Beetle scales at 25x (Nikon BD Plan 20/0.4)

eurythyrea · Post by **eurythyrea** » Mon Jan 03, 2011 5:30 am

I've just ended the work with my new objective, the Nikon BD Plan 20/0.40 210/0. I know it has small working distance, but it's quite enough for me to experiment in this range of magnification. Unlike my Leitz 50x, I am satisfied with this lens' results.

Click for a 2400px version!

These scales cover the whole prothorax of the scarab beetle Hoplia argentea. Stacked from 61 shots, the bellows was adjusted to 210mm from the bayonet to the objective's thread. So I got more than 20x magnification, around 25x. Increments: 4 micron between each shot.

The habit photo of the beetle:

Shot with the Canon MP-E 65/2.8 lens @ 2:1, the photo is cropped around 20%. View larger!

At last here are two photos of the objective and how I operated it with:

Regards, Nikola

Mitch640 · Post by **Mitch640** » Thu Jan 06, 2011 4:09 am

Interesting adaptation. Are the scales actually curved flat plates, or are they more like little balls? Hard to tell from the image, as I can't see an edge on them.

Nice work.

eurythyrea · Post by **eurythyrea** » Thu Jan 06, 2011 5:57 am

You are right Mitch, on this picture doesn't seem the spatiality of the scales. I took a look on it through a stereo microscope and ascertained these are flat plates.

Thank you for commenting!

liuto · Post by **liuto** » Thu Jan 06, 2011 11:28 am

Beautiful work, Nikola!
I have a question regarding the objective: I had no problem to get rid of the outer ring, but how did you manage to loosen the inner ring?

Thanks
Hermann

rjlittlefield · Post by **rjlittlefield** » Thu Jan 06, 2011 11:38 am

liuto wrote:how did you manage to loosen the inner ring?

I have a similar objective whose threads turned out to be sealed by some clear compound resembling nail polish. I could not get it apart by simple twisting, but it came loose easily after applying a tiny amount of ethyl acetate to the thread junction and allowing it to wick in and sit for a minute. "Tiny amount" means something like 1 microliter -- just enough to wick into the threads but not go any farther.

--Rik

liuto · Post by **liuto** » Fri Jan 07, 2011 8:32 am

Thanks Rik, worked out perfectly!

eurythyrea · Post by **eurythyrea** » Sat Jan 08, 2011 4:08 am

Thank you Rik replying instead of me

I was not lucky like you in removing the inner barrel. I tried it with a few drops of lubricant, but did not work. Then I drilled two small holes in to the barrel opposite to eachother. You can see it on the picture a small gold-coloured fleck. I could seize the barrel with a modified pliers through these small mortises.

Rik, did not you afraid of ethyl acetate makes some harm in the lenses?

jotafoto · Post by **jotafoto** » Sat Jan 08, 2011 6:31 am

It's funny, I have the same objective by name, but has a different construction. I think they're the same dog but with a different collar. Right?.
Does anyone know if there is any optical difference between the two models? I guess mine is older.

greetings
Javier

rjlittlefield · Post by **rjlittlefield** » Sat Jan 08, 2011 11:03 am

eurythyrea wrote:Rik, did not you afraid of ethyl acetate makes some harm in the lenses?

Yes, but in the same way that I am afraid of my table saw -- work very carefully to avoid damage or injury. That is why I spelled out such a small amount of solvent (1 microliter). I had also examined the lens beforehand to determine that the solvent would have to travel a long way, something like 2 cm along a surface, to get anywhere near the glass.

--Rik

NikonUser · Post by **NikonUser** » Sat Jan 08, 2011 11:48 am

A grease solvent such as Xylene may also work.
I suspect the front lens is cemented in place with the same cement as oil immersion objectives. These are routinely cleaned with strong oil solvents such as Xylene, and Toluene.

Brodie Foster · Post by **Brodie Foster** » Sat Jan 14, 2012 12:22 am

eurythyrea · Post by **eurythyrea** » Sat Jan 14, 2012 1:08 am

Brodie, till then I bought 2 of them for my friends, and both cases managed to remove the inner barrel only with pure ethyl acetate (99%). Did not try other tinctures. However, I wasn't able to measure such small amount of the liquid (did not use the syringe), I put a bit more I think. Not only to the holes, but to the thread as well, where the barrel connects the main part. You have to repeat the operation 2-3 times because this liquid evaporates very quickly. And wait a few minutes, then try to screw them using rubber gloves. I believe it will work for you too!

rjlittlefield · Post by **rjlittlefield** » Sat Jan 14, 2012 1:30 am

Brodie Foster wrote:Rik, did you use ethyl acetate only because it was a possible solvent to what resembled nail polish or will it work on other compounds? If it will work on others, does it need to be pure ethyl acetate or will one of the more basic ethyl acetate based nail polish removers be 'safe'? Or are there any more common grease solvents that may be suitable?

I used ethyl acetate because I had it, I knew it dissolves a lot of plastics, and it evaporates cleanly. Carburetor cleaner might work also; I don't recall if I tried that. Anything that leaves behind an oil could be a problem, so I would test first on a blank piece of glass to see what's left on evaporation.

--Rik

Harold Gough · Post by **Harold Gough** » Sat Jan 14, 2012 2:06 am

An interesting and attractive subject. Those scales look like jelly beans.

Harold

Brodie Foster · Post by **Brodie Foster** » Sat Jan 14, 2012 3:16 am