How to Choose an Optimized Zoom Lens for your Camera or Sensors

Interview conducted by Courtney Garner, MAJan 23 2020

AZoSensors spoke to Mark Pontin, MD of Resolve Optics about how to choose an optimized zoom lens for a camera or sensors for various applications, and the bespoke optical systems that Resolve Optics offers.

Please could you give our readers an overview what Resolve Optics does?

Resolve Optics Ltd. specializes in the design, development and manufacture of bespoke optical systems that meet the exacting requirements of our customers. Drawing upon almost 30 years experience we have built a strong reputation for specialist lens design and the manufacture of production quantities of custom lenses and optical systems on time to strict quality and target price guidelines. Our company has the proven and rare capability to produce OEM quantities of custom lenses with the look, feel and quality equivalent to the best professional photographic lenses.

Resolve Optics develops fixed focus and zoom lenses for many industry sectors. Are there any sectors in particular which are adopting zoom lenses for their cameras and sensors or is this a general trend in industry?

Technically speaking, a zoom lens is a single lens made up of multiple glass elements, which can change their effective angle of view by moving certain elements within the lens as a whole. Visually, this gives the effect of "zooming in" or "zooming out", while maintaining a sharp image. Because of their operational convenience - zoom lenses are widely used across many industry sectors including defense, space and aerospace. Typically, you would choose a zoom lens for an application if you want to be able to view a general area but then also have the ability to zoom in and magnify a particular part of that area.

What are the benefits of Resolve Optics’ zoom lenses for use with cameras and sensors, and what makes them different to other lenses?

Resolve Optics zoom lenses are based upon “Focus Tracking Zoom” technology.  Our focus tracking zoom lenses offer the benefit that once set up on your camera they will maintain sharp focus throughout the zoom range of the lens. The highly reliable mechanical design of a focus tracking zoom lens means that, unlike an electronic zoom lens, they can be routinely used in environments subject to radiation.

Also their rugged, stable and highly reliable operating mechanism makes focus tracking zoom lenses perfect for space, aerospace and military applications. We offer both off-the-shelf and custom focus tracking zoom lenses which can be supplied either motorized or non-motorized.

What are the key factors to consider when choosing which optimized zoom lens to use for a particular application?

Selecting the optimal zoom lens will depend on what your application requires. For example, for a security and surveillance application I would select a zoom lens that will enable you to monitor a large area but also have the ability to zoom in
and closely inspect a particular object of interest or concern. By comparison a zoom lens used in an industrial inspection (machine vision) application should will give the operator a wide view while moving towards an object but also be able to zoom in and read serial numbers or detect damaged components.

What is the benefit of using custom zoom lenses compared to standard off-the-shelf products for specific application challenges?

Today, zoom lenses are the most commonly used lenses on all types of cameras. The major advantage a zoom lens has is its versatility. Using a zoom lens you can quickly and properly frame and capture a fleeting opportunity. Zoom lenses also capture many different framings of the same subject within seconds. A subject with a rapidly changing distance also favours a zoom lens. Despite these advantages 'off the shelf' zoom lenses have their limitations.

To fulfil the potential of technological advances in many industries the need for zoom lenses which meet the exact needs of customers has risen dramatically. For applications that require high definition or large image format, operation in the UV spectral or IR spectral region or require a compact design 'off the shelf' zoom lenses are either not available or represent at best a significant compromise.

Resolve Optics custom zoom lenses are characterised by their compactness, high resolution and focus tracking throughout the zoom range. Custom zoom lenses can be developed in non-motorised or motorised formats and in materials to suit the widest range of applications. Recent custom zoom lens projects have included UV Zoom lenses for nuclear fuel inspection, HD Zoom lenses for broadcast TV, a miniature Zoom lens for aircraft head-up displays and pipeline inspection as well as IR Zoom lenses for machine vision applications.

How big of an investment is the optimized design of custom zoom lenses, and how long is the development time?

The cost of design and development really depends on the customer’s application and the complexity of the design that is required to meet those needs.  If we are talking about a custom lens design then generally we would design, develop and supply 5 off prototypes for less than you would pay for one high-end megapixel camera. After the prototypes have been approved the reduced unit cost of the production lenses is dependent on the quantities ordered.

Design through to supply of prototype will generally take between 4 to 6 months for fixed focus lenses and from 12 months for zoom lenses. These times are based on completely new designs.

Thank you for sharing these insights with our readers. Please could you also give an example of a ‘real world’ application and the problems solved by a Resolve Optics focus tracking zoom lens?

Most projects we undertake to develop an application optimised focus tracking zoom lens are commercially sensitive and consequently we cannot divulge the customer name. However, I would like to tell you about a compact, high performance zoom lens we developed for aircraft head-up displays.

Our aerospace industry customer required a compact, high performance lens to record high definition images for a head-up display in aircraft. The design challenge was that the system was to be used in several different aircraft, and consequently the distance to object was never the same. This meant that using a fixed focus lens was out of the question, and off-the-shelf zoom lenses were just too big.

We suggested a modified version of our miniature zoom lens. The core of the miniature zoom lens fitted into a special robust body that enabled the zoom and focus movements to be locked so that they did not move even when subjected to aircraft vibration. The new lens can be zoomed to a desired focal length, focused and locked up with only the iris motorised during flight. This approach saved many hours of development time they would have been needed to design a new lens for this application. This lens is currently used by several air forces around the world.

How can our readers find out more about Resolve Optics' optimized zoom lenses?

Readers can visit our website at https://www.resolveoptics.com/ and contact us here.

About Mark Pontin

Mark Pontin is Managing Director of Resolve Optics Ltd - a leading developer and provider of custom optical design and OEM quantity special lenses for small and large high technology businesses since 1993. Please address any questions relating to this interview or Resolve Optics custom optical design, manufacturing and consultancy capabilities to Mark Pontin on +44-1494-777100 or [email protected].