Mark Smith
Veteran
Something I like about this board is the productive sharing of information. Last week some one posted about using Expo Discs for white balancing and so out of curiosity i looked that item up and decided to buy a pair, the neutral and the portrait versions.
With a camera like the AF 100 you're going to want to have a solid white balance and good in camera color rendition right from the start because the camera is 8 bit. While color manipulation is possible in post, you want you image going into post to be as close to what you intend the final result to be as you can get it. Using an Expo Disc is one way to go about getting a solid white balance.
After some experimentation and use in the field, I found the Expo Disc was a really good tip.
There are 3 basic ways to set a white balance:
Use a preset or variable preset . The AF gives you three choices, 3200K, 5600K and a variable preset which is user definable.
Incident white balance which is what the Expo Disc does,
Reflected white balance which is the usual method of placing a white reference card in the light you want to shoot in, pointing the camera the card and doing a white balance.
What I like the most is the ability to get consistent results white balance wise under varying and mixed light conditions Snap a disc on the lens point the camera at your sources , White balance and you are good to go.
Expo Discs advance this cause by making faster, consistent and more accurate color balancing on set possible, especially in fluid situations. Who hasn't grabbed a WB off a stray sheet of paper, a crew member's t shirt or the side of a car when in a hurry? The reason I find Expo disc so convenient is that you have the disc in your pocket and the ideal placement for it is over the lens for snapping a WB, which defeats the "random grab a WB off of anything that looks white and is close by" scenario.
The expos are designed to work like a light meter lumisphere , integrating the incident light falling on the disc. So if you are in a mixed light situation, snap the disc over the lens, from where your subject will be, point the camera back at the light illuminating the subject and snap your WB. If you have some overhead flo's and some tungsten mixing in just make sure you can see both sources through the lens, snap disc over lens and WB . The Expo disc acts to integrate the various sources and give you the necessary white balance.
I find the incident method with a Expo disc easier than using reflected light off a white card because white card placement in a mixed source environment can be easy to get wrong. White cards by nature are two dimensional and getting the card placed so the various light sources illuminate the card properly can be very tricky.
On thing that you have to be careful of with the expo disc however is that the light or lights you want to white balance to MUST strike the face of the disc unlike doing a white balance with reflected light.
Clearly there are situations where a reflected white balance os going to be a better choice than incident, for instance if you can't get the camera to where the light is. Low light is a tough situation for using an Expo Disc as the disc cuts light transmission by about 1 1/3 stops, so if you are already in a situation with low illumination levels you may be better off with a reflected white balance than a incident one. For many of the situations that I find myself in, the Expo disc / incident WB method works and gives me very consistent results in less time than using a white card / reflected WB method.
With a camera like the AF 100 you're going to want to have a solid white balance and good in camera color rendition right from the start because the camera is 8 bit. While color manipulation is possible in post, you want you image going into post to be as close to what you intend the final result to be as you can get it. Using an Expo Disc is one way to go about getting a solid white balance.
After some experimentation and use in the field, I found the Expo Disc was a really good tip.
There are 3 basic ways to set a white balance:
Use a preset or variable preset . The AF gives you three choices, 3200K, 5600K and a variable preset which is user definable.
Incident white balance which is what the Expo Disc does,
Reflected white balance which is the usual method of placing a white reference card in the light you want to shoot in, pointing the camera the card and doing a white balance.
What I like the most is the ability to get consistent results white balance wise under varying and mixed light conditions Snap a disc on the lens point the camera at your sources , White balance and you are good to go.
Expo Discs advance this cause by making faster, consistent and more accurate color balancing on set possible, especially in fluid situations. Who hasn't grabbed a WB off a stray sheet of paper, a crew member's t shirt or the side of a car when in a hurry? The reason I find Expo disc so convenient is that you have the disc in your pocket and the ideal placement for it is over the lens for snapping a WB, which defeats the "random grab a WB off of anything that looks white and is close by" scenario.
The expos are designed to work like a light meter lumisphere , integrating the incident light falling on the disc. So if you are in a mixed light situation, snap the disc over the lens, from where your subject will be, point the camera back at the light illuminating the subject and snap your WB. If you have some overhead flo's and some tungsten mixing in just make sure you can see both sources through the lens, snap disc over lens and WB . The Expo disc acts to integrate the various sources and give you the necessary white balance.
I find the incident method with a Expo disc easier than using reflected light off a white card because white card placement in a mixed source environment can be easy to get wrong. White cards by nature are two dimensional and getting the card placed so the various light sources illuminate the card properly can be very tricky.
On thing that you have to be careful of with the expo disc however is that the light or lights you want to white balance to MUST strike the face of the disc unlike doing a white balance with reflected light.
Clearly there are situations where a reflected white balance os going to be a better choice than incident, for instance if you can't get the camera to where the light is. Low light is a tough situation for using an Expo Disc as the disc cuts light transmission by about 1 1/3 stops, so if you are already in a situation with low illumination levels you may be better off with a reflected white balance than a incident one. For many of the situations that I find myself in, the Expo disc / incident WB method works and gives me very consistent results in less time than using a white card / reflected WB method.
