Another DIC question
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Another DIC question
Doe anyone by any chance have any info on the Nikon 'S2' slider prisms used with CF objectives? I've seen some for sale marked S2 B and S2 C but I can't find out anything about them
Thanks for any help
Louise
Thanks for any help
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I haven't tried them but they fit into the 27mm nosepiece from the infinity optiphots. These were wafer scopes with apparently little or no academic usage and it is hard to find good documentation on them.
My suspicion is that they're pretty good and similar to their current epi dic in quality if not in logistics.
My suspicion is that they're pretty good and similar to their current epi dic in quality if not in logistics.
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Re: Another DIC question
Thanks. They are being offered for sale ostensibly with CF objectives - no mention of 'epi' usage. I'll drop the seller a line to see if he knows any more.Scarodactyl wrote: ↑Fri Oct 15, 2021 3:09 pmI haven't tried them but they fit into the 27mm nosepiece from the infinity optiphots. These were wafer scopes with apparently little or no academic usage and it is hard to find good documentation on them.
My suspicion is that they're pretty good and similar to their current epi dic in quality if not in logistics.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
These guys?
https://www.ebay.com/itm/Nikon-S1-B-Nom ... 4726232585
Yeah they're for the infinity CF plans off the late infinity optiphots. That's about the only line explicitly labelled 'CF' on thr objective itself for whatever reason.
https://www.ebay.com/itm/Nikon-S1-B-Nom ... 4726232585
Yeah they're for the infinity CF plans off the late infinity optiphots. That's about the only line explicitly labelled 'CF' on thr objective itself for whatever reason.
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Re: Another DIC question
Similar ones but marked S2. I've asked the seller but don't expect to hear back straightaway. Also, sellers don't usually know many technical details. Someone, somewhere must have some useful info and practical setup details for them...Scarodactyl wrote: ↑Fri Oct 15, 2021 5:37 pmThese guys?
https://www.ebay.com/itm/Nikon-S1-B-Nom ... 4726232585
Yeah they're for the infinity CF plans off the late infinity optiphots. That's about the only line explicitly labelled 'CF' on thr objective itself for whatever reason.
Thanks
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
Yeah, these are all optiphot 100+ epi prisms. They go into slots in an m27 brightfield/darkfield nosepiece. I have one of the nosepieces (came with two free objectives, couldn't resist) but no prisms and only one cf plan bd objective (well, a later chinese clone). I can show you what parts are needed to set one up (since I use an illuminator, head and mag changer from the same line), I just haven't ever found a manual for one as far as I remember.
Re: Another DIC question
I have had about as much luck trying to find more specific documentation for the Olympus Vanox DIC stuff. It has to be out there somewhere, but I sure can't find it.
Re: Another DIC question
Reflected light Nomarski:
http://alanwood.net/downloads/olympus-v ... ctions.pdf
The BH2 Nomarski DIC guide, as the old Vanox has similar components:
http://alanwood.net/downloads/olympus-b ... ctions.pdf
Last edited by deBult on Fri Oct 15, 2021 8:29 pm, edited 1 time in total.
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Re: Another DIC question
It's annoying, isn't it
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I'm only interested in transmitted light DIC so the S1/S2 sliders are apparently of no use after allScarodactyl wrote: ↑Fri Oct 15, 2021 6:39 pmYeah, these are all optiphot 100+ epi prisms. They go into slots in an m27 brightfield/darkfield nosepiece. I have one of the nosepieces (came with two free objectives, couldn't resist) but no prisms and only one cf plan bd objective (well, a later chinese clone). I can show you what parts are needed to set one up (since I use an illuminator, head and mag changer from the same line), I just haven't ever found a manual for one as far as I remember.
I'd have thought their setup (for the Optiphot-100) would be the same as other dic Optiphots so one of the manuals for them might be helpful?
