Choosing a Camera

Microscope cameras make it possible to capture, record and share incredible images as increased sensitivity, speed and field of view have driven digital microscopy to new heights.  However, as with all new technology, deciding on the right camera option to suit your needs can often lead to just as many questions as answers.  As you navigate the digital imaging landscape, its helpful to consider the criteria that will ultimately help you in your camera selection.

CCD vs. CMOS

These acronyms refer to the two types of image sensors that cameras use.  The first type, CCD, stands for Charged Coupled Devices.  Basically, the way CCD works is that a charge builds up in each pixel during image capture.  As soon as the image capture is complete, the data is then read sequentially.  The second type of sensor, CMOS, stands for Complementary Metal-Oxide Semiconductor.  CMOS sensors employ a parallel approach in which the charges are read out simultaneously.  In simple terms, cameras that use CCD have advantages in terms of light sensitivity and noise and are more appropriate for applications that require higher performance.  CMOS cameras deliver the image at a faster rate due to the parallel processing format.  They are usually adequate for simpler digital imaging and are a less expensive than CCD.

Pixel Size

6.45µm or larger generally offers clear images with low noise.  However, it is important to note that larger physical pixel size means fewer pixels can fit on the sensor, reducing resolution.  

Sensor Size

The larger the sensor, the more pixels it can fit.  2/3”-1” sensors are used in most scientific cameras in order to maximize both pixel size and quantity. The sensor size also determines which magnification c-mount adapter you should use.

Resolution

Although it seems counter-intuitive, higher magnification objectives actually require fewer pixels. In fact, if you are working at a higher magnification, the optical system is limited to about 3–5 Megapixels that can be transferred to the sensor of a camera.  Therefore, if you go out and purchase that 20 Megapixel camera hoping to maximize clarity, know that the “extra pixels” will have NO EFFECT on the resolution of the image, while negatively impacting speed, capacity and sensitivity.  However, for lower magnification, a higher pixel count will capture more detail from your microscope.

Color Reproduction

Our eyes respond differently than camera sensors. Therefore, cameras use various techniques to reproduce (on a monitor) colors similar to what you observe through your microscope.

Dynamic Range

This refers to how well a camera is able to segment shades of gray or color.  A greater dynamic range means the camera will better capture subtle color changes in the image.

Frame Rate

This is the number of frames that are captured per second. The human eye can handle about 30 FPS.  For fluid live imaging, the camera should at least achieve this frame rate.  Note, some applications require even higher rates. Frame rate for microscope cameras is variable and can depend on the amount of light the microscope is emitting. 

Speak with an Expert

Selecting the right camera for your particular needs is not a simple process.  It will ultimately depend on the specifics of your application and will involve determining the appropriate sensor (CCD vs. CMOS) while balancing the other criteria listed above. If you are unsure which is the right camera for your application, give us a call at 215-925-2285.  At I. Miller, we combine expertise in the latest digital imaging with 80 years of microscope experience to help our customers make the best digital microscopy decision.