Nikon gene sequencer objectives
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Nikon gene sequencer objectives
Those 20X .75 Nikon planapo objectives 1501-9398 are .17 cover slip corrected are they not?
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Re: Nikon gene sequencer objectives
No, they are corrected for a flow cell with glass that's between 0.3 and 0.4 thick:
https://www.photomacrography.net/forum/ ... x+0.75+oem
https://www.photomacrography.net/forum/ ... x+0.75+oem
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Re: Nikon gene sequencer objectives
There are cheap normal ones too, though the main guy listing them for 100 bucks doesn't have any at the moment. Maybe there will be more, maybe not.
Re: Nikon gene sequencer objectives
Phil, I've bought three of the ones marked .17 and all seem to be cover slip corrected. There are some out there meant to look through a thicker bit of glass - if not specifically marked .17 that's likely what you'd get.
Amazing objectives for the price and they'll work just fine on something like a Leica DMLS stand which have the same 200mm reference tube length. Maybe minor differences with Leica tube lens corrections, but the Nikon 20x Plan Apo objectives still look great IMO.
Amazing objectives for the price and they'll work just fine on something like a Leica DMLS stand which have the same 200mm reference tube length. Maybe minor differences with Leica tube lens corrections, but the Nikon 20x Plan Apo objectives still look great IMO.
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Re: Nikon gene sequencer objectives
They are likely designed to use # 1 haemocytometer cover slips, which are .40, then. Perhaps those objectives were actually originally for blood counts. Some sort of automated haemocytometer?viktor j nilsson wrote: ↑Mon Dec 28, 2020 9:47 pmNo, they are corrected for a flow cell with glass that's between 0.3 and 0.4 thick:
https://www.photomacrography.net/forum/ ... x+0.75+oem
Or the original sample carrier used with them caused a similar slight capillary action that can take place in a haemocytometer , distorting thin cover slips.
Unfortunately, cheap haemocytometer cover slips are #2, .50. The #1 are relatively expensive. Maybe India?
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Re: Nikon gene sequencer objectives
Nope, they come from gene sequencer and were designed to peek into a flow cell and detect fluorescence from DNA. The quote below is from this thread:
http://www.photomacrography.net/forum/v ... 91#p243091
http://www.photomacrography.net/forum/v ... 91#p243091
abednego1995 wrote: ↑Thu Dec 27, 2018 3:59 amThose non-labeled PA20's are from the GAIIx's and the labelled PA20xs are for the MiSeq platform from illumina. (The internal code for the MiSeq is "BOLT" and you'll see that on some PA20's still in their shipping packages.)
As for the 300 micrometer coverslip correction for the non-labeled versions, go see their patent. It describes beautifully the need for coverslip correction, and how to balance it with multiplexing runs using both/many surfaces in a flow-cell.
https://patents.google.com/patent/US8143599
Cheers,
John
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Re: Nikon gene sequencer objectives
Note there are two types of these nikon oem objectives. I don't think the exact difference has been nailed down (maybe different cover slip thicknesses?)
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Re: Nikon gene sequencer objectives
It seems that nonetheless, .40 haemocytometer cover slips would be ideal.
Re: Nikon gene sequencer objectives
I do see two Nikon OEM product codes (0500-0087 and 1501-9398) and one with the proper labels. Need to get a 20x for regular use, but not sure which one.
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Re: Nikon gene sequencer objectives
The one with a normal label is the one you want. The other two are also excellent but require a thicker cover slip.
This is one of the nicest objectives you will use, it's just great. Just be sure you're ready for the longer parfocal distance, m25 thread and infinity correction.
This is one of the nicest objectives you will use, it's just great. Just be sure you're ready for the longer parfocal distance, m25 thread and infinity correction.
Re: Nikon gene sequencer objectives
Thanks! Wow. They sold for just $100 a few months ago.Scarodactyl wrote: ↑Mon Jan 04, 2021 5:27 pmThe one with a normal label is the one you want. The other two are also excellent but require a thicker cover slip.
