lens has marks on the inside...?


TPF Noob!
Dec 26, 2007
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hi my dad has this 10 yr old canon ef 300mm 1:4 L IS lens. im noob and dunno what is means but it is huge.

i noticed when i took inside thru the side where it goes in the cam i can see some marks but its on a layer of glass behind another layer so i cant get to it.

is there a way for me to clean it? i cant seem to notice the mark on the pic maybe i didnt know where to look.

the cam is a 10 yr old canon eos-1.

thanks for the help. and i love this forum already.
If you don't notice it on your pictures, personally, I wouldn't worry about it.
Shoot a few frames against different colored backgrounds to see if you notice anything in the images. If no, than you are fine. If there is noticable change, than contact Canon or a authorized dealer to have it cleaned and maintained. Been 10 years so it is due for a check-up maybe. Good news is the EF 300 f/4 L IS is a stupendous lens so enjoy. Many a newb do not get to start off so lucky. :mrgreen:
Guys regardless if it's visible or not, if it's fungal growth get it cleaned ASAP. Fungus only spreads, and gets worst, and if left too long will etch the glass. Not something you want to have happen on a $2000 lens.

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