"AAvK" <notforspam@[EMAIL PROTECTED]
> wrote in message
news:HDgkj.1102$Ca7.211@[EMAIL PROTECTED]
>
>>> Okay, but there are no threads there.
>>>
>> The fitting may be missing. On most shutters the cable
>> release socket is a separate part held in with a nut or
>> clip or some other way. I've had to makeshift sockets for
>> a couple of Ilex shutters were they were missing.
>
> Ya know what? I just got the lens, and in that hole there
> ARE threads there!
> They just didn't show it in the shots they took for ebay.
> But the threads are
> different than the modern tapered standard, just no taper,
> straight walls with
> threads. I attempted to use a tapered thread cable
> release, the threads at the
> widest did catch at the top of the hole and it did trip
> the shutter but I know now that I need a short throw /
> short pin type, with this older style of non tapered
> thread. Do you know what I can do about that? Or, where
> the right
> one can be found? Maybe a bushing adapter is out there?
>
> The glass in this lens is beautiful to look at, though
> there is some crystalization
> of the adhesive they used, around the edges of the front
> cell. A very little around the rear cell's edge, it's
> workable (the seller dod not reveal this on their
> page). No yellowing in the glass ttlg. A bit of a
> stop-down should cancel any
> possible effect.
>
> This is a very small lens and shutter! So it must be for
> 4x5 indeed. The front
> cell is 14" and the rear is 11" just as you described!
> 6-3/4" together. So that's 171.45mm, 279.4mm, and 355.6 -
> all with an image circle that will cover 4x5"
> only? Would you know what the image circles are, from
> your books?
>
> The Regno works like a charm all around, but not tight
> like a newer one, or a compound. Definitely light-tight
> though, I took a good close look using light.
> The two patent dates are as follows: May 30 1911 and Aug
> 13 1912. So this
> shutter is around 100 years old. Lovely device.
>
Congratulations:-)
Beware of dating something by patent dates. I think some
products carried the patent dates or numbers long after the
patents expired. I don't know what the law was on this. A
patent date rather than a number indicates the object was
made before 1927. The patent law was changed then to require
the actual patent number although one could still mark the
date also. Patents in the US have a life of 17 years (some
exceptions now) so a patent issued in 1911 would have run
out in 1928. I suspect the lens and shutter are later rather
than earlier due to the shutter having a cable release
rather than an air release.
Since the T-R lens has four cemented surfaces in each
cell you are doing pretty well to have only slight cement
damage. I am not sure why some lenses seem more vulnerable
to this than others but some of the factors are, the quality
of the canada balsam used, the method of curing it, the
ability of the edge paint to seal the edge from the air. The
cleanliness of the glass surfaces before they were cemented
are also important.
The T-R has a coverage of perhaps 75 or 80 degrees when
the two cells are combined. This is at a fairly small stop,
perhaps f/45. The individual cells have much smaller
coverage, perhaps half of the combined lens, so they won't
cover much more than the "normal" format of the combined
lens.
Like other lenses of this general sort (Dagor,
Convertible Protar, etc.) the lens is somewhat of a wide
angle lens, that is, it covers a pretty wide angle, but the
stop used will depend on the angle. For "normal" the optimum
stop is probably around f/16 to f/22. When used at maximum
coverage its around f/45. The individual cells are much
slower than the combined lens and generally will be sharp at
around f/36 to f/45. Stops smaller than about f/45 can be
used, especially for depth of field, but the diffraction
blur is usually enough to be visible on the ground glass and
will be visible in prints.
Gundlach made some extreme claims for the lens
especially for its coverage, but they simply are not so.
However, its a perfectly usable lens. Note that while the
cells are intended to be used behind the stop they can also
be used in front. Theoretically the performance should be
better when behind the stop but in practice there is not
much difference. However the bellows draw is significantly
shorter when in front so its sometimes possible to use the
longest FL cell this way when the camera does not have
enough bellows draw to permit it to be used in its normal
position. Again theoretically the speed will be slightly
greater when in front but the difference is probably not
significant in practice.
As I mentioned Wollensak made good shutters although
some of their lenses were dogs (but not all). Probably the
most famous of the old Wollensak shutters was the Optimo.
This shutter was made with shutter blades which turned 180
degrees when the shutter was tripped (and went back the
other way the next time it was tripped). This allowed the
shutter to have higher speeds than standard shutters
although the highest speeds marked on some of them is purely
wishful thinking.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@[EMAIL PROTECTED]
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