This is one of the nicest objectives you will use, it's just great. Just be sure you're ready for the longer parfocal distance, m25 thread and infinity correction.
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Re: Nikon gene sequencer objectives
Yup, I got a few. Maybe that guy will list more, maybe not. They go up in waves.
Re: Nikon gene sequencer objectives
Do these Nikon 20x PLAN APO work with Leica DML DIC? There's different sliders marked A, D, E, etc and I'm afraid those are specific for Leica objectives.PeteM wrote: ↑Mon Dec 28, 2020 10:56 pmAmazing objectives for the price and they'll work just fine on something like a Leica DMLS stand which have the same 200mm reference tube length. Maybe minor differences with Leica tube lens corrections, but the Nikon 20x Plan Apo objectives still look great IMO.
Re: Nikon gene sequencer objectives
Haven't tried them, having both Leica and Nikon DIC. Given how many DIC prisms Leica has on offer (A,B,C,D,E . . . sliders or wedge type on top and K1, K2, K3, K4, K5, K6 . . .in the condenser), I suspect there is some combination with shear angles that works. Will have to try it with those I have one of these days.
The Nikon 20x Plan Apo .17 cover is such a fine objective, at such a great price, that one might be happy just with brightfield, darkfield, oblique, VOILA, pseudo-DIC, Rheinberg etc.
Not sure what you mean by the "DML" model, though. Well into a few thousand dollars new price, today's Leica stands don't have the provision to add DIC sliders up top. I think it begins around the DM2000 level. Most affordable ways to get it would be a used DMLB or DMR/B - both excellent scopes.
The Nikon 20x Plan Apo .17 cover is such a fine objective, at such a great price, that one might be happy just with brightfield, darkfield, oblique, VOILA, pseudo-DIC, Rheinberg etc.
Not sure what you mean by the "DML" model, though. Well into a few thousand dollars new price, today's Leica stands don't have the provision to add DIC sliders up top. I think it begins around the DM2000 level. Most affordable ways to get it would be a used DMLB or DMR/B - both excellent scopes.
Re: Nikon gene sequencer objectives
DMLS or DMLB but I just remembered DMLS doesn't have the slots on top.
The price is indeed very good. Waiting for one in the low to mid $100's to show up.
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Re: Nikon gene sequencer objectives
I have what seems like a question that should have been answered somewhere but I don't know where it has been. Nikon claims that the CFI objectives are ca free. That seems pretty cut and dried but Scarodactyls results with the tests of his Chinese eyepieces might throw that into doubt, given that with a Nikon objective and Nikon eyepieces there was more lateral ca than with the Chinese eyepieces.
Leica has corrections in the telan lens. How can a Nikon objective give a perfect peripheral image on a Leica stand, irregardless of the reference length?
Leica has corrections in the telan lens. How can a Nikon objective give a perfect peripheral image on a Leica stand, irregardless of the reference length?
Re: Nikon gene sequencer objectives
I've put a Nikon infinity trinocular head on a Leica stand. Resolves the telan lens question. They're widely available and cheaper to find than Leica heads. Requires an intermediate piece in infinity space to match the dovetails.
Also tried using them direct with the Leica head (and thus the Leica telan lens) and found them still-exceptional objectives. There's probably some difference of course, but not obvious to the eye while viewing typical slides.
You might recall, back when we were asking about Leica corrections over the years, that Wayne corrected the impression about a 180mm tube length for Leica infinity in the Delta and HC era and you were arguing for almost all of the Leica corrections moving into the objective as with Nikon and Olympus.
If you're right, there should be little difference. If some of the old Leica marketing hype amounts to much about their "harmonic" system adds up to much, there's probably some sort of aberration not immediately apparent to my eye. Either to be ignored or resolved by fitting a Nikon head.
