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UV Buttercup with Katoptaron LDM-1/s
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PostPosted: Tue Nov 06, 2018 9:14 pm    Post subject: UV Buttercup with Katoptaron LDM-1/s Reply with quote

This is a really quirky lens. A Katoptaron LDM-1/s. The LDM part stands for Long Distance Microscope, and it is a mirror only lens with focal length of 800mm. Unusually for a mirror lens it also has an adjustable aperture.

Here's picture of the lens.
#1


The camera mounts onto the extension tube on the left hand side of lens in the image above.

I'm quite fond of UV imaging at the moment. and I tried out the lens with a UV image of a Buttercup. The illumination was a single 365nm UV LED moved around during image acquisition, taken on my ACS UV modified Nikon d810 at ISO2000, and 1/2s exposure. Whitebalanced in Darktable. The flower was 2 meters from the front of the lens. Not sorted out my mount for the lens yet, so the lens was sat on the kitchen floor. I used self timer and exposure delay mode.

Firstly the full frame image (reduced resolution for sharing);
#2


And a crop from the image above (again reduced resolution slightly for sharing here). The Buttercup shows the characteristic black center in UV.
#3


PostPosted: Tue Nov 06, 2018 9:21 pm    Post subject: Reply with quote

Congrats, very rare and special lens this is! You seems to get good use out of it!
Personally I would recommend to use a stronger UV light, say a Nichia 365nm
LED torch for instance, as this also gives a bright preview image.


PostPosted: Tue Nov 06, 2018 10:05 pm    Post subject: Reply with quote

Thanks Klaus. It's an amazing lens. Yes, better light is on the list of things to get or build.


PostPosted: Tue Nov 06, 2018 10:36 pm    Post subject: Reply with quote

Congrats on the acquisition of this very rare lens! Image quality seems really good.

Cheers!

Abbazz


PostPosted: Wed Nov 07, 2018 10:15 am    Post subject: Reply with quote

Thanks Abbazz. Yes this lens has a lot of potential, and is a very interesting piece of history.


PostPosted: Wed Nov 07, 2018 12:40 pm    Post subject: Reply with quote

I am not specialist but what about sun light?

Otherwise nice find, indeed.


PostPosted: Wed Nov 07, 2018 1:15 pm    Post subject: Reply with quote

Sunlight is good for UV imaging, Spleenone. However any movement from wind when taking pictures outside is a huge issue, and exposure times with the small aperture this has would be very long as even modified cameras aren't that sensitive to UV. So ideally a still, wind free, environment is better for this one. And besides, here in the UK, sunlight is a rare thing Smile


PostPosted: Wed Nov 07, 2018 2:11 pm    Post subject: Reply with quote

Understand then. Hope you will have better conditions next time. Good luck for your trials.


PostPosted: Fri Nov 09, 2018 5:21 pm    Post subject: Re: UV Buttercup with Katoptaron LDM-1/s Reply with quote

JMC wrote:
This is a really quirky lens. A Katoptaron LDM-1/s. The LDM part stands for Long Distance Microscope, and it is a mirror only lens with focal length of 800mm. Unusually for a mirror lens it also has an adjustable aperture.

Here's picture of the lens.
#1


The camera mounts onto the extension tube on the left hand side of lens in the image above.

I'm quite fond of UV imaging at the moment. and I tried out the lens with a UV image of a Buttercup. The illumination was a single 365nm UV LED moved around during image acquisition, taken on my ACS UV modified Nikon d810 at ISO2000, and 1/2s exposure. Whitebalanced in Darktable. The flower was 2 meters from the front of the lens. Not sorted out my mount for the lens yet, so the lens was sat on the kitchen floor. I used self timer and exposure delay mode.

Firstly the full frame image (reduced resolution for sharing);
#2


And a crop from the image above (again reduced resolution slightly for sharing here). The Buttercup shows the characteristic black center in UV.
#3


Please find the patent for that lens

patent from : http://www.macrolenses.de/ml_detail_sl.php?ObjektiveNr=315

That lenses
    are uv ok because they are made of mirrors only
    can have a stop because light rays does not go back and forth

.. The drawbacks are
    quality image can be very poor if mirror or adjustements are not 100% perfect or if some dust goes on the mirrors (there is NO front lens or mirror blocking dust)
    the lenght is long because of the light path and because they have no refractor lenses inside = this is not what we are looking now for mirror lenses


Last edited by PBFACTS on Fri Nov 09, 2018 6:13 pm; edited 2 times in total


PostPosted: Fri Nov 09, 2018 6:03 pm    Post subject: Re: UV Buttercup with Katoptaron LDM-1/s Reply with quote

PBFACTS wrote:


Please find the patent for that lens


That lenses
    are uv ok because they are made of mirrors only
    can have a stop because light rays does not go back and forth

.. The drawbacks are
    quality image can be very poor if mirror or adjustements are not 100% perfect or if some dust goes on the mirrors (there is NO front lens or mirror blocking dust)
    the lenght is long because of the light path and because they have no refractor lenses inside = this is not what we are looking now for mirror lenses


If you copy stuff from my macrolenses site (where I have that patent image), then have the curtesy please to at least cite the source... http://www.macrolenses.de/ml_detail_sl.php?ObjektiveNr=315 Smile

Guess you haven't understood why this lens is so special, it is capable of working with UV light, this IS "what we are looking for", the "UV-people" Twisted Evil