So I'm shooting some 16mm as soon as my film gets in, I also run an HVX rig, and my main question is how useful light meters are, especially with my HVX? I have a Sekonic L-508 meter. I know the HVX200 is rated at ISO320, but what would the fractional shutter speeds(1/250) be equivilant to in terms of shutter plane(180 deg.)????
Light meters...
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PerroneFord
Deals in Lead
http://provideocoalition.com/index.php/freshdv/story/shutter_speed_vs_shutter_angle/
There are some who say that light meters aren't important in video, but there are those of us who disagree. I would have been utterly lost shooting this film I am working on right now without my meter.
Is that an L-508c you have?
There are some who say that light meters aren't important in video, but there are those of us who disagree. I would have been utterly lost shooting this film I am working on right now without my meter.
Is that an L-508c you have?
PerroneFord
Deals in Lead
Oh, then you'll need to do some calculatin'! 
atomick
Active member
In principle, I'd be on the fence about the use of light meters for video, but I gotta agree with Perrone that I find having one pretty useful.
My L-358 gets more use on continuous-light shoots than with strobes, so I find it pretty great for video. I sometimes tech scout and do lighting setup tests with it and sans camera, at least at first...great to get a sense of how many more stops' worth of lens or light that I need. Did this just a few weeks ago for a corporate shoot, helped tremendously...the cost of the light meter was paid for in preventing unnecessary light rentals!
My L-358 gets more use on continuous-light shoots than with strobes, so I find it pretty great for video. I sometimes tech scout and do lighting setup tests with it and sans camera, at least at first...great to get a sense of how many more stops' worth of lens or light that I need. Did this just a few weeks ago for a corporate shoot, helped tremendously...the cost of the light meter was paid for in preventing unnecessary light rentals!
set the HVX200 to Film Cam mode and use the Shutter speeds in Angle format.
Also, having a lightmeter on a Video set is somewhat useless. Spot meters are good, measuring contrast, but, the video CCD's are different speeds in different light levels...
Also, having a lightmeter on a Video set is somewhat useless. Spot meters are good, measuring contrast, but, the video CCD's are different speeds in different light levels...
Barry_Green
Moderator
I wouldn't say having a light meter on a video set is useless; they're certainly useful for roughing in and setting ratios. Where I object to them is when someone wants to use one to set exposure on a video camera. That's not a reliable process.
j1clark@ucsd.edu
Veteran
Could you explain that, given that 'still digital' photographers seem to use ISO values.
What I observe is that because analog video didn't use meters, but used electronic monitor equipment, as the transition to digital has occured, because video had no prior history of extensive meter use, there was no attempt to come up with compatible definitions.
However, until recently, most 'prosumer' digital video cameras either didn't have signal monitors, or most prosumers didn't use them because of the expense, or the additional bulk of more equipment to lug around. They tended to use the 'screen' as their 'monitor' device.
j1clark@ucsd.edu
Veteran
If the meter reports the amount of light either incident, or reflected, and the video sensor responds to that light in a consistent fashion, how is the process unreliable.
PerroneFord
Deals in Lead
Barry and I basically disagree about this, but I think he feels that the response of the camera sensors is not linear with respect to shutter angles, and overall light levels. So it's somewhat unreliable to say that my camera is rated "ISO320" and have that hold. I agree with him on that.
That said, I don't "typically" use the meter to tell me my extremes. I am doing it with this 5DMk2 shoot, but only because we have no other options. I shot a camera test to see if my readings would put me in the ballpark, and they are holding close enough for my purposes.
I rate my EX1 at ISO 400 at 23.976fps and it runs close enough to my meter for me to rely on the meter implicitly. But that has been verified on nearly 100 shoots.
Use the meter to keep your overall scene in the safe zone, and to set your ratios and you'll be fine. Rely on it to keep you safe at the bleeding edges and you may end up very disappointed. But I still never go to a paying gig without one.
its close... but like you still need a waveform.. and if youre going to a waveform anyway.... why bother with a light meter ya know? Other than fun factor... metering is still fun...
Davdo
Active member
It's a lot easier to walk to scene and check values with a meter in hand than a waveform monitor (heavy!). In general, I think it's really valuable to be able to measure values independent of where the camera is pointing - and being able to measure with no camera at all.
When I go out, 85% of the time the crew is just me and a sound guy, and if we're lucky, a PA (who knows nothing about anything) and the producer/director who has his/her own things to deal with. So I'm doing my own lighting and it is just a real time saver to be able to set my frame, and then go light it accurately without having to run back and forth between the lights and the monitor to check my ratios. When it comes down to it, I still set exposure based on the zebras, but I can't tell you how easy that is when I've already got my lighting set just right.
I'm with Barry on this one, although I would be so bold as to say, without a doubt, that in small-crew situations, a light meter is a very valuable tool.
