View Full Version : Fast Shutter speed (not needed)


Guy Godwin
December 29th, 2007, 12:06 AM
Hello folks!!
I hope everyone had a fantastic Holiday season and enjoying the Bowls like me!!

Anyway, I am wondering the impact of having a shutter set too fast. I am using an XL2 but don't think this pertains to that unit. Over the holiday in the Mountains the temp got up in the 60's and I had the opportunity to have my childeren out side. The sun was setting and the lighing was very good. I have 13 month old twinns and a 6 year year old football freak playing with his cousins.

I used this chance to tinker with some setting's. The color setting was good etc..etc.. I had the Iris open and the shutter at 1/1000 (very fast).

I was able to get very detail shots of the white stripe on the football as it rotated while being passed. However, my shots of the everything else did not seem as good as I would have expected. I know this shutter is extreme, but what I am wondering is how much does it effect the other slow moving image quality with this type of shutter?

Does anyone has any experience with this?

Just my novice experience tells me that these images will not be as crisps as there is less exposure time (at that moment).

Phil Hoppes
December 29th, 2007, 09:28 AM
Shutter speed in a video camera is not unlike shutter speed in a SLR still camera. The faster your shutter speed, the better your ability to capture a fast moving object. Also, the more light is required illuminating your subject for a given fix F-Stop on your iris as you are allowing a shorter exposure time. Video has a few additional parameters that you don't have with a still camera. That is FPS and the method (interlaced or progressive) in which you shoot. The shutter on a video camera, to my knowledge, operates no differently than the shutter on a SLR. You set a speed for the shutter and it will open and close at that speed rate. There are a few things however that get interesting, when it comes to slow shutter rates and frame rates. If, for example, you set a shutter speed slower than the frame rate, you have a problem. Actually I've never done this on my camera so I don't know what happens but my guess is the camera will not allow you to do it, at least without some intervention. I know with the XL2 you can set it up for basically time laps video. Here, you have intervened and set a very low recording rate. With this setting you should now be able to set a shutter speed that is less than 1/60 for 60i or less 1/30 for 30p.

For fast moving objects, ie, sports, you have shown to yourself that a fast shutter speed will capture detail that would otherwise be missed. The $60,000 question, however, is do you need that detail. Others have posted there is no reason to shoot faster than 1/60 in 30p. I disagree, but my needs are quite specific. As I've posted on your other post, it is critical that my customer be able to review the final product frame by frame and see specific details. That is a pretty unique requirement. Shooting 1/2000 at 30p works super for this, where as shooting 60i leaves a slew of interlace artifacts that are quite annoying. If, on the other hand, you will only view your final product in full motion, 60i is much better choice as to the eye/brain combination, 60i appears a little smoother. It remains to be seen if you can actually pick out the extra detail a faster shutter speed will give you.

If you really want to slow down high speed action, then you need to either shoot in a high speed video or high speed film camera so your recording rate is substantially higher than 30/60 FPS. These are both available, for cubic dollars I might add..........

Greg Boston
December 29th, 2007, 10:53 AM
to my knowledge, operates no differently than the shutter on a SLR. You set a speed for the shutter and it will open and close at that speed rate.

Phil, there is no mechanical shutter to open and close such as you would find on a SLR. The shutter is an electronic gate that ends the light charge accumulation on the CCD prematurely (with respect to frame rate). Some cameras (such as my F350), can be set for slow shutter. I can dial in an accumulation of up to 64 frames ( a little over 2 seconds in 30P).

-gb-

Phil Hoppes
December 29th, 2007, 11:43 AM
Phil, there is no mechanical shutter to open and close such as you would find on a SLR. The shutter is an electronic gate that ends the light charge accumulation on the CCD prematurely (with respect to frame rate). Some cameras (such as my F350), can be set for slow shutter. I can dial in an accumulation of up to 64 frames ( a little over 2 seconds in 30P).

-gb-

Thanks, that is what I wondered about. I kinda figured it was not mechanical as in a SLR but I was not sure. In terms of it's basic function, however, I would not think that there would be much difference. On a frame by frame basis as opposed to an DSLR, a 1/125 shot or 1/1000 shot, should, all other things being equal (ISO, F-stop) produce similar results. Granted, my 40D has MUCH better resolution than my XL2. The results would be a little difficult to compare given the differences in the delivery of the final image (Raw or JPEG vs 30p or 60i compressed DV) I'm curious, is this too how DSLR's work too?

Answered my own question. My 40D is mechanical.

Greg Boston
December 29th, 2007, 01:41 PM
There are some who say that the electronic shutter of a video camera will produce a slightly different motion signature than that of say a motion film camera which does use a mechanical shutter (but not the curtain type that has been used in SLR still cameras). But for all intents and purposes, they are very similar in how you apply them to the creative process.

