Help! Dust INSIDE Zoom Lens

[Berni Crumb]

I searched the archives and didn't find anything showing my particular problem, so here goes:

Today, I was changing from my Canon Zoom EF 75-300mm lens to my Canon Zoom EF 28-105mm 1:4-5.6 lens and before I connected the latter to the camera it's lens cap fell off. That's when I noticed bits of dust inside the front of the lens and more laying on the next piece of glass in the lens assembly. I had noticed a few dark marks on some of my lighter images and initially figured that it was from dust on the sensor, but they only appear when I use the 28-105mm lens.

Is there any way to safely clean dust from inside of a zoom lens or am I looking at either a $$ cleaning bill or a $$$$$$ expenditure to replace the lens?

Thanks!

[john]

Dust in a zoom is normal- they suck air in and out when zoomed in and out. Some are pretty "blowy" - even causing "eyeblow" which means the ingress of air is sufficient to be felt on the eye when it is up to the viewfinder. I wouldn't worry about it, the effect on your images is probably pretty negligible. If you have dark areas on your images it may be worth checking if your sensor is dirty- I think it more likely than dust in the lens elements.

[Aaron]

@japers45 John pretty much nailed it.

[Alexis Birkill]

Here's a fun example of just how little difference dust particles or small marks on the lens actually make to the final image:
http://www.lensrentals.com/blog/2008/10/front-element-scratches

[Berni Crumb]

@japers45 @grizzlysghost @abirkill Thanks for responding to my question. John, the reason that I had dismissed dust on the sensor is because the marks on the images only show up when I use the lens that has the visible dust inside of it, not when I use any of the other lenses that I own. But I'll double-check the sensor, just in case. :-) Alexis, thanks for the link. That was an eye-opener for me! :-) I'll just pay attention to my aperture when using the 28-1005mm lens in the future, to minimize any potential effects the interior dust has on my images.

[Jan Hall]

@abirkill Thanks Alexis thatt's a really interesting link, not least because it shows how much cheaper it is to rent lenses in the US than it is here in the UK.

[john]

@bernicrumb , Hi Bernie, might be worth checking both front and rear elements- often we spend ages inspected the front of the lens but neglect the element that is closest to the sensor. Just a thought. Hope you get it sorted.

[Weng]

@abirkill great link.

Funny thing is I had one small chip in the front element of my 24-105L lens - its pretty much bang on in the centre of the lens. This actually resulting in a lighter "spot" in the centre of all my images - actually really obvious especially if i changed the image to B&W.

@bernicrumb back to the original question, if the dust in the lens really bothers you, I'd send it in to get repaired