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!

8. TS130 2.5" x0.7 field flattener 684 mm f/5.3:

This is my first APO refractor, a 130 mm triplet lens at f/7. Compare to my old Pentax 500 mm this lens has much better sharpness and no visible chromatic errors, but of course this comes with a cost, money.

This is a telescope, not a camera lens. A telescope is built for visual use and then it don't need to have a flat field. When doing photographing the focus field must be flat, otherwise not correct focus over the sensor. To correct that you need a field flattener. This is the setup with a 2.5" field flattener with 0.75 reducer. This field flattener is not optimal for a full frame sensor and give a bit to high vignetting.

In center the signal is about 67'000 and at the corners about 36'000. The signal drops 47 % at the corners. With an APS-H sensor it had performed very well. Here is some information about the mechanical work I have done around the field flattener and off-axis adapter.

Signal drop at corners relative center = 47 % or 0.92 EV (full frame sensor).

TS130 f/7 (not exactly this):

• https://www.teleskop-express.de/ shop/ product_info.php/ language/ en/ ... 130-mm-f-7-Triplet-APO ...

With this telescope I get a very high quality of the data, but the light pollution is the same. See the photo of Planetary nebula M57 with this 2.5" field flattener.