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Old November 17th, 2006, 11:03 AM   #31
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Quote:
Originally Posted by Thomas Smet
It doesn't matter. The HD-101E still shot a 50p video and the DSP dealt with a 50p stream. It was only the encoder that had to drop every other frame to give you a 25p encoding. This is why through the component outputs you could get the full 50p video. The same amount of pixels and data are still being pushed through the image block as before. The only difference now is that the encoder can finally handle the full 50p stream that comes from the DSP. Due to the better A/D handling and less noise you may find the HD200 to be a little bit better in low light due to the fact that you may be able to use a little bit more gain then you had in the past with the HD101E.
Great point Thomas. You're absolutely right. No wonder the light requirement looked identicle (to me).
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Old November 17th, 2006, 02:15 PM   #32
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Originally Posted by Werner Wesp
When shooting 50p, your standard shutter speed will be 100 (or up - for me it'll mostly be 100). that's twice as fast as the standard shutter speed on the HD101, so There needs to be a difference in adequate light.

But, I did indeed forget that the camhead of the HD101 already works in 50p, so the amount of light will be the same as amount the hd101 needs with a shutter of 100.....
You should not use a shutter speed of 100 if you shoot 50p. The shutter speed should also be 50 no matter what format you record in. Remember both cameras are really shooting the same 50p but the older one had to dump the frames down to 25p to go to tape. You still use the same 50 shutter speed however for the same type of motion. You would only use a 100 shutter speed if you plan on slowing down the footage to 50% and use it as 25p slow motion. The reason for this is because when it is slowed down it will act like a 50 shutter speed again so it will look natural and have the same style of motion blur as your normal speed 25p footage. Think of the HD101E as not any different then shooting with the HD200. The frames will look exactly the same except the 101E footage with have every other frame dropped due to the limits of the encoder. Just because you will now be able to record 50p doesn't mean the shutter speed has to change. The frames in the camera are still the same you just now get to record all of them.
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Old November 18th, 2006, 06:34 AM   #33
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Hhmmm, with the shutter speed the same as the time interval for recorded frames you normally don't get those natural results. Of course, at 50p it might be difficult to see. (just try 25p at shutter 25... you'll know, i'm talking about the 180 shutter look)

Anyhow, unless it is staged you never know beforehand what piece of footage you'll be slowing down. The interesting part just consists of the fact you CAN slow everything down smoothly if you want.

If I wouldn't be slowing it down anyway, I'd be shooting in 25p - which looks a lot more filmic, and you have to respect the cinematic rules in order to keep it looking good. Everything I'd shoot would be on 50p with shutter 100 then - but you are right, it would look as a HD100 with shutter 100 then...
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Old November 18th, 2006, 10:57 AM   #34
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50p is no different then 50i where 50i would use a shutter speed of 50. With 50i you have 50 interlaced fields. The only difference between interlaced and progressive is that with progressive each moment in time is the full resolution of the frame and not half the resolution. a shutter speed of 50 is the normal value of shutter speed regardless if you were shooting 12, 25, 50 or 100 fps.

Now if you prefer to shoot a shutter speed of 100 thats your choice but the HD200/HD250 is in no way worse in low light because you choose to shoot with a shutter speed of 100. In the case of 25p or 50p they represent the same moments in time it is just that the 50p has more images to represent that moment in time.

Remember an interlaced camera will usually shoot with a shutter speed of 50 or 60 depending on if it is PAL or NTSC. Those interlaced frames show us the same moments in time as a 50p or 60p video. So in order to have a natural 50 hertz looking video just like the motion you would get with interlaced cameras you will use a shutter speed of 50.

With 25p you would still use a shutter of 50 because the shutter represents that type of time interval. If you use a shutter speed of 25 with 25p you get a fake amount of motion blur because a shutter speed of 25 is not natural. By shooting 25p you are shooting at half the framerate but those frames still need to represent the same moments of natural time.

You also have to remember that with 24p and 25p the 180 degree rule may apply but with 50p and 60p it is no longer film motion but video motion so the 180 degree rule doesn't really apply anymore. The extra frames help reduce the jitter and make everythign look natural.
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Old November 19th, 2006, 06:53 AM   #35
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Originally Posted by Thomas Smet
You also have to remember that with 24p and 25p the 180 degree rule may apply but with 50p and 60p it is no longer film motion but video motion so the 180 degree rule doesn't really apply anymore. The extra frames help reduce the jitter and make everythign look natural.
Not entirely. If you would shoot 50i and slow it down, you still get the 180° shutter, because the footage is de-interlaced before slowing down (so it'll effectively be like half-res 25p before slowing down). In order to be able to slow any piece of 50p footage down - and keep it looking natural - you'll have to aquire everything with a 100 shutter. In normal frame rate (i.e. not slowed down 50p) it is probably to fast to see it isn't natural. Still, motion recorded in 1 frame is the motion that appears in the total interval - i.e. 1/50th of a second.

