Cleaning dust from w/in a Canon EF-S 17-55mm f/2.8 IS USM lens

[motleypixel]

Okay folks,

Do you have a Canon EF-S 17-55mm f/2.8 IS USM lens with enough dust inside to drive you nuts?  Is this dust affecting image quality?  The previous statement is the real question.  In my case there was one particular piece of dust  that was large enough to see at 17mm close focus at f/2.8.  The reality is that I almost never shoot like that with this lens.  For me, it was the challenge and hopeful benefit of having a clean lens and possibly a better calibrated lens.

Here's my video on how I removed the front element and cleaned the inside of the lens:

Cleaning dust from w/in the Canon EF-S 17-55mm f/2.8 IS USM Lens

I had to cut out a lot of video...almost 10 extra minutes to get it under the 10min limit.  In this thread I will explain in more detail the procedure and further explain how the front element is calibrated and front/back focus issues.

-Roy

[DigitalScape]

Roy, great video.  I do not think I would have the confidence to open up one of my lens.

[motleypixel]

Thanks John!

UPDATE:  Watch the video again, pretty much forget about all the calibration and front/back focus bull shit.  Just use tape to mark your front element and put it back exactly the way it came out.

-Roy

[antifire]

Hello photography masters,

I skipped the part where you're supposed to mark the front element using tape--that is, the most important part. Basically, I now have no idea which screw hole to use Sorry about being such an airhead! I guess my question is, does it matter which hole to use? And if it does, how can I fix this misalignment (besides sending it in to Canon). I can't test the lens yet because I don't have a cropped body to mount it onto (another story). Thankkk you!!!!

[DigitalScape]

Ohh, sorry to hear that - Roy is the best to answer your question.  He checks the forum fairly regularly, so you should hear from him soon.

[motleypixel]

antifire,

Welcome to the forum...we hope you hang around and post some stuff  To answer your question, I'm pretty sure it doesn't matter, I was all caught up thinking I knew what I was doing with infinity focus adjustments etc. when in fact, I didn't know a damn thing about infinity focus (got the lens clean...free of dust though, which is the purpose of this tutorial).  What I would do is drop the front element into the recess (gently) and then rotate it CW until you hear it "thud" or drop, then means it's resting good, then simply what whatever holes you want to fix the element into the lens.  I really don't think it matters, i.e. no optical affect, it's just important to get that element to drop in good.

be careful with the silicon trick to seal behind the lens ID ring...DON'T USE TOO MUCH, or you'll get that crap on the lens surface...NOT GOOD!

-Roy

[antifire]

pheww...hahaha thanks! I feel much better now. Sure, I'll stick around. I probably won't contribute much to technical discussions tho, I'm just an enthusiastic newbie and occasional airhead.