Charles, Rik: thanks -- more extremely interesting info! The distinct competitive issues of ordinary vs. bellows lenses makes perfect sense. Then variables like PMF happen along, and the situation gets murkier for me...
Eric
Lens Resolution (was 'Nikon Multiphot brings $3,550')
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Eric:
I wasn't trying to imply that I could do a better job than you, or even offering to do any work for you. I apologize if it came across like that.
I found Rik's comment "EL Nikkor f/2.8 at f/5.6 (ghastly compared to everything shown here)" somewhat unsettling. I like this lens.
I reasoned that you weren't photographing scales on a moth wing. Thus it might not be a valid conclusion to think that a lens that is unsuitable for moth scales would be unsuitable for fly parts (legs, antennae, genitalia) as these are more 3-dimensional than a moth wing, and would likely not have the very fine striations seen on the scales.
I was curious for my own sake to see how my El-Nikkor 50/2.8 @ f/5.6 would perform; no way I could compare it with the Luminar or the Oly lenses (as I don't have them) but I figured I could get some idea if this lens performed ghastly. I just wanted to know what parts of what fly you were photographing; again for my own curiosity about the usefulness of the El-Nikkors.
I wasn't trying to imply that I could do a better job than you, or even offering to do any work for you. I apologize if it came across like that.
I found Rik's comment "EL Nikkor f/2.8 at f/5.6 (ghastly compared to everything shown here)" somewhat unsettling. I like this lens.
I reasoned that you weren't photographing scales on a moth wing. Thus it might not be a valid conclusion to think that a lens that is unsuitable for moth scales would be unsuitable for fly parts (legs, antennae, genitalia) as these are more 3-dimensional than a moth wing, and would likely not have the very fine striations seen on the scales.
I was curious for my own sake to see how my El-Nikkor 50/2.8 @ f/5.6 would perform; no way I could compare it with the Luminar or the Oly lenses (as I don't have them) but I figured I could get some idea if this lens performed ghastly. I just wanted to know what parts of what fly you were photographing; again for my own curiosity about the usefulness of the El-Nikkors.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
As a follow up; I had this preparation in a genitalia vial.
Genital capsule, not flattened, and a wet mount (in glycerine) of a male Anthomyiid fly.
Straight line from A-B is 1.18mm.
Cropped from a 3mm width FOV; about 8x mag on sensor.
reversed El-Nikkor 50/2.8 @ f/5.6, 45 frames @ 0.010mm ZS PMax stack.
Bottom image is 800x800px actual pixels.
This lens did a decent job; I would guess adequate for this subject; certainly not ghastly.
NU09222
NU09223
Genital capsule, not flattened, and a wet mount (in glycerine) of a male Anthomyiid fly.
Straight line from A-B is 1.18mm.
Cropped from a 3mm width FOV; about 8x mag on sensor.
reversed El-Nikkor 50/2.8 @ f/5.6, 45 frames @ 0.010mm ZS PMax stack.
Bottom image is 800x800px actual pixels.
This lens did a decent job; I would guess adequate for this subject; certainly not ghastly.
NU09222
NU09223
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
NU,
No worries, and I really appreciated your offer. I will send you examples of the kinds of images I'm after. They involve detailed shots showing stucture, setae etc. of fly genitalia (shapes of these things are important for identification in the group). I have work to do on the images before I can share them; hopefully soon.
Re. the El-Nikkor 50/2.8: I haven't used it much yet at higher (+5x) mags yet, so can't offer much info for a personal opinion. The most important aspect would be photo results, and the evidence is clear here. Your images, which we see here on Photomac forums from the 50/2.8, are just splendid: the lens, in the right hands, can give great results.
I hope to do to some more shooting done with Zuiko 20 when the new flash parts arrive. Of course, I'm still learning on how to use this lens (f stop!), so we'll have to wait and see; with luck, maybe something to share.
Eric
No worries, and I really appreciated your offer. I will send you examples of the kinds of images I'm after. They involve detailed shots showing stucture, setae etc. of fly genitalia (shapes of these things are important for identification in the group). I have work to do on the images before I can share them; hopefully soon.
Re. the El-Nikkor 50/2.8: I haven't used it much yet at higher (+5x) mags yet, so can't offer much info for a personal opinion. The most important aspect would be photo results, and the evidence is clear here. Your images, which we see here on Photomac forums from the 50/2.8, are just splendid: the lens, in the right hands, can give great results.
I hope to do to some more shooting done with Zuiko 20 when the new flash parts arrive. Of course, I'm still learning on how to use this lens (f stop!), so we'll have to wait and see; with luck, maybe something to share.