I cannot see the point of shooting 50p with a 50 shutter-speed. definition won't go up (because the shutter speed is the same), slowing down isn't interesting because it'll look blurry and unnatural anyway (because the shuttertime is as long as the framerate-interval). The only thing is that you'll be able to pan at any speed you want, instead of respecting the filmic rules to keep it looking good... but your final result will look less crafted then anyway. For non-slowed-down clips 25p is fine (imo), you just have to craft your shooting skills. 50p definately opens up new possibilities, but only at shutterspeeds of 100 and up...

Quote:
Originally Posted by Thomas Smet
50p is no different then 50i where 50i would use a shutter speed of 50. With 50i you have 50 interlaced frames. The only difference between interlaced and progressive is that with progressive each moment in time is the full resolution of the frame and not half the resolution. a shutter speed of 50 is the normal value of shutter speed regardless if you were shooting 12, 25, 50 or 100 fps.
Not at all. 50p records full frames while 50i records 25 frames that consist of 50 half frames. But 2 adjascent fields do not share any information in their image - the frames in 50p do...

Furthermore, suppose you shoot 100 fps at a shutter speed of 50 (which you say is a normal value), what would be the point of shooting 100fps then? 2 following frames would be exactly the same because they are recorded in the same time interval - it would be virtually like shooting 50p. Try to shoot 25p with a 12.5 shutter speed - you'll know what I mean. Obviously a shutter speed of 50 would be fast enough not to notice when shooting e.g. 100 fps, but it would serve no point of recording 100 frames then.
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Old November 19th, 2006, 03:08 PM   #36
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Originally Posted by Werner Wesp
Not entirely. If you would shoot 50i and slow it down, you still get the 180 shutter, because the footage is de-interlaced before slowing down (so it'll effectively be like half-res 25p before slowing down).
This is just plain wrong, it depends on the deinterlacing method. A bob, which most tape decks use, will effectively create half-res 50/60p. Adaptive deinterlacing and motion compensation can create what appears to be full-res 50/60p. Field Blending is the only deinterlacing technique which would result in half-res 25/30p.

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In order to be able to slow any piece of 50p footage down - and keep it looking natural - you'll have to aquire everything with a 100 shutter.
Again, incredibly wrong. Watch a sports broadcast some time, 99% of the slomo you see is shot by cameras operating at a native 1/50 or 1/60 shutter. Yet that slomo does not look any less "natural."

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I cannot see the point of shooting 50p with a 50 shutter-speed.
Because you are living in your own very tiny indie film world while completely ignoring the fact that people use this camera for other things. Remember that the 50p and 60p capabilities of this camera aren't simply for being able to shoot slomo, but primarily for being able to shoot at the native frame rate of the broadcast HD standard of your country. Being able to slomo it for 24p is just a bonus. Shooting video for broadcast requires the look resulting from a frame interval shutter speed

Quote:
For non-slowed-down clips 25p is fine (imo), you just have to craft your shooting skills.
You have obviously never shot sports highlights. I invite you to go to a hockey game and shoot from the glass and tell me that 25p is fine. Because this sort of situation is exactly why I waited for the HD250 over the HD100.

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Furthermore, suppose you shoot 100 fps at a shutter speed of 50 (which you say is a normal value), what would be the point of shooting 100fps then? 2 following frames would be exactly the same because they are recorded in the same time interval - it would be virtually like shooting 50p. Try to shoot 25p with a 12.5 shutter speed - you'll know what I mean.
Wow. You don't even know how your camera works. Not only is your argument irrelevant (we're talking about shooting at the reciprocal shutter speed of the frame rate, not saying that 1/50 is the "ideal" shutter speed), when shooting at 1/12.5 the camera is shooting at 12.5 frames per second and pulling that frame down over 4 50p frames. You are not shooting "25p with a 1/12.5 shutter", you are shooting 12.5p. If it were actually physically possible to shoot with a shutter speed longer than the frame interval, the effect would be of motion blur from adjacent frames overlapping. From a temporal resolution standpoint it probably would be pointless to shoot that way, but it could be a rather interesting effect if you want maybe a "dreamy" sort of look. After I submit this post I'll work up a demo in my 3D software, which does allow these sort of weird shutter effects.
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Old November 19th, 2006, 03:48 PM   #37
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Quote:
Originally Posted by Stephan Ahonen
Again, incredibly wrong. Watch a sports broadcast some time, 99% of the slomo you see is shot by cameras operating at a native 1/50 or 1/60 shutter. Yet that slomo does not look any less "natural."
I'm not sure this is entirely accurate either. The slow motion I see on TV sports (for example footbal or gymnastics) is much too sharp in freeze frame to have been shot with a 1/60 shutter.

