QHY5III Series
USB3.0 high-speed camera
QHY5III Series
User’s Manual REV.1.2
QHY5III Series
This document is an online document. You may save this PDF file or print it
out. QHYCCD reserves the right to change this user manual without prior notice.
QHY5III Series
01 Software Installation
1. Download and install ASCOM platform
2. Download and install Camera Driver
Note that QHY5III series cameras use the same drivers, so you can download their drivers from
any webpage of cameras belonging to QHY5III series.
3. Download and install ASCOM Driver
As you most probably want to use your cameras as an expose camera, please download the
Capture version. If you want to use it as a guide camera, please download the Guide version.
4. QHY5III series cameras use SharpCap as the default capture software. Please download
SharpCap. QHY5III series cameras can run on SharpCap 2.7 or later versions
Note that QHY5III series cameras requires the latest qhyccd.dll for the new version of SharpCap,
and QHYCCD has already made SharpCap Patch for it. You should download and install it prior to
using SharpCap.
5. Connect QHY5III series cameras to your PC with USB3.0 cable. For the first time the system will
find a new device and search the driver. You can skip the online searching by clicking “Skip obtaining
driver software from Windows Update” and the computer will find the drivers. After installation is
complete successfully, you can find the device in the device manager as shown in the picture below
QHYCCD has developed a software named UpdateCheck that can check if the drivers installed on
your computer are the latest versions as well as update the drivers if needed. If the status of
some driver is “Need Update”, you can directly download its update package in this software
freeing you from the inconvenience of looking for and downloading it from our website.
QHY5III Series
Take QHY367C (It’s only an example, and QHY367C doesn’t belong to QHY5III series) for
example, you can see the drivers we need are the latest versions and don’t need to be updated
as shown in the following picture.
Note that after you downloading and installing the new drivers by using this software, be sure to
pull the USB cable out and then plug it in to enable the new drivers.
QHY5III Series
02 Use QHY5III in SharpCap
1. Connect camera
2. Run SharpCap. If everything ok, the video image will appear automatically and you will see a
FPS number
3. If you run the SharpCap earlier than connect camera. You can use menu->cameras->rescan for
cameras to search the camera and check on the camera name (eg.QHY5III174).
4. To make sure the camera running the software will start the camera at lowest speed. So you
may see the frame rate is much slower than the highest frame rate that declared on QHY5III
webpage. Now you can try to increase the performance. First you can try to set the exposure
time to 1ms. Then try to reduce the “USB Traffic” value. For modern computer like the i7-4core.
It should get max performance. But please note not all computer can get best performance. The
CPU loading, the save-energy setting, the mainboard performance and USB3.0 port performance
may effect it. Sometimes the display performance will also effect it. So you can try to use “zoom”
function to reduce the display size and see if it will help.
The QHY5III174 maximum frame rate at full resolution is about 138FPS. The QHY5III224 is
150FPS, QHY5IIII290 is 135FPS and the QHY5III178 is 50FPS.
5. Adjust the offset. You may find the when block the light the image is not really zero.
Sometimes this will cause the image contrast is not so “good”. You can adjust the offset to get a
better background. You can open the histogram to confirm it.
QHY5III Series
If you are using the color camera, like QHY5III290C, QHY5III224C, QHY5III178C, QHY5III174C, It is
very important to set the offset to a low value and let the histogram peak is close to zero.
Because the color camera color balance is multiple a ratio to the pixel value in the FPGA. The bias
will be multiple also and it may affect the color balance.
6. If you want to try the 16bit image. It is best to set the USB Traffic >=5(For QHY5III174).
Otherwise the USB transfer may hang because the data bandwidth is exceed the capability. Then
switch the Color space to “mono16”
7. By check the “LX” mode you can expand the exposure setting range and do long exposure
time. QHY5III series camera has the anti-amp light control circuit and it can reduce the amplifier
glow significantly, especially for the IMX174, IMX224.
A typical long exposure image in +25C, 5sec exposure and 50% gain of QHY5III174M
QHY5III Series
QHY5III Series
03 Color Balance for Color QHY5III Camera
SharpCap will start at the default RGB balance for color camera. Here is the screenshot of the
QHY5III224C start up
For color camera. SharpCap will show the WB Red/Green/Blue progress bar.
Since the color balance is the ratio between Red to Green and the Blue to Green. You can keep
the Green color to 128 and adjust the red and blue.
QHY5III Series
For example, in this image the blue is 255 and red is 161, green is 128. It looks the color is well
white balanced. If you need more blue, since it has reach to 255 and you can not get more. In
this condition, you can reduce the green a little and you will have more room for the ratio.
