Opticstar DS-336C XL User manual

OPTICSTAR
Microsoft Windows
(64-bit & 32-bit)
XP/Vista/7/8

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
1
1.
The DS camera is sealed to protect the sensor and electronics, do not
open your camera,
this will make the camera susceptible to moisture
and dust.
2. Do not drop your camera as this can result in serious damage.
3. Only use the supplied power supply unit (3.3VDC 3A regulated).
4.
Do not point the camera to a bright light source like the Sun without the
appropriate filters.
5. Do not over-tighten adaptors attached to the camera.
6.
Treat the camera glass window with the same care as you would of a
photographic lens.
CAUTION
!
Manufacturer’s Warranty
This product has a 12 month back to base warranty. For after
sales support please contact Opticstar at: [e-mail]

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
2
Contents
CONTENTS..................................................................................................................................................................2
INTRODUCTION........................................................................................................................................................4
PACKAGE CONTENTS.............................................................................................................................................. 4
SYSTEM REQUIREMENTS.......................................................................................................................................4
INSTALLING THE SOFTWARE DRIVERS............................................................................................................. 5
SOFTWARE APPLICATIONS...................................................................................................................................8
OPTICSTAR VIEW........................................................................................................................................................ 8
NEBULOSITY .............................................................................................................................................................. 8
ASTROART................................................................................................................................................................. 8
MAXIM DL ................................................................................................................................................................ 8
INSTALLING OPTICSTAR VIEW............................................................................................................................ 9
CAMERA CONTROL................................................................................................................................................... 10
FRAME RATE............................................................................................................................................................ 10
CAMERA CONFIGURATION ........................................................................................................................................ 10
Colour Adjustment Tab........................................................................................................................................ 11
Exposure Tab...................................................................................................................................................... 11
Other Tab............................................................................................................................................................ 11
Quick Fluro Tab.................................................................................................................................................. 12
IMAGE CAPTURE....................................................................................................................................................... 12
IMAGE PROCESSING`................................................................................................................................................. 13
INSTALLING NEBULOSITY V2 AND THE DS-336C XL PLUGIN...................................................................... 14
RUNNING NEBULOSITY V2........................................................................................................................................ 14
MAIN PANEL ............................................................................................................................................................ 15
Advanced Sub Panel............................................................................................................................................ 15
VIDEO MODE............................................................................................................................................................ 16
SUPPORT .................................................................................................................................................................. 16
INSTALLING THE DS-336C XL PLUGIN FOR ASTROART V3/V4.................................................................... 17
BINNING MODES....................................................................................................................................................... 18
HIGHER IMAGE QUALITY .......................................................................................................................................... 18
HIGHER SPEED ......................................................................................................................................................... 18
STARVIEW ............................................................................................................................................................... 19
CAPTURE SETTINGS .................................................................................................................................................. 19
COLOUR SYNTHESIS ................................................................................................................................................. 20
SUPPORT .................................................................................................................................................................. 20
INSTALLING THE DS-336C XL PLUGIN FOR MAXIM DL V4/V5..................................................................... 21
BINNING MODES....................................................................................................................................................... 22
HIGHER IMAGE QUALITY .......................................................................................................................................... 22
HIGHER SPEED ......................................................................................................................................................... 22
STARVIEW ............................................................................................................................................................... 23
CAPTURE SETTINGS .................................................................................................................................................. 23
COLOUR SYNTHESIS ................................................................................................................................................. 24
SUPPORT .................................................................................................................................................................. 24
TROUBLESHOOTING............................................................................................................................................. 25
SYSTEM REQUIREMENTS........................................................................................................................................... 25
INSTALLATION ISSUES .............................................................................................................................................. 25
Windows does not Recognise the Camera............................................................................................................. 25
Camera Driver Check.......................................................................................................................................... 26
Camera Driver Removal...................................................................................................................................... 26
Re-installing the Camera and Drivers.................................................................................................................. 27
CAMERA PERFORMANCE........................................................................................................................................... 27

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
3
USB BUS SPEED .......................................................................................................................................................27
USBEXTENSIONS .....................................................................................................................................................28
USB PORT ISSUES.....................................................................................................................................................28
GOOD PRACTICES...................................................................................................................................................29
CAMERA CLEANING ..................................................................................................................................................29
CAMERA POWER REQUIREMENTS ..............................................................................................................................29
OVEREXPOSING THE CAMERA TO STRONG LIGHT .......................................................................................................29
SUPPORT ...................................................................................................................................................................29
OTHER SOFTWARE.................................................................................................................................................29
MICROSCOPE ATTACHMENTS............................................................................................................................29
CAMERA SPECIFICATION.....................................................................................................................................30
If you have any queries regarding the camera or you require after
sales support, please email us at: [email protected] Please
include your camera’s serial number as displayed on the camera’s
case.
