#80: Dust-excluding lens changer

I’m looking forward to the day when a single, adaptive camera lens will be smart enough to take whatever image I need (that day is coming, albeit slowly. See this for example).

Until then, changing lenses is still going to be a painful process in which you run the risk of coating your sensor array with dust particulates which are invisible -until your photos are viewed on a big screen.

lens_system158.gif

So, today’s invention is to adapt the idea behind the old-fashioned spherical/rotary lens changer on microscopes, for retro-fit use on digital SLR’s. This allows lenses to be substituted, whilst keeping the instrument’s interior pristine.

No-one wants to have to carry all their lenses on the camera though.

The invention would therefore have to be a bayonet-fit device, attached once to the camera body (in as near sterile conditions as possible). The simplest form would resemble a linearly sliding, rectangular ‘sluice gate’ or guillotine with two apertures – of the type used in old slide projectors (shown from above, in red).

A substitute lens can be slotted into one side of the gate, whilst still wearing its own cap on the camera-facing end. The gate can then be slid across the camera body until the new lens locks into place. At no point is the camera body left open to the atmosphere. If you were being ultra careful, the gate movement itself might be used to create a small, transient internal overpressure, making life even harder for any specks determined to get inside.

The camera-facing caps on the lenses could be made to slide radially off and on, driven by the motion of the gate itself, without ever exposing the internals of your expensive optics.

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