Jump to content


Photo

Light Meters & Motion Picture Film


  • Please log in to reply
22 replies to this topic

#1 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 24 May 2008 - 04:40 PM

I have a brand new K3 16mm camera, with a 1985 serial on it. I would like to use a good spot meter to make sure everything is good exposure wise. I've never used a meter before so everything seems rather confusing, especially between spot meters and incindent meters. (one measures light while the other measures a grey card?)

I would like to start shooting film this summer. I understand that you simply enter the ISO and Shutter speed, as a result you are given the Fstop that you should set your lens to.

How do I know if the light meter is leaning towards a digital ISO mode rather than film?
Are digital ISO's different from Film?

are there any discrepancies between kodak / fuji?

some one told me to just use the meter in my Nikon D70s, however the lowest ISO is 200 on my Nikon, i'll mainly be using kodak 7201 50D. so that doesn;t work...

Lets say for a second I'm using Kodak 7201, 50 Daylight film

So I set the ISO for 50. The k3 operates at 1/60th of a second (@24 FPS) So I enter 60 into the meter.

let say it gives me an Fstop of 5.6 or something, but I want the shallow field of depth f1.9 offers... so I would probably want to use a neutral density filter right? how do you take that into consideration when using a light meter?? if the nuetral ednsity filter reduces by -2.0 stops, would I change that 5.6 to 3.6?

Lets say i'm using f5.6, but I need to over expose or under expose by 1 full stop for whatever reason, do i just change the Fstop to 4.6 or 6.6? is that how it works?

Light meters seem to be retardedly expensive, I don't understand if these are inteded towards portrait still photography or motion picture film or both or what.

this is the list I am looking at to buy from:

http://www.vistek.ca...r.aspx?n=1&r=28

any info would be much appreciated! thanks
  • 0

#2 Brad Linton

Brad Linton

    New

  • Basic Members
  • Pip
  • 1 posts
  • Other

Posted 24 May 2008 - 09:03 PM

Incident and spot meters measure light in different ways, but the principles behind using any method of light reading are the same.

ISO (speed of film), F-stop (aperture of the lens), and shutter speed (duration of exposure). These are the basic principles of properly exposing film. There is no difference between Kodak and Fuji, or a still photography and movie camera. Film is film.

Yes it is possible to use a 'normal' still photo camera w/ a meter to get you light meter readings. These cameras use a spot meter, so a gray card is a good idea, as a spot meter needs a neutral surface to get an accurate reading.

F-stops: This needs to be explained.

1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 <------ these are f stops. So two stops less than 5.6 would NOT be 3.6, it would be 2.8.

Don't be intimidated by all this stuff, you basically know it already and it's pretty simple anyway. A good way to practice exposing film is to take a still photography camera with manual settings and shoot a roll of film. And if you want to jump right into shooting motion picture film on your Krasnogorsk you should be ok too. I say go for it. You'll learn a lot after just one 100' roll. Good luck.

And yes, light meters are expensive.

-Brad
  • 0

#3 Chris Keth

Chris Keth
  • Sustaining Members
  • 4427 posts
  • 1st Assistant Camera
  • Los Angeles

Posted 24 May 2008 - 09:53 PM

Yes it is possible to use a 'normal' still photo camera w/ a meter to get you light meter readings. These cameras use a spot meter, so a gray card is a good idea, as a spot meter needs a neutral surface to get an accurate reading.


The majority of SLRs don't use a spotmeter. They do use a reflected meter, but they are rarely of a small enough angle of acceptance to be described as a spotmeter.

A spotmeter simply tells you what exposure to use to render whatever you meter as middle grey. If you happen to meter something that really is middle grey (such as a greycard in the light you want to expose for) then you are pretty set.

Most of the usefulness of a spotmeter is not in reading surfaces that are 18% grey, though. The real usefulness lies in being able to read your deepest shadows and your brightest highlights separately. From that information, you can discover how the scene will record on film. Perhaps it will be very flat and you want to add some contrast. Perhaps (this is very common outdoors) there will already be too much contrast and you need to fill your shadow areas to make sure that all of the information you want will record on film in a useful way.