I think super motion cameras are possibly more the standard, shooting at 180 frames a second (NTSC) at high shutter speeds. These cameras also send out a regular video feed, etc. etc.:
http://www.evs.tv/Products/SuperMotionMode.asp
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Old November 19th, 2006, 06:52 PM   #38
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Originally Posted by Jack Walker
I'm not sure this is entirely accurate either. The slow motion I see on TV sports (for example footbal or gymnastics) is much too sharp in freeze frame to have been shot with a 1/60 shutter.
I do live broadcast sports production for a living. When I say this stuff, I'm not pulling it out of my ass, I'm saying it because I've run the cameras, I've been in the trucks, and I've looked at the camera CCUs that say they don't have shutter engaged. Of course it is up to the individual preference of each video operator whether they use shutter, but I know that if someone made a habit of putting shutter on everything, they'd get a lot of complaints from camera operators who won't like the loss of two stops of exposure, especially with a zoom extender that's also cutting out two stops. Focus is hard enough at the end of a 70x lens without the video operator opening the iris even more with unnecessary shutter.

Quote:
I think super motion cameras are possibly more the standard, shooting at 180 frames a second (NTSC) at high shutter speeds. These cameras also send out a regular video feed, etc. etc.:
http://www.evs.tv/Products/SuperMotionMode.asp
I'm well aware of the existence of supermo cameras, and they're not used nearly as much as you would think. While some big shows like Monday Night Football can get trucks built specifically for their shows, most shows rent trucks built by a truck company that's trying to do it for the least amount of money possible. For most truck companies it's simply not a worthwhile investment. I've only personally been in two trucks that have had a supermo camera, the MNF camera truck, and a truck that was doing college football for ABC. This is out of countless trucks from many different truck companies.

The other big issue with supermo is that the camera taken live on the air looks very juddery and the picture quality does not match the other cameras in the show. It's enough of a downside that you'll generally only see it used in shows that can afford to hire enough crew where you can have a guy running a camera that will only show up in replays. The one exception I've seen was the recent NBC Stanley Cup coverage where they used supermo on the high-tight shot, which for hockey is taken live very often. The quality difference between the high tight and all the other cameras was blatantly obvious.
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Old November 19th, 2006, 07:10 PM   #39
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I'm sure you are right. There's just something that I can't understand about it. I don't understand how they make frozen images of fast moving people and objects that are completely sharp but are exposed for 1/60 of a second.

But then I also don't see how they keep everything in focus with the distances changing so fast from far to close... I guess just experience and turning the focus control based on the distance of the object from the lens.

Then there are the flying cameras that are also in focus. Are they just very wide angle and using a fixed focus?
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Old November 19th, 2006, 07:45 PM   #40
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..........

Last edited by Jack Walker; November 19th, 2006 at 08:16 PM.
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Old November 19th, 2006, 09:06 PM   #41
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Originally Posted by Jack Walker
I don't understand how they make frozen images of fast moving people and objects that are completely sharp but are exposed for 1/60 of a second.
How often do you see an actual freeze frame? If you actually freeze-framed the footage you'd see that moving objects are actually blurred, it's just that when you see a sequence of blurred frames, your eye turns the motion blur into the illusion of motion.

Quote:
But then I also don't see how they keep everything in focus with the distances changing so fast from far to close... I guess just experience and turning the focus control based on the distance of the object from the lens.
That's pretty much it. Not many people can do it completely perfectly, even on a show like MNF you'll sometimes see an operator struggling with focus on a very tight shot of a player running toward him.

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Then there are the flying cameras that are also in focus. Are they just very wide angle and using a fixed focus?
I take it you're referring to Skycam (or Fox's Cablecam, or whatever CBS is calling theirs)? It's not a fixed focus, but typically the shot is wide enough that everything can be in focus due to a large depth of field. Remember the photography rule that depth of field is related to object magnification on the imaging surface (film, CCD, whatever). With 2/3" chips head-to-waist is about the point where the depth of field starts to isolate an individual subject. Skycam is always at least head-to-toe, usually even wider, so focus is not that much of an issue.
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Old November 19th, 2006, 10:29 PM   #42
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I made some examples of how shutter speed affects motion rendering, including a hypothetical example of what an effective 720 degree shutter would look like and I have uploaded them here. In practice, you can achieve this effect by taking each frame and averaging it with the frame directly after, but ONLY with 1/50 or 1/60 shutter in 50 and 60p modes. You might end up with a slight "gap" in the motion trail, I haven't actually tried it.
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Old November 20th, 2006, 01:52 AM   #43
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I watch F1 all the time, and those super slo-mo shots of the tyres in the chicanes definately are made with a higher shutter then the frame rate. Don't know what the frame rate is, but it could be as high as 400. By the way. a high shutter speed is just the thing for sports. Otherwise you'd lose the sharpness due to motion.