Also tried using them direct with the Leica head (and thus the Leica telan lens) and found them still-exceptional objectives. There's probably some difference of course, but not obvious to the eye while viewing typical slides.
You might recall, back when we were asking about Leica corrections over the years, that Wayne corrected the impression about a 180mm tube length for Leica infinity in the Delta and HC era and you were arguing for almost all of the Leica corrections moving into the objective as with Nikon and Olympus.
If you're right, there should be little difference. If some of the old Leica marketing hype amounts to much about their "harmonic" system adds up to much, there's probably some sort of aberration not immediately apparent to my eye. Either to be ignored or resolved by fitting a Nikon head.
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Re: Nikon gene sequencer objectives
I think the best results I've gotten with Nikon objectives were via direct projection. I'll try to do a proper test of it with these objectives at some point, I just need to design and print out an m25 to m26 adapter to fit them onto my scope (edit: sorry I forgot I don't have a good stand for transillumination right now and epi isn't doing it with a cover slip). I've used them for photography via direct projection before but that was with a Leica Z16 in between it and the head, plus it was looking at mineral inclusions within gemstones which isn't necessarily the most ideal approach. I was still impressed by the total lack of CA in that configuration though.
Last edited by Scarodactyl on Sat Jan 09, 2021 7:55 am, edited 1 time in total.
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Re: Nikon gene sequencer objectives
I still don't understand why the Nikon objective with Nikon eyepiece created lateral ca when the Nikon objective with Chinese eyepiece was ca free. If the Nikon objective is cfi, then the eyepiece should be neutral and there should be no lateral ca. No eyepiece should be able to improve the lateral ca.
Pete M . I argued that Leica had moved the corrections upstream yes, which they did but they do not make the statement that the objectives are ca free. They use the term harmonious correction, a euphemistic term for there being corrections in several places. If Nikon objectives are in fact ca free, then there must be some lateral ca and distortion when using the Nikon 20X planapo objective in a purely Leica system. It helps when assessing an objective's performance to have a known quantity with which to compare it to. In this case , against a Leica HC Plan Apo 20X 0.75 for instance in the same microscope. I can only judge the difference between my Reichert 25X .65 planapo and the Bausch & Lomb 25X .65 Flat Field Apochromat by putting each one in it's respective system and comparing with the same sample and equivalent condenser arrangement .
Even with Reichert Austria objectives in a Reichert U.S.A. stand, there is a tiny bit of difference at the periphery in the corrections. It isn't easily seen as originating in the optics until you try the comparable Reichert U.S.A. objective. It is easily corrected by installing eyepieces with a tiny degree of compensation. Using a Reichert 100X 1.32 planapo phase objective is impressive on it's own . It is hard to determine that the imaging at the periphery is not normal because the general sense of the image is so good but installing the eyepieces with the needed corrections to neutralize the difference between the system and the objective's requirements shows the error.
Pete M . I argued that Leica had moved the corrections upstream yes, which they did but they do not make the statement that the objectives are ca free. They use the term harmonious correction, a euphemistic term for there being corrections in several places. If Nikon objectives are in fact ca free, then there must be some lateral ca and distortion when using the Nikon 20X planapo objective in a purely Leica system. It helps when assessing an objective's performance to have a known quantity with which to compare it to. In this case , against a Leica HC Plan Apo 20X 0.75 for instance in the same microscope. I can only judge the difference between my Reichert 25X .65 planapo and the Bausch & Lomb 25X .65 Flat Field Apochromat by putting each one in it's respective system and comparing with the same sample and equivalent condenser arrangement .
Even with Reichert Austria objectives in a Reichert U.S.A. stand, there is a tiny bit of difference at the periphery in the corrections. It isn't easily seen as originating in the optics until you try the comparable Reichert U.S.A. objective. It is easily corrected by installing eyepieces with a tiny degree of compensation. Using a Reichert 100X 1.32 planapo phase objective is impressive on it's own . It is hard to determine that the imaging at the periphery is not normal because the general sense of the image is so good but installing the eyepieces with the needed corrections to neutralize the difference between the system and the objective's requirements shows the error.
