This image is taken with Canon EF 70-200mm f/4L lens at about 100mm. I cooled the CCD to -5C with ambient temperature around 32C. I collected 2x900s Luminance frames at 1x1 binning and 2x300s RGB frames at 2x2 binning. Calibration performed with matching dark and bias frames, 10 each.
I did not collect nearly enough color data - only the stars picked up much saturation. However, even with only two stacked frames in each color, the noise level is considerably less that the DSLR. Focusing without the EOS electronics is still challenging but possible. At 100mm focal length, the peripheral stars are showing some radial elongation, similar to field curvature issues.
I was also able to get a single set of LRGB frames of a field containing the Eagle Nebula and Omega Nebula.