Camera Selection Query - Covering Entrances at a Distance in the Dark

[Harv]

Hi All,

As a newbie, the latest challenge which has been given is to cover 2 standard size firedoors.

In the event of a break in, these are the 2 most likely points of entry, as they are to the rear of the building and very concealed.

The possible camera mounting points for these are 13M and 20M away from either ones to look face on to the doors.

Phil has kindly calculated that this means we need (for a 1/3" sensor camera) a 30mm lens and a 50mm lens respectively to get a good closeup on each door. The plan is to have some bulk head lights illuminating the doors, triggered by passive sensors (possibly outside the building) so that the lights are on when they make entry.

The ideal solution is to put a metal grid over the inside of the doors and lock it each night, however as they are firedoors, this means someone unlocking and signing to say they have done so each day.

I've been thinking about this a little and this sounds good, althought i have a few questions:-

1) Is the light idea a good solution - I'm not sure IR illumination is practical at these distances?

2) How long will the cameras need to settle and get good images when going from complete darkness to lights on?

3) The doors are in the warehouse part of the building, although they are not in any way exposed to the elements, there will be a certain amount of dust blowing about. Should they be be put in some kind of enclosure, or do the lenses just need cleaning regularly?

4) It would be possible to mount the cameras above and to the side of the doors. At this distance, I would guess a camera with an IR illuminator could be used, however, would this give a good image of someone making entry? Or would the camera need to be mounted a little out into the room to get a good picture?

Many thanks in advance..

Harv

 

[Phil]

Hi Harv,

As per your numbers:

1. The distances are not a problem for infra-red lights, but bear in mind two things; infra-red lights are a lot more expensive than standard white light bulkhead fittings; Only monochrome cameras can utilise infra-red illumination, so (if you can) it is better to use white light and capture real-life colour images. By the way, have the lights illuminate the scene, but do try to keep them out of the picture (otherwise they will cause glaring and the camera will attempt to darken the whole scene to cope with the bright lights within the scene).

2. You are quite correct to be concerned about this, it depends on the camera but most will take 2 or 3 seconds to cope with the change from darkness to lights on. You don't need masses of light, so low-energy, white light, bulkheads left on overnight are probably the optimum solution.

3. If regular cleaning is likely to be needed, then it is best to fix the cameras inside some sort of camera housing. This is often where fixed dome cameras are beneficial (camera, lens and housing all combined in one purchase), but due to the distances that your cameras will be fixed from your doors you'll need lens focal lengths that are not available in a ready-made fixed dome camera. Therefore, best to mount your cameras in traditional wall-mount camera housings (as if they were outdoors). They can then be wiped clean without fear of damage to the lens or the likelihood of mis-aligning them when cleaning.

4. If you are aiming to capture details of anyone entering the doors, then it is better to be opposite and to look at them. Cameras mounted to the side or above are likely to only deliver side or top-of-head views which might not be that helpful. NB sometimes we opt to mount beside or above a door and to look back into the room and capture people leaving, but this option is typically taken with glass doors, where there can be problems looking at and through them due to sunlight i.e. if you try to capture people with the sun behind them through a glass door you may only capture their silhouette.

Hope that helps.

 

[Harv]

Hi there,

Many thanks for your reply.

In light of all this, I think that mounting opposite is the solution to go for, as once they are in, they may choose a more convenient exit route.

I'll arrange for some bulkhead lights to be fitted, out of shot, on daylight sensors.

Could you recommend a suitable housing for an Acti 4200 + lens?

Harv

 

[Phil]

Hi Harv,

Hmmm, cube cameras are tricky to mount in a housing. I just nipped-off to ACTi's site as I knew I'd seen a solution recommended there in the past, and found that they had updated their recommended camera housing for the ACTi 4200 IP camera today!

Take a look at that and see what you think. That type of housing is typically used for fixing to a horizontal surface, such as the ceiling, rather than a wall.