Using a light meter

Post by **Freya** » Tue May 30, 2006 11:35 pm

Sorry for such a horribly basic, basic question, but I need to get this right!

I've actually shot a lot of film, video, and even some still photography, but with modern cameras being what they are, I've virtually never had to use an external light meter as there was always one built into the camera. Sometimes the camera had a light meter bult in that gave a reading you had to dial in yourself but that was about it.

I've been having to face up to the fact I'm going to need to use the external meter on a film I'm working on because one of the cameras I am using has a dead meter built in. It is my favourite S8 camera because I love the lens on it, but I have another S8 camera (whose lens I hate) which I have been using a lot because it has built in metering that works (and an interlavometer too). I've been taking the meter around with me (an old weston master 2 cine meter) and comparing the results against those from the built in camera meter, and while sometimes I seem to get results preety close, occasionally I'm getting results wildly different.

I went to the university and checked my meter against the ones there to discover that the meter is only perhaps slightly off. I have to face the fact that I'm doing something wrong.

The lecturer there suggested I should be angling my meter to the floor a bit, whereas I've been trying to point it at the subject I want to film.

It occurs to me that the meter in the camera sees the light in the scene that you have framed for. The light you have allowed to come through the lens whereas the meter just sees what light is there. Theres no way you can zoom in the meter or frame it especially. Perhaps this is the problem I am having. It seems from my experience that maybe it was but I wasn't sure and was hoping to experiment more to find out.

However, yesterday I got caught in the middle of a large open field when it started to hail and rain very, very violently. By the time I had run across the field to the moscow state circus, I was absolutely drenched. I think some water must have got into my working camera as now it keeps reading the maximum amount of light possible, even when it is quite dark. The meter is dead in other words.

Perhaps it will dry out and be okay, but I've not been so lucky lately and I need to learn to use the meter anyway.

Oh yes I almost forgot to say, I'm shooting reversal (K40!), yes it's going to be a blast! ;)

Any tips or help are welcome. Am I doing anything obviously wrong?

love

Freya

Post by **Scotness** » Tue May 30, 2006 11:54 pm

How close to the subject are you when you run the meter over them? If your meter is reading the whole frame then are you standing back a long way? I'd go in to your poiint of interest and read that quite closely (eg 6-8 inches away from an acotrs face) - then do the same with the brightest and dullest points in the frame and overall try and get the subject in the middle and the other brightest and lowest points one stop over and one stop under respecitively since you're using k40

hope this helps

got to fly

Scot

Post by **Scotness** » Wed May 31, 2006 12:02 am

Also there's some good info about lighting super 8 and k40 on this page

http://www.mango-a-gogo.com/inmyimage/imaglink.htm

Scot

Post by **audadvnc** » Wed May 31, 2006 12:02 am

Hello again, Freya, long time no see on this board. When not using the internal lightmeter of my camera, I use a very standard, film school issue Sekonic L-398, which measures incident light, as opposed to in-camera lightmeters which are reflective lightmeters. Assuming you are lighting an 18% gray card, both meters should give the same exposure reading. But keep in mind that in camera lightmeters also compensate for light losses due to the reflex viewing optics, so if you use a separate lightmeter you'll probably neet to derate the reading about 1/2 to 1 stop to get the same exposure on film.

Post by **Scotness** » Wed May 31, 2006 12:04 am

double post

Post by **Freya** » Wed May 31, 2006 12:53 am

audadvnc wrote:Hello again, Freya, long time no see on this board.

Well the board got a bit too nasty for a while back there, and on top of that I've been quite ill and things in my life have been very bad the last 2 years or so. You know, bad people and all that. The bad people always find a way to screw things up for you. Anyways...

When not using the internal lightmeter of my camera, I use a very standard, film school issue Sekonic L-398, which measures incident light,

Well like I say, sadly I only have a weston Master 2 cine meter, and even more sadly, the university seem to only have weston euro meters, which are similar but not cine models. At least it made it easy to test my meter against theirs! ;)

I'm afraid I don't have the invercone either.

as opposed to in-camera lightmeters which are reflective lightmeters.

As I understand it, the weston master is also a reflective light meter.

Assuming you are lighting an 18% gray card, both meters should give the same exposure reading. But keep in mind that in camera lightmeters also compensate for light losses due to the reflex viewing optics, so if you use a separate lightmeter you'll probably neet to derate the reading about 1/2 to 1 stop to get the same exposure on film.

