How to compare IP video cameras?.
How to compare IP video cameras? In any case, mathematics is stronger than emotional arguments. In our age of emotional marketing, such a complex issue as choosing equipment for security systems cannot be done only on the basis of price or brand loyalty. The consumer, installer or manager choosing video cameras for their company's range faces a difficult task — on the basis of what criteria, what methodology to compare products.
The easiest way to perceive is a visual display, and here we have a tool — a bubble chart. It is called a bubble chart because each element of comparison in it is shown as a circle, the horizontal position of which on the chart gives us a visual representation of the price (the further to the left, the cheaper) — you can show it as an absolute price value, bringing all cameras to a single currency, or a deviation from the average price — the position on the chart will not change from this. Vertically — technical characteristics and here the first difficulty arises: how to objectively evaluate why one is better than another? Obviously, you need to compare by the sum of the characteristics, for which you first choose which characteristics, and what weighting factors each of them has.
And here we must rely on an objective opinion. At security exhibitions, we surveyed 150 specialists involved in IP video surveillance on the subject of what characteristics of IP video cameras they consider the most important (150 survey at the All-Over-IP exhibition + the survey is constantly conducted on our website). Obviously, a number of parameters, such as «design» or «flexibility of settings» are emotional and are not subject to mathematical analysis. Of course, it would be possible to expand the survey and conduct it even on such parameters. But this means that we must find a sufficient number of specialists who are able to evaluate at least several manufacturers and their model range, objectively providing information on the ease of use and configuration of a particular camera. It is clear that this is a virtually impossible task, the result of which does not correspond to the costs — after all, now the average release period for new models is less than a year, and updating the internal software is even less. Therefore, we act differently. Most of the characteristics included in the main ones according to the survey results are quite comparable objectively. Well, so that everyone can get an idea of the design, the convenience of the settings, we now supplement each review with video information, where you will not only see the appearance, interface, settings, but also how this or that camera shows in day and night conditions.
Specifically about mathematics.
Now, regarding the actual vertical position of the device on the bubble chart. Let's take the total characteristics of each product as 10. Then, the resolution (if we're talking about IP video cameras), which received the maximum number of points as a result of the survey, will have the maximum weight of 1.6 (16% of 10). That is, the camera with the highest resolution will receive 1.6 points. The camera with the lower resolution will receive less than 1.6 exactly as much as it is lower (if we were comparing 1 and 2 megapixels, the 2-megapixel one would receive 1.6, and the 1-megapixel one would receive 0.8). And so on for all the countable characteristics. The result is the total number of points for each camera and sets its position on the vertical axis. Just like with the price, we usually use the deviation from the average characteristics in order to visually divide the chart into 4 squares. Keeping in mind that products to the left of the center are cheaper and those above the horizontal axis have better specifications, those in the upper left square have the best value for money.
Where is the truth in camera specifications?
In almost all of our comparisons, we use not only the declared characteristics, but also those that we can measure, such as sensitivity. It should be noted that this is the parameter whose reliability in the specification of a video camera is the lowest. You can hardly argue with the resolution: when comparing two CMOS IP cameras with the same resolution, you can completely trust what is written. The presence of any connectors or options is also difficult to dispute. But the debate about sensitivity has been going on since the moment video surveillance cameras appeared on the market. Manufacturers resort to tricks and real forgery. For example, sensitivity can be specified for a high-aperture lens, while a much cheaper one is supplied with the camera.
When measuring sensitivity, we use the built-in one — for cameras supplied with a lens, and then you get the characteristic of a composite product, or the same lens for CS-mount cameras (then with a different lens the sensitivity characteristic will be different, but our task — comparison — will be accomplished).
WDR is a fashionable trend.
Another parameter that is hard to trust is Wide Dynamic Range. There is no standard in measurements, and even if the manufacturer writes the WDR value in decibels, a direct comparison is impossible. It should be noted that this indicator is greatly underestimated in video cameras — the surveyed experts do not even put it in the top 5 and it adds only 2 points to cameras (or 0.02 points when comparing), and just if it is there. On the other hand, the presence of WDR is useful only in some cases and giving it too much weight is also pointless.
Better and/or cheaper.
If for the consumer the review is a kind of guide to choice (even if it does not claim absolutism), then for the manufacturer it is a direct guide to action. Very often you have to explain yourself to the vendors that participated in the test — the position on the diagram characterizes the product much more harshly than words (elementary psychology — you need to be above everyone else on the ordinate axis), on the cost axis it is not so critical, it is good to be approximately in the middle (reasonable choice — and did not cheapen, and did not raise the price). But the harsh truth of life should be perceived as useful criticism. Competition exists in order to make your products either better or cheaper than others, or to achieve a better price-performance ratio. And if the characteristics of your video camera are low, then you need to do something — reduce the cost, release new models, in general, move forward. Well, we will help with marketing.
DSSL CEO I.V. Oleynik