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Re: [OM] Olympus' frontmounted converters

Subject: Re: [OM] Olympus' frontmounted converters
From: "Per Nordenberg" <per.nordenberg@xxxxxxxxxx>
Date: Thu, 20 Apr 2000 10:35:28 +0200
----- Original Message -----
From: "Frank van Lindert" <lindertv@xxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Monday, April 17, 2000 10:19 AM
Subject: Re: [OM] Olympus' frontmounted converters


> Yes, Per - it is the same thing. I bought a used Centurion D-1.45x
> lens for my C-1400XL. Although it may be fine optically (good glass),
> this lens is a disaster from a technical point of view. The housing is
> completely made of plastic - but this is not the most important
> disadvantage. What is worse is, that the mount is of the snap-in type
> common to the lens caps! Conseqeuntly you will have a very high risk
> of loosing the lens during work.... I have epoxied the needed step-up
> ring to the snap-in mount to convert it into a normal screw-in lens.
> Since then it does its work properly. Only drawback is that the lens
> will no longer take its rear cap.

Thanks Frank. Interesting, but also somewhat sad that this lens is not quite up 
to
the standards of the iS converters. I imagine that there is also a certain risk
that a plastic snap-in type of mount might develop a play with heavy use.


> >Another iS converter not mentioned on Oly's official digital pages but often
> >discussed in rec.photo.digital is the 1.7x B-300 teleconverter.
>
> This one is a much better choice - although bulkier and heavier.
> All metal, sturdy - and more magnification.
> Olympus has recommended the B-1.7x when the first digital SLR's came
> on the market - but stopped doing so when the more profitable (for
> Olympus, that is) Centurion lens was relaunched for digital use
>
> >Someone mentioned
> >that he had managed to glue a 77 mm filter ring into the plastic outer lip of
the
> >B-300, so that a filter could be mounted. Has anyone here tried this? How 
> >does
> >this comply with the recommendation from Oly that filters cannot be used with
> >these frontmounted converters? Presumably they mean filters mounted between 
> >the
> >camera and the converter, but how about if the filter could be mounted in 
> >front
of
> >the converter? If this indeed_is_possible it would be of interest not only 
> >for
all
> >iS-3(000)(B-300 users, but also for all digital camera/B-300 users as well as
> >owners of any Zuiko lenses compatible with the B-300.
>
> I have never tried it myself, but filters are not possible on the
> front without attaching a ring or other device which will take them.
> Only place for filters is, like you say yourself, between the
> tele-converter and the lens itself. This is easier done on the
> IS-cameras than on the digitals, because the latter are more prone to
> vignetting. But vignetting might occur on the IS too, in particular
> when the zoom is not at full length.

Even if there is no visible vignetting in the viewfinder, I imagine that there 
is
a risk of vignetting in the images. Especially with the iS series since only 85%
of the image is seen in the viewfinder. Of course there is always also the risk 
of
damage to the protruding front element of the converter if you attempt to mount
anything at the front. I think I'll leave my B-300 just as it is...


> I have thought of combining the two converters, by glueing a 55mm ring
> inside the frontal ring of the 1.45x. The 55mm thread will in its turn
> take the 1.7x.
> This will cause severe vignetting with the digicams, but conversion
> goes up to 2.45x, which means 270 mm focal length for the Camedia
> SLR's. Even when you can only use the centre of the picture this might
> be nice for special occasions. I tried it by taping the two lenses
> together, and the results are promising. Another future project...

Sounds very interesting Frank. Let us know how it works out. Myself, I have 
only a
small C-900 compact type of Oly digital, but maybe I will gear up in the 
future...

Per Nordenberg
Zoo keeper at Kolmården


--
Do not walk while looking through the viewfinder of your camera
(you could get a real closeup view of the bottom of the Grand Canyon).
                                                     - Unknown







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