As we said before. If you are doing planetary imaging you should set the offset value as low as
possible. To make the background close to zero. Then you can easy to get correct color balance.
Otherwise it will not easy to get it. The following image shows the offset is good and you can not
get good balance.
The reason is that the Color balance is a ratio of the RGB sensitivity difference. So we use a ratio
to multiple the RGB value and get it done. But if there is a bias exist. The ratio will not be correct.
For example, the G sensitivity is two times than R.
G=2R In order to get white balance. We multiply a ratio of 2 to R
R’=2R= G so we get R=G
When a bias exist. The bias is a constant add to each pixel. So the image you see is:
QHY5III Series
Now the ratio R’’:G’’=(R+bias)/(2R+bias) and it is not equ to 1:2 . It shows the bias will effect the
true value of the R:G. And the ratio of R:G will arious when the image light changed. It is hardly
to correct with a fixed ratio.
But for DSO capture, You should keep the offset above zero and avoid the background is cut off.
A background from 1000-5000 is a good value(16bit mode) for DSO imaging.
QHY5III Series
04 Use QHY5III with ASCOM
You can connect many software which support ASCOM. Currently QHY5III only support normal
ASCOM connection. Does not support the ASCOM VIDEO connection. Please note QHY5III always
transfer maximum bit depth (QHY5III174, 224, 290, 185 is 12bit and QHY5III178 is 14bit) by
ASCOM to make the best DSO imaging performance. The image format is 16bit bit width and
patch zero on low bit.
1. Download and Install ASCOM platform from http://www.ascom-standards.org/
2. Make sure the QHY5III ASCOM driver is installed. If not please install it
4. In camera model select list, select ASCOM and then select QHYCCD-Cameras-Capture
5. In properties, select QHY5IIIxxx Camera
6. Normally, you can set the gain=1 and offset=10 to start. The speed and overscan calibration
options are no using in QHY5III camera.
This is a screen shot that QHY5III174M running in MAXIMDL. Since the QHY5III has no large oncamera frame buffer. In a small chance you may meet the frame drop. In this condition, you
need wait a longer time than the expected exposure time to get a frame.
When you change the exposure. CMOS sensor will generate one or more short exposure frame
and you may receive this frame. And the next frame will be a normal frame with correct
exposure time.
QHY5III Series
PHD Guiding
You can use PHD Guiding software and the on-camera guide port of QHY5III Camera. PHDGuiding
can connect with QHY5III camera via ASCOM.
1. In PHDGudiing 2.5. Select ASCOM Camera Choose in Camera and On-camera in mount.
QHY5III Series
2. Select Connect and In ASCOM camera chooser , select QHYCCD-Camera-Capture
3.In QHYCCD Setup, Select QHY5IIIxxx camera
6. Normally, you can set the gain=1 and offset=10 to start. The speed and overscan calibration
options are no using in QHY5III camera.
7.Select “connect all”
to connect the camera and mount
QHY5III Series
button to begin preview.
9. Select a star in the screen and click
to start calibration and guiding.
QHY5III Series
05 Use BroadCast Video Streaming
BroadCast video steaming is a special function that QHY5III series cameras support. It can send the
video image to multiple target software via QHYCCD BroadCast video driver. For example, you can
use the SharpCap software to control QHY5III series cameras and at the same time the video
appearing on the SharpCap will be sent to any of software that support the WDM camera, like the
HandyAvi, Adobe video encoder, online chat software etc. This function is very useful for the video
live broadcast applications.
1. Install the BroadCast Driver
2. Connect camera to your PC and start SharpCap
3. Turn on “Enable Live Broadcast” at the bottom of Camera Control panel in SharpCap as shown
4. Select “QHYCCD camera (WDM)” as your webcam in the software you are using. The camera
used in the following example is QHY5III290.
QHY5III Series
QHY5III Series
06 QHY5III Guide Port Sequence
The QHY5III guide circuit has an opto-coupler inside.The “common” pin is normally the
GND. Normally the four direction pin of the mount is pulled up by the mount circuit. And
when guide pulse comes, the QHY5III will pull down the level on the direction pin.
