It would have been nice to take an image as soon as the lenses came in from the sunlight, but it took approximately 1 minute to recalibrate the camera. So 1 minute it is.

Of interest is the lens cap of the Canon lens. It is by far the hottest point in the image, at over 27 deg F above the background. A second hotspot was the range window of the Canon lens. I assume the clear window acted like a magnifying glass and caused the range scale to heat badly. It also cooled fairly quickly though.

The average surface temperature of the Canon (ignoring the range window and lens cap) is 9 degrees cooler than the average surface temperature of the Vivitar. This average does include the very hot black grip bands on the zoom and focus rings.