DAVE WADDELL /
05.01.2007 12:00 PM
Selecting THE RIGHT LENSES for mobile video units

One of the most critical factors affecting the production of live sports or entertainment shows is the broadcast lens. The image quality, durability, operational features and lens types work together to ensure the success of the telecast and provide a high-quality viewing experience.

Truck companies select lenses carefully because the right complement of lenses will attract new customers and encourage return business. The wrong lenses could cause potential customers to have second thoughts about booking a mobile unit. When choosing lenses for use on a mobile video unit, the main issues to consider are customer service, lens assortment, operational features and performance.

Customer service

The effectiveness of the manufacturer's technical support is arguably the most critical issue to consider when choosing lenses for a mobile unit. Sales representatives from lens manufacturers strive to foster strong, long-lasting relationships with their customers. The true test of the strength of these relationships is when a lens fails.

When a lens doesn't work right, there's no way to fake it. Mobile truck owners immediately call for tech support, and the issue needs to be resolved quickly. When a call to the manufacturer produces immediate results, such as a quick turnaround on service or the issuance of a loaner lens, the manufacturer gains the trust of the mobile truck company, which increases the chance for repeat business.

Lens assortment

Identifying the market and the type of lenses customers expect to use is the second step in selecting the right lenses for a mobile unit. Mobile units are unique because they are severely restricted in terms of total vehicle weight and space, so determining exactly which lenses to have onboard is judicious.

Broadcast lenses are not cheap, and mobile units usually require buying more than just one lens. Typically, a 53ft expando covering network sports requires at least half a dozen lenses. Some events need more than 20 lenses.

Today's sports networks need to capture all the action in any game, from the Super Bowl to college sports. For the most part, their migration to HDTV production is virtually complete. As a rule, they seek out native HD trucks and require top-quality HD lenses.

Trucks catering to high-profile sports networks typically carry six to eight big box telephoto lenses. These telephoto field lenses can reach across the playing field to zoom onto a player's face, zero in on the touchdown or close in on spectators on the other side of the stadium.

The lens package typically includes four or five ENG/EFP-style lenses, so versatility is an asset. A 22X is often chosen for stand-up interviews, roving camera shots and shots that are otherwise difficult to capture, such as standing from the inside lanes of the race track to capture cars as they come zooming around the bend. Wide-angle lenses for closeup work, jibs or Steadicams, and smaller, low-cost lenses (18:1 or 20:1 lenses) are all ideal for mobile trucks. These lenses can be aimed at the scoreboard or game clock, affixed to goal posts, put on Cablecam systems or attached to bucket cameras. Remote control is especially important for lenses and cameras in unmanned positions.

Trucks are often designed and built for either sports or entertainment applications. A truck may be built just to serve a specific package of games for one particular sports network, for example “Sunday Night Football” on ESPN. Or a truck could be designed to cover productions such as the Grammies or Academy Awards.

In many cases, truck owners want the flexibility to serve either the sports or entertainment market to keep their trucks booked and on the road year-round. While entertainment and sports shows can employ the same type and sizes of lenses, the mix may differ depending on the production style and shots the director wants. Also, for entertainment productions, lenses may be placed on jibs, cranes and Steadicams to get the right shots.

Operational features

On big box lenses, camera operators spend their time peering into the viewfinder. If they can't feel the controls with their hands, having a digital display in the viewfinder that indicates the status of every feature is not only convenient, it's indispensable. This allows the camera operator to see if the lens' image stabilization, focus, 2X extender or other features are on or off, as well as the position of the zoom, focus and other imaging parameters.

For sports, camera operators can find it difficult to keep the image steady, especially when they're zoomed all the way in on a big box lens weighing 50lbs to 60lbs. Scaffolds and camera towers typically shake and sway. Excited spectators jump up and down in the stands, causing movement. Even high winds can affect the image stability. For this reason, it pays to have image stabilization on lenses, especially on the big box 101X, 87X and 88X HD lenses.

Special focusing features are catching on because they enhance the operator's ability to keep a moving subject in focus. For example, if a camera operator wants to follow a racecar traveling at 200mph, focus features can zero in on a particular subject and automatically keep it in focus with push-button ease. Zoom and focus features are especially beneficial in HD, where accurate zoom and focus are critical.

Large lenses incorporate a 2X extender. The 2X extender is a must-have feature for sports. It doubles the focal length of the lens. For example, a 100mm lens with a 2X extender becomes a 200mm lens. The compromise is that the 2X extender also doubles the light loss, so it is not always the correct choice for low-light situations.

It's also beneficial to have an RS-232 (computer output) port on the lens. This enables the lens to interface with external devices. This feature is growing in popularity for use with the Sportvision 1st and Ten marker, which superimposes a bright yellow line to illustrate where the first down line is on the field. The marker enhances viewer enjoyment of football games.

Many sports are also using virtual advertising, which keys images onto the playing field in a way that makes them look like physical signage. These types of features require precise information about the lens position via this port.

Performance

It goes without saying that broadcast lenses for live sports and entertainment shows must have superior precision glass. Images in HD reveal much more information than ever before, and any aberration caused by the lens can be distracting. F-stop ramping or the ability of a lens to produce a consistently bright image even at the extreme telephoto end of the zoom range is also important.

In addition, lenses must be extremely rugged and roadworthy. Lenses on trucks are often put on cameras, removed, packed into cases, put into the belly of the truck and driven countless miles, with this process repeated on a regular basis.

The lenses must be durable enough to withstand extreme temperatures. To reduce maintenance and fogging problems, some lenses feature packages that eliminate moisture and fog while the lens is being focused.

Protecting a lens from moisture and dust requires constant vigilance, but doing so will ensure that the broadcast lens will be operational and maximize profits for 10 years and beyond.

The perfect fit

In the broadcast industry, viewer demand for live coverage of news, sports and entertainment has increased mobile TV productions, and that demand will only continue to increase. To be successful, mobile truck owners need to select the correct lens to deliver high-quality content to broadcasters and viewers.


Dave Waddell is the marketing manager for Fujinon, broadcast and communications products division.



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