Eric
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Planapo
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- Location: Germany, in the United States of Europe
NU wrote:
I think what Rik was saying is that the 2.8/50 EL-Nikkor performs ghastly at 5.6 and at the magnification he ran his test, and compared to the 38 mm and 20 mm Oly and Nikon CF objective shot at much larger apertures.
At lower magnifications the 2.8/50 EL-Nikkor at f/5.6 gives "excellent" results, and Rik, of course, is aware of that.
Once a very knowledgable friend and outstanding photographer (who might that be?!
) told me that at f/5.6, because of diffraction, one should not go much higher in magnification than 3 - 4x for best results. Hence the EL-Nikkor can't compete with the other lenses under Rik's test conditions from above.
Though, as you show us here, even at 8x the EL-Nikkor shot at f/5.6 gives very nice results for purposes where the end picture won't undergo too much extra enlargement. And in fact, the insect's genitalia here are pictured ways better than we were used to see them in earlier photomacrographs, e.g. from older publications, before the times of "stacking".
--Betty
I think there is some misunderstanding.I found Rik's comment "EL Nikkor f/2.8 at f/5.6 (ghastly compared to everything shown here)" somewhat unsettling. I like this lens.
I think what Rik was saying is that the 2.8/50 EL-Nikkor performs ghastly at 5.6 and at the magnification he ran his test, and compared to the 38 mm and 20 mm Oly and Nikon CF objective shot at much larger apertures.
At lower magnifications the 2.8/50 EL-Nikkor at f/5.6 gives "excellent" results, and Rik, of course, is aware of that.
Once a very knowledgable friend and outstanding photographer (who might that be?!
) told me that at f/5.6, because of diffraction, one should not go much higher in magnification than 3 - 4x for best results. Hence the EL-Nikkor can't compete with the other lenses under Rik's test conditions from above.Though, as you show us here, even at 8x the EL-Nikkor shot at f/5.6 gives very nice results for purposes where the end picture won't undergo too much extra enlargement. And in fact, the insect's genitalia here are pictured ways better than we were used to see them in earlier photomacrographs, e.g. from older publications, before the times of "stacking".
--Betty
Betty:
I think you missed the point. Eric in not photographing the scales on a moth's wing. So perhaps it is irrelevant, to Eric's research, how any lens performs with moth scales.
Different horses for different courses.
I think you missed the point. Eric in not photographing the scales on a moth's wing. So perhaps it is irrelevant, to Eric's research, how any lens performs with moth scales.
Different horses for different courses.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
-
rjlittlefield
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- Location: Richland, Washington State, USA
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There are two very different issues going on here. Sometimes it's hard to keep them straight.
Several posts back, NU suggested renaming the topic title to be "Lens Resolution" because that's what we were really discussing. I thought that was appropriate, so I made the change.
But based on the last couple of posts, I think the topic is now morphing into "How much resolution do you need to illustrate a fly's private parts?" That's a fair topic too, as long as we're clear what we're talking about.
On the other hand, I certainly do believe that the image quality needed by a researcher depends on that researcher's interests.
Much earlier in this thread, Eric said that he was interested in "5x to about 15x" and that "I would like to find microlenses that could approximate the results of an objective lens -- at 1/5 to 1/10 the time & effort." Taking those statements at face value, I prepared some illustrations showing the resolution of various lenses at around 10X magnification (on sensor). You've seen some of them in my earlier posting. Here are some more, this time stacked:
Personally, I think it's pretty clear that resolution tracks aperture size in the pattern predicted by theory: wider aperture higher resolution, narrower aperture lower resolution. Of the lenses that I've tested (Luminar 16/2.5, Olympus 20/2.0 and 38/2.8, EL Nikkor 50/2.8, and Nikon CF M Plan Achro 10X/0.30), I don't see any significant differences in image quality that are not nicely explained by just asking what aperture gives the best quality for that lens.
So again, I'll assert the basic issue is "simple": decide how much resolution you need, then pick your lens and aperture to give that much and no more.
However, there's a powerful reason I put the quote marks around "simple". In fact, making that decision about resolution may not be simple at all.
What NU has pointed out, I think, is that the actual resolution needed for illustrating fly genitals is not as high as one might guess. Just because those parts might commonly be examined through a 40X or 100X microscope does NOT necessarily mean that you need the full resolution of a 4X or 10X objective to get the job done.
