Welcome to the Autumn 2024 edition of ‘Lens Innovation’ – a twice yearly eNewsletter from Resolve Optics Ltd. Each issue of Lens Innovation contains features written to keep you informed about the latest technological developments, applications advances and breaking news in the optical design and manufacture industry.
Please do not hesitate to contact us if you would like to comment on a particular feature or ask further questions. We welcome your feedback.
Mark Pontin – Managing Director
INFORMATION GUIDELINES:
What are the advantages of focus tracking zoom lenses?
Compared to a fixed focus lens, which just covers a single focal length, a zoom lens covers a wide range of focal lengths. The ability to capture many different focal lengths with a single lens is invaluable. Zoom lenses allow you to adjust focus within a stated focal length range. This is typically done by pointing the camera at an object, setting the zoom position and then focusing to achieve a sharp image. Whilst this is a great solution for capturing still images it poses an issue for video recording as you would spend a great deal of time trying to frame and focus the image.
A focus tracking zoom lens is necessary for any application where live images are required, or you need constant focus within a range of distances. Zoom tracking involves the automatic adjustment of focus in response to zoom movements for the purpose of keeping an object of interest in focus. A focus tracking zoom lens is designed to maintain focus at any point within its focal length range. Zoom tracking is important when users want their subjects always in sharp focus even when they are zooming in or out. A tracking zoom lens does not require auto focus once tracking is set and a well-designed tracking zoom will maintain good resolution and focus throughout the zoom range.
Focus tracking zoom lenses are used in many applications including broadcast TV, CCTV, machine vision, nuclear monitoring, and military surveillance. Different applications require different solutions. Broadcast TV may demand high resolution from a very compact zoom. Military applications typically require the zoom to be rugged and able to withstand shock and vibration. Nuclear applications require the zoom to be radiation resistant utilising special glass types to avoid discolouring when exposed to radiation.
For further information on focus tracking zoom lenses – watch video
VIEWPOINT:
When an off-the-shelf lens just will not work.
Whether you are designing a new product or looking to extend the life of an existing optical product, choosing an off-the-shelf lens may offer the initial attraction of availability and competitive pricing but can be fraught with compromises.
For instance, while the variety of off-the-shelf lenses is huge, they all share the same limitation. They are typically designed for standard sensor formats and lens mounts. The issue with this is there really is not such a thing as standard sensor format anymore. Sensor manufacturers now produce sensors to any size that happens to fit their required pixel count. This leaves you with a choice of either a trial-and-error approach to finding an off the shelf lens or talking directly to someone like Resolve Optics who can quickly tell you what lens is required and whether it is available off the shelf or that you need a custom lens design.
Other parameters that can impact the suitability of an off-the-shelf lens for your camera, sensor or optical instrument include:
Size – increasingly optical applications are constrained by a lack of space in which the measurement device can be situated.
Resolution – to gain more information from an optical measurement typically requires higher resolution. Achieving highest resolution is rarely done with a standard off-the-shelf lens.
Aperture – Lens performance is affected by how much light you can get through it – this is commonly known as the lens F-number. Custom lens design helps you achieve the maximum F-number within the constraints of your application.
Wavelength – Most applications have a key bandwidth or wavelength at which optical measurement / sensing is optimally conducted. Rarely do off-the-shelf lenses provide peak performance in the key bandwidth / wavelength for your target application.
Operating environment – off-the-shelf lenses are not typically made for harsh operating environments. If you need something more rugged, able to withstand extremes of temperature and pressure or even radiation then a custom lens is best.
Security of supply – choosing to incorporate an off-the-shelf lens into your optical product may seem like a good idea but it offers you no security of supply. A key consideration for many companies when choosing a product is security of supply. With a custom lens design from Resolve Optics there is no risk of the lens ever being discontinued, for as long as you keep placing orders, we will continue to manufacture the lens.
While choosing an ‘application optimised’ custom lens design has many advantages, if a suitable off-the-shelf lens is available, Resolve Optics will always make this known to you.
Download white paper “Are off-the-shelf lenses always the best solution?”
TECHNOLOGY FORUM
What are the advantages and disadvantages
of different lens mounts?
There are many standard mounts available for lenses. From small compact threaded mounts like the M12 S-Mount commonly used in small surveillance CCTV applications and board level cameras through to the much larger bayonet style F-Mount found on Nikon photography cameras, with many others in between.
When choosing a mount, factors for consideration will include lens size, register distance, and how secure you need the lens to be?
For instance – a larger mount size can accommodate a larger lens, which lets more light reach your sensor. The distance between the lens mount and the image sensor is termed the register. A shorter register allows for shorter-focus lenses and more compact cameras.
