I've just bought a Nikon PApo 60x NA1.4 160/0.17.
It may have been rash, but if we don't get along I can return it and get my £60 / $100 back.
It has a chip. I realised that may mean almost nothing, or that it's scrap.
I've read the recent thread about Condensers, Here http://www.photomacrography.net/forum/v ... 522#170522
The best/only condenser I have is the Olympus NA 1.25, on a CH microscope.
I intend to try it with that and a diatom slide, with direct projection. I have some "Cedar Tree" immersion oil which I hope will serve.
I can compare it with a couple of others, eg a CF 60x NA 0.85 PAchro with correction collar.
Is there anything which those with (even more!) experience of dud lenses can advise I particularly look for?
Ebay Item 261927223491
I have some xylene to clean oil off, though I've never used an immersion objective. I assume it's possible to see, if something has got in around the front glass.
It sold previously and was returned, the buyer complained only about the chip, not the performance. I'm hoping he was too fussy!
Checking a High NA objective
Moderators: rjlittlefield, ChrisR, Chris S., Pau
The chip doesn't seem to realy affect the optical surface but the matte surronding glass if true it won't have any effect by itself, but the seller picture is pretty crap, you can post a good one for sure.
The price is really good! Likely you did well.
Without an apples to apples reference is difficult to test for a bit suboptimal performace, likelly a good subject would be a diatom test slide with a bit oblique lighting. You must be able to see a contrast a least as good as your CF 60x NA 0.85 and more resolution on smaller details. Be sure to observe that the DOF is smaller, that will be indicative that your condenser is providing enough NA to spot some resolution difference.
Be aware that these objectives have very very small working distance and despite the oil immersion are sensitive to coverglass thickness, oil and mountant RI and mountant thickness over the sample, in my limited experience they are the most difficult to test.
Does your CH allows for Köhler illumination?. BTW oil the 1.25 top condenser lens to the slide to gain its maximunm NA.
The price is really good! Likely you did well.
Without an apples to apples reference is difficult to test for a bit suboptimal performace, likelly a good subject would be a diatom test slide with a bit oblique lighting. You must be able to see a contrast a least as good as your CF 60x NA 0.85 and more resolution on smaller details. Be sure to observe that the DOF is smaller, that will be indicative that your condenser is providing enough NA to spot some resolution difference.
Be aware that these objectives have very very small working distance and despite the oil immersion are sensitive to coverglass thickness, oil and mountant RI and mountant thickness over the sample, in my limited experience they are the most difficult to test.
Does your CH allows for Köhler illumination?. BTW oil the 1.25 top condenser lens to the slide to gain its maximunm NA.
Pau
. I worked this out a couple of years ago but it's "gone".So I think not, those work with critical illumination, but IMHO this isn't as bad as people says.ChrisR wrote:It'll be a humble CH2. There's an aperture diaphragm in the condenser but no field diaphragm. Light is diffuse.
In fact many Köhler microscopes like mines do not do strict Kölher but a mix, they have a field diaphragm but include a frosted glass to even the illumination and allow to remove it to center the lamp but don't rely in focusing the lamp filament at the back focal plane.
Maybe a round hole in a black carboard could do one of the field diaphragm funtions: to limit the illuminated field to cut glare.
Pau
cedar oil , maybe not the best to test with. Cargille , has a bit of an edge on it and that difference would be more evident with high N.A. ideally the chip should fill with oil and be pretty transparent.
i have a Bausch & Lomb planchro phase objective , that looks like it was used to hammer nails with. no cracks but the front lens looks like the moon. dry it has almost no image at all but oiled , I cannot tell the difference between it and a good one but it is only a 1.25 N.A. as Pau indicated , 1.4 N.A. objectives are pretty picky .
i have a Bausch & Lomb planchro phase objective , that looks like it was used to hammer nails with. no cracks but the front lens looks like the moon. dry it has almost no image at all but oiled , I cannot tell the difference between it and a good one but it is only a 1.25 N.A. as Pau indicated , 1.4 N.A. objectives are pretty picky .
Where do you get your oil, Phil?
Cargille's UK distributor doesn't look like it would be quick.
Let me guess you've had a bottle 20 years?
There have been stories here and elsewhere of objectives being knocked and not working properly afterwards. Some seem to be tougher than others. I imagine damage would often show as an asymmetric feature, though I haven't had one like that.
