NEX-5 Video - crazy shutter speeds.

Started Jan 29, 2011 | Discussions thread
dvcinlv
Regular MemberPosts: 114
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Re: to make things clear
In reply to izash, Feb 1, 2011

Canon owners don't "insist." A 180-degree shutter is a convention that is easy to remember. My 16mm Bolex, for example, had a 150-degree shutter. Moreover the 180-degree rule was a film camera's convention.

Cheap, under $30,000 HD cameras have sharp edges that increase the visibility of judder. So one would want more motion blur. But, too much blur cuts resolution too much. (You can't see details lost in blur!)

For PAL, 1/40th to 1/60th is fine. For NTSC, 1/50th to 1/80th is fine.

But, it's hard to get an exact value -- hence the range 1/40th to 1/80th.

It also depends on how an object in motion passes through the frame. That determines the object's "motion vector." When you stand beside a freeway, the car vectors are VERY high. (You need a lower shutter speed.) If you shoot an intersection from a distance and cars are slowly making turns, their motion vectors are very low. (You can live with a shutter speed up to 1/100th.)

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Now about gain. The NEX and VG10 share the same parts. Only the firmware is different. The VG10 has a +21dB limit. Looks like Sony disabled this just like they disable Focus Assist on the VG10. Thank you for the feedback, I'll change that in my eBook. But, you will see noise once you go above 1600 ISO so it's pretty obvious when too much is being used. I explain how you can use a lightmeter to determine what the gain is, but that may be overkill. (But, if you do use a meter, you can instantly know how much light must be added to get the gain down to the point you want.)

Because they share the same parts, there's no reason to feel you need to buy a VG10. So if you want to explore filmmaking, you can do so with a NEX. In fact, I started with a VG10 and quickly realized if I was going to use old lenses I needed Focus Assist. So I switched to the NEX-5 to get it. There are other real advantages to the NEX-5 and the NEX-3. (But, I do miss the VF in bright light.)

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"I know RED is the first hint of anything digital... but I was under the impression that some more dedicated digital kit at least had sensors tailored to video resolutions and maybe employed less heavy chroma subsampling and video compression. ...but I would have thought the VG-10 might have provided some extra processing grunt to make more use of the sensor data and raise itself to a truly groundbreaking product."

Alas, the ability to interpolate rather than discard is what is needed yet available only from RED. What Sony will do on camcorders above the VG10 is to place a proper low-pass filter on the front of the sensor. This result in a much cleaner pix, but not a real increase in rez.

The VG10 has a camcorder shape, but no better image.

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