Compact cameras and camcorders on the microscope
DSLR cameras are simply better!
Compact cameras have one thing in common: the lens unit is
firmly fixed inside the camera body and cannot be removed. In the case
of digital single lens reflex cameras (DSLRs), the lens is connected to
the camera body by means of a bayonet fitting. In microscopy, it is an
advantage if the microscope adapter is able to project the image
directly onto the camera sensor. The adapter acts as a mechanical and
optical means of adjustment between the microscope and the camera.
Compact cameras and camcorders are primarily designed for photographing
objects and people, and not for use with microscopes. The lens makes it
possible to reproduce objects in sharp focus at various distances. With
this type of photography, it is an advantage if the lens delivers as
much light intensity to the focal plane as possible. This is achieved
by using large lens elements that capture plenty of light. The biggest
problem in use with a microscope is posed by modern zoom lenses. Every
year, the zoom range is enlarged and the complexity of the lens
construction increases. Due to the large number of spherical and
aspherical lens elements in the lens unit, the image quality is
considerably reduced in conjunction with other optical instruments. In
use with a microscope, the lens unit is overtaxed, as it was not
designed for this type of use. The consequences are a range of image
distortions, such as poor focus at the edge of the picture, washed out
colours and vignetting (peripheral darkening). Ideally, the lens unit
should be removed completely, but unfortunately in the case of compact
cameras this is not possible without destroying the camera body. The
main function of microscope adapters for compact cameras is to reduce
the negative characteristics of the camera’s lens unit and to project
the microscopic image onto the sensor. With some cameras this works
quite well, with others not so much.
With all compact cameras, microscopic images must be taken when they
are at high zoom settings, i.e. at tele setting, in extreme cases in
digital zoom mode. With a high zoom setting, the image section will
also become smaller. Often the surface area of the photo is only
25%-40% of the image visible through the eyepiece..
In
individual cases,
there may also be slight
vignetting
on the edge of the image.
Only
by using the digital zoom or image editing programmes will it be
possible to remove the undesirable black edges.
If the
photos need to be measured using
a software application, then calibration is very difficult to carry
out.
Since the magnification factor changes with the zoom setting, it is
very complicated to achieve a precise calibration. Every
time the camera is switched on or off, the lens unit moves meaning
that it needs to be recalibrated.
In
addition,
compact cameras differ from DSLR cameras in the following ways:
-
Use
of small image sensors with low signal to noise ratio.
The size of the sensor has a strong influence on the price of the
camera
-
Lower
number of pixels
-
Long-winded
navigation via one menu.
The
fewer moveable parts a camera has, the more easily it can be
assembled.
In recent
years, the gap in performance between compact cameras and digital SLR
cameras has become ever greater.
Camera prices
are falling consistently, especially in the case of compact cameras.
New
high performance technologies which bring about an improvement in
image quality are mainly only incorporated in the top of the range
SLR camera models.
However, new beginners’ models over EUR 300.00 or used DSLRs
manufactured after 2002 are also very well suited for microscopy. A
list of digital cameras according to their suitability for microscopy
can be found on our website under:
Which
digital camera works best with microscopes?
Conclusion:
In
the professional field we would advise against the use of compact
cameras for microphotography.
Those
with a serious interest in microscope photography should not cut
corners when it comes to the camera.
Digital SLR cameras are superior to compact cameras in all respects.
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