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This camera is in good condition! There are minor cosmetic wear and tear markings that should not affect use.


With the advantage of low readout noise and high-speed readout, CMOS technology has revolutionized astronomical imaging.  A monochrome, back-illuminated, high-sensitivity, astronomical imaging camera is the ideal choice for astro-imagers.

The QHY268M/C is a new generation of back-illuminated CMOS cameras with true 16-bit A/D and 3.76um pixels.  This new Sony sensor is an ideal CMOS sensor exhibiting no amplifer glow. 16-bit A/D gives high resolution sampling of the whole full well range.  Digitizing 0-65535 levels yields a smooth image with continuous gradation of greyscale levels. The QHY268M/C is a cooled, back-illuminated, CMOS camera based on the Sony IMX571 sensor with native 16-bit A/D and 3.76um pixels.


1GB DDR3 image buffer

In order to provide smooth uninterrupted data transfer of the entire 26MP sensor at high speed, the QHY268 has 1GB DDR3 image buffer. The pixel count of the latest generation of CMOS sensors is very high resulting in greater memory requirements for temporary and permanent storage.  The QHY268 has adopted a large-capacity memory of up to 1GB.  Data throughput is doubled. This large image buffer meets the needs of high-speed image acquisition and transmission of the new generation of CMOS, making shooting of multiple frames smoother and less stuttered, further reducing the pressure on the computer CPU.


Internal Humidity Sensor

QHY268M has a unique internal humidity sensor (while QHY268C doesn’t). The Blue curve shown below represents humidity.

Native 16 bit A/D: The new Sony sensor has native 16-bit A/D on-chip. The output is real 16-bits with 65536 levels. Compared to 12-bit and 14-bit A/D, a 16-bit A/D yields higher sample resolution and the system gain will be less than 1e-/ADU with no sample error noise and very low read noise.

BSI: One benefit of the back-illuminated CMOS structure is improved full well capacity. This is particularly helpful for sensors with small pixels. In a typical front-illuminated sensor, photons from the target entering the photosensitive layer of the sensor must first pass through the metal wiring that is embedded just above the photosensitive layer. The wiring structure reflects some of the photons and reduces the efficiency of the sensor. In the back- illuminated sensor the light is allowed to enter the photosensitive surface from the reverse side. In this case the sensor’s embedded wiring structure is below the photosensitive layer. As a result, more incoming photons strike the photosensitive layer and more electrons are generated and captured in the pixel well. This ratio of photon to electron production is called quantum efficiency. The higher the quantum efficiency the more efficient the sensor is at converting photons to electrons and hence the more sensitive the sensor is to capturing an image of something dim.

Zero Amplify Glow: This is also a zero amplifer glow camera.


TRUE RAW Data: In the DSLR implementation there is a RAW image output, but typically it is not completely RAW.  Some evidence of noise reduction and hot pixel removal is still visible on close inspection.  This can have a negative effect on the image for astronomy such as the “star eater” effect.  However,  QHY Cameras offer TRUE RAW IMAGE OUTPUT and produces an image comprised of the original signal only, thereby maintaining the maximum flexibility for post-acquisition astronomical image processing programs and other scientific imaging applications.

Anti-Dew Technology: Based on almost 20-year cooled camera design experience, The QHY cooled camera has implemented the fully dew control solutions. The optic window has built-in dew heater and the chamber is protected from internal humidity condensation. An electric heating board for the chamber window can prevent the formation of dew and the sensor itself is kept dry with our silicon gel tube socket design for control of humidity within the sensor chamber.

Cooling: In addition to dual stage TE cooling, QHYCCD implements proprietary technology in hardware to control the dark current noise.




Advanced Functions

Multiple Readout Modes

Multiple Readout Modes are special for QHY 16-bit Cameras (QHY600/268/461/411).  Different readout modes have different driver timing, etc., and result in different performance. See details at “Multiple Readout Modes and Curves” Part.

Random change thermal noise suppression function

You may find some types of thermal noise can change with time in some back-illuminated CMOS cameras. This thermal noises has the characteristic of the fixed position of typical thermal noise, but the value is not related to the exposure time.  Instead, each frame appears to have its own characteristics.  The QHY600/268/461/411 use an innovative suppression technology that can significantly reduce the apparent level of such noise.




UVLO Protection

UVLO(Under Voltage Locking) is to protect the electronic device from damage caused by abnormally low voltages.

Our daily life experience tells us that the actual operational voltage of an electrical device must not significantly exceed the rated voltage, otherwise it will be damaged. For such precision equipment as cameras, long-term work at too low input voltage can also be detrimental to the working life of the camera, and may even make some devices, such as power manager, burn up due to long-term overload. In the all-in-one driver and SDK after 2021.10.23 stable version, the camera will give a warning when the input voltage of the camera is below 11V.

Optimizing USB Traffic to Minimize Horizontal Banding

It is common behavior for a CMOS sensor to contain some horizontal banding. Normally, random horizontal banding can be removed with multiple frame stacking so it does not affect the final image. However, periodic horizontal banding is not removed with stacking so it may appear in the final image. By adjust the USB traffic in Single Frame mode or Live Frame mode, you can adjust the frequency of the CMOS sensor driver and it can optimize the horizontal banding appeared on the image. This optimized is very effective to remove the periodic banding in some conditions.

A typical Periodic Horizontal Noise under certain USB_TRAFFIC values.

After Adjusting the USB Traffic to avoid the periodic horizontal noise.

Reboot the camera by power off and on

The camera is designed to use the +12V to reboot the camera without disconnecting and reconnecting the USB interface. This means that you can reboot the camera simply by shutting down the +12V and then powering it back on. This feature is very handy for remote controlling the camera in an observatory. You can use a remotely controlled power supply to reboot the camera. There is no need to consider how to reconnect the USB in the case of remote control.


Updated: QHY268 12bit High Speed Mode

If you have certain needs for the frame rate of the device, such as meteor monitoring, etc., you can make selective updates.
Since most of the software that provides continuous mode (i.e. video output), such as SharpCap, only supports 8-bit or 16-bit mode, you need to select 8-bit mode output to achieve frame rate improvement in 12-bit High-Speed Mode.
Data comparison (USB3.0 at full resolution):
Before upgrade: 8-bit, 6.8fps
After upgrade: 8-bit, (12-bit out), 14.5fps max.

The implementation of this function requires updating the firmware, driver, and corresponding software SDKs at the same time.

To update the driver and software SDK, download the Allinone package (BETA) 20220817 or newer, and check the system driver and the required SDK to update them.

Click the link to download the Allinone(BETA)20220817:

Firmware update: You need to download firmware update package 20220824 or newer. If you have previously kept an older version of the firmware upgrade tool locally, please discard it. The zip package contains the firmware upgrade tool, the new version of QHY268 firmware, and firmware upgrade instructions. Please read the upgrade instructions in the firmware installation package carefully. If you encounter any problems during the upgrade, please contact QHYCCD.

Click the link to download the firmware upgrade tool:

Firmware Upgrade Instructions:


Multiple Readout Modes and Curves

Readout Mode #0 (Photographic Mode)

Readout Mode #1 (High Gain Mode)

Readout Mode #2 (Extended Full Well Mode)

Readout Mode #3 (Extend Full Well Mode-2CMS)

Readout Mode #4 (Photographic Mode-2CMS)

Readout Mode #5 (High Gain Mode-2CMS)

Please pay attention to the values of the important gain, like gain 26 (unity gain), gain 56 (high gain mode)


Absolute QE

Multiple Readout Modes are special for QHY 16-bit Cameras (QHY600/268/461/411).  Different readout modes result in different performance. These readout modes are currently supported in the QHYCCD ASCOM Camera Driver, SharpCap and N.I.N.A.

Readout Mode #0 (Photographic DSO Mode). This mode is suitable for most DSO imaging situations. Since there is a drop in the noise between Gain 25 and Gain 26 (unity gain), we recommend it as default gain setting; however, gain0 is also good enough for a 16-bit sensor.