Re: Nikon gene sequencer objectives
viewtopic.php?f=9&t=10883 this comparison? I thought BD plan 10X was CF (finite) not CFI but in any case direct projection showed the least lateral CA so the 10X/22 wasn't an improvement it was just better-corrected than the Nikon eyepiece?apochronaut wrote: ↑Fri Jan 08, 2021 2:21 pmI still don't understand why the Nikon objective with Nikon eyepiece created lateral ca when the Nikon objective with Chinese eyepiece was ca free. If the Nikon objective is cfi, then the eyepiece should be neutral and there should be no lateral ca. No eyepiece should be able to improve the lateral ca.
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Re: Nikon gene sequencer objectives
The Nikon eyepiece should have zero effect on the corrections. It should be engineered to be in perfect harmony with the objective and create neither positive or negative ca. In other words if the objective is in fact cf, then the eyepiece should be completely neutral and no other eyepiece be capable of correcting better.
Re: Nikon gene sequencer objectives
To me it seems more likely the viewing eyepieces would be engineered to balance cost vs. performance for typical visual use and not necessarily corrected to the same level of performance as the objectives. Maybe "perfect harmony" is just considered unnecessary and too expensive to achieve in a standard viewing eyepiece?apochronaut wrote: ↑Sun Jan 10, 2021 4:22 pmThe Nikon eyepiece should have zero effect on the corrections. It should be engineered to be in perfect harmony with the objective and create neither positive or negative ca. In other words if the objective is in fact cf, then the eyepiece should be completely neutral and no other eyepiece be capable of correcting better.
Lucky cancellation of lateral CA between the 10X/22 and 40mm pancake lens could be another explanation, but if you look at example photos from lens reviews there is very little visible, much less than in the image through the Nikon eyepiece I would say.
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Re: Nikon gene sequencer objectives
I can't see that taking place with a high end microscope sporting a 26mm f.o.v. Nikon should be spot on with their peripheral corrections, especially if they are promoting the concept of CFI. I think if you look at the price of those eyepieces , cost vs. performance becomes a bit of a moot point. It might be a factor in the case of the Chinese factory that is making their lower end systems such as the Eclipse 100.hans wrote: ↑Sun Jan 10, 2021 8:08 pmTo me it seems more likely the viewing eyepieces would be engineered to balance cost vs. performance for typical visual use and not necessarily corrected to the same level of performance as the objectives. Maybe "perfect harmony" is just considered unnecessary and too expensive to achieve in a standard viewing eyepiece?apochronaut wrote: ↑Sun Jan 10, 2021 4:22 pmThe Nikon eyepiece should have zero effect on the corrections. It should be engineered to be in perfect harmony with the objective and create neither positive or negative ca. In other words if the objective is in fact cf, then the eyepiece should be completely neutral and no other eyepiece be capable of correcting better.
Lucky cancellation of lateral CA between the 10X/22 and 40mm pancake lens could be another explanation, but if you look at example photos from lens reviews there is very little visible, much less than in the image through the Nikon eyepiece I would say.
I can see the lucky cancellation theory. I was interested in whether the visual difference was similar.
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Re: Nikon gene sequencer objectives
That, is due to Nikon never claiming to have a periphery perfect image in the oculars. They used to have a perfectly corrected CFD ocular for the Biophot around 1978, but didn't sell well due to it's high cost. Going back to the CFI system, Nikon's tube lens is only PSF perfect to FN18.0mm up to the very recent Ti2 which truely delivers FN25.0mm. So... it doesn't make sense to make a "perfect" ocular in the first place.
Cheers,
John
Cheers,
John
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Re: Nikon gene sequencer objectives
And why doesn't it make sense in the first place?
