-Samyang 16\2.0 ED lens
Optolong L-eNhance clip EOS filter
-Canon 550Da camera
Sky-Watcher AZ-GTi mount
Single shot (600s, ISO 800)
Location: Supseh village, Krasnodar Territory.

I managed to get an interesting result using a combination of a Samyang 16\2.0 ED wide-angle lens and an Optolong L-eNhance clip EOS filter. Despite the fact that the lens is announced only for crop cameras, it lacks the “tail” characteristic of EF-S lenses and prevents the installation of astronomical clip-filters (between the lens and the camera). Also, there are no problems with shifting the bandwidth at the edges of the frame. However, another problem appeared – elongated stars and lateral chromatic aberration. This may be due to the fact that when using the clip filter, the focus point is shifted and additional refocusing of the lens is required, while the lens provides minimal aberrations when set to infinity without a filter (a feature of lenses with internal focusing). I plan to add a thin ring between the bayonet ring on the photo lens and the body of the photo lens – this should compensate for the shift in focus and improve the view of the stars across the field.