152mm f4.5 Ektar opinions

Just acquired one of these and was wondering if anyone familiar had a few
facts or opinions about it. In particular I'm wondering if someone can
confirm this is a tessar, and what the circle of sharp coverage is like -
much room for movement on 4x5? What's the optimum aperture to use it at
?(its in a supermatic and will stop down to f45)
Is it still a decent lens by modern standards like the Commercial Ektars?
Thanks.

"John Hendry" wrote in message
news:ECmdc.52366$Pk3.7506@pd7tw1no...

"Richard Knoppow" wrote in
message
om...

I will also vouch for the 152mm Ektar. However, check
the cement in
the rear component on Ektars, I've found a couple where
it was getting
a little turbid. You have to shine a flashlight at it or
through it to
see the effect but it results in a substantial loss of
contrast. When
clear these are quite contrasty lenses.

(snip lots of interesting stuff)

When you say turbid, is it an even muddiness or does the
flashlight pick out
a texture in the cement layer?

The couple of lenses I have with this show a very slight
orange-peel effect, but only slight. The cement layer just
looks a bit cloudy when looked at with a flashlight. It
seems to show up better when looked at with reflected light
and the flashlight held at an angle. Even though slight its
enough to ruin the contrast of the lens and give it a lot of
flare around bright objects.
I am pretty sure this is synthetic cement, the turbidity
does not look the way Canada Balsam does when it gets milky.
The two lenses with this problem are both in spun mounts
which require machine work to open and making back caps to
retain the elements once recemented, so I have't taken them
apart.
Other defective synthetic cement seems to take the form of
large "bubbles". I've seen this in a Wollensak Convertible
Raptar and in some Zeiss lenses for the Contaflex. The only
cure for either failure is to recement the lenses. This can
range from pretty easy to very difficult depending on the
mechanical construction of the lens.


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

"Richard Knoppow" wrote in message
ink.net...

"John Hendry" wrote in message
news:ECmdc.52366$Pk3.7506@pd7tw1no...

"Richard Knoppow" wrote in
message
om...

I will also vouch for the 152mm Ektar. However, check
the cement in
the rear component on Ektars, I've found a couple where
it was getting
a little turbid. You have to shine a flashlight at it or
through it to
see the effect but it results in a substantial loss of
contrast. When
clear these are quite contrasty lenses.

(snip lots of interesting stuff)

When you say turbid, is it an even muddiness or does the
flashlight pick out
a texture in the cement layer?

The couple of lenses I have with this show a very slight
orange-peel effect, but only slight. The cement layer just
looks a bit cloudy when looked at with a flashlight. It
seems to show up better when looked at with reflected light
and the flashlight held at an angle. Even though slight its
enough to ruin the contrast of the lens and give it a lot of
flare around bright objects.
I am pretty sure this is synthetic cement, the turbidity
does not look the way Canada Balsam does when it gets milky.
The two lenses with this problem are both in spun mounts
which require machine work to open and making back caps to
retain the elements once recemented, so I have't taken them
apart.
Other defective synthetic cement seems to take the form of
large "bubbles". I've seen this in a Wollensak Convertible
Raptar and in some Zeiss lenses for the Contaflex. The only
cure for either failure is to recement the lenses. This can
range from pretty easy to very difficult depending on the
mechanical construction of the lens.

I see the same effect... If I look at the refelection of the sun in the rear
cell there is a bright reflection from the top surface, a weaker reflection
from the bottom surface and weaker still reflection from the cement layer.
There is a halo around the cement layer reflection that illuminates the
orange peel texture you describe. Though it doesn't look desperately severe
I can indeed imagine there are notable flare and contrast consequences. In
my case the repair route involving a machining and recapping procedure to
remove the glass and recement isn't worth it for a $50 lens (including
supermatic).