Where cost is a key decision parameter then the traditional C-mount is a popular low-cost option that is commonly used for connecting cameras and microscopes.
Another key consideration with a lens mount is its rigidity. Industrial cameras will often use a C-Mount as it offers a reasonably sturdy thread for applications where there may be low levels of vibration or shock.
However, when it comes to applications where the lens/camera will be subject to higher levels of vibration, such optics to be launched into space and certain military applications, none of these standard mounts will suffice.
For demanding applications such as these, we would recommend a custom mount. This would typically consist of a flange arrangement, which would allow the lens and camera to be bolted together. Not only does this provide a much more rugged solution, but it also provides a solution for focusing the lens without means of other moving parts. This can be achieved by use of shims between the camera and lens.
To discuss a suitable mount for your optical application: click here.
DESIGN FOCUS:
New product design – what comes first, the lens or the sensor?
When designing optical systems for new products, the lens and sensor must be carefully matched to ensure that the image sensor can accurately capture light and convert it into an electrical signal. As specialist lenses suppliers we would love to be able to say the lens comes first but alas this is rarely the case, and for very good reasons.
It is very difficult to design an optical solution if you do not know what the image format and pixel size is. So, we must agree that selecting a suitable sensor for your application comes first. It is then critical to source a lens that exactly matches your sensor’s design specifications to achieve optimum performance and best results. You need your lens to provide enough resolution to get the best out of your sensor, but you equally do no want to over spec the lens, where it is providing a resolution that your sensor cannot see, wasting money and potentially causing other image problems.
When planning a new product design, it is critical to also consider what space you will have available to fit both the sensor and lenses. For instance, if you are space limited – then you should consider keeping your sensor format as small as possible as this helps keep the lens smaller in diameter and in some cases length.
If the clarity and sharpness of captured image is vital to your application, then you should remember that lenses typically have a much bigger impact on image quality than the sensor. In such a scenario – sourcing a custom designed lens perfectly matched to your sensor could be the answer to unlocking the full potential of your optical product.
Learn more: click here.
PROJECT REPORT:
Resolve Optics lenses at the heart of Space-TV.
Over the last 24 months we have worked closely with microsatellite video specialists – Sen to supply them with radiation tolerant, space ready 4K lenses optimised for three different ground sampling distances.
Sen’s latest mission to livestream Earth in 4K launched into orbit aboard a SpaceX supply ship on March 21, 2024, bound for the International Space Station.
The launch, designated SpaceX CRS-30, was SpaceX’s 30th commercial resupply services mission for NASA. SpaceX’s cargo Dragon, loaded with supplies, science experiments and Sen’s payload arrived at the ISS on Saturday March 23.
Sen’s payload, called “SpaceTV-1”, will be hosted on the outside of the ISS through a commercial payload agreement with Airbus U.S. Space & Defence, supported by the International Space Station (ISS) National Laboratory.
The payload has three camera views. One camera, with a wide angle ‘panoramic’ lens, will film Earth’s horizon. Another camera will look straight down at Earth and image a scene around 240 km x 180 km, with each pixel representing approximately 60m of the ground (“ground sample distance” or GSD). Another camera looks at the forward-facing docking port of the International Space Station.
Learn more about this groundbreaking project: click here.
BREAKING NEWS
Executive spotlight on satellite lenses.
Lenses used in satellite applications must meet certain basic requirements to survive the harsh conditions in space. In a recent interview with SatMagazine, our Managing Director – Mark Pontin discusses key drivers that determine size and weight of optics, the implications of specifying wide spectral coverage, high resolution, or long focal length performance. In addition, he also talks about the importance of the comprehensive testing facilities that Resolve Optics offers for the space ready lenses and optical systems it produces.
Read interview in full click here.
Sustainability update.
As a business, we are committed to reducing our impact on the environment and having an ISO 14001 accredited Environmental Management System in place is helping us to do this. As part of our work on improving our sustainability – Resolve Optics has increased over the last year the proportion of lens packaging that is either recyclable or reusable.
Learn about quality at Resolve Optics: click here
THE LAST WORD:
Podcasts for Photonics users.
For those of you who use optics, lasers, sensors or metrology and spectroscopic instruments then the biweekly “All Things Photonics”® podcast could be of interest to you.
Notable previous podcast guests have included Nobel Prize winner Donna Strickland; Columbia University Professor of Electrical Engineering – Michal Lipson; Inventor of the CMOS image sensor – Eric Fossum; Serial entrepreneur – Jason Eichenholz; and SPIE President and founder of the Vanderbilt Biophotonics Center – Anita Mahadevan-Jansen.
Airing on Tuesdays you can find episodes on Apple Podcasts, Spotify, or streamed directly from Photonics.com/Podcast.