Sensor dirt, DA 12-24, and Kx

This came up a while back. I thought it was just sloppy lens-changing technique and my incompotence. But I've just returned from a week walking in Herefordshire/Mid-Wales, and almost EVERY SINGLE photograph I took with the DA 12-24 had sensor dirt on it.

I cleaned the sensor every morning and evening with a Lenspen (didn't get the chance to get a fancier cleaner), did test shots against white wall & sky, no dirt ...then... I take the 12-24 for another day's walk, no lens changes, CPL & Hood on, even putting the lens cap on/off quite a lot - camera mostly handheld for about 3-4 hours walking across hills/forests. And I can see on successive shots more and more dirt getting onto the sensor as the day goes by!

Lets just say, I'm now horribly familiar with the Clone/Heal tool in Lightroom........ !... !!!...!!!!!!

By the end of the week, I got fed up with spending an hour on the laptop just doing crude touch-ups (I'd have had to delete almost every photograph otherwise, as I took a LOT of wide landscapes and it really shows-up on the blue sky) - and experimented with the Sigma 30mm on instead. And guess what. Not a SINGLE bit of dirt on the sensor after two days.


So - is this a design fault with the DA 12-24 (the rear element has a certain "dust pump" look to it as it is moved back and forth...), the lack of weather sealing on the Kx (I missed the infamous £150 K7's by minutes!), or should I just bang my head on the table with frustration?

Surely it must be dust within the lens rather than on the sensor?

well there was definatly "stuff" on the sensor that I removed each time (could just about see with naked eye) - and test shots with different lenses had dirt until cleaned.

I don't know if the zoom action of the (12-24) lens was blowing it back onto the sensor each day though.

The higher the F-stop, the more "in focus" the dirt was, if that helps indicate where the problem is? I will be able to show example photos tomorrow, as copying 10GB over wireless network is unsurprisingly taking a while...

You'll have to buy....the incredible...."Arctic butterfly!"...

Rough and crude upload, no processing done to this picture full size pic link


How will that help dirt that gets worse during the day though, when I haven't changed the lens....

You sound as if you're over-cleaning flossie, and a lens pen isn't a sensor cleaner, so that might not be good.

Some sample images would be helpful.

Could the over cleaning be causing a build up of static electricity on the sensor and thereby attracting more dust.
I change lenses almost 2 to 3 times a day and only clean my sensor every couple of months. but I do use a rocket blower and the Arctic butterfly.

Dare I suggest that may be there is dust within the camera and this is being dislodged during the shooting day. I find it hard to believe that the seal is not adequately dust proof. My 12-24 seems fine I have not used it on your body but I have on the K7,K20 and an ist and have had nothing more than the expected amount of sensor dust.

I wouldn't go anywhere near a sensor with a lens pen, and the time I used one on a lens I was disappointed.

yes it wasn't an ideal tool - but it was all I had available (apart from a blower, which did nothing even by eye). It worked though... don't forget I had two days with no dirt when I changed lens...

John - see pic linked in post next to yours.

The crud on that photo you linked to looks more like dirt on the lens than on the sensor tbh. Sensor dirt tends to show up as soft, annoying, blotches.

Please don't use a lens pen on your sensor any more. Either invest in an Arctic Butterfly or have it cleaned professionally occasionally.

I haven't yet cleaned the sensor on My K20D. It will need doing soon as there are a couple of blotches showing, but whilst I can heal them easily I am not too bothered. I will use my Butterfly for it.

The shot posted above was at F 22 on a tripod - here is a handheld one at a more normal F 10 taken a little earlier that day (again, no processing or editing on this upload, pic chosen at random to include a lot of sky). Notice not only are the blobs more fuzzy, but there are a LOT less on them. (slight vignetting at top left corner caused by hood being slightly off).


EDIT : CURSES - have just found marks on a few of the pictures taken on the Sigma too. Although nothing like as bad.

Looks like Artic Butterfly called for...

You will probably find you are not actually removing the dirt from the sensor,just moving it around......plus using the lens pen,with which you will have cleaned your lens ,could introduce grease to the problem!...The butterfly is the answer!....good luck!

Ken

A tip for next time it happens.
You can save the action of cleaning the dirt and apply it to all photos after it if off course the dirt doesn't move around.