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meter for mini DV?


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#1 Vinny Murphy

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Posted 22 June 2005 - 03:37 PM

Could anyone recommend a light meter for use with mini DV (dvx100A) shooting at 25p? Thanks in advance.
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#2 Matt Irwin

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Posted 23 June 2005 - 01:14 AM

You'd be better off using a calibrated reference monitor via the s-video port on the DVX. You can use a meter with DV, but I find that their only use is determining ratios. With a monitor you'll be able to see exactly what you camera is recording.
You could also use a waveform monitor, which will show you the luminance throughout your frame. If those are out of your price range, I think there are software versions that will run on a laptop (check the latest American Cinematographer issue).
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#3 Joshua Provost

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Posted 27 June 2005 - 05:26 PM

It has been said before, but a video camera is basically a big light meter. Like any light meter, it is calibrated to adjust the image to 18% medium gray. However, because of the potentially complex image in the frame and the range of luminances possible in a single frame, it uses various methods to determine which parts of the frame to expose to. So, auto exposure may not always be accurate.

However, that does not mean you necessarily need a light meter. If you get an 18% gray card, you can get accurate exposure from that, if used properly. Put the gray card in front of the subject you want to expose, zoom/position the camera so the card fills the frame and allow the camera to auto expose. Lock the exposure. You are now properly exposed for your subject.

From there you can do creative things such as could be done with film, such as over or underexpose and compensate in post for different looks. There isn't as much room to play as with film, but you can try it out.
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#4 Lars.Erik

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Posted 27 June 2005 - 10:37 PM

I use a Sekonic L558C. This is an incident and spot meter. I find it quite useful in the pre-production. Here I use it in determing the light fixtures for each room/location etc. Location scouting etc.

And when shooting I use the LUX function a lot. (FC in the U.S.) This is useful for working faster in knowing what watts you need when you run into problems.

Another fast way of working is just using your hand. Just place it in front of the actors faces and slowly turn it. I find that in many cases it works. This takes experience though. But just play around doing it. After a while you'll get it.

But as both Matt and Joshua said; the best light meter is in your cam, this with the aid of zebra is what I use when I do the final touch of light setups. And a 20" inch monitor of course. :D

In case of ISO, the speed varies from 320 to 1000 depending on your light setup. In most cases I've heard people set their DVX100a to 640 when shooting 25P. Personally I'd go for something about 400.

The best way to calibrate this is to use a TRUE 18% gray card. Fill the image of the cam with it. On the card put one of the lamps you're using, and if you have a waveform monitor, (which I advice you to have) make sure the IRE says 100. Now use your meter, the spot function, and take a reading on the card. Now all you have to do is turn the ISO knob until it matches the f-stop in your cam. That's the ISO for that setup.

I find it's in the 1/2 stop, 3/4 stop accuracy when it's been calibrated.

Hope this helps.
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#5 Stuart Brereton

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Posted 29 June 2005 - 06:25 PM

I've been thinking about this quite a lot recently. There is a very good case for using a lightmeter on video shoots. Not because you need to meter the light for exposure, after all you can judge that off a monitor, but for 2 other reasons.

first, it gives you repeatability. if you know that Actor A's keylight was reading at t4 then you can keep that light level constant. I've done shoots where you judge the key by eye, and think you've got it right, but over the course of a day as you and your eyes get tired, there are variations in the light levels which could have been avoided with a light meter.

second, it teaches you to measure light. rather than look at a monitor and say "the backlight is a bit hot" you can look at it and say "the back light is a stop over". then when you ask your sparks to adjust it, you can say 'put a 1 stop scrim in it' instead of 'just take it down a bit'.

In short, it engenders a discipline to your work, which in turn helps you to work faster and more accurately.
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#6 Lars.Erik

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Posted 30 June 2005 - 03:31 AM

first, it gives you repeatability. if you know that Actor A's keylight was reading at t4 then you can keep that light level constant. I've done shoots where you judge the key by eye, and think you've got it right, but over the course of a day as you and your eyes get tired, there are variations in the light levels which could have been avoided with a light meter.