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
It's analogous but not identical, different nosepiece style, prisms and objectives, plus a different illuminator design.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
Re: Another DIC question
I've already got those. They are a decent general guide but I'm after more specific information, like what exactly is present in a BH2-NAN slider/analyzer (is it just a polarizer or does it have a waveplate? Why does it only rotate 45° instead of 90° etc...) or what the exact differences are between the flip-out T-2 and T-4 DIC prisms. Things like that are not present in those documents, nor does there seem to be anyone left at Olympus willing or able to help with that information.deBult wrote: ↑Fri Oct 15, 2021 8:26 pmReflected light Nomarski:
http://alanwood.net/downloads/olympus-v ... ctions.pdf
The BH2 Nomarski DIC guide, as the old Vanox has similar components:
http://alanwood.net/downloads/olympus-b ... ctions.pdf
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Re: Another DIC question
Sorry, I was only aiming at you re the Optiphot-100Scarodactyl wrote: ↑Fri Oct 15, 2021 9:14 pmIt's analogous but not identical, different nosepiece style, prisms and objectives, plus a different illuminator design.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I've been using my optiphot epi-DIC prisms successfully in several ways. First I used one (the 10/40/100 prism) as objective side prism, and used the others as condenser prisms. By trial and error, and changing the top lens of my wild m20 achromat aplanat condenser, I found some combinations that worked really well at 10x and 20x, but was not able to get really good food DIC at 40x. It was also finicky to set up, so like most people I ended up buying a complete set when I found my Vanox AH with DIC locally for a great price. However, the DIC worked great with the plan achromats it was designed for, but less well with the planapos. The quality was especially bad at 10x and 20x, which was ironic we these were the magnification where my home-made setup worked extremely well at. So I found a new use for my epi-DIC prisms, as I removed the phase rings from the DIC condenser, and replaced them with three epi-DIC prisms. So now I have six different prisms, and some of the epi-DIC prisms work a lot better than the original ones with my planapos, and I now have good to great DIC at 10,20,40,60 and 100x.Scarodactyl wrote: ↑Fri Oct 15, 2021 9:14 pmIt's analogous but not identical, different nosepiece style, prisms and objectives, plus a different illuminator design.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
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Re: Another DIC question
The photo is from when I was testing if it would work. In the end I replaced the last phase ring as well, and attached the prisms with double-sided tape
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Re: Another DIC question
Oh yes, I'm sorry I was thinking of yours of course. You did an amazing job on that.
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Re: Another DIC question
Viktor - well done for getting it working! So which did you use for the condenser prism? I've had the impression that condenser prisms can be Wollaston prisms since you can position them correctly in relation to the lens (with a DIC condenser). I've noticed that Nikon prisms are all mounted at a slight horizontal angle - 5 deg - in their holders. I've assumed that's to prevent reflections though I'm not certain.viktor j nilsson wrote: ↑Sat Oct 16, 2021 3:24 amI've been using my optiphot epi-DIC prisms successfully in several ways. First I used one (the 10/40/100 prism) as objective side prism, and used the others as condenser prisms. By trial and error, and changing the top lens of my wild m20 achromat aplanat condenser, I found some combinations that worked really well at 10x and 20x, but was not able to get really good food DIC at 40x. It was also finicky to set up, so like most people I ended up buying a complete set when I found my Vanox AH with DIC locally for a great price. However, the DIC worked great with the plan achromats it was designed for, but less well with the planapos. The quality was especially bad at 10x and 20x, which was ironic we these were the magnification where my home-made setup worked extremely well at. So I found a new use for my epi-DIC prisms, as I removed the phase rings from the DIC condenser, and replaced them with three epi-DIC prisms. So now I have six different prisms, and some of the epi-DIC prisms work a lot better than the original ones with my planapos, and I now have good to great DIC at 10,20,40,60 and 100x.Scarodactyl wrote: ↑Fri Oct 15, 2021 9:14 pmIt's analogous but not identical, different nosepiece style, prisms and objectives, plus a different illuminator design.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
Do you think it's worth buying the Nikon epi (cf, Optiphot?) prisms and trying to use them for transmitted light? The cf prisms are relatively cheap though I don't know what their markings mean (as mentioned in my op) S1, S2, B, C etc. A new N2 condenser prism would set me back £1000 and about the same for an objective slider... A lot of money for a pensioner like me!