The camera does not incorporate any optics and therefore it cannot
reach focus by itself. A C/CS mounted lens must be used with the
camera or it must be attached to a telescope with the nosepiece
adapter that is included with the camera. To attach it to a
microscope, please use an appropriate attachment.
It is not necessary to connect the power supply unit to the camera
at this point since the camera itself is powered through the USB 2.0
port. The 3.3V mains power supply unit is only used by the onboard
cooling sub-system.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
4
Introduction
Your Opticstar DS-336C XL single shot camera will enable you to capture
images of deep sky objects, the planets and their satellites as well as images of
the Moon and Sun with the use of an appropriate filter. The camera is also
capable in operating in video mode and it is also suitable for microscopy and
industrial applications. The camera incorporates thermo-electric cooling (TEC)
reducing the levels of noise dramatically during longer exposures.
The DS-336C XL is the successor to the popular DS-335C ICE but includes a
number of significant enhancements such as:
Double the speed and the frame rate in focus and preview modes.
New CCD sensor with more than twice the light sensitivity.
Even higher light sensitivity due to Gain function in hardware.
Improved dynamic range and image quality.
Package Contents
Please insure that you check that no parts are missing. In the event of a part
missing please inform your local supplier immediately. Your camera should
include the following:
1. Camera.
2. USB cable.
3. C-mount to 1.25” telescope drawtube.
4. T-mount (M) to 2” telescope drawtube.
5. Printed camera setup manual.
6. CD with drivers, full manuals and software.
7. Mains PSU for powering the cooling subsystem. AEU/UK/US PSU adaptor
is included for US and UK customers.
System Requirements
You will first need to install the camera and drivers before installing the View
and Nebulosity software. Please follow the instructions closely for a successful
installation. You will require a PC running Microsoft Windows (64-bit or 32-bit)
XP/Vista/7/8 with a free USB2.0 port.
If you experience any difficulty during or following installation please refer to the
Troubleshooting section in this guide.
If you have installed the camera drivers in the past and you wish to replace the
drivers to a different version you must first remove the original drivers. Please
refer to the Troubleshooting section on how to remove the currently installed
drivers.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
5
Installing the Software Drivers
Follow the instructions below closely ensuring that you make the right
selections.
1. Un-install any previous versions of the software.
2. Insert the supplied CD in the CD/DVD drive.
3. Plug the camera to a USB2.0 port
(ideally to one attached directly on
the motherboard of your computer).
4. The Windows Device Manager will list the camera as 3.1MCCD
USB2.0 Camera as shown below.
Once conn
ected to the computer, the
Device Manager will show the camera.
During installation do not allow Windows to automatically select the
best drivers. If you allow Windows to automatically select the
drivers, installation will fail.
The software drivers can be installed by
the user from the Device Manager.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
6
5. The Windows Found New Hardware Wizard will come into view.If the
wizard does not appear, you can install the drivers by right-clicking on the
camera entry in Device Manager and select Update Driver Software.
6. Do not allow Windows to search automatically for the driver software.
Instead, select the Browse my computer for driver software option.
7. The drivers are situated on the CD inside the Drivers folder. There are
two sub-folders named 32-bit and 64-bit. Select the appropriate sub-
folder for your operating system. All 32-bit operating systems
(XP/Vista/7/8) should use the drivers in the 32-bit sub-folder. All 64-bit
operating systems (XP/Vista/7/8) should use the drivers in the 64-bit
sub-folder.