-gb-

Richard Hunter
December 29th, 2007, 06:54 PM
If, for example, you set a shutter speed slower than the frame rate, you have a problem. Actually I've never done this on my camera so I don't know what happens but my guess is the camera will not allow you to do it, at least without some intervention. I know with the XL2 you can set it up for basically time laps video. Here, you have intervened and set a very low recording rate. With this setting you should now be able to set a shutter speed that is less than 1/60 for 60i or less 1/30 for 30p.



Hi Phil. It is easy to do this actually, the shutter speed setting is independent of the frame rate and the camera does not prevent you from selecting slow shutter speeds.

How it appears to work is that the frame rate determines the sample point (in time) for the signal on the CCDs, and the shutter speed determines when the CCD is refreshed. So if the shutter speed is longer than the frame period, the signal that is sampled (at the frame rate) will contain portions of all the light received since the previous CCD refresh. In practice, if there is any movement in the scene, or if the camera is moving, you will see a lot of motion trails due to the low CCD refresh rate. You can sometimes use this as a deliberate effect although I wouldn't want to overdo it.

Richard

Guy Godwin
December 29th, 2007, 08:46 PM
Phil, there is no mechanical shutter to open and close such as you would find on a SLR. The shutter is an electronic gate that ends the light charge accumulation on the CCD prematurely (with respect to frame rate).
-gb-

Based on this premise.

How does this effect the same shot that is at the "more suited" slower shutter? Using my example of shooting 1/1000 on kids playing in the street. My images do not look as crisp as others. Could this be a result of the shutter speed?

Daniel Browning
December 29th, 2007, 09:00 PM
Using my example of shooting 1/1000 on kids playing in the street. My images do not look as crisp as others. Could this be a result of the shutter speed?

At 1/1000, it's far more likely that the lack of "crisp" was caused by some factor aside from motion blur. Chief among those is processing. How, exactly, are you viewing this footage?

Guy Godwin
January 1st, 2008, 09:03 PM
Captured on to my PC.

Daniel Browning
January 1st, 2008, 09:14 PM
Please be more specific.

For example, if you used firewire and Windows Movie Maker's "best settings for playback on the computer", that would have caused compression and loss of detail.

Or, if you used an analog capture card with an s-video, composite, etc. cable, the AD-DA conversion may cause loss of detail.

Perhaps the softness was caused by diffraction due to a narrow aperture (e.g. f/8).

Guy Godwin
January 2nd, 2008, 08:44 AM
Please be more specific.

For example, if you used firewire and Windows Movie Maker's "best settings for playback on the computer", that would have caused compression and loss of detail.

Or, if you used an analog capture card with an s-video, composite, etc. cable, the AD-DA conversion may cause loss of detail.

Perhaps the softness was caused by diffraction due to a narrow aperture (e.g. f/8).

I used a firewire connection and captured into an .avi with Pinnacle Studio ver11.

based on these responces I assume that the shutter speed being at 1/1000 would not have a negative impact on picture quality?

Nik Skjoth
January 2nd, 2008, 12:40 PM
Definatelly not... In theory: the higher the shutter speed, the more crisp the image.

But I can emagine that with a 1/1000 shutter speed, anything but highlights would be greatly underexposed. Hence the poor image.

Eric Ramahatra
January 28th, 2008, 10:16 AM
hi,

i will be shoting a short this week end and would like some advice on setting the shutter speed : what's wrong using the higher shutter speed available for the lighting ? if i could go 1/200 or more should i do it or better to stay 1/50 (shooting at 25fps progressive).

Guy Godwin
January 30th, 2008, 11:22 AM
Eric,
For the group to understand your shoot better. Can you explain what you are shooting and what are the lighting conditions etc..What is the footage used for and what look do you want?

Example: Is it a Wedding or a basketball game. if it is basketball will the footage be used to training or just watching.

Anyway, just give some details and I am sure this group will get it right.

Nik Skjoth
March 22nd, 2008, 09:17 PM
Eric. The answer to that question is surprisingly simple. and it goes like this..

If you want to be able to see crisp movements with no motion blur, use a fast shutter speed. If you instead are looking for a more cinematic soft movement with motion blur stay at 1/50.

There are exeptions tho. If you have running or splashing water in the shot, don't go above 1/125, if you want it to look realistic like with the human eye. If you are shooting for slowmotion, multiply the shutter with the slowmotion ratio you are going for. forinstance:

regular speed shot at 25fps 1/50 shutter speed
Slow motion shot at 50fps 1/100 shutter speed.

The higher the shutter speed, the more edgy a pan, or passing object will become. You will see it more clearly when paused, but it might look harsh in full motion. (great for sports tho)

The standard for motion picture film is 1/50