In response to today's high-resolution boom, megapixel lens might be the most important accessory to specify with each megapixel camera. In many cases, end-users are looking forward to getting higher image quality and resolution. After all, too many system designers and integrators are still unaware that, for megapixel cameras, a “lens is not just a lens.” a&s talks to several Chinese manufacturers to open up Pandora's box of megapixel lens.
From the year of 2010, series of HD devices have begun to be applied into various Safe City projects due to the enhancement of infrastructures including the network upgrading and enlarging bandwidth, as a result, the megapixel lens is seeing a natural growth.
According to the statistics, the output of megapixel lens accounts for 30 percent of the total production of lens. It is estimated that there will be the positive market responding to the megapixel lens over the next three to five years.
Obviously, with the increasing demand of the megapixel camera, the traditional optical imaging quality cannot fully display the HD features of CCD camera; the lens needed for a megapixel camera is much different than the lens for a traditional analog camera. These higher resolution cameras demand higher quality lenses. No matter for the distributors or users, they all make it clear that megapixel lens will be definitely the future trend. Many manufacturers hold the view that the product should keep in step with high definition, as the megapixel lens is more advantageous than ordinary one in terms of the actual effects.
Undoubtedly, there is a great difference between the lens needed for a standard analog camera and for a megapixel camera. Applications such as license plate recognition, face recognition or identification are some typical uses for megapixel cameras but are demanding image resolution and some necessary details.
Take the traffic surveillance for example, by using the megapixel camera, not only the vehicle license can be seen clearly, each detail even the driver's appearance can also be captured precisely. Once the accident happens, it will play a vital role in helping the police track down the person.
Besides, covering large areas is also another essential use of megapixel cameras. Many integrators select them since a megapixel camera can cover the same amount of space as several analog cameras at the same resolution. Multiple cameras can be reduced for saving money on cameras, recording equipment, installation and maintenance.
In such applications, the megapixel camera has to enable image magnification (digital zoom) at any part of the image, including the edges. Using an ultra wide angle lens without fisheye distortion such as a rectilinear lens will provide a super wide field of view with better resolution at the image edges than a lens that has barrel distortion.
Without a doubt, Made-in-China had filled the gap left by the Japanese market since the earthquake caused a great loss of the labors and equipments; the lens manufacturing had paused for a long while. Nevertheless, several representative optical enterprises took the chance to get prominence.
“Through half-century's upgrading and innovation, Phenix seizes the overseas market of some Japanese high-end products by supplying the quality products with cost-effectiveness,” said Alex Wu, Overseas Manager of Phenix Optical Security Industry. “We feel sorry about the devastating disaster, but the truth is our brand has found more market and has received good feedbacks from many overseas buyers,” said Beth Wu, Vice President of Xiamen Leading Optics.
Moreover, Chinese lens manufacturers have been making nice performance around the world. Leading takes the initial to launch the latest product line in ISC West in recent years; Phenix introduces the advanced equipments and Japanese management models by incorporating Chinese cultures. Above all, they all provide the reputable OEM service for the transnational enterprises.
Apparently, the resolution keeps elevating, but it is not the case for the marginal definition. Aspheric surface plays a vital part in deciding the marginal sharpness. The aspheric lens can effectively add sufficient light to the marginal so that the blurry phenomenon of the spherical surface can be avoided to a great extent. But few manufacturers would use that in producing lens of small focal lengths. “For realize the aspheric surface of lens, the marginal glass has to be grinded carefully, and this can be the current difficulty due to the special material,” said Beth Wu.
Even so, the grinding technique remains to be the technical difficulty. Seldom can the aspheric surface lens be seen in the mass production for it is costly to coating on the glass sphere, which is an eye-catching selling point but also a necessary technical indicator.
Normally, megapixel lens can be differentiated from ordinary analogue lens in resolving power and the marginal sharpness. “We make use of the aspheric surface lens that are independently researched by Phenix, in addition to the central clarity, the marginal imaging keeps high resolution realized by our special optical design and ED ultra-low dispersion lens, “ added Alex Wu.
In general, lens manufacturers focus on three aspects - sharpness, lighting and full image. These are also the principal criteria for the buyers to test its performance. “Megapixel lens requires strict assembling technique and QC procedures due to the sophisticated material and equipments,” said Lin Feng, GM of Fuzhou Feihua Optoelectronic Technology.
When transforming the single product to the total solution, Chinese lens manufacturers are still more or less overshadowed by Japanese brands such as Tamron, Fujinon, CBC. The differences exist in the material, purity, grinding precision and coating technique.
“Compared to the Japanese lens, it is a lot easier for us to control the cost and management, the price performance ratio is favorable, and we are good at the customized service and quickly responding to customer's new products release, so many well-known megapixel network camera manufacturers prefer cooperating with us,” said Beth Wu.
It is clear that megapixel lens has a strict requirement with the whole process and the degree of accuracy. The professional technicians will be must for R&D, besides, product accessories management should be taken into account. “We optimize all kinds of optical paths design and carefully get rid of the stray light,” said Allan Cai, GM of Fuzhou Eversafe Electronics.
“Compared to the some international brands, our product line is diversified, and the lens has a steady performance in imaging quality, stray light processing, and night vision,” said Lin.
Resolution, light and full scale, these are the principal criteria for buyers to choose the lens. “We are more willing to sell our products directly to the users instead of using the distribution channel so that our customers could know more about the functionality of megapixel products,” added Beth Wu.
As HD prevails the security industry, users put more emphasis on the image quality, “When choosing the product, overseas buyers judge the comprehensive price-performance ratio by its stability, though Made-in-China does has the price advantage, the steady performance should not be ignored,” said Beth Wu.
Consequently, better image quality is realized through smart edge devices, which deliver HD quality video at a lower bandwidth and require less storage capacity.
Above all, megapixel lens still faces more challenges in design, assembling handicraft and machine precision than the ordinary lens. No matter what, the distinguished feature of megapixel lens — aspheric surface structure — plays a vital role in making the real HD effect. To-date, when it comes to IP megapixel, the full HD has been realized from front- to back-end device while HD-SDI still looks for solution at the back-end front. Megapixel lens is ready for HD as long as more matured solution at the back-end front has been designed and the real HD, by all means, should be just around the corner.