Advice on a 40x/50x microscope lens.

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arnsteins
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Advice on a 40x/50x microscope lens.

Post by arnsteins »

Can someone point out to me which microscope lens in the range 40x-50x is worth buying? I`m using it on a vertical setup with a Nikon DSLR on a bellow. The lens should have a long working distance.
Thanks!

Best regards,
Arnsteins

JH
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Post by JH »

Hi Arnsteins
Thank you for the question about 40-50x you asked here and on my webbpage-contact.

The possibilites are quite limited. I understand from your question that you need a long working distance. On this forum there is some good examples of pictures where forum members used the Mitutoyo plan apo 50x infinity (no bellows but a tube lens is needed). The Mitutoyo have 13.0 mm working distance. I do not have that Mitutoyo 50x but uses the 20x from time to time.

The finite Nikon 40x plan apo lens I like to use on my microscope has a very short working distance 0.7 mm compared to the Mitutoyos 13.0 mm but the larger NA 0.8 compared to 0.55 for the Mitutoyo means that the resolving power is approx 0.3 micrometers compared to 0.5 micrometers for the Mitutoyo.

Hope this helps
Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

rjlittlefield
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Post by rjlittlefield »

The Nikon CF Plan 50X NA 0.55 inf/0 EPI ELWD (8.7 mm) is also decent, though with less WD and more CA than the Mitutoyo. See example image #1 at http://www.photomacrography.net/forum/v ... hp?t=15581, with CA in single frame at http://www.photomacrography.net/forum/v ... 9228#99228.

The Nikon LU Plan 50x / 0.55 ELWD inf/0 EPI (WD 9.8) should also be good, but I have not used that one.

--Rik

Macro_Cosmos
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Post by Macro_Cosmos »

Longer WD = lower resolution and correction = easier lighting
Shorter WD = higher resolution and correction = harder lighting

Depends on your setup and skill level. Also many Nikon, Zeiss, and Olympus objectives require their own branded systems to achieve full performance. Think of it as a bundle sale, which is not at all cheaper.

Also note at 40x, heat could become an issue... thermal expansion. If speedlights or strobes are used, the "impulse wave" from it could also be an issue (put speedlight at full power, close eyes, face the xenon tube towards palm, you can feel it). Also there's stability problems.

The ones mentioned above are all pretty decent.

Chris S.
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Post by Chris S. »

Arnsteins,

Since you are working on a bellows (that is, without a converging lens to support infinite objective designs, finite lenses might better fit your current system). Two finite Nikon lenses that might work for you are:
  • Nikon M Plan 40x/0.50 ELWD 210/0 WD 10.9mm
    Nikon M Plan 60x/0.70 ELWD 210/0 WD 5.9mm
These are similar to the Nikon infinites that Rik mentioned; however, unlike the infinites, the finite lenses I listed can be mounted right on your bellows, without a converging lens (aka "tube lens").

As Rik demonstrated, these lenses will produce some chromatic aberration, often as purple fringes in high-contrast areas of your image. Focus stacking tends to reduce this effect. But to nearly eliminate it, one must move to Apochromatic objectives. These apochromats—especially Mitutoyo and some Olympus specimens built to have long working distance—are expensive.
Macro_Cosmos wrote:. . . many Nikon, Zeiss, and Olympus objectives require their own branded systems to achieve full performance. Think of it as a bundle sale, which is not at all cheaper.
I’d quibble with a portion of the statement above. For a long time, Nikon objectives have not required chromatic aberration correction from other optical elements, and can be used without compensating optics from Nikon. The dividing line is when “CF” glass (presumably “chroma free”) took over, replacing the non-CF glass that came before it. Nikon has used CF glass for decades. While prior, non CF Nikon objectives are seen on eBay, they are easy to visually recognize and avoid. Arsteins, if you have any questions about this, ask and we will explain. The Nikon lenses named by Rik and me are all of the CF era, and can be used free of worry about matching to other Nikon optics.
Macro_Cosmos wrote:Also note at 40x, heat could become an issue... thermal expansion. If speedlights or strobes are used, the "impulse wave" from it could also be an issue (put speedlight at full power, close eyes, face the xenon tube towards palm, you can feel it). Also there's stability problems.
I also feel compelled to quibble with this observation, even though I agree with it to an extent. In my experience, speedlights and strobes often cause subjects to move violently during exposure. For this reason, I mostly work with continuous light (and have a solid macro rig that can easily accommodate continuous light). In my particular experience, seeing flash bounce the subject around has not been limited to higher magnifications. Rather, I find that it can happen at practically any magnification. Hence, my use of continuous lighting on a very stable rig.

Cheers.

--Chris S.

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Pawel
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Post by Pawel »

Of all those mentioned above, I like to use the Nikon CF Plan but a newer version, with an improved CA ... OFN25 with a larger field.
Image
my examples are below:

Image
Image
Image
..and..

Image
and 100% crop..
Image

Macro_Cosmos
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Post by Macro_Cosmos »

Chris S. wrote: I’d quibble with a portion of the statement above. For a long time, Nikon objectives have not required chromatic aberration correction from other optical elements, and can be used without compensating optics from Nikon. The dividing line is when “CF” glass (presumably “chroma free”) took over, replacing the non-CF glass that came before it. Nikon has used CF glass for decades. While prior, non CF Nikon objectives are seen on eBay, they are easy to visually recognize and avoid. Arsteins, if you have any questions about this, ask and we will explain. The Nikon lenses named by Rik and me are all of the CF era, and can be used free of worry about matching to other Nikon optics.

