[paul cliff]

So, not only did I find dust on my sensor this morning, 2 large specs, I found that behind the glass of the rear element on my 50-200mm DAL there is a piece of dust just under a mm in size!

Hoping it was outside I used the rocket blower and cleaning cloth, no luck, definitely inside the lens.

Anyway, I've emailed Pentax to find out if I can send them just the lens or will I need to send in the whole kit (K-X, 18-55, 50-200mm), its all under 2 months old, so there should be no problems (?).

I was actually going to put the 50-200 up for sale this morning so I can get the 55-300 instead, but I don't feel comfortable selling it with dust on the inside, despite the fact it doesn't appear to effect PQ.

....grumble grumble....

[paul cliff]

Here's the culprit.

[wlachan]

Dust in lenses is just to be expected. Unless it shows up in pics, it's not worth to have it clean which often does more harm than good. One way to avoid more dust inside K lenses is NOT to blow directly at the aperture lever because there is an opening for the shaft connected to the aperture blades. Dust you bag helps greatly too.

[JeffJS]

Go ahead and sell it. Point out the 'flaw' so the buyer knows what he is getting (I see all kinds of dust in the photo). Then get your 55-300. It isn't likely to be worth sending the lens for a cleaning and will probably cost you half the value of the lens. I have serious doubt that the dust has ever had any affect on your photos. The dust on your Sensor on the other hand...