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12-13-2006, 02:25 PM   #1
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Why can't Pentax

or any other lens manufacturer come up with a high-quality, clear glass lens that would prevent sensor dust?

I've been using a Tamron 1.4 TC on my camera recently and thought - "why doesn't someone come up with something similar (without the magnification properties) that would be left semi-permanently on the camera?

No removal of this lens would mean no chance of dust entering, right?

This seems all too obvious- am I missing something?

Dustbuster has a nice ring to it...

12-13-2006, 02:30 PM   #2
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Sigma SD14: Image Sensor Dust Protector. See here:

Sigma SD14: Digital Photography Review
12-13-2006, 02:41 PM   #3
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Hmmmm...

That's the basic idea, except it seems to be an internal shield.

Now why can't they make something similar to retrofit existing cameras, simply by screwing on the lens opening (like a TC)?

Surely there'd be a huge market for them?
12-13-2006, 02:44 PM   #4
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QuoteOriginally posted by Tom Lusk Quote
or any other lens manufacturer come up with a high-quality, clear glass lens that would prevent sensor dust?

I've been using a Tamron 1.4 TC on my camera recently and thought - "why doesn't someone come up with something similar (without the magnification properties) that would be left semi-permanently on the camera?

No removal of this lens would mean no chance of dust entering, right?

This seems all too obvious- am I missing something?

Dustbuster has a nice ring to it...
I have been using dSLR for two years now and sensor dust is really no problem at all. Cleaning the sensor is easy, fast and cheap and I don't see the need for any special dust protector.

12-13-2006, 03:36 PM   #5
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QuoteOriginally posted by i.glisin Quote
Sigma SD14: Image Sensor Dust Protector. See here:

Sigma SD14: Digital Photography Review
who manufactures the camera for sigma?
that anti dust concept looks very interesting


randy
12-13-2006, 05:24 PM   #6
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I had that same idea as well! Kinda like a 1x teleconverter :-)
I have some dust bunnies on my sensor, they only show up when I shoot a blue sky at f/8 or smaller apertures. One of these days I'll get one of those blower thingies and clean the darn thing.
12-13-2006, 05:24 PM   #7
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I would think Sigma!

QuoteOriginally posted by slipchuck Quote
who manufactures the camera for sigma?
that anti dust concept looks very interesting


randy
12-13-2006, 05:27 PM   #8
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I remember a few things from a loooong time ago when I had college physics.
When light goes from air to glass, there is a speed change.
This speed change causes a vector change.
When you have a vector change you get reflection and refraction.
So seems that introduction of an extra lens, even if it's passive,
will introduce anomalies and transmission loss.
This can be reduced with fancy coatings. Coatings ease the transition by reducing the speed change in steps. But never the less,
there is a negative effect.
The question is, how much loss and anomalies is it worth to
protect the sensor? Would you introduce secondary effects from the reflections bouncing around inside the main lens?
Could you actually make something like this that works similarly
on every lens, or would it depend on the lens?

I have no idea - just throwing this out as a point of discussion.
This optical stuff is never as simple as it would seem.

Larry

12-14-2006, 02:39 AM   #9
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I doubt it would sell. It would slow the lens down, add weight and size, and wouldn't give immediate satisfaction to potential buyers. I wouldn't spend money on it.
12-14-2006, 03:58 AM   #10
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There is another source of dust in a camera. Camera itself.
I've read somewhere that ony shaking of the sensor can keep it dust free, because of it. They also said that Sigma did get rid of the outside source, but not of the dust that is already in the camera.
One of the sources inside the camera is shutter, because tiny bits of it are grinded away.
As far as another piece of glass between, even if it is a plane of glass (i.e. no curvature = no magnification), there is something called parallax, which would have to be incorporated in lens design. I think that would mean that some of the lenses wouldn't work properly. Which means no compatibility with (some of) older lenses.
It is not unheard of. Nikon's D40 is an example where they intentionally made a camera that does not work with their current lenses.
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