I bought a telephoto lens recently.

https://tokinalens.com/product/sz_900mmpro_reflex_f11_mf_cf/

I found that optical quality appeared to be good...at least for indoor tests.

Then I took it outdoors, where temperatures are cool in the winter months. Image quality suffered...horribly.

See image captions.

In cold temperatures the lens appeared to be giving images with lots of astigmatism.

(to be continued)

#photography
#TokinaLens
#LensRepair
#BadDesign
#DesignFlaw
#astigmatism
#MirrorSupport