DPReview.com is closing April 10th - Find out more

RF100-500 Purple Dot Dead Center

Started 3 months ago | Discussions thread
Bigger Contributing Member • Posts: 640
Re: RF100-500 Purple Dot Dead Center
1

I notice that your photos show a dark central subject with a relatively bright background. So I'm wondering if this could be a re-reflection of the light reflected off the sensor. The sensor tends to have a purplish cast to the specular reflections.

I think stopping down the lens (to f/16-22 in your examples) would tend to enhance this effect, since this constricts the angle of light reaching the sensor, with relatively more light reflected back on the lens axis. With a wider aperture, more light would reach the sensor off angle, and be reflected away from the lens centerline. This might explain why it doesn't happen all the time, and why it isn't commonly seen. L-series lenses are typically used closer to wide-open aperture.

 Bigger's gear list:Bigger's gear list
Canon EOS 5DS R Canon EOS R5 Canon EOS R7
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow