Shutter Speed Question

[Rob Castiglione]

A basic question (I hope) concerning shutter speed.

I am in "normal" mode at 25 fps. Currently shutter speed is set to 1/50 which is what I would normally shoot at.

I wish to set shutter speed to 1/25 (or below this sometimes for some special effects shots) while maintaining frame rate at 25fps.

However, the camera will not permit me to do this. If I try and go below 1/50 the shutter speed indicator goes red and the shutter speed is not altered. I can however increase shutter speed above 1/50 - the numbers show white and I can see in the viewfinder that the shutter is being altered.

How can I set shutter speed to go below 1/50?

Thanks in advance,

 

[Charles Angus]

I can't speak to other shutter speeds, but anything below 1/25th shutter at 25fps cannot be done. Makes sense, if you think about it.

XDCAM's have emulation of lower shutter speeds than are possible, but at the expense of motion artifacting. I think Sony calls it "frame integration", but I could be wrong. I never thought it was a very useful feature, but that's just me.

 

[David Mullen ASC]

You can select a 360 degree shutter (i.e. no shutter), I don't recall the exact procedure.

You can't shoot though at longer exposure times than the capture rate allows - i.e. if your camera is taking a new image 25 times a second, then each individual image can't be exposed for longer than 1/25th of a second. Cameras that do allow longer exposure times than the capture rate "cheat" in some way, usually by actually dropping the frame rate to increase shutter time, then making up somewhere else to correct the motion.

 

[Rob Castiglione]

Okay, thats helpful to know that I cant go below 1/25 of a second.

However, I would be content at being able to go below 1/50 which I cannot do at present. For some reason, I cannot set it to 1/25 of a second. I am sure that it must be something embarrassingly simple - but even if it is I would really appreciate someone telling me.

Reading the manual, I thought that all I had to do was set the shutter mode to "normal" which would then allow me to set the shutter speed independently of the frame rate (which I guess you cant do for a mechanical shutter).

Thanks David. What effect would selecting no shutter have?

Best

 

[David Mullen ASC]

At 25 fps, no shutter (360 degrees) would just mean an exposure time of 1/25th. It would give you more exposure at the expense of more motion blurring, which can look a little smeary and video-ish in fast motion.

 

[Rob Castiglione]

Ahh I see. I will give it a go.

Thanks again.

Rob

 

[Cail Young]

You need to turn off OPEN GATE.

 

[Rob Castiglione]

Thanks Cail. I will give it a go.

I have been working with digital media now for some time and reducing shutter speed oddly can make it LESS like video.

Rob

 

[Rob Castiglione]

PS

I dont feel all that guilty about not being able to find it - it is hidden away in the video menu and I just wouldn't have been able to work it out from the manual! I think it would be useful to have a note in the shutter speed section about the effect of the open gate setting.

 

[Joe Christofori]

"Open Gate" should be called "Shutter OFF" or something more indicative of what it is.
When I saw this menu item, I started to wonder if I was going to have to "check the Gate" on this camera.

 

[Dominic Jones]

Well, it makes sense if you're coming from a film background - it is there to approximate the experience of looking through an OVF when not turning over, hence the name.

It also isn't really shutter off, which in "normal" video cameras will limit you to a single shutter speed (usually the equivalent of a 180 degree shutter for your given framerate) - with open gate engaged, you can still skinny the shutter on the R1, you just can't open up beyond 180. The reason for this is that the camera is actually exposing at double framerate with the same shutter speed (i.e. at 25 fps, 180 deg shutter it's exposing 50fps, each at 1/50th), and passing both frames to the EVF whilst only recording one - so there is no more time available to keep the shutter open for longer than 1/2 x fps seconds...

That said, if people find the naming un-intuitive as to what it's doing, then perhaps it could be better named - but there is always the manual! ;-)

Cheers,
Dom.