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Old February 19th, 2009, 01:52 PM   #16
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Sorry Craig but you are wrong.

At 60i the shutter is 1/60th of a second. If it was 1/30th the shutter would be open for the entire frame, so both fields would be exposed for the full 1/30th of a second, effectively making a progressive frame. In interlace mode each field is exposed for 1/60th of a second then recorded one after the other so 1/60th plus 1/60th added together makes 1/30th.

If the OP wants the same effect then he should shoot at 30P with no shutter which would in effect be the same as a 1/30th shutter at 60i.

When you use a 1/30th shutter on a Z1 only one field is used for the full frame so you halve the vertical resolution.
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Old February 19th, 2009, 02:05 PM   #17
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Quote:
Originally Posted by Alister Chapman View Post
At 60i the shutter is 1/60th of a second. If it was 1/30th the shutter would be open for the entire frame, so both fields would be exposed for the full 1/30th of a second, effectively making a progressive frame. In interlace mode each field is exposed for 1/60th of a second then recorded one after the other so 1/60th plus 1/60th added together makes 1/30th.

If the OP wants the same effect then he should shoot at 30P with no shutter which would in effect be the same as a 1/30th shutter at 60i.

When you use a 1/30th shutter on a Z1 only one field is used for the full frame so you halve the vertical resolution.
This make sense.

This is a clear difference between the two cams.
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Old February 19th, 2009, 02:21 PM   #18
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[EX1 in 60i, in low-light conditions, iris open, shutter on 1/60] Turn shutter switch OFF and the image is exactly the same. No brightness increase.
Interesting. Works in 30p but NOT in 60i.
In 30p Shutter Off changes to 1/30th. You can see this by setting to 1/60 and then turning shutter off.
In 60i it's exactly as you note. Nothing happens. It stays at 1/60. Time to complain to Sony about this.

Alister you are correct and while I did not own a Z1, the PD-170, which I do have, apparently behaves the same way the OP describes the Z1. You were able to use shutter 1/30 in i60. Yes it would lower the horizontal resolution for sure but that's a tool available to the camera operator.

During a shoot in which the lighting becomes low it may make more sense to drop the resolution then to reboot the camera into 30p.
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Old February 19th, 2009, 03:06 PM   #19
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Originally Posted by Craig Seeman View Post
Omar, Sorry you feel I'm shouting.
No worries.

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Originally Posted by Craig Seeman View Post
i60 is 30 frames per second (59.97 fields per second).
p30 is also 30 frames per second.
They are both displayed at 30fps, not captured that way. One has twice the temporal resolution of the other and consequently half the exposure. It is my understanding that i60 is captured as p60, recorded as i60 and finally displayed at 30fps. If you had two cameras at the very same spot simultaneously recording a scene, one at i60 and the other at p30, every odd feild in i60 would be identical to the frames in p30 (disregarding the skipped scanlines).

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Originally Posted by Craig Seeman View Post
Your use of Hz is misleading.
i60 is 60 fields per second which is 30 frames per second.

1/15 is a measure in seconds. 1/15 of a second is just that. It has nothing to do with Hz.
Anything that is measured per second has everything to do with Hertz by its very definition (1Hz = 1 cycle per second ). A 1/15th shutter-speed would be 0.067Hz.

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Originally Posted by Craig Seeman View Post
Shutter speed doesn't "double." It's exactly what you set it to when using fractional time (as opposed to angle).
The suggestion was for shutter off, so no shutter speed is being set, just an equivalent. If there's no difference in illumination between shutter on at 1/60th and shutter off when in i60 mode then clearly they are one and the same thing. You get the same amount of illumination with shutter at 1/60th in i60 mode as you would with shutter off in p30 mode. If you don't beleive me try it for yourself.

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Originally Posted by Craig Seeman View Post
Both i60 and p30 are the same frame rate.
Only when displayed. Even then you get a different effect from them. The two feilds of an interlaced frame do not make one progressive frame.

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Originally Posted by Craig Terott View Post
I'm sorry I can't answer your question about distinct frames Omar unless I unearth some of my archived Z1 video (I no longer own the Z1).

But I can clearly explain how the two cameras behave very differently:

[Z1U in 60i ,in low-light conditions, iris open, shutter on 1/60] Now, I change the shutter from 1/60 to 1/30 and the image gets noticably brighter.

[EX1 in 60i, in low-light conditions, iris open, shutter on 1/60] Turn shutter switch OFF and the image is exactly the same. No brightness increase.

My observation demonstrates that there is no change, in 60i, between 1/60 and shutter OFF.

Was the motion you got with the Z1U smooth with a 1/30th shutter? If not then I strongly suggest SLS Frame: 2.
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Old February 19th, 2009, 03:34 PM   #20
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Was the motion you got with the Z1U smooth with a 1/30th shutter? If not then I strongly suggest SLS Frame: 2.
It was, at times, muddy. People dancing fast, for instance, would appear rubbery. I had to be selective about when to use it. I especially avoided using it if there was any fast motion in the frame, but it worked well for things like a very slow first dance. Or for a distant balcony shot in dim church.
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Old February 20th, 2009, 06:58 PM   #21
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At 60i, shutter off, the exposure is 1/60. I seemed to remember that we'd discussed this previously and I measured the shutter speed because I believed that shutter "off" would be 1/30. Actually we were talking about 50i, but that is irrelevant. see: shutter on or off - Page 2 - The Digital Video Information Network
So Craig's "complaint" is valid.
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Old February 22nd, 2009, 12:49 PM   #22
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I followed this thread, but I am wondering if my concern is the same as the one outlined here.
In my old camera (Sony VX2000), I had the possibility of shooting at 1/15th of a second and that gave me really clear pictures in the dark. Unfortunately with the EX1 that I have now, the slowest speed is 1/40th when using the 1080p30 HQ format. But when I choose 1080p24 HQ the slowest speed is 1/32nd. Same thing with choosing the format HQ720p. There is no way to get a speed as slow as 1/15th of a second.
Why Sony did not provide this possibility in this camera?
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Old February 22nd, 2009, 05:27 PM   #23
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Why Sony did not provide this possibility in this camera?
My old FX1 had shutter speeds down to 1/3, which gave interesting effects. The EX instead has frame accumulation (2 to 8, or 16/32/64), which is the equivalent.
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Old February 22nd, 2009, 06:27 PM   #24
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You can also use EX SLOW SHUTTER for slow shutter speed effects. It's basically the same as SLS but with even slower settings.
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Old February 23rd, 2009, 02:52 PM   #25
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Francois: 1/15th is two frames at 30P/60i, so using SLS set to 2 frames will give the same result.
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Old February 23rd, 2009, 02:59 PM   #26
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Francois: 1/15th is two frames at 30P/60i, so using SLS set to 2 frames will give the same result.
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