Camera with a sticky substance on the back
It's a very common problem with older cameras and is an irreversible
breakdown of the foam which was used to provide light-proof seals on
the camera back and also to cover the pentaprism and provide a mirror
buffer. (The pentaprism and mirror buffer are part of the viewfinder
system).
The first problem is that when the foam turns to goo it
allows light to leak into the camera and spoil the film, but that's the
least of it. Where it gets serious is that the goo spreads inside and
can gum up delicate moving parts; worst of all the goo is somewhat
corrosive and can damage the coatings on the pentaprism leaving
permanent residual ghosting images in the viewfinder.
The good
news is that it's a well understood problem and every professional
camera repairer can remove the goo and restore the camera as part of
the regular service that all SLR's should periodically undergo. The
foam will be replaced by modern materials which do not degrade. Some
repairers also replace the mirror buffer, others will just remove the
old foam and omit the buffer, but I always insist on a new buffer. At
the same time, the repairer will give the camera a thorough CLA service
(Clean, Lubricate, Adjust) which for a camera in non-professional use
will often see it through a few more years, but I'd recommend getting a
CLA done annually if you're well off and every couple of years if funds
are tighter. The CLA will also ensure that the light metering is
correct and on cameras using the older mercury oxide
batteries can include a meter recalibration to allow use of modern
silver oxide equivalents which have a higher voltage as the mercury cells are no longer
available. (Some folks use manganese dioxide batteries, but
they start off at a voltage slightly higher than the camera was designed for and constantly
drift down with use to way below the nominal voltage, so metering is neither consistent nor
accurate). A regular CLA with foam removal costs a bit more than a
regular CLA but is a once only expenditure. Some repairers charge for
recalibrating the meter for silver oxide batteries, but most won't if you politely
explain that you can always take the camera elsewhere.
DIY kits
are also available and some are very good indeed, but they can be
fiddly and messy to fit and none of them address the more serious issue
of the pentaprism. In practice, repairers will remove the old foam from
the pentaprism but almost never fit a replacement. It's not strictly
necessary and the reluctance to fit a replacement stems from the risk
of further damage to the pentaprism by the adhesive. The outside of the
pentaprism is normally painted black from new, but foam goo usually
attacks the paint and partially removes it. it also attacks and removes
any optical multicoatings on the prism. When this has occurred there is
no fix: the problem will not worsen once the foam has been removed but
there will be residual damage visible in the viewfinder as ghostly dull
patches, but this is something which can be tolerated and will not
affect image quality.
If you want a cheap quick fix, then use a
q-tip (UK= cotton bud), a wooden cocktail stick/toothpick and some
alcohol to remove all visible traces of gooey foam. Omit the mirror
buffer altogether and take your chances with the prism foam. To replace
the rear light seal just use a length of woollen yarn: you'll find that
if you twist it slightly it will reduce in diameter and allow you to
press it into the slot where the foam was using a toothpick. Usually
you can get away without gluing it, but if any glue must be used then
use a few very sparing dots of something easily removed such as Copydex
or the rubber cement sold for repairing bicycle inner tubes. At the
hinge end of the camera back will be a thicker, wider bit of foam. Just
use a few dabs of glue or to secure a good thick double or even triple
width of yarn. The fix isn't a professional one, but it's good enough
and was how the seals were made before rubber foam was invented. It
also buys you the time to decide whether you like using your Nikon enough
to invest in a professional CLA with the additional options.
I
hope that my reply has given you a few options and will enable you to
get your camera into working condition again. All I ask is that you
return the favour by taking a moment to rate my answer.
1/10/2010 1:15:11 AM •
Nikon...
•
Answered
on Jan 10, 2010