If you are interested in using spotmeters, I suggest you read Ansel Adam's book "The Negative." It's the classic textbook on the zone system and exposing film with a spotmeter.
  • 0

#4 Chris Keth

Chris Keth
  • Sustaining Members
  • 4427 posts
  • 1st Assistant Camera
  • Los Angeles

Posted 24 May 2008 - 09:57 PM

By the way, for an inexpensive lightmeter, look for a used Sekonic L-398. It is an analog meter (no batteries) and they are tough as nails. When you find one, just send it to quality light metric in hollywood and they will calibrate it for you, so you know it is working properly. I bought mine used for $20, calibrated it for $20ish I think, and I still use it from time to time as a backup. My main meter is a minolta autometer 4, which I bought used for around $100.

You can spend as much or as little on a meter as you want, really. There is no need to get sucked into the cult of crazy meters that do everything. In your place, it is a good thing to have to do some math and some thinking about those things in your head.
  • 0

#5 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 24 May 2008 - 10:43 PM

It helps to memorize the f-stop whole numbers for starters, though it is also displayed as a scale on many meters.

As already mentioned, they are:
f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22...

Note that the number under the fraction symbol doubles or halves every other stop more or less. The lower numbers on the scale correspond to a larger aperture that lets more light in, and the higher numbers are the opposite, they create a smaller aperture that cuts the amount of light coming in. So generally to overexpose, you'd be opening up the iris more, like going from f/4 to f/2.8, for example, to gain one more stop of exposure.

Yes, you need ND filters if your meter says to shoot at f/8 and you want to shoot at a wider aperture to reduce depth of field. The ND filter scale is ND.30 (cuts one stop), ND.60 (cuts two stops) ND.90 (cuts three stops), ND 1.2 (cuts four stops). So if you have f/8 as a base exposure and you put an ND.90 on the lens, you'd open up to f/2.8 to compensate.
  • 0

#6 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 25 May 2008 - 04:47 AM

I really appreciate all the help guys, I fully understand how the Fstop range works now, I always had an... "idea" but was never quite sure, so today was a good day to get it all cleared up.

So if you have f/8 as a base exposure and you put an ND.90 on the lens, you'd open up to f/2.8 to compensate.


I See!! Everything I've learned of photography is from trial and error, so it's been rough but it's worked out really good so far since I started with my Nikon in 2005.

Just curious with the K3 going all the way down to f1.9, if I used a ND1.2, I could just set the lens for 1.9 and move it a notch over? Would this work or does it have to be Exactly on f2.0? (Even tho the shallow field of depth coming from F2.8 is more than enough)

This is starting to sound reallly exciting!!! I can't wait to shoot my first 100 foot roll of film and see how it turns out. I'm actually going to shoot a few rolls outdoors, and a few rolls indoors.

So 1 other thing that i've read quite a bit and I think it tells you this on the Kodak website as well. You apparently want to over expose all your film by a third of a stop? (1/3) they say. How would you go about this if lets say you were given an fstop of 11? my guess would be. 16 - 11 = 5, then 5 x 0.33 = 1.65, so then to some how add 1.65 to 11.

or to save yourself from the math part, just generally move the fstop dial up 1/3 the way? :lol:
  • 0

#7 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 25 May 2008 - 05:15 AM

The real usefulness lies in being able to read your deepest shadows and your brightest highlights separately. From that information, you can discover how the scene will record on film.

Could we talk about this a little more in detail?

Is this for when the scene is mainly white in most areas, or mainly dark in most areas, and you want to compensate a little by under or over exposing?

or does this just allow you to look around and see where the high contrast areas are?

my guess would be to stay away from the high contrast zones, and stick with the low contrast areas. (unless you want the high contrast look)

(they say 50D is specifically for this) high dynamic range film that evens out your high contrast areas better than most other films. (correct me if I am wrong!)
  • 0

#8 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2008 - 12:11 PM

You can pretty much treat f/1.9 on the lens as f/2.0...