~~Dave
PerroneFord
Deals in Lead
So what do you do when you have no zebras? And no waveform? Like on the 5Dmk2? For me, this is like a throwback to shooting film. And I rather like it.
Barry_Green
Moderator
I basically agree with what Perrone said up in post #10, that's pretty much the core of what we're talking about but the part that isn't brought up here is that the light meter can't tell you what the video camera is going to DO to your image. You may have 1/3 of a stop difference between the shadow on one face vs. another, fine -- but will that even show up? Or will it be grossly exaggerated? Video cameras have gobs of settings, gamma curves and picture profiles, and the meter doesn't know what the camera is going to do with those differences. A waveform monitor will show you exactly what the camera has done with the signal.
For something like a 5D, which has no useful video monitoring tools, Perrone's approach is exactly what a professional should do. Test it, verify it, then go with it, it's the right way to do it.
And if you have a meter like the new Sekonic 758, which lets you profile your camera and put in what the gamma curves to do the signal, then by all means, meter to your heart's content.
If one wants to rely on a light meter, testing and verifying (as Perrone has done, on over 100 shoots) is a prerequisite to getting successful results, because you can then know what the camera does to your signal. On the Panasonic such as the HVX200, the camera can respond at 100 ISO, 200, 320, 400, or 800 ISO -- without changing any camera settings whatsoever! If you're shooting in low light enough that it needs to be wide open at f/1.6, the effective ISO is 100. If you're shooting in bright light so bright that you need to go to f/11, the effective ISO is about 800. In general, the exposure curve on an HVX is at about 320 ISO, but it can vary hugely at the edges. If you're dealing with circumstances like that, how can a meter be relied on to set exposure properly? That's my point -- the response is nonlinear depending on where you are in the exposure curve, and if your meter doesn't account for that, you can end up pooched.
Using a meter for setting ratios, roughing in the lighting, using it for scouting, that I have no problem with. Using it for setting the final f-stop... if you know exactly what you're doing, and you've profiled your camera and know how it responds, then fine, go right ahead. But if you're walking in blind and just assuming "hey, this camera is 320 ISO, so I'll just set my meter to 320 and la-de-da..." well, that's asking to get burned.
Whereas with a production monitor and a waveform monitor, you know exactly what you're getting at every stage of the way. Hence why I say for video work, that is the preferred method whenever possible.
For something like a 5D, which has no useful video monitoring tools, Perrone's approach is exactly what a professional should do. Test it, verify it, then go with it, it's the right way to do it.
And if you have a meter like the new Sekonic 758, which lets you profile your camera and put in what the gamma curves to do the signal, then by all means, meter to your heart's content.
If one wants to rely on a light meter, testing and verifying (as Perrone has done, on over 100 shoots) is a prerequisite to getting successful results, because you can then know what the camera does to your signal. On the Panasonic such as the HVX200, the camera can respond at 100 ISO, 200, 320, 400, or 800 ISO -- without changing any camera settings whatsoever! If you're shooting in low light enough that it needs to be wide open at f/1.6, the effective ISO is 100. If you're shooting in bright light so bright that you need to go to f/11, the effective ISO is about 800. In general, the exposure curve on an HVX is at about 320 ISO, but it can vary hugely at the edges. If you're dealing with circumstances like that, how can a meter be relied on to set exposure properly? That's my point -- the response is nonlinear depending on where you are in the exposure curve, and if your meter doesn't account for that, you can end up pooched.
Using a meter for setting ratios, roughing in the lighting, using it for scouting, that I have no problem with. Using it for setting the final f-stop... if you know exactly what you're doing, and you've profiled your camera and know how it responds, then fine, go right ahead. But if you're walking in blind and just assuming "hey, this camera is 320 ISO, so I'll just set my meter to 320 and la-de-da..." well, that's asking to get burned.
Whereas with a production monitor and a waveform monitor, you know exactly what you're getting at every stage of the way. Hence why I say for video work, that is the preferred method whenever possible.
j1clark@ucsd.edu
Veteran
When I did extensive still photography, I would 'calibrate' my process using the Zone System, where I would find the characteristics of a particular film, early on it was Tri-X, later Fujifilm Neopan, then the several developers and print papers, I would use. Some times I would just do it to verify 'nothing had changed'...
So, yes I understand completely the concept of finding the characteristic of a sensor's response, now that I've moved to digital media.
And, sure, if a monitor were easily available, I would use that too... I've been testing with Adobe's On Location, since I don't have the money to buy actual equipment...
