BIO RAD VERSADOC, Руководство пользователя

Страница: 46 / 61

User's Manual
•
4-
6
4.3.7 Focus Adjustment
To focus the lens on the sample for sharp images you must choose the FOCUS button in
the Quantity One acquisition window. This button allows focusing on a small part of the
image. When using this mode the white epi lights turn on automatically and the shutter is
opened and closed repeatedly and the acquisition window is continuously updated to allow
you to focus your lens on the sample. The exposure time during the focus mode is adjusted
automatically to allow proper unsaturated images. If during focus mode the images still
show up saturated, then you must adjust the aperture to a lower setting to view the images
in the focus mode. If the images still show up as saturated (all white), then you may turn off
the epi lights by clicking on the button labeled "Lights On" (see figure 4.1). This will turn off
the white lights and now you may open the main door and adjust the focusing ring (See
Figure 4.5) on the lens to achieve a sharp focus on your sample.
4.3.8 Exposure Time
The exposure time refers to the period of time that the shutter will remain open and light will
pass from the sample to the CCD. As such, the longer the exposure time, the brighter the
captured image will be. For high intensity applications including colorimetric and high
intensity fluorescence experiments, an exposure time of only a few seconds is typically
required. For low intensity applications such as chemiluminescence, an exposure time of
several minutes may be required. The exposure period required to produce an optimal
image varies considerably and may need to be optimized for your particular sample. Typical
exposure conditions for different sample types have been included in Table 4.1 as a guide
to selecting a suitable exposure time. This table also indicates the preferred lens for the
sample and if any accessories are recommended.
Table 4.1. Recommended exposure times and setup
Sample Recommended
Exposure Lens &
Filter
Accessories
Used
Fluorescent Stain Gel 3-30 sec. Zoom/IR None
Fluorescence End-Label
Gel
30 sec. – 5 min. Zoom/IR None
Fluorescent Blot 0.5-5 sec. Zoom/IR Sample/Chemi Tray
Chemifluorescent Blot 0.5-5 sec. Zoom/IR None
Colorimetric Gel 0.1-1 sec. Zoom/IR VersaDoc white light
conversion screen
Colorimetric Blot 0.1 to 1 sec. Zoom/IR Sample/Chemi Tray
X-ray film 0.1-1 sec. Zoom/IR VersaDoc white light
conversion screen
Weak
Chemiluminescence
5-10 min. 50 mm Sample/Chemi Tray (if
sample is small)
Strong
Chemiluminescence
10 sec. – 2 min. 50 mm Sample/Chemi Tray (if
sample is small)