I also feel compelled to quibble with this observation, even though I agree with it to an extent. In my experience, speedlights and strobes often cause subjects to move violently during exposure. For this reason, I mostly work with continuous light (and have a solid macro rig that can easily accommodate continuous light). In my particular experience, seeing flash bounce the subject around has not been limited to higher magnifications. Rather, I find that it can happen at practically any magnification. Hence, my use of continuous lighting on a very stable rig.

Cheers.

--Chris S.
Thanks for the corrections, my statements were fairly loose and general. At about 1-2x, I've never experienced something too detrimental with flashes; once I got to 10x, it has became an issue, especially with butterfly and moth wings. But then, I've never shot butterfly wings at 1 or 2x, it's mainly minerals.

arnsteins
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Post by arnsteins »

Thanks for your good advice. I think I want to try the M Plan 40x to see if it works. Would this be equal to the one you mentioned, @Chris S?
https://www.ebay.com/itm/NIKON-M-Plan-4 ... :rk:4:pf:0

I`m aware of the sensitivity with vibration, that`s why I`m thinking about taking my system from vertically to horizontally. Could it be easier to manage the vibration factors then?

Thanks!!
/:-A

Adalbert
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Post by Adalbert »

Hello Arnsteins,

What about the cheap Oly MSPlan 50x (ca. $100) ?
https://www.photomacrography.net/forum/ ... highlight=


tube-lens=200mm => 50:1
Image


tube-lens=100mm => 25:1
Image

BR, ADi

arnsteins
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Post by arnsteins »

But I need a tube lens, and I was trying to look for fixed lenses to use on my bellow. ;)

-ArnsteinS

Adalbert
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Post by Adalbert »

Hello Arnsteins,

In my examples I have used the normal photo-lenses as the tube-lenses:
100mm = CANON EF 100L macro
200mm = CANON EF 70-200L 1:4

BR, ADi

rjlittlefield
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Post by rjlittlefield »

arnsteins wrote:But I need a tube lens, and I was trying to look for fixed lenses to use on my bellow.
Bear in mind that for an additional ~$100 you can mount a Raynox DCR-150 between the objective and bellows to serve as a tube lens. The combination of objective+Raynox acts just like a finite objective, except for being physically larger.

--Rik

Chris S.
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Post by Chris S. »

Depending on what other optics Arnsteins uses on his bellows, I may sympathize with his desire to work only with finite objectives on his setup. This even though, as others have pointed out, infinite objectives can work fine on a bellows with even a modest converging lens added. What would bother me is the fiddling around that this would require when changing magnifications, assuming that one has finite objectives for other magnifications.
arnsteins wrote:Would this be equal to the one you mentioned, @Chris S?
https://www.ebay.com/itm/NIKON-M-Plan-4 ... :rk:4:pf:0
That objective would work on a bellows, but it is not the same as the one I mentioned. I suggested the Nikon M Plan 40/0.50 ELWD, whereas this auction is for a Nikon M Plan 40/0.40 SLWD. At the risk of repeating things you know already, let me point out the differences.

The number after the front slash is the numerical aperture ("NA") of the lens. The resolving power of a lens is limited by its numerical aperture; the higher the NA, the finer detail the lens can resolve. So a well-designed lens with an NA of 0.50 has noticeably finer resolution than a well-designed lens with an NA of 0.40.

Balancing against the greater resolution of the NA 0.50 lens is decreased working distance ("WD") compared with the NA 0.40 lens. Working distance, in this case, is the amount of room between the front of the objective and an in-focus subject. Nikon objectives with greater-than-normal working distance can be labeled "LWD" (Long Working Distance), "ELWD" (Extra-Long Working Distance), or "SLWD" (Super-Long Working Distance. As this designation moves from "Long" to "Extra-Long" to "Super-Long," working distance increases, and NA goes down.

The Nikon M Plan 40/0.50 ELWD has 10.1mm of working distance, which is quite a lot for a 40x objective, and not hard to work with. The Nikon M Plan 40/0.40 SLWD would have a bit more working distance (I don't know how much off-hand), but at the cost of reduced resolution due to the smaller NA. Though I've seen some fine photographs made with 40/0.40 SLWD objectives, to my mind, the sweet spot for macro work is the 40/0.50 ELWD.
arnsteins wrote:I`m aware of the sensitivity with vibration, that`s why I`m thinking about taking my system from vertically to horizontally. Could it be easier to manage the vibration factors then?
Between vertical and horizontal macro rigs, I don't think either is inherently more vibration-resistant than the other. Far more important are details of your particular build. If you're having issues with vibration, could you start a new thread asking for help with this? I'd suggest including detailed pictures of your macro rig, and a description of the environment in which you use it. (And rest assured--vibration is probably the most common issue faced by photomacrographers. We've all been frustrated by it.)

Cheers,

--Chris S.

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Post by ChrisR »

Nikon MPlan:
Image
Chris R

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