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RF100-500 Purple Dot Dead Center

Started 3 months ago | Discussions thread
Tristimulus Veteran Member • Posts: 9,998
Re: Image reprocessed so that the Purple dot is visible

The central hot spot (purple, blue, green, whatever depending upon the coating and the incident angle of the internal reflection) is common on cheaper telezoom lenses. Seen in some higher end lenses too.

Very often seen in cheap telescopes whith little or no light baffling.

The optical configuration of zoom lenses vary when zooming and the hot spot becomes more pronounced at certain focal ranges. The range mostly affected depends upon the lens, the optical configuration and coating.

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