Haze, uncoated lenses and B&W film.

In a Tessar this would be the "rear" element right? I've taken the lens apart
and there art two front elements that can be un-screwed apart. Then there's a
rear element behind the shutter. I'm assuming that that rear "element" is a
cemented doublet.

dr bob wrote:

wrote in message
...
[...]

Maybe Richard K. will ultimately respond in this thread. Until then: he
once helped me identify a problem with one of my Ektar lenses with similar
characteristics to the original poster. The Tessar lens has a cemented
double and the cement (older Canadian balsam e.g.) was aging. Looking with
a semi-point light source, as mentioned previously, and shifting the glass
to a certain angle, I could perceive an "orange peel" effect. That was
causing my problem. This can be re-cemented (IMO with difficulty) if one
has the proper equipment and patience.

Truly, dr bob.

In a Tessar this would be the "rear" element right? I've taken the lens apart
and there art two front elements that can be un-screwed apart. Then there's a
rear element behind the shutter. I'm assuming that that rear "element" is a
cemented doublet.

dr bob wrote:

wrote in message
...
[...]

Maybe Richard K. will ultimately respond in this thread. Until then: he
once helped me identify a problem with one of my Ektar lenses with similar
characteristics to the original poster. The Tessar lens has a cemented
double and the cement (older Canadian balsam e.g.) was aging. Looking with
a semi-point light source, as mentioned previously, and shifting the glass
to a certain angle, I could perceive an "orange peel" effect. That was
causing my problem. This can be re-cemented (IMO with difficulty) if one
has the proper equipment and patience.

Truly, dr bob.

In a Tessar this would be the "rear" element right? I've taken the lens apart
and there art two front elements that can be un-screwed apart. Then there's a
rear element behind the shutter. I'm assuming that that rear "element" is a
cemented doublet.

dr bob wrote:

wrote in message
...
[...]

Maybe Richard K. will ultimately respond in this thread. Until then: he
once helped me identify a problem with one of my Ektar lenses with similar
characteristics to the original poster. The Tessar lens has a cemented
double and the cement (older Canadian balsam e.g.) was aging. Looking with
a semi-point light source, as mentioned previously, and shifting the glass
to a certain angle, I could perceive an "orange peel" effect. That was
causing my problem. This can be re-cemented (IMO with difficulty) if one
has the proper equipment and patience.

Truly, dr bob.

wrote:


In a Tessar this would be the "rear" element right? I've taken the
lens apart and there art two front elements that can be un-screwed
apart. Then there's a rear element behind the shutter. I'm assuming
that that rear "element" is a cemented doublet.

Correct (assuming you in fact have a Tessar type and not a triplet --
look for an internal reflection in the rear group to confirm it's a
doublet; you can likely also see the seam between the two glasses on the
edge of the lens if it's out of its cell, but don't remove it from the
cell yourself unless you're trying to recement it). To a very rough
first approximation, a Tessar is a Cooke triplet in which the rear
element is replaced with a cemented doublet. The same relationship of
positive and negative elements exists in both, if the doublet is treated
as a single lens for comparison. What the doublet adds is improved
chromatic and spheric aberration correction due to the introduction of
one more glass/glass interface and the opportunity to use another
refraction/dispersion selection in one or the other element of the
doublet, compared to the Cooke triplet.

Of course, the down side is that the Canada balsam used to cement most
lenses until the early 1970s or so is subject to breakdown from long
term exposure to excessive heat, humidity, or UV, and can support fungal
growth. On the bright side, Canada balsam softens with heat that (with
care and a little luck) can be applied without damaging the glass, so
lenses cemented with balsam can frequently be successfully recemented
with a modern UV cure resin optical cement.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

wrote:


In a Tessar this would be the "rear" element right? I've taken the
lens apart and there art two front elements that can be un-screwed
apart. Then there's a rear element behind the shutter. I'm assuming
that that rear "element" is a cemented doublet.

Correct (assuming you in fact have a Tessar type and not a triplet --
look for an internal reflection in the rear group to confirm it's a
doublet; you can likely also see the seam between the two glasses on the
edge of the lens if it's out of its cell, but don't remove it from the
cell yourself unless you're trying to recement it). To a very rough
first approximation, a Tessar is a Cooke triplet in which the rear
element is replaced with a cemented doublet. The same relationship of
positive and negative elements exists in both, if the doublet is treated
as a single lens for comparison. What the doublet adds is improved
chromatic and spheric aberration correction due to the introduction of
one more glass/glass interface and the opportunity to use another
refraction/dispersion selection in one or the other element of the
doublet, compared to the Cooke triplet.

