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G-Claron single cell use
G-Claron single cell use
I just read a 10 year old post about using a G-Claron as a 'pseudo-
convertible' by using one cell; performance would probably be better
than 'vintage' convertibles.
I had previously wondered about splitting plasmats but wrote it off as
'sacrilege' on already decent lenses, but seeing the post made me
realize it's been done.
Anyone actually try this with a G-Claron 150 and does it have any
unique qualities, or just 'work'.
Thanks
Murray
I just read a 10 year old post about using a G-Claron as a 'pseudo-
convertible' by using one cell; performance would probably be better
than 'vintage' convertibles.
I had previously wondered about splitting plasmats but wrote it off as
'sacrilege' on already decent lenses, but seeing the post made me
realize it's been done.
Anyone actually try this with a G-Claron 150 and does it have any
unique qualities, or just 'work'.
Thanks
Murray
Re: G-Claron single cell use
"murrayatuptowngallery" <murrayatuptowngallery@yahoo . com >
wrote in message
news:1192929646.407079.297720@y27g2000pre.googlegroups . com ...
>I just read a 10 year old post about using a G-Claron as a
>'pseudo-
> convertible' by using one cell; performance would probably
> be better
> than 'vintage' convertibles.
>
> I had previously wondered about splitting plasmats but
> wrote it off as
> 'sacrilege' on already decent lenses, but seeing the post
> made me
> realize it's been done.
>
> Anyone actually try this with a G-Claron 150 and does it
> have any
> unique qualities, or just 'work'.
>
> Thanks
>
> Murray
>
I think, without looking it up, that the G-Claron is a
Plasmat type. These will work as convertibles. The best of
the old convertibles was the Zeiss Convertible Protar
sometimes called a Double Protar. The difference is that
these lenses are individually corrected for coma where some
other convertible lenses, notably the Goerz Dagor and Dogmar
are not. This allows the Protar to be used at larger stops
with reasonable sharpness in the corners. Dagor cells must
be stopped down to around f/45 to get rid of enough coma to
be sharp away from the center. Protars are OK at f/36 or
maybe even a little wider.
Nearly any symmetrical lens can be used as a
convertible but, as noted for the Dagor, some aberrations,
especially those corrected by the symmetry, will be present.
My experience with the convertible type of Symmar is
that they perform about as well as a Convertible Protar, but
not better. Actually, I think the correction of the
individual Protar cells is a little better.
I don't know if the early Plasmat type Symmar (the
first lens of this name was a Dagor type) was specifically
corrected for coma but it probably was. Later ones are
corrected for best performance in a complete lens but single
cells probably perform pretty well when stopped down enough.
This should apply to the G-Claron.
FWIW, the Plasmat was derived from the Dagor by
air-spacing one of the elements. I has similar performance
but much less zonal spherical aberration, an inherent fault
of the Dagor type. Plasmats can also be corrected for
astigmatism to a very high degree. Like the Dagor they are
essentially wide angle lenses although most have perhaps
about 10degrees less coverage than an equivalent Dagor. The
single cells of convertible lenses of all types have quit
narrow coverage, the plate size being about the same as the
assembled lens.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix . net com . com
"murrayatuptowngallery" <murrayatuptowngallery@yahoo . com >
wrote in message
news:1192929646.407079.297720@y27g2000pre.googlegroups . com ...
>I just read a 10 year old post about using a G-Claron as a
>'pseudo-
> convertible' by using one cell; performance would probably
> be better
> than 'vintage' convertibles.
>
> I had previously wondered about splitting plasmats but
> wrote it off as
> 'sacrilege' on already decent lenses, but seeing the post
> made me
> realize it's been done.
>
> Anyone actually try this with a G-Claron 150 and does it
> have any
> unique qualities, or just 'work'.
>
> Thanks
>
> Murray
>
I think, without looking it up, that the G-Claron is a
Plasmat type. These will work as convertibles. The best of
the old convertibles was the Zeiss Convertible Protar
sometimes called a Double Protar. The difference is that
these lenses are individually corrected for coma where some
other convertible lenses, notably the Goerz Dagor and Dogmar
are not. This allows the Protar to be used at larger stops
with reasonable sharpness in the corners. Dagor cells must
be stopped down to around f/45 to get rid of enough coma to
be sharp away from the center. Protars are OK at f/36 or
maybe even a little wider.