You generally don't make the adjustment on every shot for the same amount of overexposure you want to give the stock, you just treat it as if it were a slower speed stock by using a lower ASA value for starters. For example, pretend your 50 ASA stock is 40 ASA (1/3 over) or 32 ASA (2/3 over), set your meter to that base rating for starters and then don't think about, just pretend your stock is 40 or 32 ASA instead of 50 ASA.

Meters generally allow adjustments in 1/3-stop increments, which is why it is easier to re-rate the stock in one-third amounts than a half-stop amount, for example.

For the most part, color negative has so much latitude that you can expose for the subject and how you want it to look, but if you have an unusual situation like an all-white landscape of snow or a near-black landscape of, I don't know, lava rocks, then you can open up one-stop for the black subject or close down one stop for the white subject to retain more detail.
  • 0

#9 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 25 May 2008 - 12:16 PM

ohhh I never would have thought that, thats very clever. So yea your right you never have to worry about that.

do light meters always give you an even F stop reading, or could it be in between F5.6 and F8?

like 6.5 or 6.7, etc. or anywhere on the scale thats not even. in this case would I just take my best guess as to where to set the ring dial?
  • 0

#10 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2008 - 12:20 PM

My Minolta & my Spectra give you the in-between readings in 1/10 increments, like f/2.8 3/10 (or as f/2.8 .3) for example. So you know that 3/10 is about 1/3 past f/2.8, or 7/10 is about 2/3 past (or 1/3 open from the next stop.)

On the older analog Spectra, it's a needle that swings between the numbers on the dial.

So yes, all meters give you an inbetween reading since rarely do you have exactly a whole f-number of light.
  • 0

#11 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 25 May 2008 - 02:34 PM

How forgiving is Kodak Vision II? lets say something goes wrong and your out a whole stop high or low.

would the film be completely unusable in that part of the roll, would you be able to correct it in final cut?
  • 0

#12 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2008 - 03:33 PM

You can easily correct for a one-stop mistake in exposure, though one-stop over tends to look better when corrected than one-stop under looks when corrected, but it just depends.
  • 0

#13 John Brawley

John Brawley
  • Sustaining Members
  • 834 posts
  • Cinematographer
  • Atlanta Georgia

Posted 25 May 2008 - 05:25 PM

How forgiving is Kodak Vision II? lets say something goes wrong and your out a whole stop high or low.

would the film be completely unusable in that part of the roll, would you be able to correct it in final cut?



One of the great things about shooting film is that it is so very forgiving, especially with overexposure. IN fact i often wonder about metering to tenths of a stop when there's so much resilience in the neg.

I was shooting a short a few years ago (pre vision) and had an exterior that I forgot to stop down for after checking focus. I accidently overexposed the shot by close to 5 stops. In telecine they *saved* the shot, with only an extra increase in noise. It was in the edit and although you can there's something different about it, it works in the edit.

5 Stops !!!!

See if you can pick which shot it was.

http://www.johnbrawl...&...w=384&h=288

jb
  • 0

#14 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2008 - 05:48 PM

One of the great things about shooting film is that it is so very forgiving, especially with overexposure. IN fact i often wonder about metering to tenths of a stop when there's so much resilience in the neg.


I usually round-off to thirds or halves when setting the stop on the lens or calling it out to the assistant. Most lenses have the f-stop marks too close together anyway to differentiate between 4/10ths and a half-stop (5/10ths).
  • 0

#15 Frank Barrera

Frank Barrera
  • Sustaining Members
  • 464 posts
  • Cinematographer
  • Los Angeles, CA

Posted 25 May 2008 - 08:06 PM

In telecine they *saved* the shot, with only an extra increase in noise.

