Chilli-Red,
Well done with this purchase. That Viper looks to be in superb condition.
The picture it generates also looks to be very good indeed. It us always hard to capture a decent image using a camera through the large viewfinder magnifier but you did well
The video output port is very useful. I have connected Archos portable DVR's , USB PC video capture units and even video transmitters to the video output on some of my cameras.
With regard to the units size and weight. This is not at all uncommon for the period in which it was designed. Even the venerable E2V ARGUS 2 and 3 appear large and heavy when compared to modern offerings. I suppose the view was that muscular fire fighters with heavy gloved hands were going to be using these cameras and they needed something large enough to get a decent grip on. Much like military equipment. The weight might have been less of an issue for them. Modern equivalents are more ergonomic and lighter thanks to developments in technology and materials.
So why are the cameras of the period large and relatively heavy ?
Well when you look inside them you see a chassis made from a durable alloy or Aluminium. Magnesium alloy might not be used as it burns well ! The chassis is intended to hold everything together in case of a fall and also provide the skeleton onto which the various PCB's mount. The lens block will be relatively large in size, usually mounted in machined Aluminium and containing large Germanium lens elements. That adds to to quite a bit of weight on its own. PCB's of the era are relatively low component density and low integration when compared to a more modern design. That does not make them inferior, just larger and heavier. If the microbolometer is temperature stabilised it will need a reasonably large Aluminium or copper heatsink and this adds weight. The power source chosen for the camera also effected total weight. Ni-Mh cells are quite heavy when compared to modern Lithium based technologies. It is interesting that efforts appear to have been made to embrace the new Lithium Ion battery technology in the Viper.
There are two other significant items in the camera that add to its weight and bulk..... the monitor and the case. The monitor may use conventional CRT technology in cameras of this era. Such monitors are quite bulky and heavy. LCD panels significantly reduced bulk and weight. Now to the casing. As these cameras were intended to survive rough handling and and extreme environments, the casings were not your average light weight ABS ! Specific materials were selected that would provide durability, protection of the internal electronics from exterior heat and good grip for the user. In some Fire fighting cameras, such as the ARGUS 2 a clever multi layer protection system was employed. The outer casing around the camera was very resilient but sacrificial. It could be damaged by extreme heat from flames or severe impact but it was user replaceable ! Inside the sacrificial outer casing there was a 5mm thick custom shaped thermal blanket. Within the protection of the thermal blanket resided the actual thermal camera casing. This was a heavy duty, sealed, plastic waterproof module. Inside the cameras waterproof module the chassis was a custom Aluminium assembly that was shock mounted on rubber mounts. All these layers of protection added to the size and weight of the complete camera solution. The Viper may not employ the same design in its casing but you can be sure that the case will be flame resistant, thick and shaped so that a heavy gloved fire fighter can grip it well. A small easily dropped camera is not usually what a Fire fighter wants .... but that has changed over the years !
Modern Fire fighting cameras are very different beasts to the Viper. Modern technology has been used for the internal and external parts of the designs. The cameras come in various hand held formats including the standard 'linear scope' like the Viper, 'Pistol Grip' like the FLIR K series and even 'mobile phone' format like the Avon (Nee E2V) Mi-Tic. Each format has its pro's and con's depending upon the use and these cameras normally weigh more than their consumer grade equivalent due to waterproofing , ruggedisation and heat protection. I own a Mi-Tic and I must say I love it. It does go against my comment against small cameras for gloved hand holding though. The manufacturer has carefully designed it to be stable in the hand though.
I hope this small, insight into Fire fighting camera design is of interest
There are far more knowledgeable Fire fighting camera designers on this forum who may have further comment if I have missed something or made any errors in this post
Fraser