Nearly any symmetrical lens can be used as a
convertible but, as noted for the Dagor, some aberrations,
especially those corrected by the symmetry, will be present.
My experience with the convertible type of Symmar is
that they perform about as well as a Convertible Protar, but
not better. Actually, I think the correction of the
individual Protar cells is a little better.
I don't know if the early Plasmat type Symmar (the
first lens of this name was a Dagor type) was specifically
corrected for coma but it probably was. Later ones are
corrected for best performance in a complete lens but single
cells probably perform pretty well when stopped down enough.
This should apply to the G-Claron.
FWIW, the Plasmat was derived from the Dagor by
air-spacing one of the elements. I has similar performance
but much less zonal spherical aberration, an inherent fault
of the Dagor type. Plasmats can also be corrected for
astigmatism to a very high degree. Like the Dagor they are
essentially wide angle lenses although most have perhaps
about 10degrees less coverage than an equivalent Dagor. The
single cells of convertible lenses of all types have quit
narrow coverage, the plate size being about the same as the
assembled lens.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix . net com . com
Re: G-Claron single cell use
On 21 Oct 2007 00:20:32 -0700, murrayatuptowngallery
<murrayatuptowngallery@yahoo . com > wrote:
>I just read a 10 year old post about using a G-Claron as a 'pseudo-
>convertible' by using one cell; performance would probably be better
>than 'vintage' convertibles.
>
>I had previously wondered about splitting plasmats but wrote it off as
>'sacrilege' on already decent lenses, but seeing the post made me
>realize it's been done.
>
>Anyone actually try this with a G-Claron 150 and does it have any
>unique qualities, or just 'work'.
>
>Thanks
>
>Murray
I have a saved post from long ago that suggests using a yellow filter
when using it as a convertible (assuming you're shooting B&W). This
was to reduce the chromatic aberration that would otherwise be
corrected by the front cell. The same poster claimed the focal length
was about 300mm for the rear cell only.
Sorry, I've never tried it myself.
steve
On 21 Oct 2007 00:20:32 -0700, murrayatuptowngallery
<murrayatuptowngallery@yahoo . com > wrote:
>I just read a 10 year old post about using a G-Claron as a 'pseudo-
>convertible' by using one cell; performance would probably be better
>than 'vintage' convertibles.
>
>I had previously wondered about splitting plasmats but wrote it off as
>'sacrilege' on already decent lenses, but seeing the post made me
>realize it's been done.
>
>Anyone actually try this with a G-Claron 150 and does it have any
>unique qualities, or just 'work'.
>
>Thanks
>
>Murray
I have a saved post from long ago that suggests using a yellow filter
when using it as a convertible (assuming you're shooting B&W). This
was to reduce the chromatic aberration that would otherwise be
corrected by the front cell. The same poster claimed the focal length
was about 300mm for the rear cell only.
Sorry, I've never tried it myself.
steve
Re: G-Claron single cell use
On 2007-10-22, Stephan Goldstein <sgoldham@alum.mit.edu> wrote:
> On 21 Oct 2007 00:20:32 -0700, murrayatuptowngallery
><murrayatuptowngallery@yahoo . com > wrote:
>
>>I just read a 10 year old post about using a G-Claron as a 'pseudo-
>>convertible' by using one cell; performance would probably be better
>>than 'vintage' convertibles.
>>
>>I had previously wondered about splitting plasmats but wrote it off as
>>'sacrilege' on already decent lenses, but seeing the post made me
>>realize it's been done.
>>
>>Anyone actually try this with a G-Claron 150 and does it have any
>>unique qualities, or just 'work'.
>>
>>Thanks
>>
>>Murray
>
> I have a saved post from long ago that suggests using a yellow filter
> when using it as a convertible (assuming you're shooting B&W). This
> was to reduce the chromatic aberration that would otherwise be
> corrected by the front cell. The same poster claimed the focal length
> was about 300mm for the rear cell only.
>
> Sorry, I've never tried it myself.
