Light Meter to use with a f3

Mwjace

Mwjace

Active member
I'm looking for a good lightmeter that i can take along with my f3 on field shoots. Something that will help me dial in a good exposuer, especially when using exsiting ambient light. Ideally something that i could set shutter speed and cameras ISO (or Gain) too, and it would give me a F-stop. Does anything like that exsit?


if not i would like to know what some of you out there are using.


Thanks
 
Light meters are very useful for lighting consistency on a set, but I wouldn't trust one for exposure with a video camera. Trust a monitor with a waveform or learn to use your zebras. Much more reliable. That's how most people work.
 
I second Lenilenapi's advice. The F3 already has a built-in light meter that works better than any hand-held light meter you can buy. The only thing better than the camera itself is a real waveform monitor, but that is not practical in a lot of circumstances -- nor is it really necessary once you understand how to use zebras PROPERLY. Although I own and use a Sekonic 758C for a variety of purposes, when it comes time to set the exposure on the camera, I totally trust the camera itself to give me the information I need. Keep in mind that you can really get yourself into trouble with a light meter if you aren't diligent about updating the settings. Anytime you change the camera's shutter speed, change ND filters, change the gain, add glass filters to the lens, and change some of the paint menus -- you will have to take that into account on the meter. In fact, you will also have to take the time to rate the camera for each of your picture profiles, because some of those menus drastically affect the overall sensitivity of the camera and where highlights will clip. I rate my F3 at IS0 250 or ISO 400 or ISO 1000 depending on the particular picture profile being used or S-LOG.

Mike, would a BYU alum and ex-KBYU guy lead you astray? :-)

http://www.vortexmedia.com/DVD_F3.html
 
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Histogram, Zerbra, Waveform, and false color really take care of this for you. In a REC709 mode, the F3 is pretty much "What You See Is What You Get." In the hypergammas or Slog modes you have to do a bit of internal conversion, but it's still fairly straightforward to read any of the mentioned exposure readout tools to see what you have.

False color can be very handy, makes it blindingly obvious when you've overexposed or underexposed things. You can get it on small 7" portable monitors from vendors like Marshall.

Waveform will give you the greatest amount of info though.
 
Which renews my campaign for waveform in F3 in addition to Vectorscope. I love the False Color feature of my zacuto evf. I agree that a light meter is more of an impediment than a help.
 
Doug, I've been to a couple of semminars of yours at NAB last couple of years, I knew something struck me about you, Provo!!! I should have guessed :) with this knowledge I'm not sure I can trust you :)


Thanks for the info guys. I do use the Zebras but i'm sure i don't use them as effectively as i should currently I have mine set to 70% and 100% , When the time allows i do use a nice external monitor, but sometimes time just doesn't permit and i was hoping i could get away with a light meter. as for the Waveform that would be welcome i used to use it all the time on the little Hpx 170 we had.
 
Mike,
I find 70% as little too hot for caucasian faces in HD. Everyone has there own feelings about this , but I'd much rather err on the underexposure side, so i set mine for 60. Depends how much zebra you want in the face though. I allow a good chunk of my face to get the zebra and get very wary if any part is exposed above the zebra.
 
I consider "skin tones at 70IRE" to be one of those things leftover from the days of Betacams and BVW-400s...when the cameras had maybe 7 stops total of latitude and underexposing a face even a stop meant bringing it up in post didn't look so hot. I know from my first couple days with the F3 if you choose Cinegamme 4, and park your skin tones at 70, they're going to be pretty plastic looking.

The F3 with S-Log, using a Hypergamma LUT wants you to put mid-grays at either 40IRE or 33 IRE, depending on the LUT, so I'd say putting skin tones on a non-Slog'd F3 at 50IRE is probably plenty hot enough to look great.
 
Well I was talking 60% for Rec709 WYSIWYG no grading. Actually I think 50% would be a little under for final image.
Totally agree about 70% being a leftover from Beta.
 
70%? 65%? 55%? They are all inaccurate because one zebra level can't fit every face. I never judge exposure based on skintones because skin tones vary by too much from person to person in the USA for them to be a reliable indicator of anything. I have said it before, and I'll say it again, if you use skintones to set exposure you are just guessing. I'm not saying you can't guess and be right most of the time, but let's be honest, you're just making an educated guess. And you know what, my viewfinders are good enough that I can guess just as close without even using zebras -- not that I would ever do that. That's why I prefer to be more precise about my use of zebras and I never (well, 99.9% of the time) have to make adjustments in post because I am able to nail it when I shoot it.
 
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Since getting my F3 a week ago, I've been digging through my old still photography equipment, thinking about an FD adapter and (as it relates to this thread) wondering if my old gray card would help get a good exposure. Here's my thinking - If I took a white card and placed in front of my talent and set the zebras to 100 and also checked a gray card to see if the zebras were at 50 - or used the built in spot meter - then wouldn't that be a pretty good exposure? I got pretty good at getting proper exposure with my EX-1 but the F3 has such better latitude, I'm hoping it's not that much different.

