Thermal Infrared Camera - Photon - FAQs

1. What is included with a Photon delivery?

This depends on what is ordered. The Photon OEM camera core by itself is positioned as a high-volume thermal imaging component that customers integrate into products or systems of their own design. Most OEM customers interface directly to the Photon’s 30-pin electrical connector for power (in), video (out), and other select functions. This connector also facilitates camera control and serial digital data if needed. Therefore the Photon core by itself is typically what is ordered by and delivered to OEM customers.

For evaluation purposes, FLIR offers an optional OEM Accessory Kit that enables customers to operate a Photon until such time as they develop their own interface. This Kit contains a power supply, break-out box (called an I/O Module), an interface cable to the Photon, and a small adapter circuit (called a wearsaver) that attaches between the camera connector and the interface cable. A rear cover is also supplied that encloses the wearsaver adapter and allows for secure attachment to the interface cable. It is the customer’s responsibility to provide a video cable and monitor, and an RS-232 cable if remote control of the Photon is desired.

A picture of a Photon with accessory kit items can be seen here.

A Photon camera control software program (GUI) is available for download here.

The accessory kit part number is 421-0021-00. The kit includes the following items, which may also be ordered individually:

320 and 160 Accessory Kit

421-0021-00 is the part number for an Accessory Kit compatible with both the Photon 320 and Photon 160 cameras. This Accessory Kit includes the following items:

640 Accessory Kit

421-0030-00 is the part number for an Accessory Kit compatible with the Photon 640 camera. This Accessory Kit includes the following items:

333-0005-00	I/O Module
206-0001-20	AC/DC Power Supply
208-0004-02	Line Cord
308-0076-00	Interface Cable
250-0194-00	Wearsaver Connector²
261-1273-00	Wearsaver Cover²

333-0018-00	I/O Module¹
206-0001-20	AC/DC Power Supply
208-0004-02	Line Cord
308-0144-02	Interface Cable
421-0028-00	Wearsaver Adapter/EMI Cover Kit²

¹ Backward compatible with Photon 320,160,etc.
² Required for compatibility with the Ethernet Module

2. Can lenses be interchanged on the Photon? What if I want to use a different lens? Will FLIR calibrate my lens with a Photon?

We advise against customers changing Photon lenses without first understanding the implications and consequences. Each Photon is calibrated with its associated lens at the factory. The calibration data is stored in camera memory, but there is only enough memory to support a single lens. It is physically possible to change lenses, however, if a different lens is installed, the original calibration is no longer valid. If a Photon lens is changed without recalibrating the camera, it will work but the image performance will likely be degraded. In addition, several of the available lenses use different adapters to attach to the Photon camera body, so changing lenses often requires a different lens mount. Use of a third-party lens would require a custom lens mount, as well as knowledge of the back working distance to ensure lens focus from infinity down to the minimum distance capable with the lens focus system. The design of lens mounts is critical, as a poorly designed mount may introduce unacceptable image artifacts. As a result, FLIR cannot be responsible for the performance of third-party optics used with Photon cameras, nor can FLIR provide optical design information or support for other than the existing Photon lens mounts. Finally, changing lenses can only be done by disassembling the Photon, and the warranty will be voided if this done by a customer.

For qualified customers that furnish their own optics for use with Photon cores, FLIR sells a Windows(TM) application program called Alt Lens Cal. This software allows users to perform a supplementary calibration of the camera with a lens. This field-calibration process requires the use of at least one blackbody source (a highly uniform, controllable temperature reference) that has an area greater than the diameter of the front of the lens. It also requires a customer-furnished PC, which should be dedicated to this task. The calibration routine calculates gain terms on a per-pixel basis with the customer-supplied lens attached to the Photon core, and stores the customer-performed calibration in non-volatile camera memory. The original factory calibration coefficients are first uploaded from the camera and stored into a file on the PC, then the new calibration data is downloaded and stored directly into the camera. Multiple calibration files can be stored on the host computer. The original factory calibration file can be restored if necessary, and the customer can actually build a library of lens calibration files for a Photon camera.