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
What condenser-side prism I used in my diy setup? I believe I used the 10/40/100 prism as condenser prism as well. The optiphot epi setup comes with a 5x, a 20x and two 10/40/100 prisms. I've empirically measured the location of the back focal plane of the Nikon CF Mplan objectives that I own, as this indirectly gives me information about the associated prisms. The M plan 10x has a BFP -1.36mm from the beginning of the thread, the M plan 40x has a BFP -1.13mm from the beginning of the thread, and the M plan 20x has its BFP -4mm from the beginning of the thread (not the shoulder, for some reason I measured to the upper edge when mounted in the nosepiece). So it makes sense that the 10x and 40x shares the same prism, while the 20x has a dedicated prism. This also gives an indication of what mismatch in the location of the fringe that Nikon thought was acceptable. In general, prisms for high mag objectives have smaller shear angles ("high resolution") than prisms for low magnification objectives. The fact that Nikon used the same prism for 10x and 100x objectives further suggest that they thought that it was more important to get the location of the BFP right, than to fine-tune the shear angle.LouiseScot wrote: ↑Sat Oct 16, 2021 9:02 amViktor - well done for getting it working! So which did you use for the condenser prism? I've had the impression that condenser prisms can be Wollaston prisms since you can position them correctly in relation to the lens (with a DIC condenser). I've noticed that Nikon prisms are all mounted at a slight horizontal angle - 5 deg - in their holders. I've assumed that's to prevent reflections though I'm not certain.viktor j nilsson wrote: ↑Sat Oct 16, 2021 3:24 amI've been using my optiphot epi-DIC prisms successfully in several ways. First I used one (the 10/40/100 prism) as objective side prism, and used the others as condenser prisms. By trial and error, and changing the top lens of my wild m20 achromat aplanat condenser, I found some combinations that worked really well at 10x and 20x, but was not able to get really good food DIC at 40x. It was also finicky to set up, so like most people I ended up buying a complete set when I found my Vanox AH with DIC locally for a great price. However, the DIC worked great with the plan achromats it was designed for, but less well with the planapos. The quality was especially bad at 10x and 20x, which was ironic we these were the magnification where my home-made setup worked extremely well at. So I found a new use for my epi-DIC prisms, as I removed the phase rings from the DIC condenser, and replaced them with three epi-DIC prisms. So now I have six different prisms, and some of the epi-DIC prisms work a lot better than the original ones with my planapos, and I now have good to great DIC at 10,20,40,60 and 100x.Scarodactyl wrote: ↑Fri Oct 15, 2021 9:14 pmIt's analogous but not identical, different nosepiece style, prisms and objectives, plus a different illuminator design.
Optiphot epi prisms (though I believe from finite optiphots) have been successfully used for transmitted DIC (by PeteM?), but I'd agree this probably won't do what you want, or if so only with a fair amount of experimentation.
Do you think it's worth buying the Nikon epi (cf, Optiphot?) prisms and trying to use them for transmitted light? The cf prisms are relatively cheap though I don't know what their markings mean (as mentioned in my op) S1, S2, B, C etc. A new N2 condenser prism would set me back £1000 and about the same for an objective slider... A lot of money for a pensioner like me!
Louise
Based on the position of the prisms in the nosepiece, the 20x prism should be a nomarski prism with an interference fringe located ~14mm from the prism. The 10/40/100 prism should have a fringe 11.2mm from the prism. The 5x prism is unknown as I don't own a M plan 5x, but presumably the BFP is far above the objective, and the 5x prism could in theory be a wollaston prism. It should at least have the fringe much closer to the prism.
All measurements subject to error!
The epi prisms as definitely a very convenient way to get some nomarski prisms to play with, if you find them for a reasonable price. I paid $180 for mine, with two m plan objectives. I've had a lot of fun for that money. Since there are so many variables that are at play when you are building your own system, it's going to be a lot of trial and error regardless of what prisms you get. For example, unless you are using a condenser with the exact same focal length as the original Nikon one, it doesn't matter if you use the objective and condenser prisms designed for your Nikon objective - the fringes won't match if your condenser FL is off. So for DIY purposes I'd rather pay for quantity and diversity than to pay a lot of money for a very specific prism if you aren't going to use it exactly as intended.
When you have several different prisms, of which two are identical, a bunch of different objectives, and a condenser with interchangeable top lenses (that alters the FL of the condenser), like I did, then you can try lots and lots of combinations. Chances are pretty good that some of them will work. If you are also able to move the prisms up and down, and tilt them, then you have even more combinations to try.
Speaking of which. I just checked my notes, and the best DIC at 10x was when the lower prism was oriented in the same direction as the top prism, and the best DIC at 20x was with the condenser prism flipped upside down.
Oh and regarding tilting. It is probably mainly to prevent reflections. But tilting also alters the location of the inference fringe, up to several millimeters. That can be useful for matching prisms and objective BFPs in some cases.
