White balance lens cap
 

Neat invention (click here), it's probably old news to some, but I'm going to have to pick one up!

Before you spend $100, try using unbleached coffee filters over your lens. There was a huge thread about it at Fred Miranda's Canon forum a few months back. Those that tried it raved about the results.

Jeff,

I couldn't locate the "coffee filter" thread...

It does sound interesting though! Might work well with a mattebox?

Please tell me more.

== Ed ==

Basically, they were using 3 bleached coffee filters, layered together, to white balance through. When compare to other methods, including the expensive commercial versions, the color accuracy of the coffee filters won every time. Someone even figured a way to sandwich the filters between two UV filters, for a more permanent WB device.

If I can figure out a way to "snap" this home-made white balance device onto the front of my mattebox it would be convenient to use... Or, maybe I could just rig a 4x4 slide-in filter mount using these bleached coffee filters as the media? Kind of a new aspect of mattebox "filters"?

These filters belong to the "incident light" WB world which was used on all camcorders 20 years ago. Remember however that the light that falls on yr cam isn't allways the scene light.

Jeff...

I tried your suggestion - 3 unbleached coffee filters. But I'm thinking you might've meant "bleached" instead? Anywho.... I went ahead and bought some bleached ones.

The results were awesome! Good idea! Thanks for the suggestion. I've been white-balancing off of pieces of white paper, and when I'm at home... the side of my stove.

Whodathunkit... coffee filters! Thanks again!

thanks for the correction Linda. Yes, I most certainly meant the bleached (white) coffee filters.

Hey Jeff, is there a way to read archives of this subject thread on Fred Miranda's Canon Forum that you referred to?

I looked but couldn't see any link...

Thanks, Ed

If you can find it. That board has terrible software and searching is almost impossible. That's why the same topics get asked again and again.

Im a little confused. Do you just thru the filters say attached to your lens or do you WB off the filters set up in the shot instead of the regular white paper?

I assumed that Jeff meant for me to kind of cup the filters over the lens and aim it towards whatever I was shooting at. However... in my case, I just pointed my camera down towards the floor. Results were the same.

If I was supposed to do something different, I'd sure like to know!

The discussion on the other forum was white balancing through the filters. In other words placing them over the lens and pressing the WB button. This is the incident method of WB (or metering) that Andre referred to above.

What I wanted to explain, is that the method of putting a diffuse filter (white paper,coffee filter..) in front of the lens is simular as that used on older camcoders with the separate sensors and white window. It measures (and compensates for) the light falling (incident) onto the cam, this light spectrum can be different from the light falling on the subject. Using an optical transparant (color) filter (not adviseable for coffee making!) is a different storry, and if the filter is taken off after white balancing, the results are like using colored cards for white balancing.

"Remember however that the light that falls on yr cam isn't allways the scene light."

So, this would possibly be along the same lines as color balancing using a white piece of paper close to the camera and then shooting something in different light??? (A stage scene for instance?) The result would be that you'd not get an accurate white balance setting???

But it is also possible that a white balance using the "incident" light method could yield a perfectly accurate balance if the color tempearture of the light at the camera is the same as what is lighting up the subject you are shooting?

But not necessarily so always...