Just to mention...
I made a series of tests after having a discussion with "Ray" on this forum on AS and MLU. I never published the results, because I had not the energy to formalize it. The test was carried out on this basis.
- An 80-200/2.8 APO lens was used at maximum focal length
- Lens was mounted on a Velbon 630 CF tripod with RRS BH 40 head and RRS plates
- Series of exposures were made W/WO MLU and WO MLU and AS and finally AS + free hand
- Sharpness was eveluted as LP at 50% MTF using Imatest
- Shutter times between 1/125s and 1/15s were used
The results were essentially:
- Pictures with MLU were twice as sharp as without
- When MLU was not used but AS was enabled little effect f AS could be seen
- Freehand shots with AS were essentially equally sharp to tripod shots without MLU
The visual differences may have been smaller than what was measured with Imatest.
I always used MLU religiously, but now I have good reason...
Best regards
Erik
With a short lens the a900 AS will degrade your image if you don't turn it off when using a tripod. I have tested this with the CZ 24-70.
However, with the 500 mm mirror lens on a tripod on a breezy day I found the AS worked very well when left on.
I think the bottom line is pretty simple - if there really is NO vibration, the AS gets confused and will blur your shots. (Hunting, maybe?) But if there is even slight vibration, the AS is in its element and does a nice job.
In a day or two I'll take delivery of the 300 mm f2.8 and a 1.4X and I'll post my findings.
Bill