MicrobeHunter.com Microscopy Forum

I asked this in another place but on second thoughts it would prob be best asked here (this way it will not take the other thread (on 60x objectives) off topic) !

Many ebay adverts for objectives show "DIN", I think this is the same thread as the RMS 0.8" thread which I have on my old (UK 60 - 70's) 'scopes, can anyone comment please ?

ie. will it fit my existing 4-port turrets ( ps. I am not asking about 160 vs infinity, barrel or tube length etc. )

Thanks.

Yes, thread is the same. Parfocality is at 45mm

75RR wrote: ↑

Mon Jun 29, 2020 6:27 pm

Yes, thread is the same. Parfocality is at 45mm

Thanks.

Does parfocality matter here?
There are 37mm and 45mm parfocal objectives that all conform to RMS- or DIN spec.

(Just don't mix them or you're 'screwed' )

Galf wrote: ↑

Sat Jul 18, 2020 8:52 pm

Does parfocality matter here?
There are 37mm and 45mm parfocal objectives that all conform to RMS- or DIN spec.

(Just don't mix them or you're 'screwed' )

D.I.N. specifies 45mm parfocal distance. J.I.S. specifies 36mm distance. So to conform, yes, it matters.

i guess that would be the dif between 160 and 195s ??

More like 185 vs 195

If you are talking about ‘tube length’ DIN standard is 160mm

MichaelG.

.

This is a convenient reference:
https://www.edmundoptics.co.uk/knowledg ... bjectives/

SOME GOOD INFO THERE ....thanks..

MichaelG. wrote: ↑

Sat Jul 18, 2020 10:58 pm

This is a convenient reference:
https://www.edmundoptics.co.uk/knowledg ... bjectives/

Good ref, thanks.
So MTL =160mm in DIN and 170mm in JIS

Except I am still confused !
it describes what "conjugate distance" is in a finite system ( I think that is what 185 and 195 are about ?)

"characterized by either the DIN or JIS standard; all finite conjugate microscopes are either one of these two standards"

but it does not give a figure (185 or 195) for which standard is what, unless I missed something ?

MichaelG. wrote: ↑

Sat Jul 18, 2020 10:58 pm

This is a convenient reference:
https://www.edmundoptics.co.uk/knowledg ... bjectives/

Good ref, thanks.
So MTL =160mm in DIN and 170mm in JIS

Except I am still confused !
it describes what "conjugate distance" is in a finite system ( I think that is what 185 and 195 are about ?)

"characterized by either the DIN or JIS standard; all finite conjugate microscopes are either one of these two standards"

but it does not give a figure (185 or 195) for which standard is what, unless I missed something ?

EDIT 160+45 = 205 or 170+36=206 doesnt compute !! so it is something else ?

EDIT2 Ah, I think,,,
MTL-OTL 160-150=10mm in DIN, so 205-10=195 bingo! Why didnt they say that !

EDIT3 but 170-146.5=23.5 and 206-23.5= 182.5 Doh,,,, does 2.5mm matter among friends

Help !!

But altogether all these systems use the same thread to mount the objectives to the revolver.
Even infinite objectives come with the same thread.

The old Leitz standard is 170mm tube length and only later the standardized 160mm. The distance that the object is projected in the tube is 152mm which is very close to the common standard of 150mm. So 150 + 45mm = 195 and 150 + 37mm = 187 is very close to 185. These are my calculations to make sense of the numbers.

To add to my confusion - objectives are not marked with 185 or 195, so how does one keep track of which is which if one's purchases get mixed up in a box ?

If ebay sellers are to be believed ( ? ! ) the 185vs195 is not a DIN/JIS matter : one that I looked at lists both 185 and 195 for 160 tube.

Specification
Magnification: 4X, or 10X, or 20X, or 40X, or 60X, or 100X
Conjugate Distance: 185 mm
Standard DIN achromatic objective lens
Suit Microscope: Biological Microscope
Not explicit in the text, but their pictures show the barrels marked 160/0.17

Specification
Magnification: 4X, 10X, 20X(S), 40x(S), 60X(S), 100S(S, Oil)
NA: 0.1, 0.25, 0.40, 0.65, 0.85, 1.25
Conjugate Distance: 195 mm
45 EP
Standard DIN 160/0.17 HD achromatic objectives
Suit Microscope: biological microscope

I bought a 185 objective by mistake once and had to buy an adapter to make it parfocal with the rest of the objectives on the turret. It was physically shorter

My op was about the compatibility of thread and was well answered by @75RR, so that's ok Thank you.

regarding 185/195, 1year ago :
viewtopic.php?p=68606#p68562

EDIT Yep, there is another variable - 'Chinese Student' (as well as 'DIN' & 'JIS') according to @apocronout in that topic.

DrPhoxinus wrote: ↑

Sun Jul 19, 2020 12:23 pm

I bought a 185 objective by mistake once and had to buy an adapter to make it parfocal with the rest of the objectives on the turret. It was physically shorter

So that would suggest a JIS PD (36mm) ?
Have you still got it, can you measure its PD, or is there yet another variable out there ?

I realize that the actual conjugate focal planes will vary with the placing of the object ( or with the desired focal plane of the eyepiece). But how to tell what is the optimum (design) conjugate distance.
It is interesting that in all the ebay ads the 185s are cheaper, is this because they are less sought after ?

Oh dear, my head hurts

OliverK almost solves the mystery here
https://youtu.be/-4HzdclIW3A
where he adds 35mm PD to the mix but confirms that they can be (intended to be ?) used with a 160mm tube.
So, did the 35 (or 36 or 37) arise from the JIS standard but get adapted to 160mm tube by the Chinese Early and Student designs ??

Again my knowledge is limited to Leitz gear. The older Leitz objectives (the black scope era) had 37mm as a standard parfocal distance and JIS with 36mm is probably a derivation of that. Mind that the older Leitz's had 170mm tube length. The 35mm is, as I see it, the Chinese answer to the standardization to 150mm of projection distance. Leitz had 152 and Zeiss somewhat smaller than 150.
Later 45mm became a new PD standard when objectives became larger as well. Also in DIN I guess. Both in 170mm and 160mm tubes for Leitz scopes.

Info from Leitz 'Abbildende und beleuchtende Optik des Mikroskops''.