QHY5III Series
07 QHY5III Guide Port Cable RJ11 Pin Sequence
This connector is fully compatible with the EQ5/EQ6/Celestron/iOpton Guide
Socket. The Pin Sequence is (When face to the connector of the cable)
The Socket side (mount side) is
If you are using other mount, please check if it is the same pin sequence with the
QHY5III Series
08 FAQs
1. Does QHY5III support 12bit or 14bit ?
QHY5III174, 224, 290 support 12bit output and QHY5III178 support 14bit output. All
these output is convert to 16bit image to transfer and save. (For 12bit, it is 0-4095 map to
0-65535, for 14bit it is 0-16383 map to 0-65535)
2. How to get maximum FPS?
Since QHY5III is very high data bandwidth. Not all computer can get the maxium FPS.
Normally I7-4core should no problem for that. The CPU load will aslo effect the maxium
FPS. So please reduce the CPU load by close other applications when using camera. If
the CPU load is too high, the software may become very slow or hangs.
3. How to avoid the camera hangs?
If you camera always hangs. It may be caused by many reasons. You can check the
following things.
3.1 If there is power leak for your mounts and computers? The power leak may cause the
leak current transfer from computer to the camera via the GND. This may affect the USB
transfer and cause the data packet lost and cause it hang. You need make sure the
computer and the mount is well grounded.
3.2 If the USB port’s voltage not enough? Some computer’s USB port +5V is not enough.
It may cause the camera always hangs. In this condition you can use a powered USB3.0
HUB to connect camera and get the good +5V power for camera.
3.3 If your cpu load is too high? If CPU load is too high, it will cause many frame lost and
cause the camera hangs. You can increase the USB traffic value to reduce the FPS and
get more stable video transfer.
3.4 If the USB cable connection is good enough? Sometimes the contact issue in the
USB cable to camera or USB cable to computer will cause the signal loss and cause
camera always hangs. Especially when you move the cables. In this condition. You can
try to add a little silicon oil into the USB socket/plug .This can increase the contact a lot
3.5 Avoid the statics. Sometimes the static electricity on human body will cause the
camera hang. You can touch the computer metal case for first before touch the camera
to let the static electricity on your body release.
QHY5III Series
3.6 Some computer’s front USB port is not so good for high speed transfer (The reason is
it connected to mainboard by a cable and which has no good signal integrity). If you
found the camera always hangs on front USB port. You can try the USB port on backside
of the computer (which is connect to chipset directly on the mainboard).
4.What’s the interface to telescope? How to use C/CS lens on QHY5III
Because QHY5III camera has 1.25inch eyepiece style design. So it can be intert into the
1.25inch eyepiece tube. No need extra adapter.
QHY5III has the CS thread front part. It can connect with CS lens. The back focal length
is 11mm to 11.5mm. Please note this value is a little less than the 12.5mm standard CS
back focal length. But you can use the 1.25inch spacer to get it to 12.5mm. The reason
that does not design to 12.5mm is to avoid the back focal length is longer than 12.5mm
lens and you will no any other method to get the infinine on the imager.
You need select the C or CS lens by the CMOS sensor size. Normally speaking the CS
lens only covers 1/3inch sensor size. So QHY5III178 and QHY5III174 can only use the C
lens. QHY5III174 may need 1inch C lens. When using the C lens, the backfocal length is
17.5mm, you need buy the C-CS entender to extend 5mm back focal length.
5.How to clean the CMOS sensor and the optic windows of the camera
If you found there is dust on the cmos sensor. You can screw off the front part of the
QHY5III. The SONY CMOS sensor is clear glass and it is no any coating, so that it is
quite easy to clean it. You can use the tools that clean the DSLR or just a lens paper to
clean it.
The optic window is the IR cut coating or AR coating. So you need to be careful when
cleaning it. You can also use the DSLR clean tools or the lens paper. Don’t use big force
to clean it. The coating is not so hard and it is easy to get scratch when you use big force
on it.
6. Does QHY5III working under FireCapture?
Yes. The lastest FireCapture supports QHY5III already. Please go to FireCapture
website to download it.
QHY5III Series
7.How about the anti-amplifier functions in QHY5III series
The different QHY5III models has different behavior under the anti-amp light controllers.
The QHY5III174 and QHY5III224 has great improvement under this technology. The
QHY5III178 has tiny glow but QHYCCD’s anti-amp light control will reduce it a lot in long
exposure time. The QHY5III290 has almost no amplifier light itself.
8.The debayer sequence of QHY5III color camera in major astronomy software:
Pixel Insight
Note1: These is the test results by using 16bit image format
Note2: These is under full size readout, not the ROI.