Anti-virus software may attempt to block the installation. In such cases
the anti-virus software should be temporarily disabled. Alternatively,
when prompted, add the installation files to the trusted list.
Select the software drivers manually.
The software drivers are situated on the
CD inside the Drivers folder.
Windows may demand the user to have Administrator access rights in
order to install the software. Otherwise the installation will be
terminated by Windows.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
7
8. Windows may display a warning prior to installing the driver software.
Ignore the message and select Install the driver software anyway.
9. Once the drivers have been installed,
Windows will identify the camera as
Opticstar 336C.
10.If Windows asks you to restart the
computer before proceeding, please
do so.
11.Your camera and drivers are now
installed. Please refer to the
Troubleshooting section in this
guide if the camera and driver
installation failed to complete
successfully.
Ignore the Windows warning.
The drivers installed successfully.
Note that if later you remove the camera from your computer and
re-connect it to a different USB 2.0 port Windows will ask for the
drivers again. Repeat the above procedure to re-install the drivers
for the newly selected USB 2.0 port.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
8
Software Applications
The Opticstar DS-336C XL camera can be controlled by Opticstar View,
Nebulosity, AstroArt and MaxIm DL.
Opticstar View
View operates the camera in video mode. It can be used to capture
and store video on the computer in AVI format. Single frames can be
captured in BMP format. View is ideal for microscopy and suitable to
capture planetary images at high frame rates. It supports automatic
exposure times as well as manual.
Nebulosity
The DS-336C XL is bundled with a copy of Nebulosity v2 as
standard. Nebulosity is a fully featured application that provides
camera control and image processing. Nebulosity needs to be installed
as a first step but it will not provide DS-336C XL camera support by
default. The DS-336C XL software plugin for Nebulosity must be copied into the
folder where Nebulosity has been installed.
Nebulosity is ideal for astronomy. It supports long exposures, single or multiple
frame capture, and video modes for real time visual observation of deep sky
objects.
AstroArt
Users of AstroArt will be interested in the DS-336C XL plugin for
AstroArt.This plugin adds camera support with 8 binning modes
including 1x1, 2x2, and 4x4 in colour and monochrome. Some very
fast focus and preview modes are also supported. Please refer to the
following pages for detailed instructions.
MaxIm DL
MaxIm DL users will need to install the DS-336C XL plugin for
MaxIm DL. The plugin enables MaxIm DL full camera control with
many binning modes including: 1x1, 2x2, 4x4 binning in colour and
monochrome. There is also support for fast readout speeds in most
modes. Please refer to the following pages for detailed instructions.
Please note that the AstroArt and MaxIm DL software applications
are not bundled with the Opticstar DS-336C XL camera but may be
purchased separately.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
9
Installing Opticstar View
Opticstar View is a
software application
that can be used to
control the camera,
capture single frames or video,
perform image processing and
image measurements.
View can be used for a wide
range of applications outside
astronomy including
microscopy.
1. To install View, navigate to the View folder on the CD and open the
View_setup.exe file.
2. Windows will display “Welcome to the Opticstar View Setup Wizard”.
Click the Next button to continue.
Installing Opticstar View. Running Opticstar View.
After the installation has finished, View can be run by clicking on the Windows
Start button and selecting Opticstar View from the programs list.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
10
Camera Control
Run View with the camera connected to
the computer. On the right hand side
panel of the application, under the
Capture tab, the camera will be identified
as “Opticstar 336C”.
By default, the camera will be running as
soon as View opens. In order to change
the image resolution, the preview must
be stopped by clicking the Stop Preview
button. This button toggles between
Start Preview and Stop Preview
modes.
The Default button resets the camera
settings to the default values.
Frame Rate
When lower resolution modes are
combined with manual exposure times,
they can increase the frame rate (frames
per second) at which the camera
operates. At full resolution, the maximum
frame rate is achievable in 8-bit mode
only.
Camera Configuration
The exposure time as well all other
camera parameters can be configured by
clicking the Advanced button. This
button is situated below the Start
Preview / Stop Preview button.