If I get better than I would from a Hi-dry, that'll do, for the money. I've got a couple of 100x oil cheapies that came on student Olympus microscopes, which should provide a comparison of sorts.
Cargille's UK distributor doesn't look like it would be quick.
Let me guess you've had a bottle 20 years?
There have been stories here and elsewhere of objectives being knocked and not working properly afterwards. Some seem to be tougher than others. I imagine damage would often show as an asymmetric feature, though I haven't had one like that.
If I get better than I would from a Hi-dry, that'll do, for the money. I've got a couple of 100x oil cheapies that came on student Olympus microscopes, which should provide a comparison of sorts.
Yes; how did you know? Reichert and Leitz oil from the olden days, mostly.
I get a bit nervous when using N.A. 1.4 objectives. Almost all of mine are old enough that the glasses in them are pretty standard stuff but more modern ones would likely have some very exotic glasses and I don't really know if the front element is one of them, so that an oil of a specific refractive index may be specified.
the rule of thumb I have used is to get the front element into the oil where it can be viewed some how. A well slide can usually be employed. If a scratch or chip disappears, then I presume the objective is good to go and the oil and objective are a fine match. This isn't so necessary except with a damaged objective, where the idea is to get the imperfections to disappear. If this fails, I call up the former boyfriend of an acquaintance. He is a professional magician.
Cargille makes oils of different refractive indexes and viscosities. I did some tests , years ago with some different oils and I was surprised at the differences with high N.A. objectives.... not so much with lower N.A. ones
High dry .90 or .95 objectives can be remarkable, when compared to lower N.A. versions but that is usually due to the fact that they are fluorites or apochromats. I have the opportunity to compare a high N.A. planfluorite to a higher N.A. oil planapo from the same manufacturer directly, and the oil planapo is definitely superior but I find
that the extra fuss to use the oil , is not really worth it unless I go up to a 100x and then the swap to the lower mag. oil objective makes some sense.
I get a bit nervous when using N.A. 1.4 objectives. Almost all of mine are old enough that the glasses in them are pretty standard stuff but more modern ones would likely have some very exotic glasses and I don't really know if the front element is one of them, so that an oil of a specific refractive index may be specified.
the rule of thumb I have used is to get the front element into the oil where it can be viewed some how. A well slide can usually be employed. If a scratch or chip disappears, then I presume the objective is good to go and the oil and objective are a fine match. This isn't so necessary except with a damaged objective, where the idea is to get the imperfections to disappear. If this fails, I call up the former boyfriend of an acquaintance. He is a professional magician.
Cargille makes oils of different refractive indexes and viscosities. I did some tests , years ago with some different oils and I was surprised at the differences with high N.A. objectives.... not so much with lower N.A. ones
High dry .90 or .95 objectives can be remarkable, when compared to lower N.A. versions but that is usually due to the fact that they are fluorites or apochromats. I have the opportunity to compare a high N.A. planfluorite to a higher N.A. oil planapo from the same manufacturer directly, and the oil planapo is definitely superior but I find
that the extra fuss to use the oil , is not really worth it unless I go up to a 100x and then the swap to the lower mag. oil objective makes some sense.
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Charles Krebs
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Chris,
Of course nobody wants to see this on their objective. But it is nearly all on the very outer periphery. If you need to live with some damage that's where you want it to be. My guess would be that in use you would have a tough time seeing any difference from a pristine version (assuming this is the only issue).
Normally these go for $600-$900. You paid about $100. If the damage were in the center of the lens I 'd be very leery and would send it back. But if I didn't have a 60/1.4 and wanted one, I would certainly consider this for $100. Naturally the only way to be sure it to try it. (But If you don't have some experience with high mag, high NA objectives you may have trouble making an assessment).
Of course nobody wants to see this on their objective. But it is nearly all on the very outer periphery. If you need to live with some damage that's where you want it to be. My guess would be that in use you would have a tough time seeing any difference from a pristine version (assuming this is the only issue).
Normally these go for $600-$900. You paid about $100. If the damage were in the center of the lens I 'd be very leery and would send it back. But if I didn't have a 60/1.4 and wanted one, I would certainly consider this for $100. Naturally the only way to be sure it to try it. (But If you don't have some experience with high mag, high NA objectives you may have trouble making an assessment).
I have no experience with high mag, high NA objectives and have trouble making an assessment.But If you don't have some experience with high mag, high NA objectives you may have trouble making an assessment.