If in fact you can get by with less resolution, then you can stop down to increase DOF and use a longer lens to get more working distance. At the same time, you can also reduce the overall magnification and the pixel counts, which further increases DOF and also reduces your processing time per frame. There is a very big win to be had in choosing the correct resolution and pixel counts to match.
As for my choice of the word "ghastly", I suppose that was too vivid a term. It's hard not to be impressed at how bad f/5.6 at 8.3X looks, when you're flashing it against images that have two to four times higher resolution. But certainly that doesn't mean it's inadequate for any particular subject, even a very small one. Everything depends on what you need to see in the final image.
--Rik
Edit: to correct a misleading typo.
Several posts back, NU suggested renaming the topic title to be "Lens Resolution" because that's what we were really discussing. I thought that was appropriate, so I made the change.
But based on the last couple of posts, I think the topic is now morphing into "How much resolution do you need to illustrate a fly's private parts?" That's a fair topic too, as long as we're clear what we're talking about.
I have trouble believing that the image quality a lens produces depends very much on whether it's looking at parts of a moth or a fly. So I'm confident that the panels I've prepared accurately reflect the images that the lenses will produce.it might not be a valid conclusion to think that a lens that is unsuitable for moth scales would be unsuitable for fly parts (legs, antennae, genitalia) as these are more 3-dimensional than a moth wing, and would likely not have the very fine striations seen on the scales.
On the other hand, I certainly do believe that the image quality needed by a researcher depends on that researcher's interests.
Much earlier in this thread, Eric said that he was interested in "5x to about 15x" and that "I would like to find microlenses that could approximate the results of an objective lens -- at 1/5 to 1/10 the time & effort." Taking those statements at face value, I prepared some illustrations showing the resolution of various lenses at around 10X magnification (on sensor). You've seen some of them in my earlier posting. Here are some more, this time stacked:
Personally, I think it's pretty clear that resolution tracks aperture size in the pattern predicted by theory: wider aperture higher resolution, narrower aperture lower resolution. Of the lenses that I've tested (Luminar 16/2.5, Olympus 20/2.0 and 38/2.8, EL Nikkor 50/2.8, and Nikon CF M Plan Achro 10X/0.30), I don't see any significant differences in image quality that are not nicely explained by just asking what aperture gives the best quality for that lens.
So again, I'll assert the basic issue is "simple": decide how much resolution you need, then pick your lens and aperture to give that much and no more.
However, there's a powerful reason I put the quote marks around "simple". In fact, making that decision about resolution may not be simple at all.
What NU has pointed out, I think, is that the actual resolution needed for illustrating fly genitals is not as high as one might guess. Just because those parts might commonly be examined through a 40X or 100X microscope does NOT necessarily mean that you need the full resolution of a 4X or 10X objective to get the job done.
If in fact you can get by with less resolution, then you can stop down to increase DOF and use a longer lens to get more working distance. At the same time, you can also reduce the overall magnification and the pixel counts, which further increases DOF and also reduces your processing time per frame. There is a very big win to be had in choosing the correct resolution and pixel counts to match.
As for my choice of the word "ghastly", I suppose that was too vivid a term. It's hard not to be impressed at how bad f/5.6 at 8.3X looks, when you're flashing it against images that have two to four times higher resolution. But certainly that doesn't mean it's inadequate for any particular subject, even a very small one. Everything depends on what you need to see in the final image.
--Rik
Edit: to correct a misleading typo.
Last edited by rjlittlefield on Wed Jan 09, 2013 2:20 pm, edited 1 time in total.
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Planapo
- Posts: 1581
- Joined: Tue Nov 07, 2006 2:33 am
- Location: Germany, in the United States of Europe
NU wrote:
So, I think we agree and had just to defend the EL-Nikkor against Rik's "strong language".
NU wrote:
Can't see. 
Perhaps it's my innate English speech impediment. 
--Betty
Aye! That was exactly the point I intended to make, i. e. that the 2.8/50 mm EL-Nikkor is an excellent lens when being used within its limitations, and the apple is not compared with oranges.Different horses for different courses.
So, I think we agree and had just to defend the EL-Nikkor against Rik's "strong language".
NU wrote:
Hmm... Now did I?!Betty: I think you missed the point.
