Microscope objective markings

[Scoper]

I have an objective labeled PHP and PL..what is it?

Also any documentation on objective markings?

Thanks

[Scarodactyl]

Pl usually means plan. Ph-anything usually indicates phase of some sort (phase positive maybe?) Markings are not consistent from maker to maker so you'd need to be more specific.

[Scoper]

Thanks for responding.

I suspected that PL meant plan…likely for 18mm.

PHP…I suspected phase but the second P had me stumped.

Those are the only markings other the usual.

I did look at length on the Internet without success.

Anyone else?

FWIW.. this site needs a sticky containing the different markings for objectives snd eyepieces.

[dtsh]

Thanks for responding.

I suspected that PL meant plan…likely for 18mm.

PHP…I suspected phase but the second P had me stumped.

Those are the only markings other the usual.

I did look at length on the Internet without success.

Anyone else?

FWIW.. this site needs a sticky containing the different markings for objectives snd eyepieces.

If you look at the back of the objective, you should see a phase ring if it's a phase objective. If you happen to have a bertand lens or a centering telescope, you should be able to see it without removing the objective from the scope. There might be some phase designs where that's not true, but it's been the case for the ones I've seen.

[apochronaut]

PHP is mostly phase positive but then with Olympus PL means " positive low" for a phase objective. No maker?

[josmann]

FWIW.. this site needs a sticky containing the different markings for objectives snd eyepieces.

This is a great idea but unfortunately there’s no unified standard for markings. Still, some general guidelines could be written down…

[apochronaut]

The site needs so many stickies that it would probably be glued shut if they were all left up.

[Scoper]

The site needs so many stickies that it would probably be glued shut if they were all left up.

LOL…well said!

[Scoper]

When an objective has a notation of “php2” on it, what is it telling us?

As I mentioned before I have seen a number of Chinese objectives with the notation “php” which is a phase designation.

How do you think the “php” versus “php2” objectives differ?

Any documentation available discussing this?

Thanks

[Scarodactyl]

2 would indicate which annulus to use in the condenser. It will be system specific.

[apochronaut]

Positive phase is formerly known as Dark phase. Negative as bright phase, so the same as php in negtive would be phn, if the mfg. made such.
Additionally there were degrees of contrast with each. By adjusting the lambda shift of .25 to .50 depending on the system by a small number of ångstroms, the contrast was raised or lowered.
Any system that just says phase contrast, is a dark phase system and not far off what more complimented systems would call a DM or Dark M., since dark phase became the main phase system used, almost universal. I continue to look for phase objectives for the series 4 in some inane quest to have a complete set and see 20 times the Dark M phase objectives that I see for any other type.

[deBult]

When an objective has a notation of “php2” on it, what is it telling us?

As I mentioned before I have seen a number of Chinese objectives with the notation “php” which is a phase designation.

How do you think the “php” versus “php2” objectives differ?

PHP2 is commonly used by Zeiss to indicate the matching Zeiss phase plate in the condensor.

Please note phase plates are not compatible and are bound to a single microscope make and era.
E.G. Olympus phase objectives and condensors of the short barrel (36mm) era do not match those of the long barrel (45 mm) era. And Zeiss plates do not match Olympus or Leitz (and yes there are some lucky exceptions to this rule).

[apochronaut]

It can be overlooked that a condenser is a magnifier as well, that's why it condenses light. Since ideal phase performance relies on immaculate overlap of the diaphragm and annular ring, one could adjust the size of a non native diaphragm's image at the objective's annular ring by using a different magnification condenser, or for lower magnifications the same condenser missing it's top lens. It would take some experimentation but it is theoretically possible.
There is nothing fancy about phase diaphragms. They are just a bright doughnut of specific dimensions surrounded by an opaque background. The whole device could just as easily be made out of a piece of eggplant skin and it could be made to work until the skin withered, or a cutout in a sheet of black paper.

Old valuable threads drift to the end pretty easily on this forum, and since phase is back in the news a bit, I am going to resurrect an old thread. It is a 1948 relic I found in a manual covering developing phase applications : a work in progress for sure.
https://www.microbehunter.com/microscop ... php?t=5032

[Scoper]

When an objective has a notation of “php2” on it, what is it telling us?

As I mentioned before I have seen a number of Chinese objectives with the notation “php” which is a phase designation.

How do you think the “php” versus “php2” objectives differ?

Any documentation available discussing this?

Thanks

Anyone have documentation that covers these notations?

They are seen on Chinese objectives.

Also when an objective has a notation of xx/xx/xx/0..what is the 0 telling us?…no cover slip?

Finally I see objectives with color rings that tell us what power class they are..what about objectives that have two rings…is that a phase objective?

Thanks

[Scarodactyl]

It's system specific and documentation on chinese systems is weak at best. There are many systems out of China.
Two rings is not a standardized marking. In Mitutoyo objectives it marks a superlong working distance variant.

[apochronaut]

There is a designation for a " special purpose" objective. A bold red ring, which can be applied to the existing colour code of an objective.. Sometimes the purpose of these objectives can only be found out by raiding archives and they can be wierdly specific.
A number of years ago I traded an objective for another. The one I traded was odd. It was a 45X fluorite with a red ring. The swapper seemed happy at first , likely because it was fluorite, and I had not investigated the objective at all. Seemed simple enough but I found out after the fact , because the other person came back at me, that the red ring objective was specific to film emmulsions ; not exactly a high demand objective.