A window will appear with three tabs:
Color Adjust
Explosure
Other
Quick Fluro
The options under each tab are outlined
in the following sections.
Resolution Frame Rate (max)
2048 x 1536 5frames per second
1024 x 768 BIN 5frames per second
512 x 384 BIN 5frames per second
320 x 240 30 frames per second

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
11
Colour Adjustment Tab
The first three slider bars labelled: R Gain, G Gain and B Gain, can be used to
manually adjust the red, green and blue colour reproduction of the camera.
Alternatively, the camera can automatically set these values by pressing the
White Balance button. Automatic values may not be appropriate in certain
circumstances depending on the light conditions, luminosity of the target, etc.
Other values that are user selectable include Gamma and Contrast.
User defined settings can be stored for future use. There are four sets of
parameters that can be stored for future use. They are labelled A, B, Cand D.
Simply select one of them and click the Save button.
Exposure Tab
When auto-exposure is used, the user
cannot specify the exposure time.
However it is still possible to add a “bias”
by increasing or decreasing the Target
value. Likewise, the Gain value is not user
definable in auto-exposure mode.
To set the exposure time manually, simply
un-tick the Auto Exposure option. In this
mode, the time can be set in milliseconds
and the Gain value can be set manually.
The Target value cannot be set in manual
exposure mode.
Other Tab
Various other configuration settings are
situated under the Other tab. The
camera’s frame speed can be set by the
Frame Rate pull down control. The Data
Width can be set to 16-bit (better image
quality) or 8-bit (higher frame rate).
The camera can only operate at 5 frames
per second at full resolution in 8-bit mode.
When the user selects manual exposure
time and 320x240 resolution, then the
cameras can achieve up to 30 frames per
second.
The Anti-AMP Glow option can improve image quality by compensating for any
amplification glow generated by the electronics.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
12
Quick Fluro Tab
The Quick Fluro tab can be used for fine focusing under challenging conditions
such as fluorescence microscopy. View sets a combination of values
automatically to assist the user in focusing more precisely. The values set
include exposure time, gain and frame rate. Additionally, the Fine Mode option
allows the user the set the exposure time manually by selecting the time in
seconds and milliseconds.
Image Capture
There is a second group of user controls on the
right hand side panel, headed Camera
Capture Config. The Capture button can be
used to capture a single frame or a series of
frames in BMP format. The location of the
captured files and the number of frames can
be specified by clicking the Config button.
By adjusting these options it is possible to
specify how many frames to capture and a
time lapse between the frames. The captured
frames are also displayed as thumbnails on the
bottom right hand side corner.
Video can be captured in AVI format by clicking
the Start Video button. This button toggles
between Start Video and Stop Video. Once
the Start Video button has been pressed, the
camera will capture and store the data on the
hard disk until Stop Video is clicked by the
user.
The location of the stored file(s) can be specified by clicking the Config button.
By default, video data is stored uncompressed in order to preserve high image
quality. Optionally, it is possible to compress the AVI files by clicking the Video
Compress button.
Captured images can be processed in View by clicking the Open And Edit
button underneath the captured image.
The image to be processed should be present in the folder in which the image
was stored. This folder can be specified by pressing the Configbutton.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
13
Image Processing`
View can be used to perform measurements on the captured image(s). It is
also possible to apply various filters and perform image processing operations.
A brief outline of View’s image processing functions is listed below:
Basic operations including Crop, Mirror, Flip, Invert, Rotate, Bright, etc.
Copy and paste user defined regions.
Distances can be measured between user defined points, circles, etc.
Angles can be calculated by defining three points on the image.
Operations can be performed on any user defined region.
Colour operations can be performed on individual R, G, B channels.
Data combine of two images.
Data calibration.
Image-zoom as a per cent of the original image.
Linear filters to soften, sharpen, emboss, blur and Gaussian.
Non-linear filters for median, erode, dilate, contour, edge and jitter.
Transform filters for pinch, punch, twirl and cylinder.
Fluorescence filters for gamma, colorize, mix and combine.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
14
Installing Nebulosity v2 and the DS-336C XL Plugin
Nebulosity v2 is a fully featured image processing software especially
designed for amateur astronomers. Follow the instructions below to
install the Nebulosity software.
