Caltar lens sharpness

Hope that some of you may have experience with this lens and might have
a comment.

My Caltar 90mm HR f/5.6 lens does not seem to be as sharp as I would
expect, at least in comparison to my Schneider Symmar 180mm f/5.6.
Comparison was made with 4x5 Ektachrome EPP shot on a view camera.
Caltar was shot at around f/11. Schneider is best at f/45 but still
very sharp at much wider apertures, and movements don't seem to affect
it.

The image of a table top group of products using a bit of tilt with the
Caltar appeared soft. Nowhere in the image was there any acute
sharpness, even though the depth of field was consistent from front to
back of the subject. Outdoors shooting a building focused near
infinity, with slight shift of the film, the image is better but still
not critically sharp.

A Kodak plublication I read stated that the Schneider, being a
convertible lens, was sharpest at minimum apertures. I could not find
any such info on the Caltar.

Thus, my question:

Is the Caltar better at minimum or wider apertures? Does it fall apart
with movements? It does not appear to have any significant cloudiness
on the internal elements when viewed under bright light.

Any thoughts you may have will be much appreciated.

Above you say that your Symmar is sharpest at f/45, is that a
misprint? If not it probably refers to the single cells when used
alone. The combined lens is best at around f/22 depending on field
angle. If you want the greatest coverage then you may have to stop down
to f/45 but there will be some loss of sharpness in the center of the
image due to diffraction by the stop.
The Caltar should also be best at around f/22 for its "normal"
coverage, that is for a diagonal about equal to the focal length. If
you are using it as a wide angle lens you will probably have to stop it
down more. Its pretty hard to make a direct comparison of two lenses
where one is double the focal length of the other. AFAIK the Caltar is
not a convertible although single cells of any symmetrical or nearly
symmetrical lens can be used alone.
Both of these are excellent lenses and should be quite sharp.

--
Richard Knoppow

The 90mm HR Caltar is a fine Rodenstock lens and should be extremely
sharp. It's not at its best at near distances, but it should still be
quite good.
Shorter focal length lenses should generally not be stopped down all
the way, since diffraction is a problem. The Caltar should be best at
f11 or f16.

See that both lens cells are screwed on all the way. Check for thread
damage. If all's OK, then remove the cells and rattle them carefully,
listen for any loose elelements.

Some shutters come with "anchoring" studs - if not removed or allowance
made for insertion into a hole on the lensboard, your whole assembly
might be out of alignment.

Are you using a Fresnel lens? If inserted on the wrong side it may be
causing a focus shift - that would be even more noticeable with your
180mm Schneider, although you're shooting way stopped down with it and
your DOF might be compensating for softness.

If I were in your situation, I would carefully reconsider the setup for the
picture. It seems to me to be purely operator error.

If I were in your situation, I would carefully reconsider the setup for the
picture. It seems to me to be purely operator error.

Hi Richard, and thanks for your post.

The Schneider lens was sent in for service in New York about two years
ago. When it came back from service, the tech had marked two
additional stops on the lens barrel at f/64 and f/90. The factory
marks topped out at f/45. Never tried the smaller apertures, but am
now curious about what they might produce. Will look for fuzziness in
the center of the image, per your message.

In actuality, I normally shoot product stuff witht the Schneider at
f/32 with multi pops from the speedlights in a darkened room. Per your
suggestion about the maximum sharpness residing at f/22, I will try it.

Regretfully, I have not made a serious assesment of the Caltar lens,
but simply made this post after a few shots. It is a very nice piece,
and certainly there must be some cockpit error on my part.

Many thanks for your reply. And, best regards to all on this
listserve, which is one of the best. I work in the pro and commercial
audio industries and very much respect a solid comminity like this. So
may others suffer from an idiocy that degenerates into name calling and
a waste of time.

Hi Richard, and thanks for your post.

The Schneider lens was sent in for service in New York about two years
ago. When it came back from service, the tech had marked two
additional stops on the lens barrel at f/64 and f/90. The factory
marks topped out at f/45. Never tried the smaller apertures, but am
now curious about what they might produce. Will look for fuzziness in
the center of the image, per your message.

In actuality, I normally shoot product stuff witht the Schneider at
f/32 with multi pops from the speedlights in a darkened room. Per your
suggestion about the maximum sharpness residing at f/22, I will try it.

Regretfully, I have not made a serious assesment of the Caltar lens,
but simply made this post after a few shots. It is a very nice piece,
and certainly there must be some cockpit error on my part.

Many thanks for your reply. And, best regards to all on this
listserve, which is one of the best. I work in the pro and commercial
audio industries and very much respect a solid comminity like this. So
may others suffer from an idiocy that degenerates into name calling and
a waste of time.

Thanks, Bob.

Will take a few things apart and ensure that the elements are firmly
seated. Have not tried to take apart the front and back elements, but
will do so to make sure they are in line. As for the lens mount, it is
a simple flat plate and seems to be seated against the lens board. The
shutter was attached to the lens when I bought it, but will check it
out to see if there is something in the way of firmly seating.

Many Thanks!

Bob G wrote:
The 90mm HR Caltar is a fine Rodenstock lens and should be extremely
sharp. It's not at its best at near distances, but it should still be
quite good.
Shorter focal length lenses should generally not be stopped down all
the way, since diffraction is a problem. The Caltar should be best at
f11 or f16.

See that both lens cells are screwed on all the way. Check for thread
damage. If all's OK, then remove the cells and rattle them carefully,
listen for any loose elelements.

Some shutters come with "anchoring" studs - if not removed or
allowance
made for insertion into a hole on the lensboard, your whole assembly
might be out of alignment.

Are you using a Fresnel lens? If inserted on the wrong side it may be
causing a focus shift - that would be even more noticeable with your
180mm Schneider, although you're shooting way stopped down with it
and
your DOF might be compensating for softness.

Thanks, Bob.

Will take a few things apart and ensure that the elements are firmly
seated. Have not tried to take apart the front and back elements, but
will do so to make sure they are in line. As for the lens mount, it is
a simple flat plate and seems to be seated against the lens board. The
shutter was attached to the lens when I bought it, but will check it
out to see if there is something in the way of firmly seating.

Many Thanks!

Bob G wrote:
The 90mm HR Caltar is a fine Rodenstock lens and should be extremely
sharp. It's not at its best at near distances, but it should still be
quite good.
Shorter focal length lenses should generally not be stopped down all
the way, since diffraction is a problem. The Caltar should be best at
f11 or f16.

See that both lens cells are screwed on all the way. Check for thread
damage. If all's OK, then remove the cells and rattle them carefully,
listen for any loose elelements.

Some shutters come with "anchoring" studs - if not removed or
allowance
made for insertion into a hole on the lensboard, your whole assembly
might be out of alignment.

Are you using a Fresnel lens? If inserted on the wrong side it may be
causing a focus shift - that would be even more noticeable with your
180mm Schneider, although you're shooting way stopped down with it
and
your DOF might be compensating for softness.

You are probably right, and I apologize for any wasted time in this
listserve.

jjs wrote:
If I were in your situation, I would carefully reconsider the setup
for the
picture. It seems to me to be purely operator error.