shutter on or off

[Robert Bale]

Hi, if i am shooting at 720p50 should i have the shutter on auto or off,

rob.

[Serena Steuart]

You shouldn't have the shutter on auto. Always select an appropriate shutter speed or angle. If you are shooting 50P then choose shutter speed 100, if is 50i shutter 50. You can shoot also with shutter off, in which case the related actual shutter speeds will match your frame rate (50 for 50P). These shutter speeds are common settings, but you change them to suit the subject.

[Mark Sudfeldt]

I'm shooting 1080 50i and the lowest shutter speed listed in the menu is 1/60 . . . . where do you find the lower speeds? Camera is setup for PAL.

Mark

[Serena Steuart]

Originally Posted by Mark Sudfeldt

I'm shooting 1080 50i and the lowest shutter speed listed in the menu is 1/60 . . . . where do you find the lower speeds? Camera is setup for PAL.

Mark

Menu/camera set/shutter: step up or down with joystick or scroll wheel. Minimum speed is 1/33, max 1/2000. Or if you select angle you can select between 180 and 11.25 deg.

[Mark Sudfeldt]

Just changed the formats around and tested the shutter speeds: both the i formats will only go down to 1/60; all the p formats go down to 1/33. Is that normal or is it my camera?

Mark

[Serena Steuart]

Originally Posted by Mark Sudfeldt

Just changed the formats around and tested the shutter speeds: both the i formats will only go down to 1/60; all the p formats go down to 1/33. Is that normal or is it my camera?

Mark

I hadn't noticed that (not using interlaced). One might expect that to cause flicker problems with 50Hz lighting. So set shutter angle 180.

[Dominik Seibold]

shutter-off = shutter-speed of 1/framerate = 360°-shutter
So 50p/50i with shutter-off results in a shutter-speed of 1/50.
When shooting 50 or 60fps I would go in most cases with shutter-off.

[Serena Steuart]

Originally Posted by Dominik Seibold

shutter-off = shutter-speed of 1/framerate = 360°-shutter
So 50p/50i with shutter-off results in a shutter-speed of 1/50.

Are you sure about that 1/50th? 50i is 25 fps -- I refrained from making that statement without actually measuring the exposure period. Obviously you are correct for 50P.

[Ian Briscoe]

I think it's widely accepted that what Dominik is saying is correct.

50i is 50 interlaced frames per second so whether shooting progressive or interlaced it still has to record that many frames per second. Shutter Off = frame rate.

Ian

[Dominik Seibold]

EX1s sensors can capture 1080p only. 1080i/720p is done by post-processing.

[Serena Steuart]

Originally Posted by Ian Briscoe

I think it's widely accepted that what Dominik is saying is correct.

50i is 50 interlaced frames per second so whether shooting progressive or interlaced it still has to record that many frames per second. Shutter Off = frame rate.

Ian

No, 50i is 25 fps. 50 fields/sec. I'm not saying Dominic is wrong, I was asking whether he is right. That is, fact, rather than opinion. The Phlogiston Theory of combustion was widely accepted. If the image is taken as progressive and processed out as interlaced, then shutter off is 1/25. However interlaced does require 1/50 sec difference between fields, so how would that be derived from a progressive image? Perhaps you're saying that 50i is actually 50P and the fields for 50i are derived from alternate frames? Seems a daft way to do things. You can see why I would prefer an actual measurement.

[Ted OMalley]

Originally Posted by Serena Steuart

The Phlogiston Theory of combustion was widely accepted.

Wow, pretty obscure, Serena! Had to look that one up.

What you're saying makes sense - I'm very intersted in understanding this all better.

[Dominik Seibold]

Originally Posted by Serena Steuart

Perhaps you're saying that 50i is actually 50P and the fields for 50i are derived from alternate frames?

Exactly.

Originally Posted by Serena Steuart

Seems a daft way to do things.

Please tell me a less daft way, if your base are progressive sensors. It's a flawless way.

Originally Posted by Serena Steuart

You can see why I would prefer an actual measurement.

Of course I checked it out long ago (I never use 50i), and the result was that with shutter-off and 50i I got a shutter-speed of 1/50.
50i also gives higher sensitivity, because the 50i-setting adds gain, to exploit the lower noise-level caused by the vertical low-pass-filter for reducing flicker.

[Piotr Wozniacki]

Anyway, in both 1080/25p and 720/25p/50p (in PAL; please adjust for NTSC), shutter off is 1/25th of a second. Period.

This is the reason why - when switching shutter on, the lowest selectable shutter speed is 1/33th.

[Dominik Seibold]

Originally Posted by Piotr Wozniacki

Anyway, in both 1080/25p and 720/25p/50p (in PAL; please adjust for NTSC), shutter off is 1/25th of a second. Period.

Sorry, but you are wrong. 720/50p with shutter-off gives 1/50-shutter.

Originally Posted by Piotr Wozniacki

This is the reason why - when switching shutter on, the lowest selectable shutter speed is 1/33th.

No, the slowest selectable shutter-speed depends on your framerate. But it's always faster than 1/fps or 360°, because else the electronic shutter wouldn't have a job to do and then it wouldn't make any difference if it is turned on or off.