Can't see. Perhaps it's my innate English speech impediment. --Betty
Rik,
Thanks very much for more of your really nice comparative tests with the Oly 20/2 & 38/2.8, Nikon 10/.30, Luminar 16 and EL Nik 50/2.8 (the Luminar did quite well...). I actually do value these kinds of moth scale tests quite highly (David Millard's "7 lenses at 4x" is a favorite, and I frequently refer to it for information; also to drool at the great glass so nicely displayed...). In fact, it was Davids "7 lenses" test that started me on a quest to find the "right" micro lens for stacking. What these various tests show me (put very simply) is: objectives (specifically the Nikon CFN 10/.30 & CFN PlanApo 4/.20) do the best job at stacking; some micro lenses do better than others at coming close to the performance of the objectives. My goal has been to figure out just which micro lens does come closest to the objective's quality re. stacking.
My own tests (with fly heads at 5 to 15x -- mostly not fit to show publicly, partly because variables -- like lighting -- were not controlled so nicely as you and David have done), along with your tests, have helped me reach some conclusions re. this list of "great micro lenses for stacking." However, I still need more info before I can finalize my personal list (I need to redo some of my tests and, especially, I need results for certain potentially great stacking lenses -- like a Photar 25/2). I do have a couple of test shots I can show (even though these vary in lighting and completeness of stack): the fly is a Paragorgopsis sp. (Ulidiidae) from Costa Rica.
Minolta 12.5/2.0 (shot at f4) @120mm [55@0.025,ZS] - full frame (some sharpening).
same as above: 100% crop (no sharpening, etc.).
Nikon CFN 10/.30 @185mm [90@0.005, ZS] - 100% crop (no sharpeneing, etc.).
Thanks very much for more of your really nice comparative tests with the Oly 20/2 & 38/2.8, Nikon 10/.30, Luminar 16 and EL Nik 50/2.8 (the Luminar did quite well...). I actually do value these kinds of moth scale tests quite highly (David Millard's "7 lenses at 4x" is a favorite, and I frequently refer to it for information; also to drool at the great glass so nicely displayed...). In fact, it was Davids "7 lenses" test that started me on a quest to find the "right" micro lens for stacking. What these various tests show me (put very simply) is: objectives (specifically the Nikon CFN 10/.30 & CFN PlanApo 4/.20) do the best job at stacking; some micro lenses do better than others at coming close to the performance of the objectives. My goal has been to figure out just which micro lens does come closest to the objective's quality re. stacking.
My own tests (with fly heads at 5 to 15x -- mostly not fit to show publicly, partly because variables -- like lighting -- were not controlled so nicely as you and David have done), along with your tests, have helped me reach some conclusions re. this list of "great micro lenses for stacking." However, I still need more info before I can finalize my personal list (I need to redo some of my tests and, especially, I need results for certain potentially great stacking lenses -- like a Photar 25/2). I do have a couple of test shots I can show (even though these vary in lighting and completeness of stack): the fly is a Paragorgopsis sp. (Ulidiidae) from Costa Rica.
Minolta 12.5/2.0 (shot at f4) @120mm [55@0.025,ZS] - full frame (some sharpening).
same as above: 100% crop (no sharpening, etc.).
Nikon CFN 10/.30 @185mm [90@0.005, ZS] - 100% crop (no sharpeneing, etc.).
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rjlittlefield
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Eric,
The images you just posted look so very good that I wonder if you are troubling over differences so fine they don't really matter.
The Nikon CFN 10/0.30 should definitely give the highest resolution of what you've shown, and the fact that it actually does so can easily be seen in the fine textures around the eye and in the longitudinal striations that are just becoming visible on some of the bristles.
The Minolta 12.5 at f/4 is considerably less sharp, but still it gives indication of all the same textures and structures except for the striations on the bristles. Stacking will go about 3 times faster at f/4 than at NA 0.30, and even more so if you reduce magnification and pixel count to match. Does the increased resolution justify the longer time?
Regarding the Photar, I don't have one to test. But from wringing out other lenses I would be surprised if there were much difference between one brand and another of the high end lenses.
Given my own arsenal, for high mag work I find myself mostly using the Olympus 38 mm f/2.8 bellows macro lens and the Nikon 10X/0.30 objective. The bellows macro lens gives ample working distance for most tasks and allows stopping down as appropriate, while the objective gives the highest possible resolution at the cost of painfully shallow DOF. The Luminar 16mm and the Olympus 20mm mostly stay in their drawers because the working distance makes them less convenient and it's a rare subject that I decide needs only the modest improvement in resolution that they provide over the 38/2.8.
As you can probably hear in my words, there are a lot of subjective factors in some of these decisions. It probably also matters that I seldom use the same setup twice. There is a big difference between the sort of one-at-a-time applications that I do, and gearing up to document hundreds of species of flies with directly comparable illustrations.
--Rik
The images you just posted look so very good that I wonder if you are troubling over differences so fine they don't really matter.