Of course, the down side is that the Canada balsam used to cement most
lenses until the early 1970s or so is subject to breakdown from long
term exposure to excessive heat, humidity, or UV, and can support fungal
growth. On the bright side, Canada balsam softens with heat that (with
care and a little luck) can be applied without damaging the glass, so
lenses cemented with balsam can frequently be successfully recemented
with a modern UV cure resin optical cement.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

wrote:


In a Tessar this would be the "rear" element right? I've taken the
lens apart and there art two front elements that can be un-screwed
apart. Then there's a rear element behind the shutter. I'm assuming
that that rear "element" is a cemented doublet.

Correct (assuming you in fact have a Tessar type and not a triplet --
look for an internal reflection in the rear group to confirm it's a
doublet; you can likely also see the seam between the two glasses on the
edge of the lens if it's out of its cell, but don't remove it from the
cell yourself unless you're trying to recement it). To a very rough
first approximation, a Tessar is a Cooke triplet in which the rear
element is replaced with a cemented doublet. The same relationship of
positive and negative elements exists in both, if the doublet is treated
as a single lens for comparison. What the doublet adds is improved
chromatic and spheric aberration correction due to the introduction of
one more glass/glass interface and the opportunity to use another
refraction/dispersion selection in one or the other element of the
doublet, compared to the Cooke triplet.

Of course, the down side is that the Canada balsam used to cement most
lenses until the early 1970s or so is subject to breakdown from long
term exposure to excessive heat, humidity, or UV, and can support fungal
growth. On the bright side, Canada balsam softens with heat that (with
care and a little luck) can be applied without damaging the glass, so
lenses cemented with balsam can frequently be successfully recemented
with a modern UV cure resin optical cement.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

wrote in message ...
It's a 127 camera and I was using the Macochrome (Ferrania) product. The
Macochrome film is a little weird, it's like an old fashioned E6 type film. I'll
try to explain what it looks like. The lens is a Tessar and the images are
"sharp" but their appears to be a veil over the scene when viewed under
magnification. This kind of effect, I've usually seen with 800 or faster film,
but it's different and hard to explain without actually seeing it. My first
thought was that it was the lens. I cracked the thing apart and cleaned it,
although except for a few specs of dust, it was pretty clean. Same problem. Then
I bought some of that hand rolled Ektachrome, 'cause by now I was convinced it was
the Macochrome. Same problem. Then I hand rolled some E200 in a closet so that I
could stop the camera down some more, and yes, the same problem, although the E200
did have better contrast, color and sharpness. So now I'm thinking it's haze,
although frankly the haze I've seen on coated lenses is not as severe. The camera
definately has the provision for a behind the lens filter, the product catalog has
them listed and the camera came with one, although it was scratched. I figured a
coated filter behind the lens would be better since it would eliminate any
reflections off of the film back onto the lens. I don't see what reflections a
front filter would stop, but as it appears the behind the lens "filter" is not of
a standard size and it would cost me over $100 to have one cut to size, I'm going
to use a series V adapter to throw a haze filter in front of the lens. Hopefully
that'll fix the problem. The camera has rise and some other neat features, that's
why I'm putting so much effort into it.

Is there a diagram or photo of this camer on the Internet that you
could direct me to? I am wondering if light is leaking in where this
rear filter is supposed to be. Or maybe the camera needs some
reflocking done to reduce reflected light.

wrote in message ...
It's a 127 camera and I was using the Macochrome (Ferrania) product. The
Macochrome film is a little weird, it's like an old fashioned E6 type film. I'll
try to explain what it looks like. The lens is a Tessar and the images are
"sharp" but their appears to be a veil over the scene when viewed under
magnification. This kind of effect, I've usually seen with 800 or faster film,
but it's different and hard to explain without actually seeing it. My first
thought was that it was the lens. I cracked the thing apart and cleaned it,
although except for a few specs of dust, it was pretty clean. Same problem. Then
I bought some of that hand rolled Ektachrome, 'cause by now I was convinced it was
the Macochrome. Same problem. Then I hand rolled some E200 in a closet so that I
could stop the camera down some more, and yes, the same problem, although the E200
did have better contrast, color and sharpness. So now I'm thinking it's haze,
although frankly the haze I've seen on coated lenses is not as severe. The camera
definately has the provision for a behind the lens filter, the product catalog has
them listed and the camera came with one, although it was scratched. I figured a
coated filter behind the lens would be better since it would eliminate any
reflections off of the film back onto the lens. I don't see what reflections a
front filter would stop, but as it appears the behind the lens "filter" is not of
a standard size and it would cost me over $100 to have one cut to size, I'm going
to use a series V adapter to throw a haze filter in front of the lens. Hopefully
that'll fix the problem. The camera has rise and some other neat features, that's
why I'm putting so much effort into it.

