The scene below makes a good test for hot spots and overall brilliance in infrared. Taken with the Zeiss 50mm and 85mm f/1.4 IR-Planars, which have special lens coatings for infrared transmission. Note the uniform illumination, absence of color shading, and absence of a bright central hot spot; the majority of lenses have troublesome issues here. It’s the special coatings that make the difference.
I’ll be taking the 25/2.8 IR-Distagon, 50/1.4 IR-Planar and 85/1.4 IR-Planar lenses with me to Yosemite this week, and I look forward to using these special lenses with Live View on my Canon 5D Mark II IR. Live View is very helpful in infrared, where backfocus can vary lens-by-lens.
Samples below handheld, processed with Canon DPP, Auto Levels, sharpened, that's it. False color can of course be converted to grayscale in a variety of ways, as I explore in my Guide to Digital Infrared Photography.