The current version of ALC software is part number 110-0106-72, and supports all versions of Photon cameras delivered beginning in 2008. Contact FLIR for ALC software for Photon cameras delivered prior to 2008.

3. What are the lens options and the minimum focus lengths for the Photon? What is the range of focus? Is it possible to adjust the focus of Photon lenses manually?

Focal Length	6.3mm	14.25mm	19mm	35mm	50mm
f/number	1.2	1.3	1.4	1.4	1.7
Field of View¹
320x240	-	46° x 36°	36° x 27°	20° x 15°	14° x 11°
160x120	52° x 40°	-	18° x 14°	-	-
640x480	-	-	-	26° x 20°	18° x 14°
IFoV² (milliradians)
320, 160	6.032	2.667	2.000	1.086	0.760
640	-	-	-	0.714	0.500
Minimum Focus Distance	~5 inches	~5 inches	~12 inches	~27 inches	~72 inches
Hyperfocal Distance³	0.25m	5 meters	7.5 meters	26 meters	35 meters
Hyperfocal Depth of Field⁴	-	2.5 meters	3.8 meters	13 meters	18 meters
Weight (Lens & Lens Mount only)	55g	56g	33g	88.5g	128g
Length (Lens only)	0.377"	1.209"	0.769"	1.709"	2.632"
Diameter (maximum)	1.250"	1.654"	1.024"	1.654"	1.772"
Coating Type	High Efficiency	High Durability		Hard Carbon⁵
Nominal Wavelength	8.0 to 14.0 microns

1 Field of View describes the angular measure of a scene imaged with the given pixel array, expressed as degrees in horizontal by vertical directions.
2 Instantaneous Field of View is the angular measure of a single pixel. Small angles are usually measured in milliradians. The IFoV is the pixel size (in microns) divided by the lens focal length
3 Hyperfocal distance is the distance beyond which all objects are acceptably sharp, for a lens focused at infinity.
4 Hyperfocal depth of field is the zone of acceptable sharpness. Increasing the depth of field increases the sharpness of an image. Smaller apertures (higher f/numbers) increase the depth of field.
5 Coating Type for 35mm and 50mm configurations of Photon 640 will be High Durability, not Hard Carbon.

4. I need to use the Photon to image an object at close range. Is it possible to adjust the focus of Photon lenses manually? What is the range of focus? What is the close focus distance?

We describe the range of focus to mean the hyperfocal range, that is, the range between infinity and some point less than infinity through which the lens remains in focus. All Photons with lenses are factory-calibrated with the lens locked at infinity focus.

All of the currently available Photon 320 lenses (14.25mm, 19mm, 35mm, 50mm) use a screw-thread mount. The lens focus is locked by a small setscrew. All of the currently available Photon 640 lenses (35mm, 50mm) also use a screw-thread mount, however the Photon 640 lens adapters use a collar with a socket-head cap screw instead of a setscrew.

To adjust the lens focus to something other than infinity focus, or to achieve the shortest possible focus, requires that the setscrew or socket-head cap screw be loosened. It may not be possible to lock the focus at a close focus point since in some cases the lens in almost out of its holder. FLIR does not offer spacers for macro focus. Extreme care should be used to avoid cross-threading the lens in the lens adapter.

The table below shows the approximate minimum focus distance for each Photon 320 lens type. Although Photon lenses are capable of focusing to shorter object distances, it is important to note that they are not designed, calibrated, or specified for this purpose. All Photon camera/lens calibrations are performed at infinity focus. Image space f/numbers can change under extreme finite conjugates. Very close focus applications using a Photon calibrated at infinity focus may result in possible image anomalies, non-uniformities, and/or degraded performance. Customers should be aware of these limitations and evaluate the images for issues.

Lens Focal Length	14.25mm Lens	19mm Lens	35mm Lens	50mm Lens
Close Focus Distance	~5 inches	~12 inches	~27 inches	~72 inches

5. How much does the Photon camera weigh?

Photon Weight Information

The camera weight will depend on which type of cover is installed, if any, and whether or not a wearsaver adapter is used. The table below shows the approximate weight of the different camera/lens configurations, as well as the weights for the covers and wearsaver connector. There can be some variation in the actual weight, but the figures shown for the Core + Lens should be accurate to within +/- 2 grams.

Weight Table For Photon 320 and 160

	No Lens	6.3mm¹	14.25mm²	19mm	35mm²	50mm²
Core	97g	132g	153g	130g	185.5g	225g
Wearsaver Cover	16g	16g	16g	16g	16g	16g
Wearsaver	7g	7g	7g	7g	7g	7g
Core + Wearsaver + Cover	120g	155g	182g	158g	212g	253g

¹ Only available for Photon 160
² Only available for Photon 320

Weight Table For Photon 640

	No Lens	35mm	50mm
Core	113g	227g	280g
EMI Board cover	22g	22g	22g
EMI Board	24g	24g	24g
Core + EMI Board + Cover	159g	273g	326g

6. Is it possible to get the Photon camera with an athermal lens?

All of the currently advertised Photon lenses are of a passive athermal design. This means that the lenses mechanically self-adjust to changes in temperature such that the lens remains in focus over wide ambient temperature ranges.

7. Can the Photon rear cover be removed? What other rear cover options does FLIR offer for Photon?

Unless otherwise specified by an OEM agreement, all Photons with lenses are delivered with a rear cover. This cover affords some protection to the electronics, but it can be removed by the customer. There is no credit given for unused rear covers. The standard rear cover has a cut-out to allow access to the SAMTEC 30-pin connector. This cut-out is sized to enable the wearsaver adapter to be installed.

Some customers have expressed concern about the integrity of the cable-to-camera connections in environments where vibration or low g-forces may exist. An optional rear cover is available for Photon that encloses the wearsaver adapter, and jack posts are provided to which the interface cable can be securely attached. The wearsaver cover is furnished as part of the Photon Accessory Kit, or may be ordered separately using part number 261-1273-00. The wearsaver cover is provided as a separate item in addition to the standard cover when delivered.

NOTE: For the Photon 320 camera, the wearsaver adapter is required for compatibility with the Ethernet Module. FLIR also recommends the wearsaver cover in cases where the Ethernet Module is used with a Photon 320.

For the Photon 640 camera, the EMI cover accessory is required for compatibility with the Ethernet Module.

Photon 320

	261-1273-00 Wearsaver Cover. Provided as part of the optional Photon Accessory Kit (along with the Wearsaver Connector). Used by most one-off customers and some OEM customers due to its secure connection ability.
	261-1082-00 OEM Shipping Cover. Provided as a standard part of the Photon Camera Core configuration.
	500-0312-00 EMI Rear Cover. Optional cover that provides some EMI mitigation by means of a separate electronics board, shielding, and grounding.

8. How are FLIR's microbolometer arrays packaged? Are they under vacuum? Why?

The microbolometer sensing elements are thermistors that are suspended, as bridge structures, above a readout integrated circuit (ROIC). The sensing elements need to be able to change temperature individually in response to small amounts of heat energy. In order to allow this response to small changes in radiant energy, the sensing elements must be thermally isolated from the ROIC. To achieve the thermal isolation, we put the sensor in a high-quality vacuum to eliminate the air gap that would otherwise exist between the thermistors and the ROIC. An air gap would enable a conduction path that effectively dampens the sensor responsivity.

9. I have lost / can’t find / don’t remember receiving the Photon camera control software / User’s Guide. How can I get a copy?

Photon cameras are delivered with instructions that provide a link to the Photon camera control software (GUI). The software can be downloaded at www.corebyindigo.com/service/softwareupdates.cfm. The User’s Guide is also available as a download, at www.corebyindigo.com/service/currentmanuals.cfm.

10. How can I figure out which lens version will work best for my application?

There are three variables that need to be known in order to determine the most appropriate lens for an application:

1. The distance from the camera to the object being imaged. This is usually expressed in feet or meters.
2. The size of the object being imaged. This is usually the largest dimension, also in feet or meters, as long as the same units are used.
3. The number of pixels that the object needs to cover in the image, usually using the larger of the horizontal or vertical dimension.

Using these variables, it is possible to calculate the optimal lens, since the sensor resolutions (640x480, 320x240, 160x120) and pixels sizes (25 microns for the Photon 640; 38 microns for other Photon versions) are known values. We provide a calculator for anyone to use at www.corebyindigo.com/tools/LensCalculator/new/ or by clicking the Lens Help button at the Photon home page.

11. Is the Photon a rolling shutter camera or a framing camera?

The Photon camera is more like a rolling shutter camera than a framing camera, but does not perform exactly the same way that a typical rolling shutter camera performs. In typical electronic shutter cameras, each pixel in the sensor cyclically goes through the following functions during one frame period: integration of signal onto a collector (analogous to exposure time onto film); sample and readout of signal; reset (to “zero”) of the integration collector. In a framing camera, the integration of signal function occurs for all pixels at the same time, while in a rolling shutter camera, the integration period occurs at different times for pixels in different rows. The actively integrating rows in a rolling shutter camera “roll” down the sensor from top to bottom during the course of the frame period. For a rolling shutter camera, the sampling and readout operation occurs directly following the conclusion of integration, and as a result also rolls from top to bottom of the sensor during a frame period; and likewise with the integrator reset function.

The differences between a Photon camera and a typical rolling shutter camera are the following:

The Photon camera’s pixels are continually integrating on the signal (IR light) from the scene, and unlike a rolling shutter camera have no integration time adjustment. The pixels in the Photon camera register integrated signal via their temperature (get hotter when more signal arrives, and colder when less signal arrives). As IR signal arrives, it contributes to the pixel heating, while at the same time there are inherent mechanisms that also allow heat to escape from a pixel. A good analogy for this is a water bucket with a hole in the bottom. Signal is continually filling the bucket with water from the top (heating), while cooling is continually allowing some water out from the bottom.
Because the integration of signal is a physical rather than electronic mechanism, unlike a typical rolling shutter camera, in a Photon camera there is no way to reset the integrated signal from an earlier frame. As a result, a bolometer pixel will have memory of the signal that was collected in previous frames. Due to the pixel’s of cooling mechanism, the contribution from past frames decays over time. The heating and cooling occur at a rate that is defined by the pixel’s time constant. Image artifacts such as tails on hot moving objects are a result of this property of the camera.
Because there is no integration period on the Photon camera and no reset of the integration, the only function that rolls down the rows in the Photon camera is the sampling of the temperature of each pixel.

12. What is needed to use Photon cameras? What type of connector is used for the power? What is the polarity of this connector?

This depends on the use, and whether or not camera control is desired. At a minimum, a cable is needed from the camera that provides power in to the camera and video out from the camera. We offer such a cable, called a “power/video cable”, as an optional accessory. Power/video cables require that the Photon be configured with a wearsaver connector and wearsaver rear cover, both of which are technically accessory items. An image of a Photon with the wearsaver and its cover can be seen on the Photon 320 page by clicking on the ‘Wearsaver rear cover’ view. The maximum length of the available Photon interface cables is 10 feet. If camera control is desired or required, then an “interface cable” is needed that goes from the camera into a break-out-box (called an I/O module). The I/O module accessory includes a standard DB-9 connector to allow a PC to communicate with a Photon via RS-232 protocol. Customers must arrange to get power to the input power jack of the power/video cable or the I/O module, or otherwise get power directly to the camera. The input power jack for both the I/O module and power/video cable mates to the Switchcraft S760 Miniature Power Plug. Pin definitions for the power interface connector on the power/video cable:

Pin #	Signal Name	Signal Definition
Pin	PWR	input power
Sleeve	PWR_RTN	input power return

FLIR offers an AC/DC power supply as a Photon accessory, as well as a rechargeable battery that will run a camera for 5-6 hours. Typically customers take the video out signal to a monitor or display of some sort.

