Always wondered...

Kryptix

Kryptix

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Probably a logical answer, but I've always wondered why SLR makers couldn't put a bit of glass over where the lens connects to, thus not allowing dirt into the bit that contains the mirror/sensor (etc).

Why can't they do this?
 
too easy to break and you dont want bits of glass flying in there...
 
KIPAX said:
too easy to break and you dont want bits of glass flying in there...
Click to expand...
Why would it break if it's as solid as a front element on a lens?
 
Kryptix said:
Probably a logical answer, but I've always wondered why SLR makers couldn't put a bit of glass over where the lens connects to, thus not allowing dirt into the bit that contains the mirror/sensor (etc).

Why can't they do this?
Click to expand...

A lot of the dust comes from the shutter itself, so there would be no way of cleaning it?
 
Furtim said:
A lot of the dust comes from the shutter itself, so there would be no way of cleaning it?
Click to expand...
If the glass was removable then... As in, it just screws in.
 
Or... they could place a piece of clear material over it instead, and use an ultra-sonic 'shaker' to periodically remove this... ;) Now that sounds like a great idea... :)
 
how about more glass for the light to have to pass through ? affecting quality
 
The real element of lenses protrude back into the body so the glass would have to be recessed but then you are interfering with the mirror and focusing system.

There just isn't the room in there for it without altering the design of quite a few lenses (mainly EF-S)
 
I'm sure they could do it if they wanted to, trouble is it would add cost, be something else to go wrong or get damaged. It would have to be removable to clean internal dust, so as it would probable be fiddley to remove your more lightly to get dust in then rather than when changing lens, easier to just keep a lens on and be carefull changing.
 
Take a look at Sigma SD14, SD10 and probably the SD9 as well. They all had a IR coated plastic film beween the lens mount and the mirror/shutter mechanism. It kept out the majority of external dust but the shutter mechanism created its own so we had just as many dust bunnies as the main stream manufacturers.
 
Obviously the proof is in the pudding but it looks like this would introduce yet another flat reflective surface parallel to the already flat and reflective sensor. Flare/glare and other artifacts ahoy!
 
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