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ForenSeil
Joined: 15 Apr 2011 Posts: 2726 Location: Kiel, Germany.
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Posted: Sat Feb 18, 2012 9:25 pm Post subject: Testing 3 lenses as tube lenses for microscope objectives |
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ForenSeil wrote:
Hi
I bought an used el cheapo microscope (26€) with RMS- objective and standart eye pieces (around 1") mount and modified it to RMS/M27 and M42 camera mount. Some "planachromat" objectives came with it - but they were all crap, showing heavy CAs, curved focues field and so on anway. So I needed a good microscope lens.
I found that Nikon and Olympus microscope lenses are good and bought a modern Nikon 10x 0.30 NA infinity microscope lens.
These good modern microscope lenses are not projecting a picture directly like their older counterparts - they are "corrected for infinty".
http://www.microscopyu.com/tutorials/java/components/infinitymicroscope/index.html
So they need another "normal" lens around 200mm which is focused to infinity to produce a picture.
Good native 200 so called "tube lenses" for microscopes cost around 200€ and above. And I didn't wan't to spend so much money for an experiment so I decided to try alternatives.
The competitors are the Schneider Kreuznach G-Claron 150 f/9 (APO), Rodenstock Rodagon 150mm f/5.6 and Tokina RMC 200mm F3.5. All are very cheap used.
Here are some pics of the setup:
And here's the direct comparision:
Here some test shots around 10:1 magnification:
Rodagon 150 f5.6
G-Claron 150 f9
Tokina 200 f3.5
Tokina 200 F3.5 (2)
Rodagon 150 f5.6 (2) von Chloressigsäureethylester auf Flickr
G-Claron 150 f9 (2)
And here a pic of the coin with exatly 1:1 magnification for comparision:
Which is the best one to your eyes?
Tokina has best colors and lowest vignetting but is less sharp than Rodagon and Claron.
Rodagon has better overall colors than the G-Claron but the G-Claron has best CA control at highlights and the highest acutance to my eyes. _________________ I'm not a collector, I'm a tester
My camera: Sony A7+Zeiss Sonnar 55/1.8
Current favourite lenses (I have many more):
A few macro-Tominons, Samyang 12/2.8, Noritsu 50.7/9.5, Rodagon 105/5.6 on bellows, Samyang 135/2, Nikon ED 180/2.8, Leitz Elmar-R 250/4, Celestron C8 2000mm F10
Most wanted: Samyang 24/1.4, Samyang 35/1.4, Nikon 200/2 ED
My Blog: http://picturechemistry.own-blog.com/
(German language)
Last edited by ForenSeil on Mon Feb 20, 2012 1:47 am; edited 1 time in total |
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s58y
Joined: 05 Sep 2010 Posts: 131 Location: Eastern NY
Expire: 2013-09-10
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Posted: Sun Feb 19, 2012 3:01 pm Post subject: |
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s58y wrote:
They look about the same to me.
I seem to recall old discussions over at photomacrography.net, where the most important thing about the tube lens was entrance or exit pupil location/size, etc. and its effect on vignetting at the corners. I don't recall the details.
The effective aperture of a 10x objective at its rated magnification is something like f/15 to f/20 (depending on N.A. and all that), so as long as the lens can produce an image at the sensor at f/15 that is as good the best lenses out there, it's good enough to be a tube lens. With the 150mm lenses, I guess you'd be working at 7.5x with an effective f/11-f/15 aperture, so your lens needs to work as well at these f ratios.
Is the lower vignetting from the 200mm Tokina because it gives 10x and a narrower field than the other two 150mm lenses?
Maybe some expert over at photography.net will come along with a better answer, but I don't see any responses over there yet. _________________
flickr photostream
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poilu
Joined: 26 Aug 2007 Posts: 10472 Location: Greece
Expire: 2019-08-29
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Posted: Sun Feb 19, 2012 4:02 pm Post subject: |
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poilu wrote:
s58y wrote: |
They look about the same to me |
+1
s58y explanation about diffraction seems logical, whatever lens will give about the same quality at f15-f20 effective on a crop _________________ T* |
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visualopsins
Joined: 05 Mar 2009 Posts: 10959 Location: California
Expire: 2025-04-11
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Posted: Sun Feb 19, 2012 5:11 pm Post subject: |
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visualopsins wrote:
Now I'm confused...
