View Full Version : DMK21F04 Shutter Speed Question
January 20, 2004, 16:16:56
We are developing an application for a DMK21F04 camera that will sometimes be used under low-light level conditions (adding more light is not an option). The camera's specifications lists manual and automatic mode shutter speeds from 1/30 to 1/3.3 seconds. However, using the Imaging Control ActiveX tools we are only able to adjust the exposure from 1/2048 to 1/32 seconds. Is there any way to get the camera to capture frames using the long 1/3.3 second integration times?
January 21, 2004, 09:05:43
The use of exposure values defaults to physical values, that are the values from -5 to -11 (1/2048 to 1/32 seconds). To use the whole range of exposure, you must switch to register values for exposure. The DCamprop.dll provides a function for switching between physical and register values:
SetPhysicalUnitsExposure ICImagingControl1, False
After you have changed the current setting of physical units / register values, you must disconnect and reconnect the camera once, to take the change in effect.
I have attached a Visual Basic 6 sample, that shows how to switch between physical units and register values.
January 22, 2004, 20:08:02
Thank you for the quick response. Based on your reply, we have successfully implemented the register method of exposure control. However, it seems that the camera is still limited to the same range of exposure values (1/2048 to 1/32 seconds), but instead of having only seven discrete value settings in this range, we now have 511 settings. Could it be that the 1/3.3 second shutter speed for the DMK 21F04 camera was incorrectly specified?
January 23, 2004, 09:15:42
I think, you interpreted 1/3,3000 as 0.3 seconds, but it is 1/3300 seconds. Therefore you are right, the maximum exposure time is 1/32 seconds.
March 23, 2008, 18:18:58
Hope you don't mind if I ask a related question....I'm using the IC TWAIN driver and a program called Irfanview to capture...I already have my exposure settings set to read from -13 to 11 instead of the actual times...to make the register and physical reading, I don't have the .dll listed. Would my programs equivelent be in my TWAIN directory? or in the irfanview directory somewhere?
March 25, 2008, 09:35:00
I am very sorry, but I do not understand your question. But the exposure setting are as follows:
-11 to 4, where the exposure time is calucalted as 2^n = seconds, e.g n=-6 =>2^-6 = 1/64 seconds
March 25, 2008, 15:24:41
Just what I needed :) Thanks Stefan!
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