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RF100-500 Purple Dot Dead Center

Started 3 months ago | Discussions thread
John Sheehy Forum Pro • Posts: 26,688
Re: RF100-500 Purple Dot Dead Center
5

nanciej wrote:

Hi

I am really hoping someone here may shine any light on this. About 16 months ago I bought the R5 and rf 100-500. Love them! I only photograph wildlife and I really only do it when I am in Africa. On the first trip with the kit, I noticed a purple dot, dead center. I only saw it on certain photos in the 140-170mm range. I sent the kit to Canon. They returned the R5 right away with a cleaned sensor. They said the brand new 100-500 was full of dirt and I would have to pay to get it cleaned. This was the issue. Every single Canon professional I had spoken to said dust would not form a perfect purple dot dead center. After some pushing and a rep from the store I do business with getting involved, Canon sent me a new 100-500.

November I found myself back in Africa and guess what? Purple dot. (images below) A couple of folks thought it might be the sensor...so I tired the lens on my R6. Same dot. It does not happen all the time. When it does, it is always between the 135-179mm range. I only ever see it at f14 or higher, which kind of makes sense. So two lenses and the issue is on two sensors.

Has anyone heard of this? Seen it? I am working once again with Canon support but the hoops!

Thanks for any thoughts.

some post adjustments and a close up.

It looks like some kind of flare. Are you using anything else in the optical path, like a filter?

That color is the color you get with near-infrared light, and some lenses are just not designed to manipulate near-IR light correctly. In some outdoor situations, there can be more near-infrared light than usual, relative to visible light.

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Beware of correct answers to wrong questions.
John
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