What is the clear glass layer over sensor?

agentlossing

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By which I mean the optical glass that's set several mm over the sensor stack, not the sensor stack itself. I bought a cheap GF3 for parts on eBay, and it was very cheap indeed because the sensor was described as broken. I found the sensor itself to be intact, but the glass in front of it, not so much. Looks like it had taken a major dose of blunt force trauma.



I'm just curious as to the effect that particular element has on the image, since I may be able to remove all the broken glass. The shutter still fires and the camera still produces an image. I don't need this camera, just wonder what effect that glass had on the image.

GX1•17/2.8•30/2.8
 

agentlossing

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Thanks! I've read that article, but wasn't sure whether it was referring to the glass which is offset from the sensor stack, or just the sensor stack itself. The gx1 sensor they have a photo of seems to have the 4mm of glass directly applied to the sensor, whereas this is in front of that stack, with space in between.
GX1•17/2.8•30/2.8
 

phigmov

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I'm afraid I don't know the answer to that one. I'd take a guess that anything between the sensor and lens forms part of the holistic 'sensor stack package' (for want of a better description).

Hopefully one of the better informed members can help out.
 

agentlossing

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I'm afraid I don't know the answer to that one. I'd take a guess that anything between the sensor and lens forms part of the holistic 'sensor stack package' (for want of a better description).

Hopefully one of the better informed members can help out.

You may be right, it's definitely coated, it looks to me to be the thing that gives the sensor that orangey hue when looked at from certain angles.
 

RobWatson

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If you have access to a spectrometer you can measure the transmission spectrum and see if is UV/IR blocking filter. If there is no obvious impact on UV or NIR transmission then it could be anti-alias filter.

Simpler test is to image your remote control and see if you get strong signals (remotes mostly use NIR LED).

Expect to find a shift in the close and far focus (as in you might not be able to focus at infinity any more.

I bet there will be more aberrations with native lenses and maybe not so much with legacy lenses.
 

Promit

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I'm pretty sure that is the element that gets replaced for an IR conversion. You should do an IR conversion.
 

agentlossing

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Thanks guys! I'm most likely just going to gut this camera for its LCD/touchscreen panel, but if I get an interesting result from the sensor without this layer, I might change my mind. The glass layer is pretty firmly fixed inside, so it hasn't been easy pulling the broken pieces out.
 

agentlossing

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I've been inside the other GF3 that I own, it's actually a relatively easy process to access the inside of the rear panel. Getting to something like the shutter would be a far riskier attempt.
 

RobWatson

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I've stripped my E-P1 down fairly comprehensively (and successfully reassembled it!). Never tried to pry out the glass block on one.

On other cameras I have and the "glue" was RTV or easily softened by tactical application of alcohol (or acetone). Shear forces are your friend here.
 

pdk42

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Someone here some time ago posted his DIY conversion of an E-PM2 (I think) to IR. His "technique" consisted of shattering the outermost glass panel and clearing out the broken bits of glass. There were pictures to prove he did it too.
 

agentlossing

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Interesting. It sounds like the IR filter may indeed be what's broken - I'll confirm this soon! Might be nice to keep an IR-converted GF3 if it continues to function.
 

agentlossing

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It seems the broken glass was most likely the dust reduction filter. I determined that whatever force broke the glass also probably damaged the shutter, as the camera sounded "off" and overexposed. So, I took the thing apart and salvaged the LCD assembly as I'd originally intended. Now my knockabout GF3 has a new(ish) LCD. Worth the $30 I paid for the damaged camera!
GX1•17/2.8•30/2.8
 
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