Wanted: 100x infinity objective

[SoftMachine]

I'm looking for an affordable 100x objective for my BX60.

Should I avoid the cheaper olympus objectives on eBay that don't use a coverslip?
https://www.ebay.com/itm/234298516614?h ... Swhxphmsjr

Does anyone have experience with chinese objectives?
https://www.ebay.com/itm/273499956873?h ... SwK4pe6z1u
https://www.ebay.com/itm/274786886715?h ... SwGWpgkltz

Anyone have one for sale?

Thanks.

[apochronaut]

Objectives marked with a /- instead of /0 have the capacity to be used with or without a coverslip Since it is oil immersion , the coverslip, immersion oil continuum acts the same as a immersion oil alone. Under such conditions, the refractive index and verifiable thickness of the coverslips should be known because the oil/glass thickness will have a limit, with the acceptable coverglass thickness being somewhat less than the normal 0.17 usually designated.
The other way around, it is common in veterinary clinics, where many dried, stained, blood smears might be run in a day to use cover slip corrected oil immersion objectives without a cover, primarily due to the inefficiency of cover slip use. In this case a thicker than normal oil layer substitutes for the oil/coverslip sandwich.

I have tried out some of the Chinese made, Olympus format, planachro objectives and my impression is that they are adequate but slightly inferior to Japanese made Olympus planachros. Often they can suffer from poor parcentering.
Other options are to buy into a Chinese 100X 1.30 PlanF , if you can get one at a good price, or to buy a Chinese 100X 1.15 N.A. water immersion planachro, which some find more convenient than an oil immersion type. Each of the two latter options will be more expensive ( about 300.00) but might be preferable. The PlanF might be hard to find for 300.00 now but it gas been available in the past.
I had some of the 100X 1.15 water immersion objectives produced to a higher spec. than normal. My early production suffered from similar problems that many Chinese mass produced objectives do, principally poor parcentering so I returned them and asked for a guaranteed specification. I have just received them and will be testing them as soon as some other stuff gets cleared away.

[Rossf]

Hello fellas -hope you don’t mind me jumping in to the convo- hey apochronaut (such a cool handle)-do you know of any Chinese 1000x infinity water immersion objectives with an iris? Also what’s the tube length of chines objectives ? I’ve got one infinity scope-Leica DM750-does it matter that much to have different infinity tube lengths ie an Olympus or zeiss infinity objective on a 200mm scope? I’ve heard Nikon work pretty good on Leica cos of same 200mm infinity tube. I love water immersion objetives-iris would be good for dark field but I find it’s good to play with sharpness/depth of focus trade off-for some microbes I prefer less sharp but a bit more depth of focus to get a sense of their real shape rather than super sharp “optical slices”-does that make sense? You might be interested that I found a 1600x Leica water objective which is super fun-giant soil rods swimming and really small flagellates dwarfed buy the motile rods-only 1.2 N/A but plan apo so it visually sharp enough IMO. Needs a bit of oblique I think to get the best out of it.
Regards ross

[apochronaut]

Hello fellas -hope you don’t mind me jumping in to the convo- hey apochronaut (such a cool handle)-do you know of any Chinese 1000x infinity water immersion objectives with an iris? Also what’s the tube length of chines objectives ? I’ve got one infinity scope-Leica DM750-does it matter that much to have different infinity tube lengths ie an Olympus or zeiss infinity objective on a 200mm scope? I’ve heard Nikon work pretty good on Leica cos of same 200mm infinity tube. I love water immersion objetives-iris would be good for dark field but I find it’s good to play with sharpness/depth of focus trade off-for some microbes I prefer less sharp but a bit more depth of focus to get a sense of their real shape rather than super sharp “optical slices”-does that make sense? You might be interested that I found a 1600x Leica water objective which is super fun-giant soil rods swimming and really small flagellates dwarfed buy the motile rods-only 1.2 N/A but plan apo so it visually sharp enough IMO. Needs a bit of oblique I think to get the best out of it.
Regards ross

I havn't seen any Chinese 100X W.I. objectives with an iris. An option is to make a small change to the rear diaphragm, which will reduce the N.A. somewhat. How much? ....is dependent on what the minimum N.A. of your D.F condenser is. I did this with a 63X 1.0 N.A. glycerin immersion objective, knocking the N.A. down to about .85 with a restrictor diaphragm and it works well.
Your objectives are M25 thread?. I do have the Chinese made NIS60 ( Nikon Infinity System 60mm parfocal -M25) 100X 1.10 W.I. objectives. Probably, if you got it down to .90 or so it would work or you had a condensor with a high enough minimum N.A.
I will check the Radical Instruments list . Often they list advanced stuff that probably can be produced but it needs to be ordered into production. I am not sure if they have stock on much of it.
edit. Radical has a staggering array of objectives listed : 120 in all with an M25 thread. In all of that there are only 3 , 100X with an iris diaphragm, all oil immersion. An Achromat 100X 0.5-1.25 a Super Fluor 100x 0.5-1.30. and a 100X 0.5-1.30 Plan Fluor.

[Rossf]

Interesting-thanks for the reply apochronaut -will I’ve to check the website-yes scope is M25-the 1600x is RMS but I just use a M25 adapter with no probs.
Regards ross