>
Ron Wisner recommends using a strong yellow filter (I imagine any
monochromatic filter would do as well) when using single cells of
his Convertible Plasmat set. This is to solve the problem of uncorrected
lateral color in a single cell. Now I do not use a #15 filter for that,
but I do use B&W filter 58ES MEDIUM YELLOW (022). Note that, when using
a single cell, the focal length tends to be quite long compared with
using a pair together.Of course, this would work only with black and
white film where blue light was not too important.
He presumably makes a corrector lens that has zero power but all the same
distortions so that it corrects a single cell. I ordered one when he first
announced it over 10 years ago, but he is yet to ship me one, so I cannot
say how well it works.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey * counter.li.org
^^-^^ 08:30:01 up 15 days, 16:06, 4 users, load average: 4.06, 4.16, 4.22
On 2007-10-22, Stephan Goldstein <sgoldham@alum.mit.edu> wrote:
> On 21 Oct 2007 00:20:32 -0700, murrayatuptowngallery
><murrayatuptowngallery@yahoo . com > wrote:
>
>>I just read a 10 year old post about using a G-Claron as a 'pseudo-
>>convertible' by using one cell; performance would probably be better
>>than 'vintage' convertibles.
>>
>>I had previously wondered about splitting plasmats but wrote it off as
>>'sacrilege' on already decent lenses, but seeing the post made me
>>realize it's been done.
>>
>>Anyone actually try this with a G-Claron 150 and does it have any
>>unique qualities, or just 'work'.
>>
>>Thanks
>>
>>Murray
>
> I have a saved post from long ago that suggests using a yellow filter
> when using it as a convertible (assuming you're shooting B&W). This
> was to reduce the chromatic aberration that would otherwise be
> corrected by the front cell. The same poster claimed the focal length
> was about 300mm for the rear cell only.
>
> Sorry, I've never tried it myself.
>
Ron Wisner recommends using a strong yellow filter (I imagine any
monochromatic filter would do as well) when using single cells of
his Convertible Plasmat set. This is to solve the problem of uncorrected
lateral color in a single cell. Now I do not use a #15 filter for that,
but I do use B&W filter 58ES MEDIUM YELLOW (022). Note that, when using
a single cell, the focal length tends to be quite long compared with
using a pair together.Of course, this would work only with black and
white film where blue light was not too important.
He presumably makes a corrector lens that has zero power but all the same
distortions so that it corrects a single cell. I ordered one when he first
announced it over 10 years ago, but he is yet to ship me one, so I cannot
say how well it works.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey * counter.li.org
^^-^^ 08:30:01 up 15 days, 16:06, 4 users, load average: 4.06, 4.16, 4.22
Re: G-Claron single cell use
Thanks, all.
Yes, the notorious vaporware field corrector - I have even heard of
it's non-existence, at least in this plane...
Murray
Thanks, all.
Yes, the notorious vaporware field corrector - I have even heard of
it's non-existence, at least in this plane...
Murray
Re: G-Claron single cell use
In article <slrnfhp6sj.9of.jdbeyer@trillian.localdomain>,
Jean-David Beyer <jdbeyer@trillian.localdomain> wrote:
>
>He presumably makes a corrector lens that has zero power but all the same
>distortions so that it corrects a single cell. I ordered one when he first
>announced it over 10 years ago, but he is yet to ship me one, so I cannot
>say how well it works.
Didn't he in fact run his company out of business by taking prepayments
and deposits for work that wasn't, in fact, ever done? I tried off and
on for several years to get a replacement back (graflok style) for my 4x5
trad and wondered why he wasn't responding to my inquiries but now I feel
lucky he didn't -- since I took the camera in to L&R for repairs a few
weeks ago and discovered there were no spare parts available (luckily
I didn't need any) I've talked to several other people who were persistent
enough to get in touch with Ron over the past few years and, if they ordered
anything, ended up wishing they hadn't...
--
Thor Lancelot Simon tls@rek.tjls . com
"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky
In article <slrnfhp6sj.9of.jdbeyer@trillian.localdomain>,
Jean-David Beyer <jdbeyer@trillian.localdomain> wrote:
>
>He presumably makes a corrector lens that has zero power but all the same
>distortions so that it corrects a single cell. I ordered one when he first
>announced it over 10 years ago, but he is yet to ship me one, so I cannot
>say how well it works.