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Re: Nikon gene sequencer objectives
First, the tube lens can't deliver. Second, we can't see outside of around FN20mm and the center of the FoV at the same time. The second reason is why they abandoned the UW FN26.5 oculars for the UW FN25.0 oculars.
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Re: Nikon gene sequencer objectives
What tube lens can't deliver. Just the Nikon tube lens or all tube lenses?
Whether someone can see a wide apparent field or not would be an individual characteristic. I guess you are referring to the circle that we can attend to. I would put it at less than a 20mm f.o.v. with 10X eyepieces. That's why I don't have a problem with an older Apochromat system that has compens eyepieces at around 13 or 14 mm. I can take in a nicely corrected whole field of view.
Being able to absorb the periphery of a wider field is important though. While I agree that 26.5mm is extreme and you have to just about crane your neck to see the periphery, I am pretty comfortable at 22mm.. Recently, I just posted about trialling the Bausch & Lomb 31-15 -62 15X eyepieces with Reichert Austria objectives in a Microstar IV. Both those and the similar AO 182 or 184 have I think a 15mm f.o.v. but since they are 15X, their apparent field of view is much wider than a 10X/20 eyepiece, probably closer to what the angle would be with a 10X if it was a 24mm. That is on the edge for me, however the 31-15 - 62 provide remarkable peripheral correction with that family of objectives. Despite not being able to attend to the periphery while staring straight ahead, it is highly usefull to be able to scan a well corrected f.o.v.
Whether someone can see a wide apparent field or not would be an individual characteristic. I guess you are referring to the circle that we can attend to. I would put it at less than a 20mm f.o.v. with 10X eyepieces. That's why I don't have a problem with an older Apochromat system that has compens eyepieces at around 13 or 14 mm. I can take in a nicely corrected whole field of view.
Being able to absorb the periphery of a wider field is important though. While I agree that 26.5mm is extreme and you have to just about crane your neck to see the periphery, I am pretty comfortable at 22mm.. Recently, I just posted about trialling the Bausch & Lomb 31-15 -62 15X eyepieces with Reichert Austria objectives in a Microstar IV. Both those and the similar AO 182 or 184 have I think a 15mm f.o.v. but since they are 15X, their apparent field of view is much wider than a 10X/20 eyepiece, probably closer to what the angle would be with a 10X if it was a 24mm. That is on the edge for me, however the 31-15 - 62 provide remarkable peripheral correction with that family of objectives. Despite not being able to attend to the periphery while staring straight ahead, it is highly usefull to be able to scan a well corrected f.o.v.
Re: Nikon gene sequencer objectives
Curious where you find specs like this? Seems like most publicly available sales literature is less technical. Patents? There are bounds given for various specific types of aberrations in some of the AO/Reichert patents I have looked at but I think they are loose/conservative and don't necessarily give a good indication of typical performance.
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Re: Nikon gene sequencer objectives
Well, that's because it isn't public (or I'm just not aware of a public source.) I asked my Nikon rep at my lab.
Another way to guess the "actual" available FN would be to look into what intermediate magnification is required for imaging on the system. This has been long 2.5x (135 format, 46mm diagonal) for Nikon. Since this hasn't changed from the 1960s I would take it as very conservative, but they didn't change it when they went CF, nor CFI. High quality widefield imaging was probably never on their agenda until digital sensors became good/large enough.
Another way to guess the "actual" available FN would be to look into what intermediate magnification is required for imaging on the system. This has been long 2.5x (135 format, 46mm diagonal) for Nikon. Since this hasn't changed from the 1960s I would take it as very conservative, but they didn't change it when they went CF, nor CFI. High quality widefield imaging was probably never on their agenda until digital sensors became good/large enough.
Re: Nikon gene sequencer objectives
Not too surprising, I guess. For lateral CA what is considered PSF perfect? Red and blue PSFs separated by approximately the distance to the first zero, analogous to the Rayleigh criterion?