Color Parrot - use on smaller lenses

To date, our testing of the Color Parrot has been entirely with our Canon EF 24-105mm f/4 IS lens, which has a filter thread size of 77 mm.

Because of our observations regarding the transmissive chromaticity of the center spot of the Color Parrot, we thought it might be instructive to test it on a lens with a smaller front diameter.

Here, we used our Canon EF 50mm f/1.4 lens, with a filter thread size of 58 mm. One might conjecture that here the light supplied to the camera for measurement would be even more preponderately that through the central spot. Thus, we might expect to enjoy even slightly better chromatic neutrality for the Color Parrot in this setting.

As in our basic tests before, focus was set at infinity. The lens aperture was set to f.4.

As an aside, a colleague, in discussing this test program in private correspondence, asked why I didn't include a "coffee filter" in my tests.

His reference was to the big wave of interest, a few years ago, in making color balance measurement diffusers from materials found about the house, such as the translucent plastic cap from a tube of Pringles' Potato Chips, or a layer or two of bleached paper coffee filters.

We had in fact made a "coffee filter" diffuser, with two layers of bleached coffee filters mounted between two (awful) Canon brand 58 mm UV filters.

Since this diffuser fit the lens being used for today's tests, we thought that, just as a joke, we would include it in the test program, and plot the results for it on the chart with the results from the commercial diffusers.

Here is the chart of the results of the "smaller lens" tests:



As before, we used the result from the WhiBal gray card as our reference.

We note that in this test, the Color Parrot did exhibit slightly better neutrality than in our tests before (although as always we need to be mindful of the prospects of modest experimental error, including quantizing error caused by reading chromaticities as integer RGB values). As is so often the case, evidently, "the nearer the bone, the sweeter the meat".