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Ron Risman's
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Review of The ExpoDisc? White Balance FilterPage One

Reviewd by: Ron Risman
Product: The ExpoDisc? White Balance Filter
Review date: July 16th, 2004


I read the press release for this product just last week and was very interested in learning more. I have been looking for a way to get more accurate white balance and exposure settings without having to sacrifice convenience, and the ExpoDisc promises to do this.

One of the big advantages of digital photography is the ability to tweak each photo to perfection. One of the big disadvantages of digital photography is the ability to tweak each photo to perfection. If you have already caught the digital photography "bug" you know what I am talking about. Taking photographs is easy compared to the time it takes to look at and tweak each photo (fixing contrast and brightness, skin tones, etc.,). While the ExpoDisc is a bit expensive for something that looks like a lens cap, it would be worth its weight in gold if I ended up with properly exposed and color balanced photographs. Let's take a look......

Explanation of White Balance from ExpoDisc?

    Varying levels of color cast typically occur in digital photography and require compensation as part of the process to create a photograph with good color fidelity.

    All digital camera imagers are optimized for recording the effects of ?white light? illumination on a subject. White light can be defined as light with a Kelvin color temperature of between 5000-5500 degrees, containing equal amounts of all visible colors. This light occurs naturally at noon on a cloudless day or created artificially by on or off-camera electronic flash lighting. To render natural/neutral colors of the subject, with no noticeable color cast in a photograph, the light must be precisely the same color temperature as the neutral rendering point of the digital camera being used.

    Unfortunately, the world hardly ever presents us with this ideal light for our specific camera model. To make matters worse, all cameras have different neutral rendering points. Even when using flash, there is enough non-white ambient light in the image to cause a color shift, or perhaps the automated features of a camera are fooled by strong color tones in a subject. In any case, varying levels of different color casts always occur in digital photography and require compensation as part of the process to create a photograph with good color fidelity.


ExpoDisc?

The ExpoDisc is, in effect, a gray card in a lens cap, without all the hassles and inconsistencies of a gray card. It is a neutral diffusion filter that gathers ambient light from 180° and passively transmits 18% of it through to your camera?s light meter.The resulting ?gray frame? accurately represents the color cast of the light in which the photograph is being taken. From this gray frame, you then can set a custom white balance, with your digital camera?s menu, that results in accurate color, in almost all lighting conditions. Your camera effectively compensates for and neutralizes the color cast it sees in the ExpoDisc gray frame.

  • Set custom white balancd (WB) 'pre-process' in camera without using a gray or white card.
  • Avoids common gray/white card errors caused by surface glare, reflected light, viewing angle, shadows, or lens flare.
  • Accurately, quickly, and easily document existing light conditions for future reference.
  • Sandwich an ExpoDisc with a color filter to create a White Balance with preferred filtration and eliminate virtually all White Balance post-processing.
  • Set accurate exposures in one step using TTL (through the lens) metering.
  • Prevent overexposed highlights.
  • Check or calibrate your camera's internal light meter for accuracy by reading the resultant RGB numbers in an image editing software like Adobe Photoshop or Elements.

Product & Packaging

The ExpoDisc? ships in a plastic box with product manual, rating card (which informs you that your ExpoDisc filter was individually calibrated on a BMI Color Densitometer. See figure 2.), a quick start card, and the ExpoDisc filter. The entire package is roughly the size of two decks of cards laying next to each other.

Page 2 (How Well Does it Work)
 
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