Keith (R.K.) Berry wrote:
>
> Thanks for that, Richard, I'll look out for a 90mm lens now. Unfortunately
> there wasn't a manual with mine as I 'bought' it used -
Maybe your Pradovit Color is the same model as Tim Hughes Pradovit
Color, so an look inside might gave you an hint.
Tim Hughes wrote:
> I bought my Pradovit Color used so I don't have the manual but I opened up
> the top cover and checked the condenser assembly which is easily removable as
> a unit without needing unscrewing or anything. It has stamped on it a range
> from 60..120 which I assume means that the condensor is designed for that
> range of focal lengths.
I´ve no Pradovit Color projector, just an Pradovit Color 2 and Pradovit
P2002 cataloge with part numbers on the back, Color 2, P2000 and P2002
use the same 50-200mm condensors.
HI100@xxxxxxx wrote:
> Thanks Richard for an interesting history of all the amalgamations in the
> German projector industry and the warnings on the "cheap" Leica's.
> Incidently do you know who actually made Kodak's top end AV projectors ?
I would like to know it too. My S-AV projector is just labeled " Kodak,
technical datas, made in Germany".
I remember to have seen pictures of an Reflecta projector, very similar
to the S-AV models just a diferent color and labeling, this was a short
time after Kodak introduced the EktaPros. Maybe Reflecta was manufactoring
S-AV for Kodak and tried to market them then independly?
This would have been great, they were moderatly priced, less than an
Pradovit P600 today (much less than the last S-AVs), but that´s hypotetic,
I never could touch one and Reflecta is no longer.
I don´t know for the actual EktaPro series, but they were anounced as
"world projector", a single projector type for all markets, unlike the
former division in S-AV Europe - Ektagraphic America. But I expect they
still have different manufacturing places for different markets.
Did you see, Leica is now selling "tuned" EktaPro projectors?
> Some enlargers and projectors used to have a setup procedure to
> optimize filament position to maximize light throughput for the particular
> lens. Interestingly the Leitz projector I have has a beautifully made set of
> lamp position adjusters so I would be interested to know if they described
> using a test "hole" slide for setting up the lamp in the instruction manual.
> (Richard ?)
The manual to my S-AV projector states:
> After swiching of the projector, look through the lens and check the position
> of the lamp filiaments.
> 135mm and longer focal length lenses: Place the pinhole slide enclosed with
> the lens in the slide gate. Switch on the projector, fit the (translucent,
> the ed.) lens cap over the lens and observe the lamp filiament images
> projected
> on the lens cap. Center the lamp as show below.
> To be correctly adjusted the filaments must be in line and should not overlap.
Diagram:
l l
ZZZZZ
ZZZZZ
l l
Explanation: You should see the lamp filament twice, not overlaping.
An pinhole slide is just an solid slide with an hole in the midle.
It´s important to have properly adjusted lamps, not only to improve
ilumination,
but also to protect the lamp. I have seen an melted quartz halogen lamp, the
heat
and light of the missadjusted lamp was projected back to the lamp.
> As far as reliabiltiy of used projectors : The rubber belts driving the fans
> need periodic replacement (Pradovit is very easy to replace, Rollei and Zeis
> Ikon not so easy.) Also the dampers on the changer mechanism usually rot
> causing them to become more noisey with age. The Pradovit I have needed a
> small Foam Rot replacement (easy) and a rubber stop replacement.
Yes, rubber detoriates when exposed to heat and light.
I bought my projector from an company which used it profesionaly and serviced
it before they sold it. I opened the projector and peeked into it, just for
curiosity, it was clean inside.
An Kodak leavelet says, the then new introduced projector, has extended
service intervals, from former 1000 to 1500 working hours. Pretty much for
amateur
use. This projector was designed for daily non stop use in museums etc, I´ve
no fear the unit will wear out while I use it.
> The focusing
> mechanisms seem to require periodic cleaning and lubrication or the (auto)
> focus gets erratic as dust is sucked through by the fan and accumulates on
> the grease.
Auto focus? My projector is so basic, it didn´t have such fancy things
like an auto focus. Hey, don´t you need this dreaded semiconductors to build
such a device? ;-)
> The Pradovit has very large gears that are much better than the
> other projectors in this respect. This is probably because they are designed
> to allow heavier longer metal encased lenses to be used.
Yeah, they are of a very nice build quality. Some friends have Pradovit C 250
projectors, lot of metal and high precision machinery, just like an OM. They
keep
the slides very cool and the Colorplan is a sharp and contrasty projecting lens.
> I could not agree more with the various comments about a good camera needs a
> good slide projector.
It´s just bad, beginers are detered from taking slides by the investment they
have to made in an decent projector and lens, and it didn´t help when they hear
of bad experiances with "El Cheapo" projectors.
The investment in an slide projector helps saving money on the long run and
garanties you to enjoy the full quality of your photography at minimum costs
without to much hassle to get decent prints.
Let us be honest, to get good quality prints you have to make them by yourself
or you have to pay pro lab prices.
> Now where is that elusive one of a kind Olympus slide
> projector with all its unique features :1000W bulb ,
Horror!! My slides melt! ;-)
Serious there are Xenon projectors with much more than 1000Ws. Slides will not
melt, but I would only project copies of my slides.
> F1.8 zoom lens,
There would not much gain in brightness with such an lens. Unlike photography,
were difuse light is used, projectors use an concentrated beam of light, so
only
an aperture of f/3.5-4 is used.
That´s the reason why projecting lenses with adjustable apertures don´t loose
that much light, but gain considerably contrast and sharpness for glassless
mounted slides.
Experience from normal photography let you expect an loose of brightness in
equall steps, like 100%, 50%, 25%, 12%, 6%, but projecting is diferent.
The "Dia Magazin" has tested this in 3/97 with following results:
2.8 = 100% brightness (full open)
4 = 92% "
5.6 = 64% "
8 = 35% "
11 = 18% "
Of course this numbers might vary with different projectors (and condensors).
> vario condensor,
Why vario? One size fits all. ;-) At least my S-AV projector has an 26-180mm
condensor. :-()
Regards
Richard
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