In sports, shutter speeds are dictated by the action rather then by the filmic result....

Quote:
Originally Posted by Stephan Ahonen
This is just plain wrong, it depends on the deinterlacing method. A bob, which most tape decks use, will effectively create half-res 50/60p. Adaptive deinterlacing and motion compensation can create what appears to be full-res 50/60p. Field Blending is the only deinterlacing technique which would result in half-res 25/30p.
Well, I'm not saying there aren't better methods of deinterlacing, but you always have a starting point with just half the information. You can blend, you can interpolate, ... and the results will indeed be better then 'just' cutting the resolution in 2....

Quote:
Originally Posted by Stephan Ahonen
Again, incredibly wrong. Watch a sports broadcast some time, 99% of the slomo you see is shot by cameras operating at a native 1/50 or 1/60 shutter. Yet that slomo does not look any less "natural."

Because you are living in your own very tiny indie film world while completely ignoring the fact that people use this camera for other things. Remember that the 50p and 60p capabilities of this camera aren't simply for being able to shoot slomo, but primarily for being able to shoot at the native frame rate of the broadcast HD standard of your country. Being able to slomo it for 24p is just a bonus. Shooting video for broadcast requires the look resulting from a frame interval shutter speed

You have obviously never shot sports highlights. I invite you to go to a hockey game and shoot from the glass and tell me that 25p is fine. Because this sort of situation is exactly why I waited for the HD250 over the HD100.
Actually I have. And it's a bitch. 25p isn't the ideal format to shoot sports in, but it can be more then fine. Most people won't even notice. If you're doing ENG and can't have full control of your framing and POV when shooting, 25p will make it almost impossible to get nice fluent shots. Still, Newscasting isn't what this camcorder is aimed at...

Quote:
Originally Posted by Stephan Ahonen
Because you are living in your own very tiny indie film world while completely ignoring the fact...
Besides - no reason to get personal...

Quote:
Originally Posted by Stephan Ahonen
Wow. You don't even know how your camera works. Not only is your argument irrelevant (we're talking about shooting at the reciprocal shutter speed of the frame rate, not saying that 1/50 is the "ideal" shutter speed), when shooting at 1/12.5 the camera is shooting at 12.5 frames per second and pulling that frame down over 4 50p frames. You are not shooting "25p with a 1/12.5 shutter", you are shooting 12.5p. If it were actually physically possible to shoot with a shutter speed longer than the frame interval, the effect would be of motion blur from adjacent frames overlapping. From a temporal resolution standpoint it probably would be pointless to shoot that way, but it could be a rather interesting effect if you want maybe a "dreamy" sort of look. After I submit this post I'll work up a demo in my 3D software, which does allow these sort of weird shutter effects.
This is EXACTLY the point I was making. Shooting 100p at a shutter speed of 50 doesn't make any sense, because it is like shooting 50p (you should've know this if you actually read my post). It is actually possible to read out a CCD when the shutter is open, by the way - the read out might just end up somewhat strange. Anyhow, the point I was making was that shutter speeds below the framerate are nonsense, because they defeat the purpose of shooting in a high framerate - I was merely reaction to this statement:

Quote:
Originally Posted by Thomas Smet
a shutter speed of 50 is the normal value of shutter speed regardless if you were shooting 12, 25, 50 or 100 fps.
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Old November 20th, 2006, 02:01 AM   #44
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Again, incredibly wrong. Watch a sports broadcast some time, 99% of the slomo you see is shot by cameras operating at a native 1/50 or 1/60 shutter.
I agree - and that's the kind of slo-mo you can see is slo-mo-ed video, instead of dedicated footage, meant to slow down (i.e. shot at high frame rates and high shutter speeds).

Quote:
Originally Posted by Stephan Ahonen
Yet that slomo does not look any less "natural."
Well yes it does. and not due to the low framerate it is in... due to the look of that footage slowed down...
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Old November 20th, 2006, 02:04 AM   #45
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How often do you see an actual freeze frame? If you actually freeze-framed the footage you'd see that moving objects are actually blurred, it's just that when you see a sequence of blurred frames, your eye turns the motion blur into the illusion of motion.
Hmmm, may be it's only here in europe they record and broadcast sports shot in high shutter speeds then. Those frame-by-frame replays usually have very little motion blur here...
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