View Full Version : 30i or 60i ?


Rich Wells
January 25th, 2008, 12:24 AM
Somehow I missed this in my training. Should I shoot at 30i fps or 60i fps on the Sony vx2000?
And If I am using 2 cameras on a project, the Sony and a DVX, should the Sony be at 30i and the DVX at 60i ?

Adam Gold
January 25th, 2008, 02:21 PM
There is no 30i mode. It's either 60 interlaced FIELDS or 30 interlaced FRAMES. All regular DV is 30fps, as in frames.

There's a 15p but it's useless.

Shoot everything at 60i.

Rich Wells
January 25th, 2008, 03:35 PM
..but what I am referring to is the shutter speed. The Sony allows these speeds: 1/4 sec, 1/8, 1/15, 1/30, 1/60, etc up to 1/ 90, 100,125, 180, 250, 350,500,725, 1000, 1500, 2000, all the way up to 1/10000.

Which one do I use normally? 1/30 or 1/60 or what?

Thanks.

Adam Gold
January 25th, 2008, 03:43 PM
Sorry, didn't understand that's what you were asking. Shutter speed and frame rate are two different things, and neither are the same as the recording mode (i/p, 30p vs 60i, etc.)

Always use 1/60. Slower will give you more motion blur and faster will be more "stroby." That's fine if that's what you want but trying to match two cams with different shutter speeds will be a nightmare.

Dave Dodds
January 25th, 2008, 03:56 PM
It depends on the look you're going for. I find the 1/30 shutter on my PD170 to be quite pleasing for many of the things that I produce myself. There's something different about it - in a good way. It gives a feeling of "not just regular video." That said, it apparently causes a reduction in resolution. I haven't noticed anything unpleasant when watching footage shot 1/30, but the loss of resolution has scared me into shooting regular 1/60 for most "for hire" shooting gigs I do. I'm a wuss.

Anyway, shoot some tests and see which you like better.

Good luck.

~~Dave

PS When mixing the DVX with the VX, I suggest shooting 60i on the DVX with a 1/60 shutter. Set the VX to 1/60. With appropriate white balance, you should be set and have nicely matching footage between the cams.

Rich Wells
January 25th, 2008, 06:04 PM
I am clear now on the difference between shutter speed and frame rate. Good. And I understand the diff between interlaced and progressive, but do these differ from "the recording mode (i/p, 30p vs 60i, etc.)" ?

Adam Gold
January 27th, 2008, 12:18 PM
It's an imprecise term, but recording mode usually refers to the combination of frame rate, lines of resolution and whether it is i or p.

Tom Hardwick
March 3rd, 2008, 01:46 AM
Whenever you drop below the default shutter speed (1/60th sec in your NTSC case) you halve the vertical resolution at a stroke. It's an ok deal when you must have static shots of buildings at night, because the resolution loss and motion blur is often preferable to the grain of gain-up I find.

tom.

J. Stephen McDonald
March 3rd, 2008, 08:17 PM
In the past, I'd often used faster shutter speeds, such as 1/250 or 1/500, when shooting sports or even wildlife, thinking it would give me sharper images. However, the subjects, especially the wings of flying birds, often showed fluttering or strobing effects, that made them seem to be in 3 different positions at once. The different frequencies of the wing beats and the frame rate, caught the wings in out-of-sequence positions. Since the short shutter time produced sharp images of the wings at these scattered positions, your eyes would register about 3 of them at any moment. Now, I always use normal or 1/60 shutter for them. This causes the motion blur that is inherent in human vision. Each frame shows wings blurred over a long part of the stroke. This eliminates the strobing of the wings and they look much the same as we'd see them naturally. Unless you're using a higher shutter speed to open the aperture and reduce the depth-of-focus, there isn't much point in using anything but 1/60. You can accomplish this with an ND filter, instead. If you intended to make still-captures from video later, high shutter speeds would be helpful, but since vid-caps generally look pretty poor anyway, I wouldn't ruin the video for regular viewing with higher than about 1/100 shutter. A news cameraman from a local station told me that they have all their camcorders rigged, so they can't be switched or automatically shifted to anything above 1/60.

Matt Helme
May 19th, 2008, 12:46 PM
I always shoot 30 interlace. It has a very good slow and almost Film like look.

Matt

http://groups.yahoo.com/groups/newjerseydocs

Tom Hardwick
May 20th, 2008, 01:10 AM
Stephen: beautifully put, and spot on. Another thing - upping the shutter speed on CCD cameras takes you deeper into CCD smear territory, so that's another reason to stay clear.

John Cline
May 20th, 2008, 04:08 AM
I always shoot 30 interlace. It has a very good slow and almost Film like look.

As Adam pointed out above, there is no such thing as 30 interlace.