<{POST_SNAPBACK}>


Very true Stuart. An excellent point to why one should use a light meter.
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#7 Phil Rhodes

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Posted 30 June 2005 - 08:07 AM

Hi,

A waveform monitor is a much more accurate and appropriate way to do those things on video. If you need to communicate with crew in terms of F stops, get a crew who know video... really, you shouldn't have to perform a translation functin for them to feel all warm and fuzzy. Any competent gaffer should be able to look at a monitor and know how much a light needs to come down - but of course on a video shoot he probably wouldn't rate the term "gaffer" in most people's books, so we'll call him "lighting assistant" or whatever low-level term you'd prefer to use. And then we'll hire a "real" gaffer and have to talk to him using inappropriate terminology... oh yes.. much better.

Phil
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#8 Stuart Brereton

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Posted 30 June 2005 - 08:31 AM

Hi,

A waveform monitor is a much more accurate and appropriate way to do those things on video. If you need to communicate with crew in terms of F stops, get a crew who know video... really, you shouldn't have to perform a translation functin for them to feel all warm and fuzzy. Any competent gaffer should be able to look at a monitor and know how much a light needs to come down - but of course on a video shoot he probably wouldn't rate the term "gaffer" in most people's books, so we'll call him "lighting assistant" or whatever low-level term you'd prefer to use. And then we'll hire a "real" gaffer and have to talk to him using inappropriate terminology... oh yes.. much better.

Phil

<{POST_SNAPBACK}>


I don't see why I refering to F stops is 'inappropriate terminology'. Video lenses are calibrated in f Stops just like film lenses. A 1 stop scrim is a 1 stop scrim regardless of what format you are shooting.

A competent Gaffer may well know from looking at a monitor how much a light needs to come down, but it is not his decision to make. It's the DPs. That's why when I ask for a 1 stop scrim, or a piece of ND.3, that what I expect to get, not the Gaffers' interpretation of what I want.

Once again you're using this as an opportunity to vent your dislike of Film and Film people. Your constant whining is tiresome, and if it is really your attitude, rather than just some bizarre pose, then I wonder why you don't find yourself employment in some other field, and spare the rest of us from your bile.

Edited by Stuart Brereton, 30 June 2005 - 08:32 AM.

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#9 Lars.Erik

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Posted 30 June 2005 - 09:27 AM

Thank you for pointing out Phil's extreme negative attitude, Stuart.

He is the most negative person on this forum. To make it short, that's the last type of person I'd want on my set.

Be more positive, Phil. TV and Film is about opening up to other people's work approach and co-operation. Have a nice day. :D

LE
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#10 Michael Morlan

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Posted 30 June 2005 - 10:08 AM

I am format agnostic Phil and, perhaps, you should be too if you want to be a master of your craft.

I light with my meter no matter what medium I am exposing. As Stuart notes, my meter, a trained eye, and knowledge of the medium's response characteristics allow repeatability from shot to shot and scene to scene.

Sure, a waveform monitor and calibrated monitor are great tools as well and, if available, should be used as rigorously as a meter. But what if you are lighting a scene when the camera isn't present? Perhaps you are pre-lighting the day before the $1000/day Varicam arrives. What are you going to do then?

I D.P.'d a short for the 2005 48-hour Project in Austin this last weekend. We were moving so fast we didn't have time to set up a monitor nor would we have had proper viewing conditions on a bright Texas day. But, from previous testing, I knew the camera had an equivalent 200ASA rating at my desired settings and, between establishing an initial f-stop with my meter and watching my zebras at 105% for clipping, I was able to deliver consistent results every time.

Edited by mmorlan62, 30 June 2005 - 10:12 AM.

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#11 Matt Irwin

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Posted 30 June 2005 - 12:47 PM

first, it gives you repeatability. if you know that Actor A's keylight was reading at t4 then you can keep that light level constant. I've done shoots where you judge the key by eye, and think you've got it right, but over the course of a day as you and your eyes get tired, there are variations in the light levels which could have been avoided with a light meter.

<{POST_SNAPBACK}>


That's a very good point. I think I'm going to try using a meter in addition to the monitor on an upcoming shoot to see how it works for me. I've never set up an incident meter for a video cam before, so just to check:

-Set the camera to desired settings (shutter speed, frame rate [24p, 30p, 60i], gain [-/+])
-Fill the frame with an 18% gray card and let the cam auto expose.
-Take a reading at the card and toggle ISO until the F-stop matches the cam.