Note3: These test is based on the software itself. (e.g.: Capture with one software and
debayer with the same software)
9. Some vertical noise on the image. Like this
QHY5III Series
If you found this issue. It should be the wrong driver (native WDM driver) caused. Please
update your software to the latest version. You can use the QHYCCD version check tools
to check. It
is http://note.youdao.com/share/?token=79C82E1DC6D34CC4AE603EAB06FB49D2&gid=723486
9. The FPS of cameras sometimes suddenly drops to zero under DDR mode on
SharpCap, what’s the solution for this problem?
Recently, we have been told by our users that the FPS of their cameras sometimes suddenly drops
to zero under DDR mode on SharpCap. It is caused by the fact that the receiving speed of computer
is relatively slower than the sending speed of camera. Once CMOS sensor starts working, it will
incessantly conduct exposure and output image data over and over again, and it cannot be
interrupted. If USB transmission was interrupted too often by the operating system, the data
QHY5III Series
overflow of DDR would ensue resulting in bad frame. Therefore, not a single frame is a complete
frame, and the FPS will drop to zero.
The first solution to this problem is to increase the value of USB traffic to decrease the FPS of the
cameras. Note that by using previous version of SharpCap Patch, the value of USB traffic cannot be
set to a value large enough, so you should go to our website to download the latest version of
SharpCap Patch.
The second solution to this problem is to turn off the DDR mode, but for computers whose
performance isn’t very good, this solution may not work very well.
QHY5III Series
09 QHY5III Mechanical Size
Front Side (Sensor)
Back Focal Length
Back focal length of QHY5III series camera is between 10mm-12mm. So that it support
both CS mount and C-mount (with a 5mm C-mount extender ring).
QHY5III Series
10 Revision History
Date of change
December 20th,
January 5th,
Content of change
First edition
May 25, 2017
Add introduction about broadcast application
(Section 5).
Added the mechanical dimensions of the screw
thread on the front end
QHY5III Series
Alberic's short exposure DSO capture
Here is a little summary of my technique of short exposures imaging applied to Deep Sky
Objects - DSOs. It's a mix between 'Lucky Imaging' technique for planetary objects and
long exposure for Deep Sky Objects.
Main advantages to use short exposures for DSO are:
- No need of auto-guiding system which may be difficult to calibrate,
- No need of super heavy, super expensive or super sturdy mounts,
- A 'planetary setup' is enough,
- Shorter exposures = less atmospheric disturbance effects on each frame. So a better
resolution can be expected in good or even in medium seeing conditions.
Main drawbacks:
- Few light compared to long exposure so the limit magnitude is lower than traditional
long exposure mode. In fact the gap is not as huge as we could expect if adding a lot of
What are the limits of 'short exposure'?
Good question...
For planetary target, limit is Neptune with an Infra-red filter, let's say 0.5 second in worst
case. In most cases, less than 100 ms.
For DSOs, few objects (some bright planetary nebulas, open clusters or glubular
clusters) could be imaged with 100 to 500 ms exposition time with the most recent
For galaxies, lower limit exposure time will be 1 second to... 'more'. And 'more' is quickly
limited by mount tracking, atmospheric disturbances, wind and dark current of the
camera when uncooled. For me a realistic value for 'more' is 5 seconds. So short
exposure for DSOs: between 100 ms to 5 sec. As you can see on my first post, for
uncooled IMX 174 which have high dark current it's better to decrease the upper limit to 3
Frames acquisition:
First, align correctly your mount as done for long exposure.
I currently use a software for planetary/lunar/solar acquisition like SharpCap 2.8 and
when it will be released, FireCapture.
Use only 16 bit Image format and save as TIFF or PNG.
Use high gain value: 60 - 90. Higher than 90% will give very noisy frames. Less than
60%, the readout noise will increase.
To reduce the noise pattern that may appear in background of final image, let the target
move a little bit on the sensor. With the Hand Pad, or if your mount has a bad Periodic
Error curve, it will do the job.
QHY5III Series
Don't forget to make 'Dark' images after choosen target imaging session, as done for
DSO with long exposure. The more frames, the best.
I don't use Bias nor Flat with IMX174. For bigger size sensors I guess that Flat will be
Before registration, I manually sort out the good images from the bad ones. I don't use
automatic sort out. Of course it takes lot of time but I'm sure it's efficient! You can use
automatic process if you prefer.
For registration, I use Registax 5.0 in monopoint mode ('Aligment Method' : 'Default').
Another solution is Autostakkert 2.6 which have optimisation options to reduce horizontal
noise pattern like IMX 174.
For post-processing I use Iris and Photoshop to adjust the curves and contrast.
see more detail and the picture at http://qhyccd.com/bbs/index.php?topic=5307.0
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