Setting shutter speed whilst filming

Hi everyone.
I see it written and said that the shutter = 2x the frame rate for shooting video. Is this to mean exactly 2x the frame rate (or closest to it possible) with no deviation or at least two times the frame rate? Seems like 1/50 for 24fps might be difficult outdoors unless one carries lots of ND filters around.

Set shutter as close as possible to twice the frame rate. That's the guideline. Yes, ND filters might be needed. That's one of the reasons I stopped using a dlsr for video.

Thanks. I didn't know there'd be a difference in a cinema camera's requisite frame rate and a DSLR. So all I have to is buy a C300 Mark II and I can save on some ND filters!

Larry Johnson wrote in post #18367703
That's the guideline.

Emphasis added!

Lots of dslr video shooters violate this every day. I read online that some prefer it. I'm a traditionalist, typically shooting 30fps at 1/60th of a second shutter speed.

What you need to look out for is how motion is represented. If you like it, and your viewers like it, ignore the 100 years of film history!

Silver-Halide wrote in post #18367704
Thanks. I didn't know there'd be a difference in a cinema camera's requisite frame rate and a DSLR. So all I have to is buy a C300 Mark II and I can save on some ND filters!

Ha. Yeah. It wasn't about the price of the ND filter, it was the hassle and didn't like the quality of the variable ones.
I bought a lumix fz2500 with built in nd filters. Would love to have a C300 or Red but I'm not rich.

Larry Johnson wrote in post #18367764
Ha. Yeah. It wasn't about the price of the ND filter, it was the hassle and didn't like the quality of the variable ones.
I bought a lumix fz2500 with built in nd filters. Would love to have a C300 or Red but I'm not rich.

Yeah you and me both. but my guess is that if I were to talk myself into say a C100 Mk II or something like it but had no money leftover for a nice mic, boom, and some light panels that I'd have been better off with my good old 5d Mark III and all those critical accessories.

You might be interested in info on the forum linked below regarding the fz2500 and wedding videography. http://www.dvinfo.net …sonic-lumix-lx-fz-series/

reading...

thanks

THer is another video on Vimeo that shows a ceiling fan at various frame rates, it's a good one, but I can't find it right now.

Notice that that they make large jumps 1x,2x,4x to show the difference. Smaller jumps won't show much difference.

I need to talk about this a bit to see if I understand what's happening.

There are two things going on related to subject motion.

One is that the shutter speed (length of time the shutter exposes the sensor for each frame) controlling exposure. So at 1/60 sec shutter speed, the sensor is being exposed for each frame for 1/60 second.

But also the shutter is chopping the motion of the subject into discreet segments with gaps in the total motion.

So at, say, 30 fps, a second of continuous motion is chopped into 30 segments. But each segment is only 1/60 second, so I've actually only captured a half second of that second of continuous motion in 30 segments with 1/60 of a second of gap between each 1/60 second of capture. At the same time, that 1/60 shutter speed is allowing a certain amount of motion blur in each frame.

If I increase the shutter speed to 1/125 of a second and keep the frame rate at 30fps (opening the aperture or increasing ISO to compensate exposure), then I've only captured 1/4th second out of that second of motion--there is a twice as much gap in the motion from frame to frame. From one frame to the next, I'm missing twice as much motion with twice the shutter speed. But that faster shutter speed also cuts the amount of motion blur in half in each frame.

Thus, the video will look choppier at the faster shutter speed because not only am I losing more of the continuous motion, but each image is also sharper. As I raise the shutter speed more, the eye begins to discern each frame as a separate image because it is sharper with more gap in the continuous motion before the next frame.

Now, my question here regards metering. Up until now, I've been using a still camera light meter. But I'm not sure what a cine meter--with an fps setting instead of a shutter speed setting--actually does for me with video. Does the cine meter presume a fixed relationship between shutter speed and fps that exists with a film camera but not with video?

RDKirk wrote in post #18418814
I need to talk about this a bit to see if I understand what's happening.

There are two things going on related to subject motion.

One is that the shutter speed (length of time the shutter exposes the sensor for each frame) controlling exposure. So at 1/60 sec shutter speed, the sensor is being exposed for each frame for 1/60 second.

But also the shutter is chopping the motion of the subject into discreet segments with gaps in the total motion.

So at, say, 30 fps, a second of continuous motion is chopped into 30 segments. But each segment is only 1/60 second, so I've actually only captured a half second of that second of continuous motion in 30 segments with 1/60 of a second of gap between each 1/60 second of capture. At the same time, that 1/60 shutter speed is allowing a certain amount of motion blur in each frame.

If I increase the shutter speed to 1/125 of a second and keep the frame rate at 30fps (opening the aperture or increasing ISO to compensate exposure), then I've only captured 1/4th second out of that second of motion--there is a twice as much gap in the motion from frame to frame. From one frame to the next, I'm missing twice as much motion with twice the shutter speed. But that faster shutter speed also cuts the amount of motion blur in half in each frame.

