optional 100 mm focal length tube lens fitted inside the optional advanced filter block
module. This infinity optics upgrade is a concession – to allow you to use any infinity
objective you happen to have lying around – and is not a recommended upgrade
because 100 mm focal length is too short for optimal image quality with most infinity
objectives. It ‘works’ but you get exaggerated lack of planarity of the image. This is
because most infinity optics tube lenses have a much longer focal length of about 250
mm so the short 100 mm tube lens of the current PUMA infinity module does not allow
enough distance for the planarity and colour correction paths of the infinity objectives
to fully work. I am currently working on designs for a more dedicated high quality
infinity optics adapter for PUMA but this is still at the design stage at the time of writing
this manual and not currently available as a upgrade.
You can use objectives of up to x100 oil immersion with a PUMA system but in order to
get a bright clear image with any objective higher than x10 you are advised to also use
the Abbe condenser upgrade discussed below.
You can also use higher magnification oculars such a x20. Thus the total magnification
achievable is between x1000 and x2000 using a x100 oil immersion objective and either
a x10 (the standard) or x20 (an upgrade) ocular.
Be advised that if you use a higher magnification ocular you will see a smaller field of
view. In particular you will not be able to see the whole augmented reality heads up
display (AR HUD) interface if you use a x20 ocular.
OptArc supplies high quality Plan Achromat objectives but you can also use legacy
objectives from Olympus, Zeiss and Leitz as well as other professional microscope
manufacturers.
Beware of cheap generic lenses. Many other brands or generic RMS objectives can also
be purchased very cheaply however those cheap objectives tend give lower quality
images, in particular the field of view will not be flat (uniformly in focus) from the centre
to the periphery. The cheap lenses will show either the central area in focus and the
periphery blurred or vice versa depending on the position of current focus. Cheap
oculars can also be purchased but these too suffer from a variety of quality issues and
often have a small exit pupil with short eye relief meaning you will need to get your eye
very close to the tube to see the whole field of view which can be uncomfortable for
long term viewing and impossible for people who wear glasses unless they remove
their glasses (then the focussing will need to be adjusted and this may cause other
problems such as worse field curvature and lack of colour registration). PUMA was
designed to be a professional microscope but if you use cheap toy lenses with a PUMA
system then your viewing experience will be like that of a cheap toy microscope.
Long Legs System
The long legs upgrade allows greater clearance
under the microscope and is required for
illumination system upgrades (including the
addition of an Abbe condenser) with the
exception of epi-illuminators.
PUMA Foundation Scope
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User’s Manual v1.0