How to get the lens apart to clear bits on the front element
Hi have recently purchased this lens from ebay second hand, and there appears to be sand or something inside.So i was wondering how easy it was to take it apart to blow this stuff out?.It is a pentax fit lens.
Cameras - Tamron - 18-250mm F/3.5-6.3 AF Di-II LD Aspherical (IF) Macro Lens...
Answers & Comments
The front element is easy to remove.
There's a plastic cover on the front of the lens which has a very small hole in it.
Get something like a very small screwdriver in that hole and prize the cover off.
Remove the 3 screws in the next plastic cover and remove it.
The next 3 screws you see hold the front lens element on.
This whole part rotates to adjust the infinity focus and is kept in position by those 3 screws.
Make sure you mark the position by maybe making a small scratch in the plastic next to one of the screws.
Or maybe scratch around one of the screws.
With those 3 screws removed the front element with the lens just falls out.
Unless you just happen to have a lens collimator handy to ensure that you've got the elements in parallel, I wouldn't even consider taking the lens apart. And, I suspect, if you have a lens collimator you wouldn't have asked this question.
Leave this job to a professional with the tools to put the lens back together again.