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Re: Another DIC question
Thanks for the info! I think the prisms I originally mentioned might be for the Nikon Diaphot 200 or 300 though I can't find a manual for it, or for the DIC accessories. I've seen a nosepiece for sale with the prisms you've mentioned - may be a possibility. Are your objectives infinity ones? How did your measure the bfp distances? I've never figured out how bfp's work with infinity objectives? Nobody ever seems to discuss it. It's probably obvious (to someone who knows!) but I'm in the darkviktor j nilsson wrote: ↑Sat Oct 16, 2021 8:41 pmWhat condenser-side prism I used in my diy setup? I believe I used the 10/40/100 prism as condenser prism as well. The optiphot epi setup comes with a 5x, a 20x and two 10/40/100 prisms. I've empirically measured the location of the back focal plane of the Nikon CF Mplan objectives that I own, as this indirectly gives me information about the associated prisms. The M plan 10x has a BFP -1.36mm from the beginning of the thread, the M plan 40x has a BFP -1.13mm from the beginning of the thread, and the M plan 20x has its BFP -4mm from the beginning of the thread (not the shoulder, for some reason I measured to the upper edge when mounted in the nosepiece). So it makes sense that the 10x and 40x shares the same prism, while the 20x has a dedicated prism. This also gives an indication of what mismatch in the location of the fringe that Nikon thought was acceptable. In general, prisms for high mag objectives have smaller shear angles ("high resolution") than prisms for low magnification objectives. The fact that Nikon used the same prism for 10x and 100x objectives further suggest that they thought that it was more important to get the location of the BFP right, than to fine-tune the shear angle.LouiseScot wrote: ↑Sat Oct 16, 2021 9:02 amViktor - well done for getting it working! So which did you use for the condenser prism? I've had the impression that condenser prisms can be Wollaston prisms since you can position them correctly in relation to the lens (with a DIC condenser). I've noticed that Nikon prisms are all mounted at a slight horizontal angle - 5 deg - in their holders. I've assumed that's to prevent reflections though I'm not certain.viktor j nilsson wrote: ↑Sat Oct 16, 2021 3:24 am
I've been using my optiphot epi-DIC prisms successfully in several ways. First I used one (the 10/40/100 prism) as objective side prism, and used the others as condenser prisms. By trial and error, and changing the top lens of my wild m20 achromat aplanat condenser, I found some combinations that worked really well at 10x and 20x, but was not able to get really good food DIC at 40x. It was also finicky to set up, so like most people I ended up buying a complete set when I found my Vanox AH with DIC locally for a great price. However, the DIC worked great with the plan achromats it was designed for, but less well with the planapos. The quality was especially bad at 10x and 20x, which was ironic we these were the magnification where my home-made setup worked extremely well at. So I found a new use for my epi-DIC prisms, as I removed the phase rings from the DIC condenser, and replaced them with three epi-DIC prisms. So now I have six different prisms, and some of the epi-DIC prisms work a lot better than the original ones with my planapos, and I now have good to great DIC at 10,20,40,60 and 100x.
Do you think it's worth buying the Nikon epi (cf, Optiphot?) prisms and trying to use them for transmitted light? The cf prisms are relatively cheap though I don't know what their markings mean (as mentioned in my op) S1, S2, B, C etc. A new N2 condenser prism would set me back £1000 and about the same for an objective slider... A lot of money for a pensioner like me!
Louise
Based on the position of the prisms in the nosepiece, the 20x prism should be a nomarski prism with an interference fringe located ~14mm from the prism. The 10/40/100 prism should have a fringe 11.2mm from the prism. The 5x prism is unknown as I don't own a M plan 5x, but presumably the BFP is far above the objective, and the 5x prism could in theory be a wollaston prism. It should at least have the fringe much closer to the prism.
All measurements subject to error!
The epi prisms as definitely a very convenient way to get some nomarski prisms to play with, if you find them for a reasonable price. I paid $180 for mine, with two m plan objectives. I've had a lot of fun for that money. Since there are so many variables that are at play when you are building your own system, it's going to be a lot of trial and error regardless of what prisms you get. For example, unless you are using a condenser with the exact same focal length as the original Nikon one, it doesn't matter if you use the objective and condenser prisms designed for your Nikon objective - the fringes won't match if your condenser FL is off. So for DIY purposes I'd rather pay for quantity and diversity than to pay a lot of money for a very specific prism if you aren't going to use it exactly as intended.
When you have several different prisms, of which two are identical, a bunch of different objectives, and a condenser with interchangeable top lenses (that alters the FL of the condenser), like I did, then you can try lots and lots of combinations. Chances are pretty good that some of them will work. If you are also able to move the prisms up and down, and tilt them, then you have even more combinations to try.
