Shutter Off?
 

I have been reading the SONY EX1 Shooting Tips on their website and I notice in all the examples and suggested settings they have they ALWAYS used shutter set to OFF. Is this what you guys do except for special effects?

The shutter setting for the generally desired film cadence is 1/2 of your frame duration, or 180° if you are using angle mode.

With 24p that means 1/48 second.

But there are many reasons why you would use something different. Examples: Shutter off gives you an extra stop of light for low light situations. And higher speed shutters might be good for action sports to make the motion crisper.

I like "shutter off," but many find that there's too much motion blur, especially at 24p.

Unlike most cameras, the EX1 sets the shutter speed equal to the inverse of the frame rate, rather than the conventional 1/2x the inverse.

24P at 1/32(the EX1 won't go below 1/32) is way too slow for me....very blurry. I believe Adam Wilt claims with the shutter off and 24p, you get 1/24 shutter, but, I think he's wrong on this fact.

The Panasonic HVX200 "shutter off" defaults to 180° or 1/(fps x 2) - the "film look"

But on many cameras (EX1 included), "shutter off" means a shutter of 1/fps. It's actually a much more logical way of doing it. The 180° shutter of film was based on necessity - there was a "blanking" time needed to pull the film through the gate. Video has no such requirement and really the 180° shutter is a choice made for aesthetic reasons - it's what we're used to seeing. But how that translates to "shutter off" on many cameras, such as the HVX, I do not know.

You can go below 1/32 on the EX1 - just choose "shutter off" at 24p. That's the same as a 1/24 shutter.

Assume you are shooting 60p with the shutter off and a flash fires.

I believe that the frame where the flash first appears would show the flash in the lower part of the frame and the next frame would show the flash in the upper part of the frame. The location of the break is random, but it should always follow the lower ... upper pattern.

What I'm not sure of and would love it if someone could try this... is how does it appear when played back?

Does it appear to your eyes as one flash or a rapid movement of the flash from bottom to top?


Bob Diaz

Bob,

I'll give it a try if I can.

For what it's worth, when I was testing my EX1 with a stroboscope synced to the SDI out, I varied the phase of the strobe and hence moved the "break" up and down in frame.

The one thing I noticed was a hairline of darkness between flashes - a line or maybe 3.

This would probably make the effect you describe slightly more noticeable. But I bet at 60p, given what we know about the refresh rate of the human eye, it would look very similar to one flash frame rather than two half-flash frames.

Eric: Your statementa about 24p being at 1/24th sec is what Bill says is not true. We need confirm or not if this fact before this thread can continue with meaning.

It has been confirmed many times that indeed, shutter OFF means one full exposure per frame, i.e. 1/24th with 24p, 1/25th with 25p, or 1/50th with 50i and 1/60th with 60i.

Michael,

It's is indeed true. That's why Sony doesn't have the base frame rate as a shutter speed menu option - instead you turn the shutter off.

Set the shutter to 1/48 (at 24p) on the menu. Now aim the camera at something. Turn the shutter switch on and off. You'll see everything get brighter by a stop with the shutter off. That's because shutter off means 1/24 shutter at 24p.

I have also tested and confirmed this by analyzing motion blur.

That you and I guess that answers why the Sony examples of normal shooting are all with shutter off. My shutter is OFF.

Evening light is coming, the day is cooling off (our first hot day here in the Californian desert) and I'm out to do some more test shots. This place really is the very best place to be for EX1 info that I have found.

Michael,

Actually, for the most pleasing footage out of the box, I would recommend a 180° shutter, or 1/48 at 24p. Shutter "on."

Don't know why Sony doesn't recommend this, except perhaps to extend the low light range of the camera.

So what does "auto" shutter do then ?

The hairline of darkness makes sense, because we know that any charge on the row elements must be dumped before "opening" the shutter for the next scan.

I'll guess that at 60p and maybe 30p, the split flash will look more like a single flash, but at 24p... that's a long delay between frames... so I don't know. I will be interesting to know the results.

Best Wishes,

Bob Diaz

Paul, Auto is the setting where the camera's TLCS itself changes the shutter for you, depending on the lighting conditions - it doesn't even inform you which shutter speed it's currently using. It's generally avoided to give the camera the control over shutter speed, but may be desirable e.g. when your priority is keeping aperture contant (i.e. for DOF control).

Thanks Piotr