PL 25 na 0.40 PHP ROSSBACH?

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Sabatini
Posts: 464
Joined: Tue Nov 12, 2019 3:09 am

PL 25 na 0.40 PHP ROSSBACH?

#1 Post by Sabatini » Wed Mar 22, 2023 1:46 am

Kind regards.
I decided to buy some face contrast objectives for $30 and three of them are supply by Rossbach brand.
10x 0.25 php
Pl 25x na 0.40 php.
100x 1.25 php.
Please, if anyone have any information regarding this brand , i have been trying to look for some info regarding these but it turns out to be a total mystery on the wed... no info about it...any clues?
Thanks in advance!.
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PeteM
Posts: 2982
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: PL 25 na 0.40 PHP ROSSBACH?

#2 Post by PeteM » Wed Mar 22, 2023 2:25 am

Sabatini, A semi-informed guess is that these are generic import phase contrast objectives, engraved to suit some reseller. I've seen similar examples - most often from China but some older Japanese ones with the black rubber grip. There is a Mexican microscope maker/reseller of that name - who sourced overseas.

You'll be able to tell something about their vintage and quality either by mounting them or just checking the back stops (black plastic?) and front lens surround (e.g. a tiny hole for the 100x?). Some of the Japanese ones were decent. Similar Chinese ones that have passed through have been OK at 10x and 20x, but not so good at 40x and 100x.

You can compare your 40x example with a known good 40x to get an idea yourself. It may be difficult to find a matching phase condenser if you didn't get one with the lot. If they are towards the low end, perhaps not worth the search?

apochronaut
Posts: 6271
Joined: Fri May 15, 2015 12:15 am

Re: PL 25 na 0.40 PHP ROSSBACH?

#3 Post by apochronaut » Wed Mar 22, 2023 1:27 pm

An odd thing about them is that a 25X is included. That is very uncharacteristic of Chinese objectives, yet I would agree that is what they seem to be. The engraving on 1980's Chinese objectives was uneven as it is on these. They slso have a resemblance in form to some I have seen and to those made for the Bausch & Lomb Galen III, also marketed under the Cambridge brand in the 1980's.

Sabatini
Posts: 464
Joined: Tue Nov 12, 2019 3:09 am

Re: PL 25 na 0.40 PHP ROSSBACH?

#4 Post by Sabatini » Wed Mar 22, 2023 2:43 pm

peteM.
Hello.
Yes I understand, they look well built. obviously they are modestly used objetives.
I will be doing some tests on them today with the Heine condenser...hopefully Heine will do the dirty work and conjugate the phase rings correctly.We will see how they performance...they actually feel solid and well built, not so sloppy in their design and construction. I will send some pics.
Thanks for your time and help.
100x
100x
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100x
100x
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25x
25x
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25x
25x
IMG_20230322_091117_11zon.jpg (108.77 KiB) Viewed 1047 times

Sabatini
Posts: 464
Joined: Tue Nov 12, 2019 3:09 am

Re: PL 25 na 0.40 PHP ROSSBACH?

#5 Post by Sabatini » Wed Mar 22, 2023 2:54 pm

apochronaut wrote:
Wed Mar 22, 2023 1:27 pm
An odd thing about them is that a 25X is included. That is very uncharacteristic of Chinese objectives, yet I would agree that is what they seem to be. The engraving on 1980's Chinese objectives was uneven as it is on these. They slso have a resemblance in form to some I have seen and to those made for the Bausch & Lomb Galen III, also marketed under the Cambridge brand in the 1980's.
Thanks Apo.
Certainly the resemblance to the Leica Galen objetives is remarkable.
Interesting reference to the 25x ,this one is well built. I just hope they have decent performance.
Will see!
Thanks

BramHuntingNematodes
Posts: 1538
Joined: Tue Jan 21, 2020 1:29 am
Location: Georgia, USA

Re: PL 25 na 0.40 PHP ROSSBACH?

#6 Post by BramHuntingNematodes » Wed Mar 22, 2023 3:54 pm

Some of those Galen objectives are really quite nice. The condenser is tough to track down.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

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