Resolution Information
Resolution is the capability of the camera to produce clear images. This is an important consideration if there is a need to focus on a subject, zoom in to a particular area or capture images for enlargement. This feature is also important if the camera will be placed in an area with low lighting.

Resolution is commonly expressed in number – the higher the figure, the better the image it will produce. The only downside is that higher resolution lenses on hidden camera equipment tend to be expensive. They are well worth it, though. Look for a figure that can handle 400 or 420 lines at the very least.

What will also determine the clarity of the image from hidden camera equipment is the type of lens. In general, a lens is either a CMOS or a CCD. If you want better resolution even at conditions with less than ideal lighting conditions, choose a hidden camera operating with a CCD.

Range
Range can refer both to the working frequency of the device and the maximum distance at which it can transmit signals. The frequency, with which the equipment will work usually starts at 900 MHz and can go as high as 2.4 GHz.

Choose one that has the frequency range that will not affect other electronic devices within the area where the equipment will be installed. Lower range camera equipment will usually interfere with common electronic items such as wireless phones, so it pays to find out if this is a concern.

Range also refers to the effective distance that a hidden camera will be able to transmit signals to a receiver. This limit is generally indicated in feet or meters. Beyond the limit indicated, transmission is likely to be less than effective and might even fail.

Wireless or wired
A wireless hidden camera is more convenient, allowing the user to choose virtually any location within or without the building. Wireless equipment works by transmitting signals by radio frequency.
Wired systems require cables to connect one equipment to another and can provide a reliable means for surveillance. They require more work in terms of installation, however.

Lux rating
Lux rating refers to the capability of the camera to operate in low light. The lower the Lux rating indicated, the more effective the hidden camera equipment will be in semi-darkness or total darkness.