Canon EF 17-40mm f/4L USM - how to clean the lens inside

[@stevehoge]

Thanks! Now that I have removed dust and lint from this area my lens is in Like-new condition!

[@CamerasLensesEtc]

You're welcome, I'm glad that my video has helped you. Thank you for the donation!

[@claymyers3323]

Very helpful, thanks!

[@CamerasLensesEtc]

Thank you for your comment, and I'm glad that my video has helped you!

[@jorgealvarez4005]

thanks

[@CamerasLensesEtc]

You're welcome!

[@isharadivani2163]

please make content on how to calibrate this 17-40 lens, because in some cases, the results are not sharp because after disassembling it when changing the aperture flexible cable or changing the aperture unit. maybe that content will help a lot of lens technicians like me. Thank You.

[@CamerasLensesEtc]

Generally, you can do that with turning the eccentric screws. I have a video about disassembling and assembling a Canon 24-105mm lens for calibration, and there is a link in the description to a blog post where show you how to do the calibration.

[@The-four-o-five]

Even though the videos from this channel are usually absolutely great, I would refrain from trying this. The front lens is a centering element and therefore adjusted (centered) using a special tool, a collimator. I don't think the mark is enough to get the lens back to its original position and I would even go so far to say repositioning is impossible to do at home with decent results. Image quality will suffer after putting the front lens element back without proper centering on a collimator. Just to clarify for those who want to know more: This type of adjustment has nothing to do with the front lens adjustments of like the Canon 17-55mm 2.8 or the Canon 17-85mm. The position you mark there is the factory adjusted optimal position for resolution. What I mean here is a centering adjustment. Compare the adjustment sections of the Nikon DX 17-55mm or Nikon Micro 105mm 2.8 repair manuals (available online) for the 1st lens group alignment.

[@CamerasLensesEtc]

Thx for the info.

[@The-four-o-five]

​@@CamerasLensesEtc Please consider taking down cleaning videos for lenses with a centering front element, especially Canon L lenses. People who seek to remove dust specs behind the front lens, which are almost always irrelevant for image results anyway, will have very real image quality issues after doing this. You have really great videos on your channel, but these ones will do quite a lot of financial damage.

[@stevehoge]

@@The-four-o-five Is there not a more careful method of marking the front element position so that it can be reassembled with the same alignment? Is precision of .1 mm sufficient to recapture original alignment?

[@carlosalbertopalacioamado8742]

please could you send me the amazon link for Plastic Spudger thanks

[@CamerasLensesEtc]

I have only ebay and aliexpress link. They are in the description below.