Initial impressions are that it's certainly not wrecked. Eyeballing, I can see a lot more detail than with a student Olympus CH's 100x NA1.3 objective - though that may be "off", too. To tell more I need to find where I put things..
I'm testing a Ferrari by driving it round the block. It really needs a better driver and a better track.
That's surprising, maybe your Oly 100X is defective as you suspect, a bit more detail, better contrast, and mainly much better chromatic correction is what you could expect normally. Another point is that the Plan Apo is a 60X so the image will look sharper due to the lower magnification even if no more detail is captured. What's your testing subject? Any sample pictures?I can see a lot more detail than with a student Olympus CH's 100x NA1.3 objective - though that may be "off", too
Pau
Chris,
I was surprised to read that you saw "a lot more detail" too, like Pau did. Did you see a lot more vertical/depth details (somewhat expected, if your definition of "a lot" is a quite a bit less than mine), or flat shallow surface details (not expected, some may even say it is the other way around).
With your Apo 60x / 1.4 your image should have more focused depth details, because depth of focus would be shallow with your Oly 100/1.3 and deeper with Apo 60/1.4.
The Apo would offer more contrast and brightness, but probably not a lot in my definition, given your 100x still has a NA of 1.3.
You may use Klaus Kemp diatom test plate and look at those dots on the smallest two diatoms (they are quite flat/shallow too, so it would be more fair to your 100x/1.3). Oblique light with condenser top oiled, all the way up touching slide bottom, diaphragm opened completely may help too. If you have Jersey / Litonotus's GUF (oblique filter with gradient dark ground), that will work even better
Edit: Also your condenser is only a NA 1.25 one when "oiled and touching", that makes it even harder to get significant difference in shallow surface details between na 1.4 vs na 1.3. It would be easier to tell the difference with a NA 1.4 condenser and highly oblique light.
I was surprised to read that you saw "a lot more detail" too, like Pau did. Did you see a lot more vertical/depth details (somewhat expected, if your definition of "a lot" is a quite a bit less than mine), or flat shallow surface details (not expected, some may even say it is the other way around).
With your Apo 60x / 1.4 your image should have more focused depth details, because depth of focus would be shallow with your Oly 100/1.3 and deeper with Apo 60/1.4.
The Apo would offer more contrast and brightness, but probably not a lot in my definition, given your 100x still has a NA of 1.3.
You may use Klaus Kemp diatom test plate and look at those dots on the smallest two diatoms (they are quite flat/shallow too, so it would be more fair to your 100x/1.3). Oblique light with condenser top oiled, all the way up touching slide bottom, diaphragm opened completely may help too. If you have Jersey / Litonotus's GUF (oblique filter with gradient dark ground), that will work even better
Edit: Also your condenser is only a NA 1.25 one when "oiled and touching", that makes it even harder to get significant difference in shallow surface details between na 1.4 vs na 1.3. It would be easier to tell the difference with a NA 1.4 condenser and highly oblique light.
Selling my Canon FD 200mm F/2.8 lens
I disagree with this point: higher NA leads to smaller DOF, so with the 1.4 it will be slightly (perhaps not easily visible) smaller DOF: what really matters is not magnification but NA.zzffnn wrote:With your Apo 60x / 1.4 your image should have more focused depth details, because depth of focus would be shallow with your Oly 100/1.3 and deeper with Apo 60/1.4.
Pau
I went back and did some calculations.Pau wrote:I disagree with this point: higher NA leads to smaller DOF, so with the 1.4 it will be slightly (perhaps not easily visible) smaller DOF: what really matters is not magnification but NA.zzffnn wrote:With your Apo 60x / 1.4 your image should have more focused depth details, because depth of focus would be shallow with your Oly 100/1.3 and deeper with Apo 60/1.4.
Pau is right, in Chris' case and most other cases, what really matters is NA not magnification.
Chris may see slightly deeper depth of focus (more focused depth details) from his 100/1.3 over 60/1.4. Though apparent/visual resolution is likely better with 60/1.4, due to its higher NA vs magnification ratio. Sorry, I am not used to 60x having a NA of 1.4 :-p
Here is how you can calculate depth of field:
https://www.microscopyu.com/articles/fo ... depth.html
So when you put in Chris' values, magnification (which is in the second part of equation) does NOT change depth of field much. Actually, in most cases, that second part of equation containing magnification only adds a tiny amount (~1%) to the first part of equation containing NA value, so practically most people may ignore magnification in calculation of depth of field.
Selling my Canon FD 200mm F/2.8 lens