BioDocAnalyze (BDA) digital - Biometra

16
Image Capture
3.2.2 The Card „Settings“
Shooting Mode For choice of capture mode. Typical settings are „Manual“ or „Auto“.
- Manual Exposure time and lens aperture can be set in lines „Av“ and „Tv“. Even for the use of
profile parameters the mode should be „Manual“.
It should be kept in mind that the camera can not set the largest apertures (= small aperture
number) together with a large zoom factor. In these cases the camera automatically
chooses the largest possible lens aperture. After the picture is taken the aperture display on
the card is actualized to the really used one.
- Auto The camera sets the capture parameters exposure time and lens aperture automatically.
Be aware that these settings are not displayed in the camera settings.
Be aware that the displayed and printed settings are not the true settings the cameras has
automatically chosen for the photo!
- Tv The camera automatically chooses the optimal lens aperture in relation to the manually
set exposure time. After the picture is taken the automatically used aperture is displayed in
the card Settings.
- Av The camera automatically chooses the optimal exposure time in relation to the manually
set lens aperture. After the picture is taken the automatically used exposure time is displayed
in the card Settings.
Lens aperture, Av For setting the lens aperture. A small aperture number stands for a wide open lens, a high
aperture number for a more closed lens. The depth of focus increases with rising aperture
number (= smaller lens aperture). Agarose gels, especially thicker gels, should be photographed
with high aperture number (= small aperture). Otherwise photos may not be focussed.
Exposure time, Tv For setting the exposure time. The time is to be set in dependance of sample/illumination
and lens aperture. For smaller apertures (= high aperture number, e.g. 8) exposure times of
up to 8 seconds can be necessary for a photo of fluorescent gels.
Resolution For choice of image resolution in pixels. The higher the resolution the bigger the file size.
High resolutions will cause longer data transfer times from camera to PC on computers
with slow processors and memory below 512 MB RAM. For an efficient operating it is
recommended to use a computer with at least 1 GB RAM and a 2.8 GHz processor.
In pixels PowerShot G10 PowerShot G9 PowerShot A640
High
Medium1
Medium2
Low
4416 x 3312
3456 x 2592
2592 x 1944
1600 x 1200
4000 x 3000
3264 x 2448
2592 x 1994
640 x 480
3648 x 2736
2816 x 2112
2272 x 1704
640 x 480
PowerShot
A620/G6
3072 x 2304
2592 x 1944
2048 x 1536
640 x 480
Zoom The optical zoom can be set with the slider or by typing in a value between 0 and 13 (G10,
G9), 0 and 8 (A640/A620), 0 and 12 (G6/G5/G3) resp. 1 to 10 (G2).
A higher zoom reduces the amount of light that reaches the camera sensors. This can cause
difficulties for the autofocus. When the autofocus does not succeed to take a focussed
picture although there is a clear object in the image center please
- set a longer exposure time (Shooting Mode Manual)
- set less zoom.
- Use the function “AF Lock” for fixation of the autofocus. (see 3.2.5)
- use the function „manual Focus“ (MF button on camera back). This manual focus is
not available for use with remote control by the computer. For use of the manual focus
please disconnect the USB cable of the camera from the PC and run the camera
BDAdigital Manual, Vers. 01_11