Rapid Rectilinear lens baffles

I have a Rapid Rectilinear in need of lens cleaning. The front and rear
elements have black baffles presumably to cut out the outer peripheral
rays (sorry for pseudo-optic speak) and improve it's performance...

I don't want to slop fluids between the glass and baffles to clean
becasue I won't be able to remove the fluid.

Does anyone know if they are removeable/replaceable? I have not run
into these before.

Thanks

Murray

"murrayatuptowngallery"
wrote in message
oups.com...
I have a Rapid Rectilinear in need of lens cleaning. The
front and rear
elements have black baffles presumably to cut out the
outer peripheral
rays (sorry for pseudo-optic speak) and improve it's
performance...

I don't want to slop fluids between the glass and baffles
to clean
becasue I won't be able to remove the fluid.

Does anyone know if they are removeable/replaceable? I
have not run
into these before.

Thanks

Murray

Baffles are sometimes included in lens cells to reduce
internal reflection (flare) but I've never seen any on a R-R
lens either. Do you have more information about the lens,
who made it, kind of mount its in, etc?
Rapid Rectilinears are symmetrical lenses with each
component made from two cemented elements. They were made
from about 1865 until the early 1930's. They are not
anastigmats but are capable of very good performance when
stopped down.


--
---
Richard Knoppow
Los Angeles, CA, USA

Hi Richard. Thanks for the reply.

One can't delete posts here apparently :O)

Once I posted, I realized I could answer my own question...by studying
the lens a bit closer.

Marked Bausch & Lomb Rapid rectilinear, f.l. not marked, on early
(1916-1925-ish?) Folding Pocket 3-A in rusted Ball Bearing shutter. If
I can't get BB shutter running I'll just play with the lens on a Speed
Graphic.

My observations: baffle is not removeable...appears to be cemented in,
as do the elements...looks like maybe air spaced achromat? Fairly thick
to my eyes

I expected the front & rear cell to be symmetrical, but they are very
much not so. Could this be the Wide Angle Rapid Rectilinear? I found a
schematic dwg of one of those with non-symmetrical elements, but the
front was visibly larger.

I call these cells non-symmetrical because they each project images at
very different focal lengths. Maybe this next part is not surprising,
that projecting an image with just the front cell and then rotating it,
two different f.l were observed...not knowing where nodes are, I just
held a measuring tape up...13-3/4" and 16-3/4" from wall to center cell
body for front cell projection only.

Comparing front and rear, one seemed to have a longer f.l. I'll look
for both elements presence in each cell. Maybe I'm crazy (you already
knew that), but since I can't get the shutter to open right now, I held
the two cells together and slightly spaced approximating the shutter
spacing and the f.l. DID fall somewhere in the roughly half of the
above distances...which seems to shoot my argument about asymmetry in
the foot...but with the cells separate I was certain I focussed at
distinctly different distances.

I decided to clean the front cell with a mix of H2O2, Windex and 91%
isopropyl alcohol and cotton swabs...it looks pretty good now. I can
see a couple spots at the edges that I suspect are in the air space
between elements.

I guess I get to repeat it all...the rear cell is dirtier and once I
clean it (assuming success), I'll be imaging on the garage wall again.

I called them baffles because there is a wide black ring behind the
back element on the front cell, and it significantly reduces the rear
'clear diameter' compared to the front element. I don't have the rear
cell with me, and I realize my visual memory is not very accurate.

murrayatuptowngallery spake thus:

I decided to clean the front cell with a mix of H2O2, Windex and 91%
isopropyl alcohol and cotton swabs...it looks pretty good now.

Hey, those are my "magic elixirs" for lens cleaning too. (Used
separately, of course.) You owe me royalties!


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

"murrayatuptowngallery"
wrote in message
oups.com...

Hi Richard. Thanks for the reply.

One can't delete posts here apparently :O)

Once I posted, I realized I could answer my own
question...by studying
the lens a bit closer.

Marked Bausch & Lomb Rapid rectilinear, f.l. not marked,
on early
(1916-1925-ish?) Folding Pocket 3-A in rusted Ball Bearing
shutter. If
I can't get BB shutter running I'll just play with the
lens on a Speed
Graphic.