1. Insert the supplied CD in the CD/DVD drive.
2. Navigate to the Nebulosity2folder on the CD.
3. Double-click (LMB) on the setup_Nebulosity2.exe icon.
4. Follow the on-screen instructions to install Nebulosity.
To add support for the DS-336C XL camera to Nebulosity v2 please carry out the
following steps.
5. Navigate to the \Plugins\Nebulosity2folder on the CD.
6. Copy all the files present inside that folder into the folder where
Nebulosity has been installed on the hard disk e.g. C:\Program
Files\Nebulosity2.
7.
To run Nebulosity double-click (LMB) on the icon.
Please refer to the Nebulosity manual found on the supplied CD in the
Nebulosity2folder for the complete Nebulosity manual. The Serial Number
can be found on the inside front cover of the camera Setup Guide (this guide).
Running Nebulosity v2
In Nebulosity, the DS-336C XL can be used in real time mode or in long
exposure mode. In real time mode, the camera can display colour images of
deep sky objects directly to the
computer as they are captured.
Nebulosity must first be
configured appropriately by the
user depending on the task in
hand.
The first step is to select the
camera model and get familiar
with Nebulosity’s right hand
panel settings.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
15
Main Panel
The camera model must be selected from the pull down
menu in the Capture Control section. The camera will be
identified as “Opticstar DS-336C XL”. Clicking on the
Advanced button opens a small window for image capture
options. Typically, these options are used when capturing
data as single frames or as a series of single frames. They
are not used for streaming real time video images.
Advanced Sub Panel
When the High Speed read option is
selected the camera outputs 8-bit data
to the computer at high speed.
Otherwise the data is output in 16-bit
format at standard speed.
The binning modes can be 1x1, 2x2 and
4x4. The 2x2 mode reduces the image
resolution to one quarter (1024x768) of
the original but it quadruples the
camera’s light sensitivity. Similarly the
4x4 mode reduces the image resolution
to one sixteenth (512x384) of the
original but the light sensitivity increases by 16 times.
Unlike other cameras, the DS-336C XL can perform binning
in colour. This is a unique feature only available on
Opticstar CCD cameras.
The StarView window runs semi independently
of Nebulosity itself and it can be used as a very
high sensitivity mini video window. It has its
own controls for exposure time, gain and
brightness. The StarView window displays colour
video at 36 times higher than normal light
sensitivity. It can be used to assist in quick
focusing and previews. The StarView window
cannot be in use when Nebulosity itself reads
data from the camera.
On the main panel, the exposure time can be entered in seconds and
milliseconds. Longer exposure times increase light gathering and sensitivity but
reduce the camera’s frame rate. The Gain value can be used to increase the
sensitivity of the camera by up to 100%. This signal amplification takes place in
the camera and it is combined with noise reduction electronics.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
16
The Offset value controls the camera’s Black Level.Typically, low data values
contain more noise (bad data) than signal (useful data). The user can use this
setting to modify at runtime the cut-off point between signal and noise. The
most appropriate Offset value depends on many factors including the exposure
time, gain value, the target,the binning mode, etc.
Video Mode
The camera can be set to video mode from
the Preferences panel. On Nebulosity’s main
menu at the top select Edit > Preferences.
For colour video, in Acquisition Mode select
Recon (RGB/square): Quality.For
monochrome video select Recon
(RGB/square): Speed.By default these
video modes work in 2x2 binning (1024 x
768 pixels). The light sensitivity of the video
can be increased by reducing the size of the
video image by ticking the Use max binning
in Frame Focus option. This option uses 4x4
binning (512 x 384 pixels). Monochrome
video modes run at high speed. Colour video
modes run at high image quality.
Close the Preferences panel by clicking the
Done / Save button. From now on,the
camera can be run in video mode by clicking
the Frame and Focus button on
Nebulosity’s main right hand panel.
The camera will display video till the Abort button is clicked. The video mode in
Nebulosity is intended to be used for real time visual observation of deep sky
objects as well as planets.