Speaking of which. I just checked my notes, and the best DIC at 10x was when the lower prism was oriented in the same direction as the top prism, and the best DIC at 20x was with the condenser prism flipped upside down.
Oh and regarding tilting. It is probably mainly to prevent reflections. But tilting also alters the location of the inference fringe, up to several millimeters. That can be useful for matching prisms and objective BFPs in some cases.
Thanks so much for your time and trouble
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I used the method described by Paolo Pozzi here:LouiseScot wrote: Thanks for the info! I think the prisms I originally mentioned might be for the Nikon Diaphot 200 or 300 though I can't find a manual for it, or for the DIC accessories. I've seen a nosepiece for sale with the prisms you've mentioned - may be a possibility. Are your objectives infinity ones? How did your measure the bfp distances? I've never figured out how bfp's work with infinity objectives? Nobody ever seems to discuss it. It's probably obvious (to someone who knows!) but I'm in the dark
Thanks so much for your time and trouble
Louise
https://www.researchgate.net/post/Is_th ... ctive_lens
I used a regular laser pointer, worked really well.
I only own and use finite objectives, and to be honest I also haven't figured out how BFPs work with infinity objectives.
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Re: Another DIC question
Thanks - ahh I'd seen that bfp link before but had forgotten about it! Hmm.. I was planning on using infinity optics though... I wonder if there's actually a difference if using them - I mean, all modern setups use infinity, but the prisms themselves must still be the same? The Nikon nosepiece I've seen is RMS so must be intended for finite objectives. Whether the prisms themselves will actually still work with infinity objectives - who knows! I could buy it and try and see... It's 4 position and going for £290 (seems a lot!). There's a 5x prism, a 10.40.100 and two others that I can't see. One might be a 20x. I suppose it would be a waste of money if I can't get the 40x prism to work with an infinity objective though maybe I could have a play with some finite objectives.viktor j nilsson wrote: ↑Sat Oct 16, 2021 9:53 pmI used the method described by Paolo Pozzi here:LouiseScot wrote: Thanks for the info! I think the prisms I originally mentioned might be for the Nikon Diaphot 200 or 300 though I can't find a manual for it, or for the DIC accessories. I've seen a nosepiece for sale with the prisms you've mentioned - may be a possibility. Are your objectives infinity ones? How did your measure the bfp distances? I've never figured out how bfp's work with infinity objectives? Nobody ever seems to discuss it. It's probably obvious (to someone who knows!) but I'm in the dark
Thanks so much for your time and trouble
Louise
https://www.researchgate.net/post/Is_th ... ctive_lens
I used a regular laser pointer, worked really well.
I only own and use finite objectives, and to be honest I also haven't figured out how BFPs work with infinity objectives.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I have tried finite Nilon prisms with infinity objectives for epi dic and it worked fine.
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Re: Another DIC question
That's encouraging! I've seen the same turret for sale in the states and with that one it says " Nikon Optiphot M-plan" and "5x, 10/40/100x, 20x DIC prisms installed"Scarodactyl wrote: ↑Sat Oct 16, 2021 11:03 pmI have tried finite Nilon prisms with infinity objectives for epi dic and it worked fine.
Maybe I'll take a chance... I just noticed it's actually up for auction starting at £290 though no bids yet. There is the issue of the high NA of my 20x and 40x infinity objectives - 0.75. Though generally it seems that DIC is based on magnification rather than NA though NA must play a role?
Louise
Last edited by LouiseScot on Sun Oct 17, 2021 12:34 am, edited 1 time in total.
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
I found a reference re infinity objectives and bfp http://asiimaging.com/docs/infinity_mic ... ics#fnt__2
They say Olympus provides it but others you have to ask or measure it:
"To measure the position of the back focal plane of an objective: place an ideal lens outside the objective and adjust its position along the optical axis until collimated light into the pair of lenses in either direction results in collimated light coming out. The external lens is now focused at the back focal plane, so remove the objective lens and see where the external lens is focused."
Mind you, I'm a bit confused in that the rays coming out of the objective are supposed to be approximately parallel so how can it have a bfp?
Still, I'll have go at the above measurement procedure tomorrow
Louise
They say Olympus provides it but others you have to ask or measure it:
"To measure the position of the back focal plane of an objective: place an ideal lens outside the objective and adjust its position along the optical axis until collimated light into the pair of lenses in either direction results in collimated light coming out. The external lens is now focused at the back focal plane, so remove the objective lens and see where the external lens is focused."