Readout Mode #1 (High Gain Mode). This mode is something like double native iso of some new digital cameras, whose danamic range can greatly incerase at the vary high iso value, like iso800, iso3200, etc. The high gain mode provide such improvement for QHYCCD 16bit cameras. We recommend you choose this mode when you have to capture at high gain, for example, a vary dark object. Please note the switch point of HGC/LGC of QHY600/268/461 is 56. That means you must set Gain 56 to make the best of it.

Readout Mode#2 (Extended Fullwell Mode). With a pixel size of 3.76um, these sensors already have an impressive full well capacity of 51ke. Nevertheless, QHYCCD has implemented a unique approach to achieve a full well capacity higher than 51ke- through innovative user controllable read mode settings. In Extended Fullwell Mode, the QHY600 can achieve an extremely large full-well charge value of nearly 80ke- and the QHY268 can achieve nearly 75ke-. Greater full-well capacity provides greater dynamic range and large variations in magnitude of brightness are less likely to saturate. 


Based on the three basic modes above, 2CMS mode can greatly reduce readout noise by secondary sampling while keeping the same full well value and system gain. We prefer 2CMS modes than basic modes in astrophotography. By the way, the recommend gain values are the same as their basic modes.

Currently QHY600 and QHY461 Series support Extended Fullwell Mode-2CMS (Mode#3), and QHY268 Series support Photographic DSO Mode-2CMS (Mode#4) and High Gain Mode-2CMS (Mode#5). Mode#4 and Mode#5 require Allinone version 20230412 or higher.


Model QHY268M QHY268C
Mono/Color Mono Color
Pixel Size 3.76um x 3.76um
Effective Pixel Area 6280*4210 (includes the optically black area and overscan area)
Effective Pixels 26MP
Sensor Size APS-C
A/D Sample Depth


Native 16-bit (0-65535 greyscale) A/D
Full Well Capacity (1×1, 2×2, 3×3) 51ke-
75ke- or above in extended full well mode
Full Frame Rate USB3.0 Port:
Full Resolution  6.8FPS  @8BIT         6FPS @16BIT
2048lines         13.6FPS  @8BIT     11.5FPS@16BIT
1080lines         25.4FPS  @8BIT     19.5FPS@16BIT
768lines           35FPS     @8BIT        25FPS@16BIT
480lines           50FPS     @8BIT        34FPS@16BIT
Readout Noise 1.1e- High Gain,

3.5e- Low Gain

(5.3e- to 7.4e- in extended full well mode)

Dark Current -20C,0.0005e /pixel/sec

-10C,0.001e /pixel/sec

Exposure Time Range 30us-3600sec
Recommend Gain* 30 (PH Mode,or Extended Full Well Mode)

56 (High Gain Mode)

*With the improvement of the CMOS technology, For these 16bit CMOS cameras, even in lowest gain it has beyond the requirement of unit gain (less than 1e/ADU due to sufficient samples).

Learn more at the “Readout Modes” part of this page.

Amp Control Zero Amplifer Glow
Firmware/FPGA remote Upgrade Fully support via Camera USB port
Shutter Type Electronic Shutter
Computer Interface USB3.0
Built-in Image Buffer 1GByte DDR3 Memory
Cooling System Two-stage TEC cooler

Less than 1S lower than ambient temperature -30C in continuous mode

More than 1S continuous mode or lower than ambient temperature -35C in single frame mode

(Test temperature +20°)

Optic Window Type AR+AR High Quality Multi-Layer Anti-Reflection Coating
Anti-Dew Heater Yes
Humidity Sensor* Yes No
Telescope Interface Support M54 or M48 (Combined with adapters ) Support M54 or M48 (Combined with adapters )
Back Focal Length QHY268M: 12.5mm*
*If companied with the QHY filter wheel, the BFL consumed is counted as 12.5mm. The actual BFL (the intercept from the CMOS chip to the top of the camera) is 14.3mm (±0.3). Since most users will match CFW with monochrome cams, please take 12.5mm as major reference.
QHY268C: 14.3mm(±0.3)*

*Since 2023, the top part of QHY268C  is the same as 268M.

Weigth About 810g About 810g
Mechanical Dimensions


QHY268C (Version after 2023)

QHY268C (Versionbefore2022)

Personal Upgrade Path

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