast. So reset of the sensor can be used instead of a fast moving mechanical shutter blade. This is used with Electronic First Shutter Curtain. But exposure is terminated by reading out the sensor, which is slow. So, EFCS uses the rear curtain to terminate exposure. It has two advantages on mirrorless. The first one is that exposure starts with shutter open. That gives short response times and zero vibration.
  • Electronic shutter uses linewise sensor reset to start exposure, but exposure is terminated by linewise readout. Reading the sensor output is a slow process, so scan time for ES is normally very long.

A camera like the Sony A9 has a sensor with very fast readout, using parallel processing. So the shutter may scan the sensor area in say 10 ms. That means it can be used in many situations, with small rolling shutter effects.
The ideal solution is a global shutter, that exposes the whole sensor at the same time. Leaf shutters work that way, but they have some limitations, too.
An electrical global shutter is quite possible, but it needs to be able to shift the charge from the photodiodes to a storage area in a very short time frame. In practice it means halving the dynamic range of the sensor and increasing noise with 41%. So it can be done, but it comes at a price.

In the end, for silent or fast shooting you need very fast readout, or a global shutter.

Leaf shutters have a great advantage with electronic flash, especially if the electronic flash is short duration. With short duration flash all the output of the flash can pass through the shutter while it is fully open. Most flashes are not fast enough to make full use of a modern leaf shutter.
HSS prolongs flash exposure time to perhaps 10ms by pulsating the flash. So if you shoot at 1/1000s you will waste 90% of the flash output.
Global shutters would be the ideal solution, but it seems that vendors are not willing to make the image quality sacrifice needed for an improvement that doesn't help the many.
Best regards

Erik

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Dem Bell Regular Member • Posts: 343
Re: Rolling Shutter VS FPS confusion

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. 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.

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

sybersitizen Forum Pro • Posts: 17,818
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.

Greybeard2017
Greybeard2017 Senior Member • Posts: 1,447
Re: Rolling Shutter VS FPS confusion

Currantos wrote:

So I am a little confused.

Silent shooting/electronic shutter is supposed to have worse/worst rolling shutter effect than mechanical. So the recommendation is to avoid it for fast moving objects.

For fast moving objects the recommendation is to use highest possible FPS to catch that best moment in an action sequence. Electronic shutter allows for higher FPS so one would switch to that.

? Conflict?

So which is it? Avoid it due to rolling shutter or use it to get the FPS?

Natural light situation?

Continuous stage/regular lights?

Advice on shooting athletes or a dance performance on stage? I want high FPS but I don't want rolling shutter. Looking for advice from mirrorless users that can choose from full mechanical, full electronic or EFCS which to use when.

If you want a fully silent shutter and high frame rate with minimal rolling shutter effect then its going to cost you.

The sensor readout time (which is the important metric for rolling shutter) is getting progressively faster and recent cameras such as latest Olympus OM-D, FujiFilm X-T3/X-T4 and especially Sony A9 may meet your needs.

You also have to watch for banding effects with some types of artificial light using the electronic shutter for the same reason as rolling shutter.

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