camcorder shutterspeed question rolling shutter etc for music instr video vixia100

[rhodycam]

Hi


I am new to camcorders, from photography. I am going to be shooting some music instruction videos, clear movement is the issue, so I do have some concern about selecting shutter speed. I have a vixia hf100 and plan on putting it in shutter speed priority at a certain rate.


From my basic research one concept is the best speed is double the frame rate, so 30 frames equal 60 shutter, 60 frames 120. This relates to the rolling shutter issue. I understand this conceptually. But these speeds seem a little low, but I am from photography and the lenses are bigger and I think that changes things. Perhaps these rates are fine for my purposes?


So, two questions:


1) For the music concept is there an optimal speed you would suggest?


2) Is there any benefit to higher multiples of the shutterspeed/frame rate concept beyond the doubling? Such as 30 rates per second x 3=90 shutter or x 4= 120 shutter speed.


Just looking for advice




Thanks!

 

[David Jimerson]

From my basic research one concept is the best speed is double the frame rate, so 30 frames equal 60 shutter, 60 frames 120.

No, it's not "best," but it was TYPICAL of film camera shutters.

A higher shutter speed makes motion look more staccato, and also darkens the image because not as much light gets in (so you need a lot more light for proper exposure). A slower shutter speed makes motion look more fluid, and lets in more light because it's brighter, but can also produce blurring as objects move faster than the shutter.

What's "best" depends entirely on your artistic needs. There's no "rolling-shutter" concern which would say "double the frame rate" is best.

Now, there are some rolling-shutter (or CMOS) issues involving lighting and light instrument flicker, but the shutter speed should be matched to the flicker, so it won't necessarily relate the frame rate.

1) For the music concept is there an optimal speed you would suggest?

As said above, that depends entirely on your artistic preferences.

2) Is there any benefit to higher multiples of the shutterspeed/frame rate concept beyond the doubling? Such as 30 rates per second x 3=90 shutter or x 4= 120 shutter speed.

Other than flicker control, it's all artistic.

 

[Bruce Watson]

From my basic research one concept is the best speed is double the frame rate, so 30 frames equal 60 shutter, 60 frames 120. This relates to the rolling shutter issue. I understand this conceptually. But these speeds seem a little low, but I am from photography...

Yeah, still photography experience isn't really much help in the video world. The common misconception is that video is really just a string of stills. And really, it's not. And that's where the "180 degree shutter rule" comes in (and it has nothing at all to do with rolling shutter, which is an entirely different problem).

Basically, to preserve the appearance and feel of motion, one uses a shutter speed that's twice the frame rate. So if you're shooting at 24 fps, you'd want a shutter speed of 1/48. This provides sufficient motion blur in each individual frame so that when you string them together and show them at 24 fps, motion looks continuous and natural.

It's not a hard and fast rule. It depends on your artistic intentions. Also, the higher you go with frame rate the less necessary the 180 degree shutter rule becomes. When you get up to the 120 fps range and higher, there's little motion blur in the individual frames any more anyway, so you can use a shutter speed that matches your frame rate (360 degree shutter) with little visual penalty (but you get that extra stop of light which becomes increasingly important as you go up in frame rate).

 

[rhodycam]

Thanks for your replies and your patience on the wrong term rolling shutter. I also heard that 90 sspeed is bad due to lighting frequency, so I will avoid it. I am going to follow the basic doubling rule for now. I also understand raising sspeed requires more light. But you lost me a bit with this sentence : “When you get up to the 120 fps range and higher, there's little motion blur in the individual frames any more anyway, so you can use a shutter speed that matches your frame rate (360 degree shutter) with little visual penalty” I understand the first part of little blur, but “matching frame rate with the 360 shutter “ I I lost it. If you can easily explain, please do so.

 

[Greg Smith]

A 360° shutter setting would mean the shutter is always open for the entire time of each frame -- 1/24 second at 24 fps, 1/120 second at 120 fps, etc. This is physically impossible in a cinema film camera (there needs to be some closed shutter time on each frame for the film to mechanically advance), but can be achieved in video. However, at slower frame rates/longer exposure times, it leads to more motion blur and can be perceived as smeary and laggy by the viewer. The traditional 180° shutter -- derived from longstanding film practice -- where the exposure time is 1/2 of the frame rate -- is a good compromise when the "shooting" and "viewing" frame rates are the same.

Most of the high speed work I've done personally has been for scientific research and technical documentation purposes, not for the viewing pleasure of a general audience, and in that case they often want the sharpest individual frames possible to make precise measurements of the event under study with the minimum of motion blur. So it's not uncommon to use a shutter speed several times faster than the frame rate, illumination permitting. I remember doing 1/30,000 of a second on a 1000 fps (film) shoot once, with a big bank of arc lamps aimed at a small test chamber.

- Greg

 

[Bruce Watson]

I understand the first part of little blur, but“matching frame rate with the 360 shutter “ I I lost it. If you can easily explain, please do so.

You didn't really lose it, you just didn't read it. What I said was "you can use a shutter speed that matches your frame rate (360 degree shutter) with little visual penalty". Emphasis mine.

IOW, after you increase your frame rate to 120 fps or higher, you can use a shutter speed of 1/120 or higher. So shutter speed matches frame rate.

But if it makes you feel better, you can always use a shutter speed that's twice the frame rate. It won't really hurt anything if that's the look you want.

 

[rhodycam]

hey, I understand now. Thanks!