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!

9. TS130 3 inch x1.0 field flattener 910 mm f/7:

To overcome the problem with the vignetting I rebuilt the telescope to adapt a 3" field flattener. With this I probably can handle a medium format sensor of the size 48 x 36 mm.

What a difference, now the signal almost doesn't drop at al at the corners. In center the signal is about 66'000 and at the corners about 62'000. The signal drops 6 %. Have a look here how I changed the 2.5" field flattener to a 3" field flattener. The abrupt signal loss you see to the right is because of the DSLR cameras mirror, it shadow the big light cone coming from optics like this. I solve that by either remove the mirror or by a new full frame mirror less camera. As it is now I can't use the last 2 mm of the long side of the sensor.

Signal drop at corners relative center = 6 % or 0.09 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 ...

The result from this telescope is now excellent even with a full frame sensor. See the photo of the globular cluster M3 at full aperture.