Thus, the video will look choppier at the faster shutter speed because not only am I losing more of the continuous motion, but each image is also sharper. As I raise the shutter speed more, the eye begins to discern each frame as a separate image because it is sharper with more gap in the continuous motion before the next frame.

Now, my question here regards metering. Up until now, I've been using a still camera light meter. But I'm not sure what a cine meter--with an fps setting instead of a shutter speed setting--actually does for me with video. Does the cine meter presume a fixed relationship between shutter speed and fps that exists with a film camera but not with video?

When it comes to a traditional analogue lightmeter like the Sekonic L398A you set the required ISO value and take a reading, you then set the readout dial so that the required index mark is aligned with the correct frame rate, this will then give you the matching aperture value, based on using a 180 degree shutter. This is standard since most cine cameras didn't have a controllable shutter, you just got the standard 180 degree shutter based on the frame rate. If you are going to move away from using 180 shutter then you will need to manually compensate for the change in exposure. That wouldn't really be a problem though, since if you are controlling the shutter speed independently from the frame rate you would just use the exposure meter as you would normally for still images. With the analogue meters it is pretty easy, since they show pretty much every possible shutter speed/aperture combination that is useable for that ISO value and light intensity.

Alan

BigAl007 wrote in post #18419003
When it comes to a traditional analogue lightmeter like the Sekonic L398A you set the required ISO value and take a reading, you then set the readout dial so that the required index mark is aligned with the correct frame rate, this will then give you the matching aperture value, based on using a 180 degree shutter. This is standard since most cine cameras didn't have a controllable shutter, you just got the standard 180 degree shutter based on the frame rate. If you are going to move away from using 180 shutter then you will need to manually compensate for the change in exposure. That wouldn't really be a problem though, since if you are controlling the shutter speed independently from the frame rate you would just use the exposure meter as you would normally for still images. With the analogue meters it is pretty easy, since they show pretty much every possible shutter speed/aperture combination that is useable for that ISO value and light intensity.

Alan

That's what I figured. Thanks.

RDKirk wrote in post #18418814
I need to talk about this a bit to see if I understand what's happening......


...Now, my question here regards metering. Up until now, I've been using a still camera light meter. But I'm not sure what a cine meter--with an fps setting instead of a shutter speed setting--actually does for me with video. Does the cine meter presume a fixed relationship between shutter speed and fps that exists with a film camera but not with video?

RD, I might be going off topic here, and you might already be familiar with them, but I wanted mention waveform monitors for video exposure monitoring. Not an expert here. Just beginning to get into video. What I've learned over the last couple of years is that it seems videographers perfer waveform monitors to monitor exposure while filming. I'd never heard of them. Maybe lightmeters are used in conjunction with them, I don't know. This video was very educational despite its long winded author/narrator. It's in two parts. https://www.youtube.co​m/watch?v=oHG38SXMUPo

I don't have a waveform monitor. All I can do is use the blown highlights indicator on my Lumix. One thing I seem to recall from my research is, when it comes to video that's going to be used for production, crushing the blacks is worse than blowing the highlights.

Larry Johnson wrote in post #18420850
RD, I might be going off topic here, and you might already be familiar with them, but I wanted mention waveform monitors for video exposure monitoring. Not an expert here. Just beginning to get into video. What I've learned over the last couple of years is that it seems videographers perfer waveform monitors to monitor exposure while filming. I'd never heard of them. Maybe lightmeters are used in conjunction with them, I don't know. This video was very educational despite its long winded author/narrator. It's in two parts. https://www.youtube.co​m/watch?v=oHG38SXMUPo

I don't have a waveform monitor. All I can do is use the blown highlights indicator on my Lumix. One thing I seem to recall from my research is, when it comes to video that's going to be used for production, crushing the blacks is worse than blowing the highlights.

I've looked into them, and I understand how they work, but to a significant extent, they fall into a category of "Things videographers do that are the same things still photographers do a different way."

Larry Johnson wrote in post #18420850
...I don't have a waveform monitor. All I can do is use the blown highlights indicator on my Lumix. One thing I seem to recall from my research is, when it comes to video that's going to be used for production, crushing the blacks is worse than blowing the highlights.

With most videographers valuing a filmic look, I teach the opposite - protect highlights almost always. Good exposure of skin tones is best, but, if exposure isn't perfect, better to slightly underexpose than overexpose.

Of course not all scenes will oblige with a latitude that accommodates this approach

Then, depending on the camera's ability to shoot flat profiles or perhaps log, one may have to decide what's important. Usually skin tones win. Or, change the scene, the shot, the lighting...

Zebras will get you through most of this, if you know how to use them. 100% setting most often in setting up for scenes without people. 70 or 75% for caucasian skin highlights. A higher end video camera will offer both Zebras and Waveform monitor... both have their uses! And, a WVF is very handy when doing post color correction / grading.