The Nikon CFN 10/0.30 should definitely give the highest resolution of what you've shown, and the fact that it actually does so can easily be seen in the fine textures around the eye and in the longitudinal striations that are just becoming visible on some of the bristles.
The Minolta 12.5 at f/4 is considerably less sharp, but still it gives indication of all the same textures and structures except for the striations on the bristles. Stacking will go about 3 times faster at f/4 than at NA 0.30, and even more so if you reduce magnification and pixel count to match. Does the increased resolution justify the longer time?
Regarding the Photar, I don't have one to test. But from wringing out other lenses I would be surprised if there were much difference between one brand and another of the high end lenses.
Given my own arsenal, for high mag work I find myself mostly using the Olympus 38 mm f/2.8 bellows macro lens and the Nikon 10X/0.30 objective. The bellows macro lens gives ample working distance for most tasks and allows stopping down as appropriate, while the objective gives the highest possible resolution at the cost of painfully shallow DOF. The Luminar 16mm and the Olympus 20mm mostly stay in their drawers because the working distance makes them less convenient and it's a rare subject that I decide needs only the modest improvement in resolution that they provide over the 38/2.8.
As you can probably hear in my words, there are a lot of subjective factors in some of these decisions. It probably also matters that I seldom use the same setup twice. There is a big difference between the sort of one-at-a-time applications that I do, and gearing up to document hundreds of species of flies with directly comparable illustrations.
--Rik
Rik,
Thanks for the compliments and, again, for the good advice. In the drama of 'Waiting for Leica Photar' I'm probably foolish about obsessing after another micro lens.
Why do you prefer the OM 38 over the OM 20? Is it simply the greater working distance, or do you have optical reasons also? An 18-20mm w.d. is fine for me, with my vertical stand setup, but 6-8mm (Minolta 12.5) is too close oftentimes (especially like when your subject is attached to an insect pin!).
Eric
Thanks for the compliments and, again, for the good advice. In the drama of 'Waiting for Leica Photar' I'm probably foolish about obsessing after another micro lens.
Why do you prefer the OM 38 over the OM 20? Is it simply the greater working distance, or do you have optical reasons also? An 18-20mm w.d. is fine for me, with my vertical stand setup, but 6-8mm (Minolta 12.5) is too close oftentimes (especially like when your subject is attached to an insect pin!).
Eric
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rjlittlefield
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My preference is only a matter of working distance, and that issue is wrapped up with my choice of illumination systems in a way that I have never thought about very carefully. I suspect it has to do with the radius of a ping pong ball versus the working distance of the lens. If I recall correctly, I was becoming very fond of ping pong ball diffusers at the same time I acquired the Olympus lenses, and the 38 was a better fit. Now that I lean more toward paper diffusers, it doesn't matter as much. Perhaps I am continuing to prefer the 38 as a matter of habit more than rational analysis!
BTW, I confirm your measurement of 18-20 mm for the Olympus 20, measured from the front of the mount to the subject focus over the span of my Olympus bellows. The same measurement for the Olympus 38 is 36-46 mm, the Luminar 16 is 9.4-10 mm, the EL Nikkor 50 is 45-75, and the Nikon 10X/0.30 objective is 8.7-9.6 mm (over the span of useful magnifications). I understand from Charlie Krebs that there are other CF objectives with longer working distances, such as an SLWD 10/0.21 with a working distance of 20.4 mm. They are not cheap, however!
--Rik
BTW, I confirm your measurement of 18-20 mm for the Olympus 20, measured from the front of the mount to the subject focus over the span of my Olympus bellows. The same measurement for the Olympus 38 is 36-46 mm, the Luminar 16 is 9.4-10 mm, the EL Nikkor 50 is 45-75, and the Nikon 10X/0.30 objective is 8.7-9.6 mm (over the span of useful magnifications). I understand from Charlie Krebs that there are other CF objectives with longer working distances, such as an SLWD 10/0.21 with a working distance of 20.4 mm. They are not cheap, however!
--Rik
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rjlittlefield
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No surprise, given the aperture. But NA 0.21 is equivalent to an f/2.16 lens with P=1, which is a noticeable improvement over the equivalent f/2.6 of the Olympus 20 mm f/2 with P=0.75 . Assuming the image quality tracks the aperture size, this could be a useful component in a tightly optimized system, even if working distance is not an issue.ChrisR wrote:It's easy to see on the camera, that it's also not as goodSLWD 10/0.21 with a working distance of 20.4 mm. They are not cheap, however!
--Rik