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Strange spots behind front lens of EF17-40mm

Started Jan 20, 2020 | Questions thread
OP Fotookes New Member • Posts: 22
Re: Strange spots behind front lens of EF17-40mm

Thanks for the input (all!)

It seems like this one will remain a mystery? Don't feel like 'just shipping it of to Canon' because of the cost most certainly involved...

I did some more checking and found a the same question being asked about this lens problem on the forum here and it created the (un)necessary confusion!

One guy did come up with an interesting theory and that was something called Schneideritis! This phenomenon really describes the spots in my lens perfectly.

It also explains why these spots exist in between two elements of one group (read: lens elements which are 'glued' together and cannot be separated in the practical sense!)

This is why sending it in to Canon will surely cost me, because there will be more than just some cleaning needed for fixing this one...

Anyway, will try an email Canon here in Japan with the question if they are aware of this kind of problem (cement holding lenses in a lens group together starting to cdumble) with their EF17-40mm...

To be continued?

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