Why was there an increase in "noise"? When printing down in telecine with overexposed footage i've never seen a problem with video noise. Do you mean weak blacks? That shouldn't be. Do you mean video noise? That shouldn't be introduced due to a very dense negative transfer either. Unless i'm missing something. do tell.

f
  • 0

#16 John Brawley

John Brawley
  • Sustaining Members
  • 834 posts
  • Cinematographer
  • Atlanta Georgia

Posted 25 May 2008 - 08:11 PM

Why was there an increase in "noise"? When printing down in telecine with overexposed footage i've never seen a problem with video noise. Do you mean weak blacks? That shouldn't be. Do you mean video noise? That shouldn't be introduced due to a very dense negative transfer either. Unless i'm missing something. do tell.

f


On the older CRT based telecines they go very noisy in the whites when grossly overexposed. Telecine noise, not film noise.

jb
  • 0

#17 Curtis Bouvier

Curtis Bouvier
  • Basic Members
  • PipPip
  • 96 posts
  • Industry Rep

Posted 25 May 2008 - 10:49 PM

I'll probably just pick this up,

http://www.vistek.ca...-iii/Specs.aspx

I have to get a bunch of other things from Vistek so i'll throw that in the order too.

David, the ND filter that comes with the K3, any idea how dense it is?
  • 0

#18 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2008 - 11:28 PM

I wouldn't get that meter -- that's the type of meter my dad used to use for his still photography, and personally, I can't figure out how to use one of those... too many dials.

I'd get something like this:
http://www.spectraci...film_video.html

I'd get the Pro IV-A, or if you want to go low-tech, the "Classic". Though I don't know about the low-light performance of the old Classic.
  • 0

#19 Satsuki Murashige

Satsuki Murashige
  • Sustaining Members
  • 3510 posts
  • Cinematographer
  • San Francisco, CA

Posted 26 May 2008 - 04:23 AM

Why was there an increase in "noise"? When printing down in telecine with overexposed footage i've never seen a problem with video noise. Do you mean weak blacks? That shouldn't be. Do you mean video noise? That shouldn't be introduced due to a very dense negative transfer either. Unless i'm missing something. do tell.

f

Hi Frank,

The way it was explained to me by a colorist, the overly dense negative (like 3-4 stops over) meant invariably less light would hit the sensor in the telecine machine because they are limited in the amount of light they can punch through it, resulting in a lower signal-to-noise ratio, ergo a noisier video image. Basically no different than underexposing video and lifting the mids in post, as opposed to exposing normally. I may have remembered the explanation wrong however.
  • 0

#20 Valerio Sacchetto

Valerio Sacchetto
  • Basic Members
  • PipPip
  • 94 posts
  • Student
  • Italy

Posted 26 May 2008 - 08:04 AM

I'll probably just pick this up,

http://www.vistek.ca...-iii/Specs.aspx

I have to get a bunch of other things from Vistek so i'll throw that in the order too.

David, the ND filter that comes with the K3, any idea how dense it is?


I wouldn't get that meter -- that's the type of meter my dad used to use for his still photography, and personally, I can't figure out how to use one of those... too many dials.


Actually i would recommend that type of meters. As a beginner doing a bit of math and seeing physically the relationship between various elements may be a good thing. Surely it's more time consuming, the low light reading is not very good but it's quite rewarding, instead of having straight a number you have to understand what's behind and figure it out by yourself. That said it's obvious that you can, and will, learn well with both types. The only thing is that i wouldn't get that type of meters brand new because i think it's a bit too much expensive.
I'd get it off e-bay (like i did, i own a sekonik l-398) and maybe invest in a digital one later, depending on how you feel maybe a spotmeter, which may be more straightforward and more sensible in low light situations.

As for the ND...when you got your meter, measure it :P (or ask someone to do it for you)
  • 0


Wooden Camera

Ritter Battery

Metropolis Post

Gamma Ray Digital Inc

The Slider

CineLab

FJS International, LLC

Paralinx LLC

Aerial Filmworks

Opal

Visual Products

Willys Widgets

rebotnix Technologies

Technodolly

Tai Audio

CineTape

Abel Cine

Glidecam

Media Blackout - Custom Cables and AKS

Broadcast Solutions Inc

Rig Wheels Passport

rebotnix Technologies

CineTape

Gamma Ray Digital Inc

Willys Widgets

Aerial Filmworks

Visual Products

Rig Wheels Passport

Media Blackout - Custom Cables and AKS

Tai Audio

Paralinx LLC

Technodolly

Abel Cine

The Slider

CineLab

FJS International, LLC

Glidecam

Wooden Camera

Broadcast Solutions Inc

Ritter Battery

Metropolis Post

Opal