D-TECT 50 AM GJD359
- CCTV Lens Guide
- Hard Drive Size Guide
Unless selecting a vari-focal camera (with an adjustable lens) It is important to select the correct camera lens option for where the camera is to be positioned. A smaller lens will give you a wider angle but will be "zoomed out more", while a bigger lens will narrow the angle down and "zoom in more". See below to give you some idea on angles of Megapixel HD Cameras:
| Lens in mm | Approx Viewing Angle (degrees) | Ideal Distance (metres) | Typical usage/notes |
|---|---|---|---|
| 2.8 | 106 | <6 | For seeing as much of the immediate area as possible such as above a doorway/low down/garage soffits (edges can appear slightly warped/distorted) - clearly "zoomed out" |
| 3.6/4 | 83-90 | <12 | A great general purpose option giving great coverage still in the corner of a room or higher up on second floor soffits with less distortion - more of a natural "zoom" |
| 6 | 56 | 6-20 | Narrows down the angle and zooms in to look past the immediate area a little to gain more detail - down a driveway for example from higher up |
| 12 | 24 | 20+ | Zooms in significantly more to look at a gate, entrance or adjascent building |
| 16 | 19 | 24+ | As above but more so |
The amount of hard drive space you require is dictated by how many cameras, as well as their resolution and frame rate settings. Finally you can often make your storage space last a lot longer by enabling motion detected recording rather than continuous, especially if there are long periods of no activity.
|
Resolution (Megapixels) |
Days of storage provided by 1TB per camera (continuous - full 25 frames per second) |
Days of storage provided by 1TB per 4 cameras (continuous - full 25 frames per second) |
Days of storage provided by 1TB per 4 cameras (50% motion- 15 frames per second) |
|---|---|---|---|
| 1 | 44 | 11 | 36 |
| 2 | 22 | 5 | 18 |
| 3 | 17 | 4 | 14 |
| 4 | 11 | 3 | 9 |
| 5 | 9 | 2 | 8 |
| 6 | 8 | 2 | 6 |
| 8 (4K) | 5 | 1 | 4 |
| 12 | 4 | 0.5 | 3 |
As a rule of thumb we recommend a minimum of 2 Terabytes per 4 x 2-4MP HD cameras, as this should give you 2 weeks to a month with a few adjustments on motion detected recording. You may only require the full 25 frames per second on certain cameras if things are fast moving.
(All of our hard drives come fitted and are CCTV specific from one of the major brands)
In depth product detail
The D-TECT 50 AM is a BS8418 compliant, PIR external movement detector with anti-masking sensing, which can be used for intruder monitoring, CCTV surveillance and other alarm warning requirements.
The detector’s PIR dual technology anti-mask sensing module is equipped with one N/O and one N/C volt-free contact. It boasts a programmable beam range of up to 50 metres, which avoids boundary overspill and offers a truly exceptional resistance to false alarms.
No other movement detectors are more versatile or offer such a wide range of features to enhance the detection of threats and significantly reduce the incidence of false alarms.
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