Tuesday, October 9, 2007
AP 610mm f6 (no field flattener), using photo-adapter with Canon EOS T-ring [ shot on 11/5 ]
AP 610mm f6 (with .75 Telecompressor), using photo-adapter with Canon EOS T-ring [ shot on 11/5 ]
Canon 200mm/2.8 (4) [ shot on 11/7 ]
Nikon 300mm/2.8 (4) [ shot on 11/7 ]
I am getting strange artifacts on right side when shooting with Astrophysics 610mm f6 (& 450mm f4.5), Canon 200mm/2.8 (stopped to f4), Nikon 300mm/2,8 (stopped to f4)
In both of the images (610mm f6 & 450mm f4.5) the artifacts are the SAME size & SAME location. The one on the bottom-right corner seems to be a "clipped donut". The one on the top-right corner seems to be a "clipped circle" (possibly a donut).
WHAT IS CAUSING THIS?
[ something in the Canon 20D lightbox..an internal reflection? ]
The fact that the SAME artifact (size & location) appears in Canon 200mm/2.8 & Nikon 300mm/2.8 shots implies it's something in the Canon 20D lightbox.
There is also some vignetting on the bottom part of the frame of the AP 610mm & AP 450mm shots. I believe this is the bottom part of the Canon 20D lightbox that is doing this.
[ I noticed the same thing when using Pentax 6x7 with the 6100mm f6 (w/field flattener). I believe the bottom of the P6x7 light box is causing the "vignetting/clipping". ]