Did I get that right? And the cam ISO won't change as long as the cam settings don't change, correct?

Edited by Matt Irwin, 30 June 2005 - 12:49 PM.

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#12 Stuart Brereton

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Posted 30 June 2005 - 02:41 PM

That's a perfectly good way to approximate an ASA for your camera, but you don't even need to be that accurate. You set your initial exposure from the monitor, then use your lightmeter to give you a reading from the keylight . It doesn't matter what ASA your meter is set to, as long as your key remains at whatever stop your meter read in the first place.
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#13 Vinny Murphy

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Posted 30 June 2005 - 02:45 PM

Thanks everyone for all the replies and sorry for not getting back earlier. It's all good stuff and I will check out the Sekonic L558C. I've checked up on the software - "DV rack" looks like it does an awful lot - field monitor, waveform monitor, vectorscope, direct recording onto a laptop - so all the tape is is a back-up, plus the image you're getting is the actual post-compression image. There's a load more stuff it does. I can see the point of using a light meter no matter what, but I'm just wondering is there a downside to using this software that you people who actually know what you're talking about can see?
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#14 Phil Rhodes

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Posted 30 June 2005 - 06:05 PM

Hi,

The only downside to a lot of T&M gear on set is that you can become a slave to it and spend all your time trying to please it. If it's video and you know you'll have a decent grade, it's almost more important to get a decently-usable image on tape for that shot than it is to have shot to shot consistency.

Oh, and, er, I'd love to be format agnostic, given half a chance!

Phil

Edited by Phil Rhodes, 30 June 2005 - 06:08 PM.

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#15 Lars.Erik

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Posted 01 July 2005 - 01:24 AM

I understand your concern, Phil. But I believe in most cases, pro's know when to use their light meters and when not to.

The point is, if you don't deliver a consistent and as a nearly perfect image to the post-production, all you do is to shift the problem to that department.

It's all about doing the best job possible.

And besides, a waveform monitor will go insane if you'd shoot let's say a David Lynch like movie, where you have bizarre colors in the frame.

Closing end, people work differently, and they shoot differently. And we all have opinions and one should respect those. People are in this business because we have a true passion and a love for it.
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#16 Stuart Brereton

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Posted 01 July 2005 - 03:08 AM

it's almost more important to get a decently-usable image on tape for that shot than it is to have shot to shot consistency.

<{POST_SNAPBACK}>


As far as I can see, shot to shot consistency and having a usuable image go hand in hand. There are many things which a Post facility can do, but doing the DPs job for him is not one of them.
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#17 David Mullen ASC

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Posted 01 July 2005 - 11:00 AM

On the first day of every HD feature I shoot, I put on my meter, and forget to ever use it. By the end of the shoot, I don't even bother putting it on.

I might use it when I have to have someone walk through an elaborate series of pools of light and they all have to be the same intensity, but that's about it.

Truth is that I set up the HD camera and set the iris on the lens to f/2.8 and light to that level. And quickly you get to know how much each light puts out so your eyeball lighting is pretty close. Generally most other lights are subservient to the key anyway. Even on film I generally only meter the key and judge the rest by eye.

This technique would work in DV too. Set up your camera & monitor, set the camera to f/2.8 and 0 db, etc. (whatever you plan on using) and start lighting till it looks right on the monitor, then do a final tweak on the f-stop. Essentially your camera IS a light meter afterall.

The point is not to be a slave to your meter, whether shooting film or video, the point is to learn to SEE. Robert Primes, ASC used to say that the meter makes you a coward but your eye makes you brave. Learn to light by eye and then take out your meter to check a few things (or use the video camera, which is a meter.)
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#18 Patrick Casey

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Posted 02 July 2005 - 11:23 AM

Hullo there,

Signed up today, so I thought that I would take this opportunity to say hi, as well chipping in my 2 cents.

I've been using DVRack for a while now, especially in combination with a DVX100a, and I've found it to be an absolute joy for indoor environments when I have lots of time, and a right bastard at any other time.

As mentioned above, you find yourself trying to "please the software" and end up spending more time on that than anything else.

However, it's great for those controlled studio shots, and I wish that I had an eqiuvalent piece of software for when I shoot larger formats.

Cheers,

/ casey
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