I thought this RMS-M42 adapter (Click here to see on Ebay) is for use only with infinity corrected RMS objectives. _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ like attracts like! ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮
Cameras: Sony ILCE-7RM2, Spotmatics II, F, and ESII, Nikon P4
Lenses:
M42 Asahi Optical Co., Takumar 1:4 f=35mm, 1:2 f=58mm (Sonnar), 1:2.4 f=58mm (Heliar), 1:2.2 f=55mm (Gaussian), 1:2.8 f=105mm (Model I), 1:2.8/105 (Model II), 1:5.6/200, Tele-Takumar 1:5.6/200, 1:6.3/300, Macro-Takumar 1:4/50, Auto-Takumar 1:2.3 f=35, 1:1.8 f=55mm, 1:2.2 f=55mm, Super-TAKUMAR 1:3.5/28 (fat), 1:2/35 (Fat), 1:1.4/50 (8-element), Super-Multi-Coated Fisheye-TAKUMAR 1:4/17, Super-Multi-Coated TAKUMAR 1:4.5/20, 1:3.5/24, 1:3.5/28, 1:2/35, 1:3.5/35, 1:1.8/85, 1:1.9/85 1:2.8/105, 1:3.5/135, 1:2.5/135 (II), 1:4/150, 1:4/200, 1:4/300, 1:4.5/500, Super-Multi-Coated Macro-TAKUMAR 1:4/50, 1:4/100, Super-Multi-Coated Bellows-TAKUMAR 1:4/100, SMC TAKUMAR 1:1.4/50, 1:1.8/55
M42 Carl Zeiss Jena Flektogon 2.4/35
Contax Carl Zeiss Vario-Sonnar T* 28-70mm F3.5-4.5
Pentax K-mount SMC PENTAX-A ZOOM 1:3.5 35~105mm, SMC PENTAX ZOOM 1:4 45~125mm
Nikon Micro-NIKKOR-P-C Auto 1:3.5 f=55mm, NIKKOR-P Auto 105mm f/2.5 Pre-AI (Sonnar), Micro-NIKKOR 105mm 1:4 AI, NIKKOR AI-S 35-135mm f/3,5-4,5
Tamron SP 17mm f/3.5 (51B), Tamron SP 17mm f/3.5 (151B), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto (Kiron)
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kds315*
Joined: 12 Mar 2008 Posts: 16627 Location: Weinheim, Germany
Expire: 2021-03-09
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Posted: Sun Feb 19, 2012 5:21 pm Post subject: |
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kds315* wrote:
ehemm, I would look up "infinity objectives" and "tube lens" - google is your friend _________________ Klaus - Admin
"S'il vient a point, me souviendra" [Thomas Bohier (1460-1523)]
http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
https://www.flickr.com/photos/kds315/albums my albums using various lenses
http://photographyoftheinvisibleworld.blogspot.com/ my UV BLOG
http://www.travelmeetsfood.com/blog Food + Travel BLOG
https://galeriafotografia.com Architecture + Drone photography
Currently most FAV lens(es):
X80QF f3.2/80mm
Hypergon f11/26mm
ELCAN UV f5.6/52mm
Zeiss UV-Planar f4/60mm
Zeiss UV-Planar f2/62mm
Lomo Уфар-12 f2.5/41mm
Lomo Зуфар-2 f4.0/350mm
Lomo ZIKAR-1A f1.2/100mm
Nikon UV Nikkor f4.5/105mm
Zeiss UV-Sonnar f4.3/105mm
CERCO UV-VIS-NIR f1.8/45mm
CERCO UV-VIS-NIR f4.1/94mm
CERCO UV-VIS-NIR f2.8/100mm
Steinheil Quarzobjektiv f1.8/50mm
Pentax Quartz Takumar f3.5/85mm
Carl Zeiss Jena UV-Objektiv f4/60mm
NYE OPTICAL Lyman-Alpha II f1.1/90mm
NYE OPTICAL Lyman-Alpha I f2.8/200mm
COASTAL OPTICS f4/60mm UV-VIS-IR Apo
COASTAL OPTICS f4.5/105mm UV-Micro-Apo
Pentax Ultra-Achromatic Takumar f4.5/85mm
Pentax Ultra-Achromatic Takumar f5.6/300mm
Rodenstock UV-Rodagon f5.6/60mm + 105mm + 150mm
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ForenSeil
Joined: 15 Apr 2011 Posts: 2726 Location: Kiel, Germany.
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Posted: Mon Feb 20, 2012 1:05 am Post subject: |
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ForenSeil wrote:
I think I will keep the G-Claron as it's the cheaper (it did cost around 22€) than the Rodagon and also a little easier to adapt to my microscope.
Bye the way I'm a litte astonished as the speed of the tube lens it didn't interfere with the effective apertures... all produced the about same effective speed.
visualopsins wrote: |
Now I'm confused...
I thought this RMS-M42 adapter (Click here to see on Ebay) is for use only with infinity corrected RMS objectives. |
Don't you mean "finite" objectives? Usually only finite objectives can be used directly on a bellows with such an adapter.
You can only use it for infintiy objetives when you are adding it with such an adapter http://www.ebay.de/itm/Adapterring-52mm-Ausengewinde-42mm-Innengewinde-M42-/130459203272?pt=DE_Foto_Camcorder_Filteradapter&hash=item1e5ff976c8 in the filter ring of a ~200mm lens. But you will need a very good tripod to make pics with it as at around 10:1 as even the vibration of an shutter will look like an earthquake on the pic if the camera isn't stabilised very well
There are also good finite objectives for photography... but they are much harder to find, especially on Ebay Germany which was one of the main reasons to go the way with a tube lens For example many finite LOMO objective are decent and cheap and the Nikon achromatic finite conjugate objectives (can be bought new around 80€) are known to produce a good quality.
s58y wrote: |
...I guess you'd be working at 7.5x with an effective f/11-f/15 aperture, so your lens needs to work as well at these f ratios.
Is the lower vignetting from the 200mm Tokina because it gives 10x and a narrower field than the other two 150mm lenses?
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NA is 0.3, so the fixed aperture should be f/1.58 and the effective aperture should be ~f/13,5 at 7.5x and ~f/17,5 at 10:1
Is that really so easy (if you don't care about vignetting)? 200mm = 10:1, 150mm = 7,5:1, 100mm = 5:1... 25mm 1,25:1...??? _________________ I'm not a collector, I'm a tester
My camera: Sony A7+Zeiss Sonnar 55/1.8
Current favourite lenses (I have many more):
A few macro-Tominons, Samyang 12/2.8, Noritsu 50.7/9.5, Rodagon 105/5.6 on bellows, Samyang 135/2, Nikon ED 180/2.8, Leitz Elmar-R 250/4, Celestron C8 2000mm F10
Most wanted: Samyang 24/1.4, Samyang 35/1.4, Nikon 200/2 ED
My Blog: http://picturechemistry.own-blog.com/
(German language) |
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