White balance cap?

I found a no-name one at a local store and was intrigued. Read about the ExpoDisc before, but this one I saw seems like a less expensive version. And then while browsing the ExpoDisc site, I found they make a cheaper alternative too: the ExpoCap.

What I'd like to know is if anyone has used or owns one and what sort of results have you got from using it?

TIA

Try a cap from a can of Pringle's. Really. For 99% results.

I have played around with this technique and it works pretty well, but generally for what I do, custom WB isn't involved. A friend does a lot of corporate event stuff so he uses the Expo (has to look like a pro, of course).

A coffee filter works too. :)

I don't quite understand how these work.. Let me get this straight, this unit fits over the lens and is translucent enough that light gets through, plus it is white in color, therefore you have basically have a white card right in front of the lens, is this correct?

Who is to say that thje color temp of the light hitting the back of this unit is the same as at the subject? Wouldn't lens hoods interfere with this? Why not just drop a white card somewhere in the area of the scene you will be shooting (or find something white like snow)? This seems like a much more accurate and only slightly harder way of doing the same thing.

If the sun is at your back, with another light source at the front and you use one of these while the lens is pointed at the scene, it seems like it would be way off.

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Originally Posted by dumpy

Who is to say that thje color temp of the light hitting the back of this unit is the same as at the subject? Wouldn't lens hoods interfere with this? Why not just drop a white card somewhere in the area of the scene you will be shooting (or find something white like snow)? This seems like a much more accurate and only slightly harder way of doing the same thing.

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It's up to the photographer to determine what's going on with the light, but if there are different temperatures going on then a custom WB might not (probably won't) work - whether you used a white/gray card or an Expo. Take the lens hood off - the Expo screws on like a filter, and a hood will have no affect on it.

You could do the same thing with a white or gray card in a lot of situations but thinking of these two where you'd probably want to set a custom WB: Event photographer has a background and two monolights set up off to the side for formal poses with couples. Photog could have an assistant hold the card (if they have an asst, which they probably don't) or dig out another lightstand and tape the card to it (not convenient). Or, something like indoor sports - what matters is the WB out on the field or on the ice - but you probably can't get out there to put a white card. The WB back where you're shooting will be close but maybe not. Expo would help a lot in these two cases.

Most of these caps and techniques require you to shoot at the Light Source, i.e. the Sky or the overhead lighting. One technique I've used is to find something illuminated by the ambient (available) lighting that I will 'call' white in the final photographs. I've use a waiters white shirt, a white reflector and of course tablecloths.

Where these caps and 'filters' come in handy is with mixed lighting. If you shoot an event where there's flourescent, incandescent, candles, and the lighting is low, they can save a lot of time for producing JPEG images. Otherwise with RAW, shoot a white card on custom white balance or just 'correct' the RAW images later.

These caps are handy if the light is changing a lot and you don't have an assistant or find someone to press in to service. They can in an outdoor setting provide a very consistent if not entirely accurate balance when the sun is low in the sky and you may be transitioning to artificial lights. Save's mucho time in post processing whether e it is a sporting event, a concert, a wedding, or some other outdoor gathering.

Just remember to keep checking and re-adjusting the WB as the light changes. Once upon a time, we had to use Color Temp Meters and play with CC filters!!

yeah I was going to say I just use whatever is white in the area, if nothing else - a piece of paper.