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Converted cameras on UK eBay - any experiences?


enricosavazzi

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enricosavazzi

I recently noticed that a UK seller is advertising converted cameras on eBay, including Sony Alpha. Any experiences or comments?

Seller's items: https://www.ebay.co....=p2047675.l2562

Seller's web site: http://www.infraredc...versions.co.uk/

 

One first comment is that full spectrum conversions by this seller seem to remove (not replace) the internal AA and IR/UV-cut filter. By reading through the lines, I assume the seller also changes the sensor's focal plane to restore the original focus plane. If done properly, this does work in a mirrorless camera. It implies that the window of the sensor package is directly exposed, which means if something goes wrong when cleaning and it becomes scratched, there is no fix. The glass on sensor packages is usually quite hard, though, and I have done exactly the same conversion years ago on a Panasonic G3 (without adjusting the sensor registration, instead I mounted a quartz window in a lens adapter for those lenses that cannot focus at infinity without it).

 

Tolerances when adjusting the sensor registration are quite low (I estimate a few tens of microns at most) if one wants to do a good job.

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I got my camera (a Sony NEX-7) from a different (US) eBay seller. The camera itself has worked nicely, but it came full of dust. Obviously every seller will be different, but I suspect people are making a big gamble with these eBay conversions!
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enricosavazzi

I got my camera (a Sony NEX-7) from a different (US) eBay seller. The camera itself has worked nicely, but it came full of dust. Obviously every seller will be different, but I suspect people are making a big gamble with these eBay conversions!

Was your camera modified by replacing or only removing the built-in filter?

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Personally, I wouldnt want a camera that doesnt replace the cover glass. Dust on the cover glass is less of a problem than dust on the sensor, and cleaning the cover glass is much safer too. Tiny cleaning marks on the cover glass dont matter, on the sensor they really do
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enricosavazzi

Personally, I wouldnt want a camera that doesnt replace the cover glass. Dust on the cover glass is less of a problem than dust on the sensor, and cleaning the cover glass is much safer too. Tiny cleaning marks on the cover glass dont matter, on the sensor they really do

True - but, when we talk about "removing the built-in filter", we generally understand it as removing the NIR- and UV-cut fiter, and usually, if separate from this filter, also the piezoelectric "dust shaker" (which generally is UV-opaque). There is an additional window that we assume is not removed, i.e. the sealed cover of the sensor chip package. When a camera is modified in this way, the sensor chip is not "naked", but still sealed behind this optical glass. In this case, this is the glass we actually refer to when we talk about "cleaning the sensor". The distance between this glass and the chip surface can be up to a couple of mm, and the glass thickness often between 0.4 and 0.6 mm. Because of the short distance (compared with the distance between front of the filter and chip surface, which can be something like 6-8 mm in a Micro 4/3 camera), even dust particles - or scratches - of a size of a few microns can project a sharp shadow on the sensor.

 

There are cases where the glass cover of the sensor package is removed. This is necessary to remove the Bayer filters and microlenses from the surface of a Bayer sensor. This is in fact the only good reason to remove the glass cover of the sensor package. In these cases, I would assume that the glass cover is replaced afterward, since a camera with a "naked" sensor chip is very likely to have a short life span.

 

There are industrial videocameras with "naked", exposed sensors, but the operating instructions insist that the lens should never be removed from the camera. These cameras are nonetheless expected to last for only a limited time, even in clean-room environments.

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