Project:
Analyzes of vignetting from my
lenses and telescopes

Contents:

1. Introduction vignetting
2. Sigma 150 mm f/2.8 APO (f/4)
3. Pentax 67 165 mm f/2.8 (f/2.8)
4. Pentax 67 165 mm f/2.8 (f/4)
5. Canon 300 mm f/4 L (f/4)
6. Pentax 645 300 mm ED f/4 (f/4)
7. Pentax 500 mm f/4.5 (f/4.5)
8. TS130 2.5" x0.7 field flattener 684 mm f/5.3
9. TS130 3" x1.0 field flattener 910 mm f/7

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

3. Pentax 67 165 mm f/2.8 (f/2.8):

One way to overcome the vignetting or reduce it is to use oversized lenses, medium format lenses. I have a Pentax 67 165 mm f/2.8 lens that I bought only for this reason.

A lens built for the Pentax 67 system is designed for a film size of 70 x 60 mm, huge! I also have an adaptor to it which let me connect it to my Canon full frame camera.

This lens has a very good behavior related to the vignetting. In center the signal is about 69'000 and at the corners about 51'000. The drop at right is not because of the lens, it's the camera house that is too narrow to handle this lens, the light cone is very wide.

Signal drop at corners relative center = 27 % or 0.45 EV (full frame sensor). And this is at full aperture, f/2.8 !

Pentax 67 165 mm f/2.8:

• http://skrasnov.com/ pentax-67/ 165mm-f28/

My most low vignetting lens at full frame. See my astrophotography I have of M45, taken with both Sigma APO 150mm and Pentax 67 165 mm.