As a note, on using 'manufacturer's recommended ISO film speeds'... I usually rated Tri-X 400 at 200, and Tri-X 320 at 160... about one stop slower than the official NBS traceable tested rating... Neopan was slightly better, but I just kept using 200 anyway. The point being even in 'film' taking the stated ISO value without question, didn't lead to happy results, at least the way I wanted happy results to come out.
j1clark@ucsd.edu
Veteran
its close... but like you still need a waveform.. and if youre going to a waveform anyway.... why bother with a light meter ya know? Other than fun factor... metering is still fun...
The one thing that has not been mentioned, which the waveform would give, is the 'noise'. Since a light meter is an integrating device, the 'noise' in the dark areas would be integrated out. The hash on the waveform would be indication of what the sensor was giving in those areas...
I understand what you're saying here, although I'm not clear on the process's used to calibrate ACTUAL ISO compared to the ISO stated by the manufacturer...
The same sort of uncertainty with that goes with the digital end of things. Like Barry said, is you open up the HVX200 to f/1.6, it's rated at about ISO100, at f/11 ISO800.
How exactly are these rating tested for in that respect? I just feel like the more I understand WHY some piece of equipment do this or that, the better I will become at handling it on location.
PerroneFord
Deals in Lead
Barry, that may be the first time I've seen you fully articulate your feelings on metering, and I am glad we're not in as much disagreement as I thought.
Frankly, and I hate to say this, but I think that those who did not grow up with film (either still or motion picture) have really missed out on a lot. You'd think that with WONDERFUL resources like ASC online and the like, those aspiring to make great images would learn. You can read about the best cinematographers in the world still going out and doing camera and emulsion tests. Honestly, I think some are just lazy. If you've got the time, use it. Get crew to stand in on the marks. Pre-scout locations if you can. And be careful of your time of day. If you're going to shoot at 5:30pm, scouting at 9am isn't going to help you understand the shape of the light whatsoever.
I guess that's why I will always keep the meter. I remember reading an article many years ago in a photography magazine about a NatGeo photographer. He was talking about his new Nikon F3 or F4 camera, and was marveling at how wonderful the metering was. But he was cautious to say that on anything tricky, he still pulled out his LunaPro and metered the scene.
I try to treat my video cameras much like film. With each picture profile and fps setting, and so forth like a stock. I have seperate profiles for 720/60p, 1080/24p, and 1080/60i. I've verified each (virtual emulsion) dozens of times in my camera tests. Like rating my 720/60p at ISO 320, my 1080/24p at 400, and my 1080/60i at 800. If you don't test, you don't KNOW that. But that's part of being professional.
When I show up on a shoot, and there's a 42" monitor and a vectorscope and waveform monitor, things are good (BTW, I'm still waiting on this to happen). But if I show up, and there's NOTHING but a playback monitor that's uncalibrated and is just being used to judge focus and framing, then I'd darn well had better done my homework so I can say with some certainty that we're safe. I also pull rehearsal footage into my laptop to see the waveform and scopes. Preferably before finals, but ALWAYS before we strike the set.
Good stuff Barry.
Frankly, and I hate to say this, but I think that those who did not grow up with film (either still or motion picture) have really missed out on a lot. You'd think that with WONDERFUL resources like ASC online and the like, those aspiring to make great images would learn. You can read about the best cinematographers in the world still going out and doing camera and emulsion tests. Honestly, I think some are just lazy. If you've got the time, use it. Get crew to stand in on the marks. Pre-scout locations if you can. And be careful of your time of day. If you're going to shoot at 5:30pm, scouting at 9am isn't going to help you understand the shape of the light whatsoever.
I guess that's why I will always keep the meter. I remember reading an article many years ago in a photography magazine about a NatGeo photographer. He was talking about his new Nikon F3 or F4 camera, and was marveling at how wonderful the metering was. But he was cautious to say that on anything tricky, he still pulled out his LunaPro and metered the scene.
I try to treat my video cameras much like film. With each picture profile and fps setting, and so forth like a stock. I have seperate profiles for 720/60p, 1080/24p, and 1080/60i. I've verified each (virtual emulsion) dozens of times in my camera tests. Like rating my 720/60p at ISO 320, my 1080/24p at 400, and my 1080/60i at 800. If you don't test, you don't KNOW that. But that's part of being professional.
When I show up on a shoot, and there's a 42" monitor and a vectorscope and waveform monitor, things are good (BTW, I'm still waiting on this to happen). But if I show up, and there's NOTHING but a playback monitor that's uncalibrated and is just being used to judge focus and framing, then I'd darn well had better done my homework so I can say with some certainty that we're safe. I also pull rehearsal footage into my laptop to see the waveform and scopes. Preferably before finals, but ALWAYS before we strike the set.
Good stuff Barry.
PerroneFord
Deals in Lead
Good LORD! A full stop! What were you developing with? I rated my Tri-X and TMAX on the numbers. I usually used Microdol for my stuff, though the school cheaped out and used HC110. Seems like another lifetime ago.
-P