Didn't he in fact run his company out of business by taking prepayments
and deposits for work that wasn't, in fact, ever done? I tried off and
on for several years to get a replacement back (graflok style) for my 4x5
trad and wondered why he wasn't responding to my inquiries but now I feel
lucky he didn't -- since I took the camera in to L&R for repairs a few
weeks ago and discovered there were no spare parts available (luckily
I didn't need any) I've talked to several other people who were persistent
enough to get in touch with Ron over the past few years and, if they ordered
anything, ended up wishing they hadn't...
--
Thor Lancelot Simon tls@rek.tjls . com
"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky
Re: G-Claron single cell use
On 2007-10-25, Thor Lancelot Simon <tls@panix . com > wrote:
> In article <slrnfhp6sj.9of.jdbeyer@trillian.localdomain>,
> Jean-David Beyer <jdbeyer@trillian.localdomain> wrote:
>>
>>He presumably makes a corrector lens that has zero power but all the same
>>distortions so that it corrects a single cell. I ordered one when he first
>>announced it over 10 years ago, but he is yet to ship me one, so I cannot
>>say how well it works.
>
> Didn't he in fact run his company out of business by taking prepayments
> and deposits for work that wasn't, in fact, ever done? I tried off and
> on for several years to get a replacement back (graflok style) for my 4x5
> trad and wondered why he wasn't responding to my inquiries but now I feel
> lucky he didn't -- since I took the camera in to L&R for repairs a few
> weeks ago and discovered there were no spare parts available (luckily
> I didn't need any) I've talked to several other people who were persistent
> enough to get in touch with Ron over the past few years and, if they ordered
> anything, ended up wishing they hadn't...
>
I have never been dissatisfied with the quality and workmanship of his
products. Most things were delivered promptly. The Convertible Plasmat
Set took a couple of years, though. But I definately got it and I use
it to the exclusion of everything else except the 90mm f/8 SuperAngulon.
The big problem was the corrector, and the problems were not entirely
his. After what I thought was too much delay, Ron offered to refund my
money, but I would rather have the lens than the money, so I have held
on. Now it seems he is trying to rectify this and is taking few or no
new orders until the backlog is taken care of. He also suggests he is
thinning out his product line to make things more manageable. This may
also reflect a drop in business due to the digital machines and bicycle
craze supplainting the photography sport.
I have _never_ had a question of his honesty.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey * counter.li.org
^^-^^ 10:40:01 up 2 days, 2:58, 5 users, load average: 5.30, 5.32, 5.26
On 2007-10-25, Thor Lancelot Simon <tls@panix . com > wrote:
> In article <slrnfhp6sj.9of.jdbeyer@trillian.localdomain>,
> Jean-David Beyer <jdbeyer@trillian.localdomain> wrote:
>>
>>He presumably makes a corrector lens that has zero power but all the same
>>distortions so that it corrects a single cell. I ordered one when he first
>>announced it over 10 years ago, but he is yet to ship me one, so I cannot
>>say how well it works.
>
> Didn't he in fact run his company out of business by taking prepayments
> and deposits for work that wasn't, in fact, ever done? I tried off and
> on for several years to get a replacement back (graflok style) for my 4x5
> trad and wondered why he wasn't responding to my inquiries but now I feel
> lucky he didn't -- since I took the camera in to L&R for repairs a few
> weeks ago and discovered there were no spare parts available (luckily
> I didn't need any) I've talked to several other people who were persistent
> enough to get in touch with Ron over the past few years and, if they ordered
> anything, ended up wishing they hadn't...
>
I have never been dissatisfied with the quality and workmanship of his
products. Most things were delivered promptly. The Convertible Plasmat
Set took a couple of years, though. But I definately got it and I use
it to the exclusion of everything else except the 90mm f/8 SuperAngulon.
The big problem was the corrector, and the problems were not entirely
his. After what I thought was too much delay, Ron offered to refund my
money, but I would rather have the lens than the money, so I have held
on. Now it seems he is trying to rectify this and is taking few or no
new orders until the backlog is taken care of. He also suggests he is
thinning out his product line to make things more manageable. This may
also reflect a drop in business due to the digital machines and bicycle
craze supplainting the photography sport.
I have _never_ had a question of his honesty.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey * counter.li.org
^^-^^ 10:40:01 up 2 days, 2:58, 5 users, load average: 5.30, 5.32, 5.26
