How Likely am i to get dust on my sensor?

duroo72
Posted 13/04/2008 - 13:46 Link
I have only one lens from K10d at the moment and dont intend to change it for a long time , therefore the lens will not be removed from the camera , my photography takes me to the coast , woods , citycentres just about anywhere really - is it still likely i will get dust on my sensor if the lens never gets removed?
Mannesty
Posted 13/04/2008 - 13:50 Link
It's incredibly unlikely, but even Pentax would not say that it is totally impossible.

You haven't said which lens you have, if it's a DA* weather sealed lens, I'd say you'll have no problem.

The coast + city centres = sand + debris + very fine dust. If it's not a weather/dust sealed lens, you could get sensor contamination.
Peter E Smith - flickr Photostream
amoringello
Posted 13/04/2008 - 13:57 Link
Is internal focusing or does the lens mechanically move in and out to Zoom or to Focus?

Some lenses cause a mild vacuum action as their parts "zoom" in and out, often sucking dust directly into your camera. So in that case, probably 100%.
But how long it will take until something significant enough to notice gets stuck there??? Probably quite a while. Taking the lens off is probably the biggest culprit.
The coating on the K10D sensor really seems to keep a lot of dust from sticking in the first place.

A sealed lens (DA* 50-135 or DA* 16-50) should almost totally eliminate dust getting into your camera.

Bring a small rocket blower, and you should be good for 95+% of dust. I have et to need more than to give a quick shot from the rocket blower to get any irritating dust off my sensor.

I still wonder though, about seals inside places such as when you remove the battery or SD card? I'm hoping those are sealed so that dust that always builds up there will say out. The outer doors are sealed but those do open and allow dust in... I just don't know how far.
iceblinker
Posted 13/04/2008 - 13:58 Link
It is always possible that there is a bit of debris already in the camera that will one day fall onto the sensor.
~Pete
duroo72
Posted 13/04/2008 - 14:19 Link
i have the standard 18-55mm to lens ?
amoringello
Posted 13/04/2008 - 14:55 Link
Then lets say 100% chance.
But over what time frame? Who knows. Could be a while. Really depends on the environment (sandy beach, dusty race track, or clean room?).
I was on two week vacation on boat and land with a sigma 18-200 lens (kept the same lens on). Never had a problem with noticeable dust getting in. (and that was back with my old istD which seemed to send out invitations to dust sometimes.)

I would not obsess over it. Even a little dust is easy to get rid of with a blast of air, or later through Photoshop... although perhaps a little irritating on a thousand+ photos from a trip.
Don
Posted 13/04/2008 - 15:05 Link
Quote:
I would not obsess over it. Even a little dust is easy to get rid of with a blast of air, or later through Photoshop... although perhaps a little irritating on a thousand+ photos from a trip.
software like aperture allows you to clone/heal out the dust spots on one image then "lift" the corrections off that image and "stamp" all the rest...meaning a clone/healing brush adjustment to a thousand+ images in a few simple clicks!
Fired many shots. Didn't kill anything.
Gwyn
Posted 13/04/2008 - 16:29 Link
I have an IST Ds, (still ) so no dust removal system. I have taken it to dust laden Tanzania, whale watching in the US to our local sand dunes, sailing and on beaches. I change lenses frequently. Yet I only got dust on my sensor to the degree of it being annoying more than 18 months after first buying the camera. Even now I rarely need to clean it, and when I do I just use my Arctic Butterfly on it. If you always change lenses with the body facing down, in as dust free an area as you can manage you will reduce the risk of dust. If you never change lenses you will reduce it further. Also make sure the camera is switched off when you change lenses.
johnriley
Posted 13/04/2008 - 18:44 Link
All good advice, thanks Gwyn!
Best regards, John
iceblinker
Posted 13/04/2008 - 21:43 Link
A tip for those at risk of becoming obsessed with sensor cleanliness:

Do not test by photographing a white piece of paper (over-exposed) at F32. It will show up every minute imperfection and you will go nuts trying to get rid of all of it. Test at F22 or F16 instead.

Better still, don't test at all and only clean your sensor if a dark speck or blob shows up on one of your normal photos.
~Pete
wasleys
Posted 13/04/2008 - 21:53 Link
Do not test … at F32. It will show up every minute imperfection … Test at F22 or F16 instead.

I have read this often and observed it in experience, but in my simplicity I don't understand why small apertures make dust on the sensor more visible. Please can someone enlighten me?

Michael
George Lazarette
Posted 13/04/2008 - 21:55 Link
Quote:
A tip for those at risk of becoming obsessed with sensor cleanliness:

Do not test by photographing a white piece of paper (over-exposed) at F32. It will show up every minute imperfection and you will go nuts trying to get rid of all of it. Test at F22 or F16 instead.

Better still, don't test at all and only clean your sensor if a dark speck or blob shows up on one of your normal photos.
More good advice.

People who get obsessive about dirt on their lenses have been known to rub the coating off.

G
Keywords: Charming, polite, and generally agreeable.
johnriley
Posted 13/04/2008 - 21:58 Link
If I ever feel concerned about dust on the sensor I remember how many dust spots used to cover my negatives, and all the concern evaporates instantly.
Best regards, John
duroo72
Posted 13/04/2008 - 22:19 Link
Excellent Replys - certainly food for thought - im taking note of the
"dont get obsessed" part as once you enter that route its a rocky route!!
iceblinker
Posted 13/04/2008 - 22:25 Link
Quote:
I don't understand why small apertures make dust on the sensor more visible. Please can someone enlighten me?
The blob you see on the image is a shadow from the speck of dust. In fact the sensor is covered with a filter, which places any particles on top some distance from the actual sensor.

The size of the lens aperture affects the angles that light enters and therefore the nature of any shadows formed. There are websites that explain the details better than I can, that you should find via Google.

A small aperture results in the dust speck forming a small dark shadow. A large aperture results in a larger but more difuse shadow. Typical large apertures will make all but the largest pieces of rubbish on the sensor invisible on your images.
~Pete

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