Yeh, Dave. The early Sony cam-corders with 0 lux nightshot could be made to ‘see’ through lightweight clothing if it was put on ‘night-shot’ during the day with a screw on an IR pass filter. Basically blocking almost all visible light and using the IR sensitive CCD to get a glimpse.
I believe it was actually trialled as a security measure in airports but as it ‘revealed all’ was dropped. Now it’s just the pervs that use it.
How do I know? – Just a keen amateur photographer!
With a spare £80 or so for the filters, almost any digital camera can be made to do it in very bright lighting (sun) conditions.