Figure 35. Timing Diagram For Frame Transfer Mode When Exposure Time < Readout Time - Princeton Instruments ProEM+ EMCCD User Manual

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minimum effective exposure time in this mode is the readout time). This mode of
operation allows you to continuously image a specimen to obtain better kinetic
information about a process.
In WinX and LightField, Frame Transfer is the default mode of operation for cameras
with frame transfer CCDs. If necessary, you can change the readout mode on the
Hardware Setup/Controller/Camera tab { Sensor expander}.
Note: In Frame Transfer mode, the minimum effective exposure time is the readout time.
The simultaneous exposure-readout mechanism is illustrated with two examples for the 512B
model. This mechanism applies to the 1024B as well but with a larger readout time.
Example 1: Frame Transfer Mode when Exposure Time < Readout Time
Consider a situation where full frame readout is 30 ms, the exposure time is 10 ms, and
three frames are taken in Frame Transfer mode. The first frame is exposed precisely for
the length of time entered into the software (10 ms) and all subsequent frames are
exposed for the readout time. The total time to acquire 3 frames is then 100 ms (3 
30 ms + 10 ms), equivalent to a frame rate of 33.33 fps (3 frames  0.100 seconds).
Note: Because the first frame is exposed for 10 ms and the others for 30 ms, the first
frame may look less bright compared to all other frames.
In Frame Transfer mode when exposure time < readout time, the total time (T
to capture N frames is given by:
Where
Exposure Time < Readout Time. Timing information shown is for illustration purpose
ProEM
 N) + t
T = (t
N R exp
T = Total time taken to capture a sequence of N frames
N
t = readout time for one frame
R
N = total number of frames in a sequence
t = exposure time
exp
Figure 35. Timing Diagram for Frame Transfer Mode when
only. Specific readout times vary depending on the model.
®
+ System Manual Version 1.B
) taken
N