My observations: baffle is not removeable...appears to be
cemented in,
as do the elements...looks like maybe air spaced achromat?
Fairly thick
to my eyes

I expected the front & rear cell to be symmetrical, but
they are very
much not so. Could this be the Wide Angle Rapid
Rectilinear? I found a
schematic dwg of one of those with non-symmetrical
elements, but the
front was visibly larger.

I call these cells non-symmetrical because they each
project images at
very different focal lengths. Maybe this next part is not
surprising,
that projecting an image with just the front cell and then
rotating it,
two different f.l were observed...not knowing where nodes
are, I just
held a measuring tape up...13-3/4" and 16-3/4" from wall
to center cell
body for front cell projection only.

Comparing front and rear, one seemed to have a longer f.l.
I'll look
for both elements presence in each cell. Maybe I'm crazy
(you already
knew that), but since I can't get the shutter to open
right now, I held
the two cells together and slightly spaced approximating
the shutter
spacing and the f.l. DID fall somewhere in the roughly
half of the
above distances...which seems to shoot my argument about
asymmetry in
the foot...but with the cells separate I was certain I
focussed at
distinctly different distances.

I decided to clean the front cell with a mix of H2O2,
Windex and 91%
isopropyl alcohol and cotton swabs...it looks pretty good
now. I can
see a couple spots at the edges that I suspect are in the
air space
between elements.

I guess I get to repeat it all...the rear cell is dirtier
and once I
clean it (assuming success), I'll be imaging on the garage
wall again.

"murrayatuptowngallery"
wrote in message
oups.com...

Hi Richard. Thanks for the reply.

One can't delete posts here apparently :O)

Once I posted, I realized I could answer my own
question...by studying
the lens a bit closer.

Marked Bausch & Lomb Rapid rectilinear, f.l. not marked,
on early
(1916-1925-ish?) Folding Pocket 3-A in rusted Ball Bearing
shutter. If
I can't get BB shutter running I'll just play with the
lens on a Speed
Graphic.

My observations: baffle is not removeable...appears to be
cemented in,
as do the elements...looks like maybe air spaced achromat?
Fairly thick
to my eyes

I expected the front & rear cell to be symmetrical, but
they are very
much not so. Could this be the Wide Angle Rapid
Rectilinear? I found a
schematic dwg of one of those with non-symmetrical
elements, but the
front was visibly larger.

I call these cells non-symmetrical because they each
project images at
very different focal lengths. Maybe this next part is not
surprising,
that projecting an image with just the front cell and then
rotating it,
two different f.l were observed...not knowing where nodes
are, I just
held a measuring tape up...13-3/4" and 16-3/4" from wall
to center cell
body for front cell projection only.

Comparing front and rear, one seemed to have a longer f.l.
I'll look
for both elements presence in each cell. Maybe I'm crazy
(you already
knew that), but since I can't get the shutter to open
right now, I held
the two cells together and slightly spaced approximating
the shutter
spacing and the f.l. DID fall somewhere in the roughly
half of the
above distances...which seems to shoot my argument about
asymmetry in
the foot...but with the cells separate I was certain I
focussed at
distinctly different distances.

I decided to clean the front cell with a mix of H2O2,
Windex and 91%
isopropyl alcohol and cotton swabs...it looks pretty good
now. I can
see a couple spots at the edges that I suspect are in the
air space
between elements.

I guess I get to repeat it all...the rear cell is dirtier
and once I
clean it (assuming success), I'll be imaging on the garage
wall again.


