Dust in lenses (DA50-200)


SPB

Link Posted 05/05/2006 - 12:17
I seem to have dust on the inner front element of a fairly new DA 50-200, I have had it bought with camera since January.

I have cleaned the outer glass - that's fine.

Also have some stubborn dust on the focussing screen, but can live with that, but I am horrified at my lens having crap inside of it.

Anyone else had this or is it just my usual good fortune?!

johnriley

Link Posted 05/05/2006 - 12:51
Dust can get into lenses as they are not air tight (if they were we wouldn't be able to focus and zoom because of the vacuum).

A small amount of dust is merely annoying and not too significant. It would take a fair bit to degrade the image significantly.
Best regards, John

SPB

Link Posted 05/05/2006 - 13:00
I used to own a Canon AE1, A1 and a couple of other cameras including a Zenith. I never had dust inside the lenses, so I am surprised that on such a modern lens I have dust.

I hope you are right and it does not affect my pictures.

MattMatic

Link Posted 05/05/2006 - 13:01
I have some fine dust particles on the inside front element of my SMC-FA 24-90. It's annoying, but doesn't affect the images.
I was going to try the suggestion of using an anti-stat gun (as for vinyl LPs) which should dislodge it... I'll let you know if I succeed.
Matt

niblue

Link Posted 05/05/2006 - 16:43
My concern with dust particles would be that they might cause some flare and loss of contrast.

SPB

Link Posted 05/05/2006 - 17:33
Mine is that there is dust there in the first place. I have a three month-old camera and two DA lenses and the zoom has already got dust inside. I have never come across this before across the three other different makes I have used in the past.

I just hope that I can put up with it, having spent what I consider enough on a new system - which up to now I really do like using.

LiamD

Link Posted 05/05/2006 - 18:29
Hi,

as the dust is on the inside of the lens, and although not airtight, should be able to keep out most foreign particles, try ringing up Pentax and see what they say.. you might get it cleaned.. or even replaced, if a bad tolerance between the barrels is to blame, as the lens is only three months old. It probably won't work, but 10p in the phone won't hurt either.

Cheers

Liam
Liam


"Make your hands respond to what your mind demands." Jesse James

Best wide-angle lens? Two steps backward. Look for the 'ah-ha'. Ernst Haas

SPB

Link Posted 06/05/2006 - 10:54
Next time I go near the camera shop, I will take this lens for sure. Also in my DL on the focussing screen I have dust that doesn't move. I bought a big bulb blower, and I even gingerly clean with a micro-cloth the focussing screen and mirror, but the stuff is still there. So I give up on that, I will ask if they can clean it in the shop.

gartmore

Link Posted 06/05/2006 - 16:27
Take out the focusing screen blow the dust off and zap it with an anti-static gun because it is plastic and might get charged and attract dust. I wouldn't do this with the sceen in the camera. I'd be really hacked off if I had dust inside a lens. In 30 years of professional work in film, TV and stills I've never seen this. Take it back.

I would be very careful with the mirror. Unlike the one in your bathroom the silver is on top of the glass. It is very fragile.

BTW I had a friend whose camera came with an army of little insects which marched across the screen, quite entertaining really.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

SPB

Link Posted 06/05/2006 - 18:50
I have no idea how to take the focussing screen out on a DL, and I hardly dare, just in case clumsy me cannot but the thing back in!

As to the lens I shall get in touch with the shop again. It really is starting to annoy me that I "saved" money by buying zooms and thank heavens I bought one "limited" the 40mm.

Maybe after I sort this episode out I will sell the zoom.

However I have a secondhand 18-35 FA J - clean as a whistle.

Perhaps my DA 50-200 is a shoddily assembled one, although it seems to take reasonable photos and its actions feel okay to me.

I have an international guarantee, so I will go to my nearest camera shop this morning and see what they will offer to do. If I get it fixed or receive a new lens, I will sell it and buy a prime lens instead.

SPB

Link Posted 08/05/2006 - 13:17
DA 50-200 now sold.

Replaced with 2 SMC Pentax-M lenses, 100 Macro and 200mm F4. What a difference in quality of feel and construction. The 200 especially a credit to whoever owned it before. In fact from the same person I just missed a 85mm F2, a shame.

So I am left with 18-35mm, 40mm, 100mm, 200mm and 500mm mirror.

Some first examples taken with the 200mm:-
http://homepage.mac.com/stevenbutterworth/Sites/Pentax-M/index.html

What a lovely lens this is with its handling and general feeling of quality build.

Now all we need is some lovely weather, today is not going to be.....
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