13. Can I just hook a Photon up to power and a monitor?

Yes. Many customers use Photon cameras in a stand-alone fashion, and typically use all or part of our accessory kit items, and/or optional accessories, for connectivity with the camera. FLIR’s standard and optional Photon accessories include cables that enable connection to the camera in a straightforward, user-friendly fashion. Our high-volume integrators are more likely to build a custom wiring harness that directly interfaces to the Photon OEM connector to achieve a specific functionality. Answers to other FAQs on this page describe the connector pin functions and vendor information needed to build custom cabling.

14. What is the occasional clicking sound made by the camera? What is FFC?

There is a shutter between the camera lens and the sensor package. This shutter is used to perform a flat-field correction, or FFC. During FFC, the shutter presents a uniform temperature source to each detector element in the array. While imaging the flat-field source, the camera updates the offset correction coefficients, resulting in a more uniform image after the process is complete.

The FFC process takes 0.7 second for all Photon camera versions. While the shutter is in the field of view of the sensor, the image just prior to the shutter moving is frozen and displayed until the FFC process finishes and the shutter moves out of the field of view of the sensor. A faint click is produced when the shutter moves in front of the sensor.

When power is applied to the Photon camera, two mandatory shutter events occur: one within 2 seconds of startup; the other within 6 seconds after the first shutter. Photon cameras are normally configured at the factory to automatically FFC at a specified interval following the initial two shutter events. The FFC interval is based on time and camera temperature. Except for the initial two shutter events, the FFC interval parameters can be modified by the user via the GUI or by serial command to the camera. An FFC can be performed on command by the user, regardless of whether the FFC is in the automatic mode or not.

Photons delivered beginning in 2008 have an option, via the GUI or by serial command to the camera, to allow the user to perform an FFC through the lens, using a uniform source or background. The shutter is disabled when an external FFC is performed. An external FFC can help to reduce the effects of non-uniformities and image artifacts inherent in the lens.

15. What is the I/O module and how does it differ from going directly into a monitor or PC?

I/O = Input/Output. The I/O module is essentially a break-out box, in the form of a molded plastic accessory. There are connectors on four sides of the accessory:
1) Interface connector to the camera;
2) Power-in & Video-out connectors;
3) RS-232 connector;
4) Serial LVDS digital data connector.

The minimum interface to a Photon is power going into the camera, and NTSC (or PAL) video coming out of the camera. There is an optional accessory called a ‘Power/Video’ cable that is sort of a hybrid of the Interface Cable and the I/O Module, except the only connectors at the I/O end are for power (in) and video (out). The power input jack is intended for a power supply such as the one offered by FLIR as part of the Photon Accessory Kit (Universal Power Supply with 6-foot cord). The input power jack mates to the Switchcraft S760 Miniature Power Plug. Pin definitions for the power interface connector on the power/video cable:

Pin #	Signal Name	Signal Definition
Pin	PWR	input power
Sleeve	PWR_RTN	input power return

Both the I/O Module and Power/Video cable are designed for use with Photon 320 cameras that have the wearsaver connector and wearsaver cover accessories installed, or Photon 640 cameras with the EMI cover accessory.

16. What is the Digital Detail Enhancement (DDE) filter?

DDE is basically a spatial filter designed to enhance the high spatial frequencies (edges etc.) and appears as boosted lens MTF. Enabling, disabling, and adjusting DDE can be accomplished by the user via the Photon GUI or by serial command to the camera. Experimentation may be necessary to see if or how much DDE is beneficial to a particular application.

Photon cameras with software versions prior to 2.2 (i.e., most cameras delivered prior to 2008) have factory-set DDE values that may not be optimal. Specifically, if the DDE values are too high in certain scene situations, the image may appear to exhibit a noticeable amount of fixed-pattern noise. We recommend resetting the Filter Gain value to 16 (not higher) and the Spatial Control value to 4, then save the changed values by clicking the "Set" button. Next, save the camera settings by clicking the Save settings button under the Camera tab. Try these new settings for awhile and adjust them as necessary to see if any improvement results.