safe exposure

T

thome

Well-known member
So i just need to know...when shooting using lights..what is the highest and lowest points you can go to in terms of light?And can you check this on a DVX?how?apart from using your eyes to judge is there a tool apart from light meter that can help you judge?in camera?
 
yow thome...without reading that link posted by our collegue above me( i plan to after posting this)... one usually uses "Zebras " at the very least to monitor exposure. I dont have my DVX nearby but check out the manual(if u dont have one u can google it...its online). However u can set ur Zebra stripes to 80% or more to help u to judge how much ur shot is overexposed.

It will look like diagonal stripes across ur LCD indicating the brightest parts of ur picture..and u can adjust iris/shutter/ND filter to whatever degree in order to get to the level of exposure u want. My zebras are always on. You will have to be the judge on how u want to be exposed as overexposure is a desired look depending on what u want or the style u are going for.

Now u can get more technical and use waveform monitors however i've never used one...and dont know much about that subject :) (that isnt an incamera tool..well not in the DVX)
 
Last edited:
aight so i browsed through the article/link posted...but that really doesnt get into the question at hand. its cool knowledge for film shooting and for general knowledge overall though. But we're not shooting film and the dynamic range of video cameras are far less than film. Also i dont think light metres are a NESSESARY tool when lighting for video. that said..i'd LUV go get one though and learn how to use it :D However waveform monitors and zebra's are what u need for video.
 
Marker

Marker

There is also a marker function that is in the DVX.

First go into the menu/ display setup and make sure the MARKER is set to ON. Now hit the menu button twice to get out of the camera menu. If you cycle through the Zebra settings you will come to MARKER ON. Once the text disappears you will have 2 white boxes in the center of the screen and you will see a % with a number on the left side just above your audio meter. This will tell you how bright the image is inside the smaller of the 2 boxes. It ranges from 0% being solid black to 99% being the brightest level. It factors in your camera settings too. If you adjust the aperture or shutter speed the % adjusts accordingly.

I have actually been experimenting with this lately so I don't have any recommendations on % levels yet. Once I get around to capturing and seeing them in edit I will try to post some images and corresponding percentages. It is a nice tool though, I am glad I came across it.

Cole
 
Use a waveform monitor. It plots all the luminance values on a graph from 0-100. 0 being black, 100 being white. If all of the values are within that graph, then you're doing good.

The waveform monitor will also allow you to see underexposure, instead of just overexposure like the zebras will.
 
Waveform monitor sounds great but also sounds very expensive...Would love to own one in the future though.Thanx
 
they have software with waveform monitors to use with ur laptop. Dont ask me which though...cuz i duno :) I think adobe Onlocation is one
 
Software?Thanx Daren..Actually there must be one out there..Im on it!Will post back if i get any
 
a good amount of software that have it i think..but i dont use them so i dont really know. these guys would know though.
 
Hey Daren..I finally got one!Its actually in sony vegas was just shown where to get it by David J!Thanx man ur a star
 
jdebmd said:
Here is an article that I found very informative. I hope it helps.
http://www.cineobscure.com/dynamic-range-and-lighting-for-film/
Click to expand...

Really informative article! I found the principals of this to be excellent - and actually quite easy to apply.


I did have a couple of question about the some of the author's calculations in regards to the actual ratios.

He says: "if you have a key light of 800 foot candles, and a fill of 200 footcandles, then your equation would be (800+200) / 200. which reduces to 5 /1, which makes your lighting ratio 5:1..."

Other articles I've read derive the above ratio by dividing 800 by 200 (thus yielding a 4:1 ratio), rather than first summing the two (800 + 200) then dividing by 200 (which yields 5:1).


Anyone care to clarify this for me?




dmc
 
Some people just calculate it differently. The one where you just divide 800 by 200, people are just thinking the ratio is key to fill, so that's how you should calculate it. But the people that add the key and fill together, then divide the fill are thinking...Well, when you flip on the key and fill, they don't just exist in a vaccum, they mix together, so you take those two added, then divide the fill.

I've sorta seen it go either way...but in all honesty, it doesn't matter too much. If you went and told your gaffer that you want something like a 3:1 ratio in a scene, and he gives exactly that, you're still going to adjust it to your eye to make it work for you.

All in all, I think it's just the thing to use to describe lighting ratios when you aren't right there looking at it.
 
Thanks RyanT - that's interesting. It makes sense what you say about the light not "existing in a vacuum" particularly when in most lighting scenarios additional sources would also be used. (ie. back light, practicals, etc.)


thanks,



dmc
 
Thanx for mentioning that Ryan,i was had the same question..Was reading different articles and wondered how they're getting their ratios coz i thot adding then dividing was standard..Thanx man
 
You must log in or register to reply here.
Back
Top