White Balance Cap Test

What is White Balance?

First off, a bit of explanation of white balance.  To digital cameras, the white balance setting defines the color of white.  For example, if you take a photo inside indoor lighting, it may look orange or green because of the color of the light source.  To compensate for this, you can set your camera's white balance settings.  This can be done by using presets such as "tungsten", "cloudy", "fluorescent", etc., but you can also have it set automatically to a reference white or grey color (a purely neutral grey).  (See your camera manual for details.) 

Note that it can be hard to see these color differences ourselves because our eyes do such a great job of compensating automatically.

Why would you want to set white balance when you can adjust it on the computer?  As mentioned, let's say that your photos come out orange, which you could fix to some extent in the photo editor.  The problem is that the colors saved in your JPEG format file are limited, and by changing the white balance, you're limited in the color values in the data file.  If you had a RAW file, you pretty much can ignore this when you take the photo, and there's no penalty in making the white balance adjustment when you process it later on the computer.  But, most people still use JPEG most of the time.  So, my advice is to try to get the photo as ideal as reasonable from the start, and you can always tweak it later in a photo editor -- but the closer you get it right in the first place, the better the result in the end.  (Or you may save yourself time by not having to edit later.)


You can use a "grey card" from a camera store, hold it in the light, and use that for the camera's reference.  However, that can be inconvenient, and might only capture part of the light that is in a scene.  There is a pricy line of lens caps that you can get that diffuse the light greatly, giving a white-ish image to the camera that it can use for balancing.  As always, there is a cheaper knockoff version, which you can find on Ebay. 

It seemed almost too good to be true, but unlike the others, the Ebay caps are cheap enough that it's easy to justify a purchase.


Well, my Ebay cap works in that it does change the balance, making whites more white, but I am not sure that it is calibrated or accurate. Using a grey card, I get a warmer look that I prefer. Using the cap, it seems to not only be a bit cooler, but adds a touch of green.  In other words, my grey card might choose 2700K G2, but the cap chooses 2600K G3.  However, the difference is very subtle.


Which is more correct?  Hard to say.  I'd like to think that my grey card is.   However, there's not a single correct answer.  It more or less comes down to personal preference.

Where the card and cap really differ is shooting into mixed light.  When you have a mix of light sources, the result can be a bit hairy.  I think the cap has a big advantage over the card in this situation, as it's going to be hard to hold a card such that it properly reflects the mix of light in the same mix that you'll be taking the photo.

On a more disturbing note, I get pretty much the same results using a semi-transparent folder. Being flat, that might be easier to carry around.  If the results are good enough, that would also save yet even more money too.  Just make sure that you're getting the results you want, and calibrate it against a reference, if possible.

I look forward to seeing someone compare this against the more expensive offerings.

For another take, see this link: http://l7foto.com/2007/05/31/white-balancing-lens-cap-review/.


I borrowed an Expodisc, which is a much more expensive solution.  However, in a quick, informal comparison, I felt that it gave better results than with the cheap cap, at least with the color.  If money were no object, I'd say go with an Expodisc.

Original date: January 21, 2008

Updated on: April 19, 2009