It's much more than 1 stop that I'm talking about. Sometimes the readings were a number of stops different. That's why I was freaked out. Other times the readings would be quite similar. I think it was mostly happening when I was zoomed in on certain objects, perhaps the dark part of a scene? Perhaps I should just try and get the meter as close to the part of the subject I am filming as opposed to pointing the meter from the camera position???

love

Freya

Post by **Freya** » Wed May 31, 2006 1:08 am

Scotness wrote:How close to the subject are you when you run the meter over them? If your meter is reading the whole frame then are you standing back a long way? I'd go in to your poiint of interest and read that quite closely (eg 6-8 inches away from an acotrs face) - then do the same with the brightest and dullest points in the frame and overall try and get the subject in the middle and the other brightest and lowest points one stop over and one stop under respecitively since you're using k40

hope this helps

got to fly

Scot

I'm next to the camera typically which is a little distance away.
I could get closer to the objects I guess. Would this be a good idea!? I should point out that the weston master series are reflective meters and I don't have the optional invercone.

No actors or actresses yet, they keep bailing on me because my films are too weird, so I've mostly been shooting the other bits for the time being.

love

Freya

Post by **studiocarter** » Wed May 31, 2006 2:28 am

Hi,

Sky throws off the Weston reflected light meters. I came to just point the meter down at grass as a universal gray card and it worked nicely.

Michael

Post by **Freya** » Wed May 31, 2006 2:40 am

studiocarter wrote:Hi,

Sky throws off the Weston reflected light meters. I came to just point the meter down at grass as a universal gray card and it worked nicely.

Michael

Ah okay! Now I understand what the lecturer was going on about angling it down slightly. It wasn't helped at the time that he was standing over a large sheet of white perspex that was reflecting a load of light up, and I was thinking, this really doesn't make a lot of sense cause that plastic is just one big white light! ;)

But grass or ground would be okay presumably as long as it wasn't snow.

I'm not sure whether it was sky that I was having problems with however, tho it was outdoors, I think it was when I zoomed in on things and the camera light meter opened the apeture because it was too dark but my meter was saying theres loads of light. The inside of an abandoned freezer springs to mind.

Perhaps I shouldn't worry so much as it seemed like it was only happening once in a while, but it just worried me. I want to get my meter readings right!

love

Freya

Post by **Evan Kubota** » Wed May 31, 2006 3:10 am

I have an old GE reflective meter that is probably pretty close to the Weston. If I were you, I'd ditch the Weston and try to get a decent incident meter. You can get one for less than $30 on eBay if you watch closely.

I have an older Sekonic Studio that's basically the same as the 'curren't L-398II (no needle lock). I paid $15 with case and the slides.

Post by **egdinger** » Wed May 31, 2006 5:23 am

I didn't notice what kind of camera you have, but there may also be under exposuer if you have a prism in the light path all the time.

Post by **Patrick** » Wed May 31, 2006 7:25 am

A spot meter is a very handy, but expensive tool. This hand held meter is of the reflective type but it allows you to meter only a very small section of the scene. With it's narrow angle of view, you can be very selective about which part of the scene you want to meter.

Post by **Guy Bennett** » Wed May 31, 2006 10:15 am

FWIW, I've used lightmeters for years with still photography, and hoped to continue to do so when I started shooting Super 8. The problem, as a couple people have mentioned, is that the reading given by an external meter has to be adjusted to compensate for the light lost in the camera's zoom lens, with its many elements. Roughly speaking the longer the zoom, the more light lost, up to 4 stops with my Nizo 801m when set at 80mm. This is the difference between f-stops - the diaphragm's maximum aperture, whether f/1.8, f/1.4, etc. -- and t-stops -- the lens's effective maximum aperture based on the amount of light that actually reaches the metering cell.

At one point, I did some tests, reading the light with both the internal and external meters with the lens set at different focals, and noting the difference, but found it too cumbersome to work that way. I just go with the camera's internal meter.

If the internal meter ever died, I suppose I could just guestimate exposure, taking the reading given by my external meter (a Gossen Lunapro D, BTW) as my point of departure, and subtracting 1/2 stop for the lens at its shortest focal (7mm), 4 stops at its longest (80mm), and somewhere in between for the other focals.

Post by **Evan Kubota** » Wed May 31, 2006 10:17 am

I generally agree with Guy. Obviously I use an external meter for my 16mm work but with super 8 it's somewhat complex to compensate for focal length, reflex light loss and frame rate as well as shutter angle. The TTL metering on my R10 has proven to be quite accurate even with a narrow-latitude stock like K40.

Post by **Guy Bennett** » Wed May 31, 2006 11:21 am

Evan Kubota wrote:I generally agree with Guy. Obviously I use an external meter for my 16mm work...

Are you able to do so because you're working with primes, Evan? Do any of the light-eating properties of Super 8 cams also effect 16mm cams (can't imagine they wouldn't, where the 16mm cams have zooms and reflex viewing systems)? I've never worked in 16mm so I'm truly in the dark (no pun intended) about this.