What is this bar?
 

I met with "Grazie" last night here in Kent UK at an Institute of Video (IoV) meeting and we discussed this but could not answer the question.

On the XM2 LCD/viewfinder top left can anyone explain what this sliding bar actually means? I have an idea after playing around with it this morning but up till now I have ignored it.

My understanding is it is a guide to say that you need to open your Iris (F stop down) if the vertical line is on the left of centre.

The opposite is true if the vertical line is on the right of centre ( you then close your Iris ((F stop up) so the vertical line goes to the middle point.

Now, I know it cannot be this simple to get the image you want and practice will tell me how close it is but what experience do you have?

An example is if someone walks into frame the line will move but I would not want to change expoure everytime as it does jump/step (it is very sensitive). Perhaps in an outdoor (good light) situation it may not be so sensitive, will find out this afternoon.

Your expertise on this is appreciated in advance.

ps - Hope you have a lovely Easter from the UK.

I guess you don't mean the zoom? I can't find any other sliders in the top left of my viewfinder and I can't imagine that the zoom slider is showing anything more or less than how wide or tele you are! The manual doesn't offer any more either.

It sounds like you are describing your exposure bar (at least that's
how it looks on my XL1S).

Sounds like you mean the exposure bar like Rob says...

Not really much in the manual about it, but it is covered a little bit on the "Shoot for the cut" DVD (which incidentally isn't that great).

The bar only appears in full manual mode. Basically, if the bar is in the centre of the horizontal line, then the the shot is correctly exposed as far as the camera is concerned...and if the camera was in full auto mode, then this is how the camera would expose the shot. If the bar is to the left of centre...the camera considers the shot to be under exposed...to the right...over exposed.

Thanks Chris/Rob,

You are correct, it is the "exposure bar".

I always use full automatic so I have to learn how to use controls correctly. I went out on a shoot this afternoon to film "The Liturgy of Passion" at a Carmelite Priory here in the UK, I was able to try the exposure bar methodology and reviewed this evening. Not bad - some shots would have been slightly under exposed (1 stop) if I had not kept my eye on this bar and opened up the iris to get in the middle.

To be honest I wish I had sussed it out earlier as it is a great guide tool. Then again I have only been filming for real for 5 months so I cannot complain.

Thanks for the confirmation.

Likewise I've only had my XM2 for a short while and even though I have filmed in full manual mode, this is the first time I've ever noticed the exposure bar. It doesn't seem to be mentioned anywhere in the manual at all. Wish I'd known about it sooner!

Wow- I've been using my GL2 in manual for some time now- never even noticed the bar- neato! What a great feature!

Yup . . seen the Bar since November 2002 . . thought it must be a way of giving "warnings" as to the amount of light getting "at" the chips. Being in manual one "really" doesn't get a chance to "question" the amoiunt of light . . .zebras here too?

Alan thanks for pursuing this here . . . got home about 11:20pm . . not too bad . . .

Grazie

I always shoot full manual with my XL1S and basically don't care
for the exposure bar AT ALL. Exposure is measured accross the
frame. So if you have a well lit person in a otherwise completely
dark room it will indicate that you almost have no exposure.

I use my eye (external broadcast monitor is best to judge this)
and zebra stripes at 90% or lower.

Yeah, Rob, sounds good to me!

I have a question for anyone who has uses the exposure bar a lot.

I was recently experimenting for an upcoming shoot. It will be a fairly high contrast scene where I control the lighting (bright face with sharp drop off, bright background light, but dark mid-distance). I was working in full manual, using the exposure bar, zebras, and an external monitor. I was trying to maximize the available contrast without blowing out the whites. I am less concerned about crushing blacks.

When the exposure bar was dead in the center the scene was rather washed out in later viewing. I was much happier with the result (viewed later in my NLE and on several monitors) when the exposure was reading quite low, probably down 1/3 to 1/2 from the middle of the range. Seemed to have a much richer contrast range.

I am inclined to shoot the scene for real with exposure on the low side, according to the exposure bar. But since I am relatively inexperienced to getting this technical and dont have the best quality monitor on the set I just wanted to check with others in case someone wants to warn me off of it. I'd hate to have to reshoot later because I let it get too low.

I should mention that I was at 0db gain and 1/60 shutter showing just a touch of zebra at 95%. F about 1.8 to 2. I like these settings but obviously I couldnt go lower light without grain.

It's just another simple tool. If or HOW you use it is totally up to you. If you want to lug an external monitor around with you, go for it....

I think you'll find that the pointer on the bar is just giving you an average of the exposure over the whole of the frame, therefore the whites will probably be over-exposed in a scene with so much contrast. If you zoomed into the hot area and exposed for that and then locked the exposure, the result should be more to your likeing. It's just using the canmera as a spot-meter. Still the best way is to check out the image on a monitor. We have to do that all the time on drama shoots - not so easy on doc type shoots though ;-)
DV will always look better slightly under-exposed anyway - a fuller and richer image as you say.

Robin.

Yes Robin. I'm starting to understand the Bar Metre as a "pointer" to what is happenning . .not to take it as gospel, but to give me a "further" indication .. working in manual, the Bar assists in that gauging - helps me when flying manual to have these "artificial" altometers working too? - yeah this is the best way I can understnad this function. Yeah, external monitors for "setrups" always . . .

. . I'm getting there . . does take time though .. . you guys, as always, do help to keep me sane! - I like the idea of going "lowish" to retain those gorgeous contrasts - neat concept Bill. Your approach is very workmanlike .. .I'd really like to do a project with you . .. hmmm .. .

Grazie

I don't mean to beat a dead horse on the exposure bar issue, but I just realized I had the "char rec" function on during part of my lighting test to record the camera data to tape. I uploaded a couple of stills to show what underexposed on the bar, but good to my eye and to the waveform monitor in my NLE, looks like.

This was a crude lighting test in an old train station I will be using. In the real shoot I will soften and broaden the lighting somewhat. Still it's relatively close to what I was going for--lots of contrast in a room withouth much color variation. Of course I will also add actors in lieu of the lighting equipment.

The first still shows the room

http://ball.tcnj.edu/images/still1.jpg

The exposure bar shows pretty low but aside from the area around the ladder the frame doesnt look particularly dark to me.

The second still is a bit brighter but still below the target on the exposure bar. I suppose I should explain that the pruple gertie ball with zebra felt on it was my stand-in for an actor's head (you use what's at hand I guess--its reflective but wrinkly and porous--so it works for me). The zebra bars dont get recorded to tape, there is a spot of blown white on the top of the ball and on the chair rail on the wall.

http://ball.tcnj.edu/images/still2.jpg

So as others have commented, zebras plus even a not so good monitor tell you a lot more than the exposure bar.

Grazie thanks for the invitiation but your a bit of far from New Jersey to get ensarled in my no budget hobby productions. How do you like your ME66+K6 with your XM2? I'm just about to spring for one for this upcoming project to run into my GL2 (dont ask how I can do this for "no budget").