Is there a diagram or photo of this camer on the Internet that you
could direct me to? I am wondering if light is leaking in where this
rear filter is supposed to be. Or maybe the camera needs some
reflocking done to reduce reflected light.

I think I've got enough to work with now. I'm going to try out all the suggestions
presented here and if they don't work, I'm going to send some of my trannies to an
expert.

RolandRB wrote:

wrote in message ...
It's a 127 camera and I was using the Macochrome (Ferrania) product. The
Macochrome film is a little weird, it's like an old fashioned E6 type film. I'll
try to explain what it looks like. The lens is a Tessar and the images are
"sharp" but their appears to be a veil over the scene when viewed under
magnification. This kind of effect, I've usually seen with 800 or faster film,
but it's different and hard to explain without actually seeing it. My first
thought was that it was the lens. I cracked the thing apart and cleaned it,
although except for a few specs of dust, it was pretty clean. Same problem. Then
I bought some of that hand rolled Ektachrome, 'cause by now I was convinced it was
the Macochrome. Same problem. Then I hand rolled some E200 in a closet so that I
could stop the camera down some more, and yes, the same problem, although the E200
did have better contrast, color and sharpness. So now I'm thinking it's haze,
although frankly the haze I've seen on coated lenses is not as severe. The camera
definately has the provision for a behind the lens filter, the product catalog has
them listed and the camera came with one, although it was scratched. I figured a
coated filter behind the lens would be better since it would eliminate any
reflections off of the film back onto the lens. I don't see what reflections a
front filter would stop, but as it appears the behind the lens "filter" is not of
a standard size and it would cost me over $100 to have one cut to size, I'm going
to use a series V adapter to throw a haze filter in front of the lens. Hopefully
that'll fix the problem. The camera has rise and some other neat features, that's
why I'm putting so much effort into it.

Is there a diagram or photo of this camer on the Internet that you
could direct me to? I am wondering if light is leaking in where this
rear filter is supposed to be. Or maybe the camera needs some
reflocking done to reduce reflected light.

I think I've got enough to work with now. I'm going to try out all the suggestions
presented here and if they don't work, I'm going to send some of my trannies to an
expert.

RolandRB wrote:

wrote in message ...
It's a 127 camera and I was using the Macochrome (Ferrania) product. The
Macochrome film is a little weird, it's like an old fashioned E6 type film. I'll
try to explain what it looks like. The lens is a Tessar and the images are
"sharp" but their appears to be a veil over the scene when viewed under
magnification. This kind of effect, I've usually seen with 800 or faster film,
but it's different and hard to explain without actually seeing it. My first
thought was that it was the lens. I cracked the thing apart and cleaned it,
although except for a few specs of dust, it was pretty clean. Same problem. Then
I bought some of that hand rolled Ektachrome, 'cause by now I was convinced it was
the Macochrome. Same problem. Then I hand rolled some E200 in a closet so that I
could stop the camera down some more, and yes, the same problem, although the E200
did have better contrast, color and sharpness. So now I'm thinking it's haze,
although frankly the haze I've seen on coated lenses is not as severe. The camera
definately has the provision for a behind the lens filter, the product catalog has
them listed and the camera came with one, although it was scratched. I figured a
coated filter behind the lens would be better since it would eliminate any
reflections off of the film back onto the lens. I don't see what reflections a
front filter would stop, but as it appears the behind the lens "filter" is not of
a standard size and it would cost me over $100 to have one cut to size, I'm going
to use a series V adapter to throw a haze filter in front of the lens. Hopefully
that'll fix the problem. The camera has rise and some other neat features, that's
why I'm putting so much effort into it.

Is there a diagram or photo of this camer on the Internet that you
could direct me to? I am wondering if light is leaking in where this
rear filter is supposed to be. Or maybe the camera needs some
reflocking done to reduce reflected light.