How thick is the filter stack?

[john_robison3]

<p>For quite some time I've wondered why a digital back wasn't developed for the OM cameras. Besides the economics of selling enough to make such a venture worth the R&D I wonder if such a contraption would even be possible because of the need for filters on top of the sensor. Would there be enough room to clear the shutter curtains and still get the sensor surface to the film location?</p>

[vivek iyer]

<p><strong>How thick is the filter stack?</strong><br>

John,</p>

<p>Quite thick. The E-410 sensor unit is about 1.5cm thick. This has- the sensor (on a flex board!) with a permanent glass on it, on top of it is a filter stack of complex materials that cut off IR and also do anti aliasing.<br>

This whole thing is then covered with a glass plate that is the dust shaker (which has an ultrasound transducer on it, on the edge).</p>

<p>In other words, it is <strong>impossible</strong> to pack the sensor unit in place of a film.</p>

<p>With the current technology, there is no need for the mirror box and hence that can be done away with and create room (as in m4/3rds).</p>

[john_robison3]

<p>Wow, thicker than I thought. I wonder how the medium format digital backs do it. There was at one time a company that that tried to develop a product called E-film but never could bring it to market. Just put the film in the film cameras and stick to the digital bodies for electronic capture. I suppose it was just a crazy idea.</p>

[jim_rais]

<p align="justify">Yes, I remember that attempt of making the e-film 35mm digital back, but ended up with nothing. If the filter stack is that thick as Vivek said, no wonder that it ill-fated the e-film. Otherwise that would be the real solution for so many of us who want to keep our analogue gear forever. It's just a pity that such a luminous idea died prematurely (and my Rolleiflex and Contax are gathering dust). It's not that I'm not happy with the E-P1, though ...</p>

[matthew_newton]

<p>Medium format doesn't have an AA filter nor an anti-dust shaker/filter to worry about. I think it just has a super thin IR filter and that is it. If it is simply a super thing filter over top of the sensor it is probably a matter of a MM or so thick and can stick up towards the curtains a bit. Look at my OM-1 I'd say there is 2-4mm of room between the curtains and the film plane. I'd think it would be possible to make a removable back, but you would have to do away with an AA filter at least.<br>

The OMs, especially the later ones could use a databack that would synch with the camera, not sure how the synch is coordinated (after fire, during shutter fire, etc), but I'd think you could allow communication between camera and digital back. It would need to be thicker then the film back, but you could use a bit of room in the film cannister area for say batteries and then a somewhat thicker back for the electronics and sensor.<br>

I'd think it would be doable, but I doubt anyone thinks there is enough of a market to sink tens of millions in to the R&D. I hold out some shred of hope that electronics and sensor prices come down enough that someone starts developing sensor backs for old film 35mm cameras as a niche market one of these years.</p>

[harold_gough]

<p>E-film was not a digital back. The genius of it was that it was shaped like a cassette with a couple of frames of film extended, this bearing the sensor. Thus it would fit into any 35mm film camera.</p>

[harold_gough]

<p>E-film was not a digital back. The genius of it was that it was shaped like a cassette with a couple of frames of film extended, this bearing the sensor. Thus it would fit into any 35mm film camera.</p>