How to find hidden cameras (2002) [pdf]
Only some of this information remains relevant today to someone interested in "finding hidden cameras". For example, I found page 10 very interesting to read about; what is presented there would probably make for a very fun hackathon project or similar.As for the info on RF detection, nope. Few things use PAL/NTSC now, mostly devices bought by people not doing research buying the tales spun by the cheaper spy shops. If you find something using analog video, I'd treat it as suspicious. If the device isn't obviously doing spy things, it's probably some completely forgotten-about system not connected to anything anymore.You'd be better served doing analog Wi-Fi RF analysis - whether just figuring out "why is there a gigantic 2.4GHz/5.8GHz/etc signal specifically in the corner of this room", or even seeing whether the camera firmware is vulnerable to the WPA2 attacks. And that's hoping the device uses Wi-Fi; if it uses a LAN, your best bet may be an EM/RF finder (which AFAIK start at $900+ for a basic good one) to try and pinpoint the camera electronics, and hope you don't get distracted with random benign things like in-wall thermometers, chemical sensors, and whatnot.As for modern camera size, I just did an image search for "phone camera module" and then "tiny camera module" and found items quite a fair bit smaller than what's shown in this PDF.- This is apparently 1x1mm, and a cursory but careful examination suggests it's _not_ optical: http://www.awaiba.com/product/naneye/- A bit more looking found this slightly more accessible random option: https://www.alibaba.com/product-detail/1-12-CMOS-tiny-indust...- I also found this generic "MC900A" camera that's very small, self-contained and spits out NTSC/PAL: http://spy.tips/shop/super-mini-520tvl-high-resolution-audio... (this is one of the random results, googling the model will find tons of this)- A bit more searching found the TS5828 5.8GHz A/V transmitter; this is not _tiny_, but it most definitely is very small.One of my rainy-day-when-I-have-more-money projects is to get a tiny camera like one of the ones above, a transmitter like the one above, and a tiny rechargeable battery, and see how compact I can make the result. I'm putting it off until I have more money because I know I'll obsess about it until it's _really, really small_...FWIW, what I just described does already exist as a finished product. Here's a 2.4GHz version: 
https://www.selfdefensegearco.com/MiniWirelessSpyCamera.htm