Posted: Sat May 19, 2007 5:08 pm Post subject: Infrared Hotspot lens tests |
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lulalake wrote:
This A.M. I tested eight lenses for the dreaded infrared hotspot, Russian and Japanese glass, seven M42 mount with adapters and one Mamiya with adapter.
For those unaware if this issue, many lenses will show a sometimes large bright circle in the center of an image when shooting infrared images.
I’m happy to say that none of the lenses showed any hotspot whatsoever.
The lenses are:
Jupiter 21A
Helios 28 (Japanese)
Helios 44M-4
Super Takumar 28
Jupiter 9
Takumar 135
Mamiya 80 (645 lens)
Sears 90-230
I tested each lens wide open, at F8, and at f16.
These were all used on an unmodified Canon 30D with exposure times of from two seconds to thirty seconds depending on sunlight and lens speed which varied from F2 to F4.5 wide open.
Hoya R72 filter
Target test area, bamboo and fig plants : (Helios 44M-4 infrared shot)
Cheers
Jules |