For more information regarding Nebulosity please refer to the user manual on
the CD.
Support
There is an active group of Nebulosity users at the following Yahoo Group:
http://tech.groups.yahoo.com/group/stark-labs-astronomy-software/. Joining
this group may be beneficial by sharing the experiences with other Nebulosity
users.
For support related to the camera or the software drivers, or the Nebulosity
plugin, please email us at: [email protected]

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
17
Installing the DS-336C XL Plugin for AstroArt v3/v4
AstroArt is a powerful image processing software especially designed
for amateur astronomers. Before installing the plugin, please ensure
that the camera’s software drivers and AstroArt have already been
installed on the computer. Follow the instructions below to add
support for the DS-336C XL camera to AstroArt.
1. Insert the supplied CD in the CD/DVD drive.
2. Navigate to the \Plugins\AstroArt folder.
3. Copy all the files from that folder on the CD into the folder where AstroArt
has been installed on the hard disk e.g. C:\Program Files\AstroArt.
4. Run AstroArt.
5. From the Plug-in menu select CCD Camera.
6. Select the appropriate camera model identified as OS-336C and click on
the Check CCD button.
7. The camera will be initialized and the StarView window will appear. The
StarView window offersreal-time video for focusing and previews. This is
an additional focus mode to the standard modes offered by AstroArt. A
second additional window will also appear titled Capture settings –
Opticstar 336C.

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
18
Binning Modes
There is support for 8binning imaging
modes. These modes have been
included in order to maximize the
performance of the camera in specific
areas including: resolution,
colour/monochrome, sensitivity and
focusing.
Higher Image Quality
The 16-bit modes offer the highest quality data but at a lower speed. The first
three modes (1 –3) offer colour binning in 16-bits per pixel. They offer the
highest quality colour data. Modes 4 and 5 offer high quality monochrome 16-bit
binned data.
Higher Speed
The 8-bit modes are (6 –8) used for higher frame rates and data readout
speeds. These modes are appropriate for focusing and fast previews (not for
data analysis). When operating in these modes, the camera is in continuous
video mode and it does not set/reset itself for every individual frame captures.
It continuously sends to the computer the data for every frame it captures
rather than waiting for the user to request the data.
Mode Binning Bit Depth Mono Colour Resolution FPS
(max)
Sensitivity
11x1 16-bit yes yes 2048x1536 1X1
22x2 16-bit yes yes 1024x768 1x4
3 4x4 16-bit yes yes 512x384 1 X16
42x2 16-bit yes no 1024x768 2.5 x4
54x4 16-bit Yes no 512x384 2.5 X16
61x1 8-bit yes yes 2048x1536 5X1
72x2 8-bit yes no 1024x768 5x4
8 4x4 8-bit yes no 512x384 5 X16

DS-336C XL Setup Guide
15/03/2012
Ä Opticstar Ltd
19
StarView
The StarView window cannot be
in use simultaneously with
AstroArt’s capture and focus
modes. StarView provides a high
sensitivity preview mode (6x6
binning) in colour. The exposure
time can be set between 100
millisecondsand 10 seconds.
The hardware Gain function can
be set using the vertical slide bar
on the StarView window.Raising
the Gain, greatly increases the
light sensitivity of the camera.
This Gain setting only effects the
StarView window. The
Brightness slide bar can be used to adjust the brightness of the StarView
image.
It is also possible to invert of reflect the image displayed on the StarView
window by ticking the Inv and Ref options in the bottom right hand corner of
the StarView window.
Capture Settings
The Capture Settings window includes
two slide bars that control two of the
camera’s most important hardware
functions. The Gain settings increases
the light sensitivity of the camera
dramatically when AstroArt captures
image data (excludes StarView). The
maximum Gain value can double the
sensitivity of the camera but it will also introduce some noise. Setting the Gain
at 50% will give a significant boost in sensitivity while keeping noise levels low.
The Black Level function sets the lowest value of image data captured by the
camera that is considered useful (e.g. signal rather than noise). Any data
captured below this level is considered noise and it is discarded. This enables
the camera to maximize its dynamic range with useful data.