An interesting lens. B&L must have built millions of R-R
lenses for Kodak and also built the Kodak BB shutters.
The R-R lens has a cemented doublet fron and back, no
air spacing except for the cells. This appears to be a
triple convertible lens. There were such lenses based on the
R-R. When the single cells are used you lose the corrections
from symmetry or near symmetry, namely, coma, lateral color,
and geometric distortion. Even when the two cells are not of
the same focal length, but are of the same type, there is
still considerable cancellation of these aberrations. In
fact, if the difference is right, it can improve the
cancellation for distant objects. Even without the symmetry
a single lens can produce a surprizingly good image if
stopped down quite a bit. Single menicus lenses should
ideally go in back of the diaphragm. Where the two cells are
of different focal lengths the longer one goes in front.
These are general rules for all convertible lenses.
I still can't guess about the black ring. It may be a
limiting stop of some sort. Are you sure it isn't some
effect of the cement oxidizing at the periphery? This is a
very common effect in old cemented lenses. Usually, the
cement turns yellow but it can also crystalize, this last is
very regognizible. If it appears to be _inside_ the glass,
its some sort of damage to the cement.
The mounting is probably what is called a spun-in or
burnished mount. The mount is made with a lip of thin metal
around the periphery of the socket for the lens. The lip is
spun down over the lens in a lath like machine. This type of
mounting is very secure but very difficult to get apart if
need be for servicing the lens. Spun-in mounts are also
typical of the back component of a Tessar.


--
---
Richard Knoppow
Los Angeles, CA, USA

David:

I just tossed the alcohol in as an afterthought...I intended to try
straight household ammonia and H2O2 but had to make do with what I
found. I know (more or less) that the alcohol wasn't the scary
part...mixing ammonia and other stuff was what I wanted to check for
Darwin award evidence on first :O)

I just used hot water and liquid soap so far on the rear cell...it
looks pretty good already.That was daring...I fogged an air-spaced lens
doing that once. I had to cook it out.

I can see one bubble in the glass at the periphery (not complaining,
just noting clarity improvement).

Richard:

The black things are definitely finished metal inserts. Looks like I
should just leave it alone.

The shutter is REAL rusty unfortunately.

While I have you...glue for re-gluing leatherette on metal body? If
they used shellac, would alcohol re-activate the old adhesive?

Thanks

"murrayatuptowngallery" wrote


Marked Bausch & Lomb Rapid rectilinear, f.l. not marked, on early
(1916-1925-ish?) Folding Pocket 3-A in rusted Ball Bearing shutter. If
I can't get BB shutter running

I have restored a few of these shutters. They run fine dry if they are
clean. I would try a good soak in lighter fluid (Ronsonol etc.), shake,
dry, repeat. It should start to work.

The speeds marked don't have a lot to do with the real shutter speeds,
do a test first.

If not:

General advice on fixing shutters.

The major reasons for jammed shutters are that someone oiled it and/or
someone tried to fix it. If it is oiling then the Ronsonol should take
care of it. Attempted repair is a bigger problem. If it looks like parts
are
missing remove the remaining parts and use it as a barrel lens. Ditto
if some parts have scratch marks on them. I have often found that removing
all the shutter parts, putting them in a marked plastic bag and using
the lens as a barrel lens is the fastest and most assured way of getting
a lens working. Amputation Vs. Flesh-Eating Bacteria. If it is a rusted
mess again give up on repair. Slight surface rust on the internals seems
to be normal on these shutters and doesn't seem to do any harm.

Digital cameras w/ close-up lenses are great for taking pictures of shutters
as you disassemble them. Mine takes verbal notes stating 'the flange on the
curved thingy needs to go to the outside ...' and such like. I find I
never take enough pictures and notes and am left wondering at put-it-
back-together time, often having to take the re-assembled shutter apart,
reverse the thingy, and try again. A video camera may be a better
choice for taking notes: it will capture everything you do.

Get a good pair of Vigor watchmakers' tweezers, #1 is fine. Sears sells
Whima (?) jewelers' screwdrivers and Exacto of knife fame sells a nice
hollow-handled set of screwdriver handle and jewelers' bits. A 7x or 10x
jewelers' loupe may be needed as might a Tensor reading light.

Work on a clean white plush towel - keeps the ball bearings from rolling
away and dropped parts from disappearing. Have a smooth floor if possible,
sweep floor first, keep a Maglight, a magnet and a brush and dust pan
handy for finding sproinged parts.

murrayatuptowngallery spake thus:

While I have you...glue for re-gluing leatherette on metal body? If
they used shellac, would alcohol re-activate the old adhesive?

Not Richard, but I can answer this one: yes, if shellac was used,
alcohol (isopropyl or methanol) would definitely dissolve it and loosen
the covering. In any case, it can't hurt. To reglue, I use modern
contact cement (apply, let dry and wait, then stick together).


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)