I just bought this lens off Amazon Marketplace, only took less than 24 hours to ship due to the fact that the person I bought it from was from South St. Paul and I live in St. Paul. He could have saved shipping and 23 bucks of insurance if he would have had driven it down here to me. I was very dissapointed when the lens arrived, although cosmetically in like-new condition as he stated, the optics were extremely messy. First thing I thought was this guy sent me his vacuum cleaner.. Because it is what he must've used this lens for. There were at least 12 pieces of dust inside the front element, you could see strings and specks everywhere...
I emailed National Camera Exchange and asked how much it would cost if they were to clean the inside of the front element without me having warranty. They said they don't do that kind of stuff and they would have to send it in to Tamron, they say it will probably average from around 150-160 dollars. I decided that it's too much considering a new one was 740 and I bought mine for 660.
I went on and decided I wanted to take the risk of cleaning it myself. The materials needed are proper screw size, I didn't use the proper screw but I used the "proper" size, I used one of those straight-lined screws instead of a + shaped one. I really don't recommend you do the same unless you want to risk stripping the screw.
I had my Giottos Rocket Blower out ready with my LensPens brush, a spoon to tap with, and a Microfibre cloth. They were all set on a clean sheet of towel set on the floor to begin with. I went into the shower and turned it on maximum temperature and left it there for about 5 minutes with the door closed in my restroom after having all my stuff set up in there. This is to allow less dust flying around. I went in later and my bathroom was completely smoked and it was very humid. I Turned off the shower and prepared sat in preparing to do my thing.
First off there are 3 small black screws holding a black cap together, remove all three.
All three screws are removed, good to go.
Now remove the black cap and you should see another 3 set of silver screws holding the front element to the lens.
Take some brown tape and tape these area where it cuts off the body from the element ring, that way you know exactly where it goes in afterward by matching up the tape. This prevents any problems that could occur if you don't put the lens in it's proper place.
It is very important that you have the screwdriver pressed tight against the screw with the right size, you don't want to strip it. The screw is extremely tight against the plastic.
Be careful not to accidentally slip when you are pushing really hard, because that could cost you your front element.
What I did was I used my spoon and tapped the screwdriver onto the screw several times, I kept tapping harder if it does not budge, then try and unscrew it again; if it does not work again then I keep tapping except a little harder. Don't tap too hard because it's plastic underneath the screw. I used a lot of force after every tap to try and push the screw loose and you should too. If it does not want to budge then it does not want to budge,
don't try and keep going because you'll strip it. A technique I do to get extra grip is I take a small face towel and wrap it around the screw, it also helps preventing your fingers from getting hurt.
Voila, now the element is out and ready to removed, gently take the front element out of the body, it is HEAVY so be careful and hold it with good strength. Place it on top of your carbon fibre cloth.
Now you see these 3 thin sheet of metal from the the pictures above?
CAREFULLY remove them and make sure it doesn't fall inside.
Here is what the inside looks like, take your lenspens and brush around the edges of the inside of your lens to loosen up any dust. Then take your rocket blower and blow against it a couple of times.
When you are done blow against the back of the front element also before putting it back on top of the body. Make sure you place those three thin sheet of metal back in place before placing the front element in there. Be careful these thin sheet of metal are very sticky and light, it was difficult for me to put them properly back in it's place. And make sure the tape matches up from the front element to the body.
When you are done with that, just put everything back the same way you took it out. The whole process is actually easier than it looks. The hard part is probably being careful of not stripping the screws or slipping and damaging the front element when lifting it from the body. Make sure you handle everything with precision and hold the items in good strength to prevent any damage. Don't loose the 3 thin sheets of metal either, like I said they are very small and light and flimsy, handle them with care and hold it lightly.
Last edited by LeDave; 12-14-2009 at 11:18 PM.