But I am curious about opinions on using white cards and gray cards.
 
don't use a white card @ 100 to set exposure. Bad bad idea. knees are all over the place in video. Use the zebras on a face to get the face where you want it. A 50% grey card is better though. But i would still put faces where you want them.
Doug is right though - every face is different and you need to use an educated eye to place the zebra correctly.
 
Get a small HD monitor.

Use the False color. Thats the best "lightmeter" you can get for digital cinema.
 
Set your light meter to FC and use it when lighting a scene inside. When lighting interviews set up the lighting the way it looks good to you and your client. Take foot candle readings of each light measuring from the subject and make a note of that setup. As you progress in your work you will quickly learn which lights need scrims and the distance from the subject the lights should be. The light meter can be a good training aid for lighting a scene.
 
A lightmeter still is a very useful tool for digital cinematography. You can check your contrast ratio, set and check your over all f-stop for a sequence of shots etc. Then you can check your scope etc to make sure you are not clipping the highlights etc . Basically you need both, especially if you are shooting only with artificial lighting.
 
Hi Mike,

I have been using my Sekonic Zoom Master L-508 lightmeter in conjunction with my F3 since I got the camera. One of the things I really wanted to be able to nail down was getting the best exposure and consistent exposure for shoots where as you mentioned you might not have an external device, or you need to go with a light rig, or often as it happens there is not a lot of time between setups and you need a quick "gauge" of what's going on with your light. I've learned to be able to rely on this, trust it, and have it work for me.

I'm not going to suggest to anyone that you ONLY use a lightmeter in place of using your eye and some of the tools available on the F3, but for example using zebras to gauge exposure on skin can be extremely inaccurate because of the way light could be hitting the face. Are zebras just starting to appear on the bridge of the nose okay, or cheek, forehead... ? Just that difference alone can amount to one or more stops in adjustments and once you start moving your setup or subjects around you can really start to get inconsistencies I find.

If you watch the F3 exposure video on Abelcine's website you can see that natively the F3 has an ISO of 800 at f4 to expose middle grey with a setting of 24fps, 1/48th shutter (or 180 degrees), 0db gain, and no ND filters engaged. As I been shooting in a variety of conditions under direct sun, overcast, indoors with controlled lighting, and outdoor snow conditions I have found that I can set my lightmeter to 24fps 180 degree shutter, take an f-stop reading and 9 times out of 10 it is accurate to my lens iris. As even with film, one has to obviously take into consideration what's happening in the rest of the scene in terms or brightness or darkness and compensate accordingly.

So for example in this scene I walked through the trail to find the brightest patch of light coming through the trees. I measured f8 on my light meter and then set the built-in ND filter to "1" which is 1/8 ND (0.9) - reducing 3 stops from f8 to f2.8. Because there was lots of snow on the ground and in the trees I stopped down the iris an extra stop and set it to f4. Below is a frame grab from the scene, and a quick edit of clips from the unfinished promo video can be seen here: http://www.dvxuser.com/V6/showthrea...om-upcoming-promo-video&p=2505760#post2505760



During one take I did actually open the iris to f2.8 and it looked fine in the LCD but watching it later on a large screen the scene was semi-blown and the shot looked bad to me, so you have to use judgement with a lightmeter like with any tool. Had I only used zebras to show me when the snow started hitting 100 it would be debatable how much or little of the snow should show up in stripes, and worse at the expense of changing the exposure on my main scene elements (the actor and horse)!

Using a lightmeter is really no different than using a grey card so if you learn to use your meter with your camera you should easily know where 50 IRE is. From there you can adjust your iris accordingly depending on the color of skin you are shooting, look or style you are after, and lastly compensate for the overall scene if needed (primarily outdoors I find is needed). One thing to be careful about as others have mentioned, is that when you start using the gamma curves you effectively start moving your middle grey point around which will skew things around. I find I can still pretty well match my iris f-stop to my lightmeter, then go through cinegamma 1,3 & 4 until I get the picture that looks the "best". I avoid cinegamma 2 because it clips at 100 but if you need a quick legal signal then cinegamma 2 is the ticket. Here is a thread where I posted a very handy PDF document I put together using screen shots from Abelcine's video to document all the cinegammas and their middle grey point on the IRE scale: http://www.dvxuser.com/V6/showthrea...n-Cinegammas&p=2445988&viewfull=1#post2445988

Some examples using a lightmeter:

f2.8 metered and f2.8 on lens:


f22 metered ambient*. 1 stop loss from overhead diffuser panel, 4 stops loss in ND filters, f4 on 85mm lens.

*This was metered away from the sun because subjects were more backlit. Typicially this works out to about 2 stops less then if metered against direct sun.

f2.8 metered, f4 on lens. Underexposed by 1 stop purposely:


I still use tools built into the F3 as a final check, but primarily the marker function (which will actually tell you the IRE value at center screen) and histogram (which I hate but still learning to like).
 
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I think Doug has sewn up the light meter vs zebra/waveform question nicely. The F3's built-in exposure tools are quick and accurate to use and they always take into account the variations made in the camera. There are lots of calculations and compensations to be made if I use my Minolta lightmeter. I'm not concerned in the slightest when I forget to bring it to a shoot. - with the exception of a green screen day.
 
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