Mind you, I'm a bit confused in that the rays coming out of the objective are supposed to be approximately parallel so how can it have a bfp?
Still, I'll have go at the above measurement procedure tomorrow
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
Nomarski prisms are nomarski prisms. Whether the objectives are infinity corrected or finite won't matter in that respect. You have the same chance of finding working combinations regardless of that. The nosepiece you are looking at sounds like mine. It will have one 5x, one 20x and two 10/40/100 prisms.LouiseScot wrote:
Thanks - ahh I'd seen that bfp link before but had forgotten about it! Hmm.. I was planning on using infinity optics though... I wonder if there's actually a difference if using them - I mean, all modern setups use infinity, but the prisms themselves must still be the same? The Nikon nosepiece I've seen is RMS so must be intended for finite objectives. Whether the prisms themselves will actually still work with infinity objectives - who knows! I could buy it and try and see... It's 4 position and going for £290 (seems a lot!). There's a 5x prism, a 10.40.100 and two others that I can't see. One might be a 20x. I suppose it would be a waste of money if I can't get the 40x prism to work with an infinity objective though maybe I could have a play with some finite objectives.
Louise
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Re: Another DIC question
Yes, it makes sense that you would need a slightly different approach with an infinity objective. I've only toyed with finite optics so my intuition with infinity objectives is limited.LouiseScot wrote: ↑Sun Oct 17, 2021 12:32 amI found a reference re infinity objectives and bfp http://asiimaging.com/docs/infinity_mic ... ics#fnt__2
They say Olympus provides it but others you have to ask or measure it:
"To measure the position of the back focal plane of an objective: place an ideal lens outside the objective and adjust its position along the optical axis until collimated light into the pair of lenses in either direction results in collimated light coming out. The external lens is now focused at the back focal plane, so remove the objective lens and see where the external lens is focused."
Mind you, I'm a bit confused in that the rays coming out of the objective are supposed to be approximately parallel so how can it have a bfp?
Still, I'll have go at the above measurement procedure tomorrow
Louise
However, it's easy to think that infinity objectives just projects a bundle of parallel rays, but that's not really the case. It's just the rays emanating from one specific focus plane that leave the objective as parallel rays. For light coming from any other plane, the rays are not parallel.
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Re: Another DIC question
I had a go with this bfp measurement yesterday but not sure if I did it correctly - I just used a focusable red laser module as a coherent light source. I focused it on a wall several meters away. I got a value of about 15mm from the rear of an Olympus uis2 40x plan achro. Unfortunately, Olympus doesn't provide a value to check against. I looked at the quoted values for their plan fluors. They are all the same: -19.1mm I assume that means 19.1mm from the rear aperture. I also measured my Amscope plan fluor 10x and that came out outside the barrel and at about +3mm from the rear. Both measured values seem sensible...viktor j nilsson wrote: ↑Sun Oct 17, 2021 5:42 am
Yes, it makes sense that you would need a slightly different approach with an infinity objective. I've only toyed with finite optics so my intuition with infinity objectives is limited.
However, it's easy to think that infinity objectives just projects a bundle of parallel rays, but that's not really the case. It's just the rays emanating from one specific focus plane that leave the objective as parallel rays. For light coming from any other plane, the rays are not parallel.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
If you by 15mm from the rear mean that the BFP lies 15mm inside the 40x objective, then I agree that both values seems sensible.
If you were to get som CF EPi Prisms, then it would be good to try to get the 10/40/100 prism pretty close to the rear end of your 40x objective.
If you were to get som CF EPi Prisms, then it would be good to try to get the 10/40/100 prism pretty close to the rear end of your 40x objective.
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Re: Another DIC question
Yes, inside the objective, measured from the rear. I've not come across anything that exactly specifies how the bfp value is specified.viktor j nilsson wrote: ↑Mon Oct 18, 2021 11:09 amIf you by 15mm from the rear mean that the BFP lies 15mm inside the 40x objective, then I agree that both values seems sensible.
If you were to get som CF EPi Prisms, then it would be good to try to get the 10/40/100 prism pretty close to the rear end of your 40x objective.
The only prisms on the horizon at the moment are in the Optiphot turret which is for RMS thread objectives. Whether I'll be able to get it remains to be seen!
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Another DIC question
The DIC turret is for M plan reflected light objectives. Anyone know whether there would be a problem using the turret as is with regular objectives and transmitted light? Or would I have to strip the prisms out?
Thanks
Louise
Thanks
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo