| Latest Review Posted | Sigma XQ Mirror 500mm F4
Well. mine is not labled XQ, but it is probably an early version of this 'lens'.
First some pictures of the lens.
The front :
http://fockert.xs4all.nl/~pentax/sigma500_2143.jpg
It comes with a lenscap, which can be used for stopping down to 5.6 :
http://fockert.xs4all.nl/~pentax/sigma500_aperturecap_2134.jpg
View with Pentax MX attached:
http://fockert.xs4all.nl/~pentax/sigma500_2140.jpg
View with Pentax MX attached and the 2x extender and required extension (all T-mount), then it becomes 1:8 1000mm:
http://fockert.xs4all.nl/~pentax/sigma500_extender_2138.jpg
Closeup of the focus unit, and ring for rotating the t-mount.
http://fockert.xs4all.nl/~pentax/sigma500_focus_2133.jpg
Closeup of the way too small plate for the tripod connection:
http://fockert.xs4all.nl/~pentax/sigma500_tripod_2135.jpg
So, and what about the image quality...
Not good, with extender even terrible.
The only good thing is the low CA, because its a mirror.
And the tripod mount is too small, you get vibrations even when using a serious tripod (Berlebach uni-6).
Later versions got a bigger tripod mount, and not without reason.
Conclusion :
Its not sharp on APS-C.
Its shaky on a tripod.
Its not usable without tripod.
Its a collectors item.
I did try to take an astrophoto with this Sigma which will show how it performs at 1:4/500mm:
http://fockert.xs4all.nl/~pentax/sigma_500F4_pleiaden_2129.jpg |
