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Varieties at 4x  
 

 
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Pillar of the Community

United States
2037 Posts
 Posted 02/13/2012  07:09 am Show Profile Bookmark this topic Add rmpsrpms to your friends list Get a Link to this Message

I just got a new piece of old glass in the mail Saturday and threw it on the bellows. Here is what I get. First image is a full-sensor shot at around 4-5x, downsized 4x. Second image is a 1600x1600 crop from the first image, downsized 2x.





This is the best I've been able to achieve at 4x so far. Anyone care to guess what the "new piece of old glass" is?

Bedrock of the Community
United States
13335 Posts
 Posted 02/13/2012  10:07 am  Show Profile Bookmark this reply Add John1 to your friends list Get a Link to this Reply
No clue. Those pics are WOW,color me jealous
John1
( I'm no pro, it's just my humble opinion )
Searched 4+ Million Cents Since 1971
Valued Member
United States
489 Posts
 Posted 02/13/2012  11:03 am  Show Profile Check brg5658's eBay Listings Bookmark this reply Add brg5658 to your friends list Get a Link to this Reply
The images and the magnification are stunning!

I have no idea on the lens, but I am excited to find out! Maybe a 28mm lens with an f of 2.8 or faster? Just a (not-so-educated) guess.
Pillar of the Community
United States
1641 Posts
 Posted 02/13/2012  11:45 am  Show Profile Check The_Duke's eBay Listings Check The_Duke's eCrater Listings Bookmark this reply Add The_Duke to your friends list Get a Link to this Reply
All I know is "those pictures are crazy good"!!
The_Duke
ANA# 3159445
http://dukescoins.ecrater.com/
Pillar of the Community
United States
1374 Posts
 Posted 02/13/2012  1:15 pm  Show Profile Bookmark this reply Add Drsandman2 to your friends list Get a Link to this Reply
What kind of set up you got going there, rmps?
Bedrock of the Community
Learn More...
10045 Posts
 Posted 02/13/2012  1:56 pm  Show Profile Bookmark this reply Add DVCollector to your friends list Get a Link to this Reply
Nice shots, as always!
Pillar of the Community
United States
2037 Posts
 Posted 02/13/2012  10:23 pm  Show Profile Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
This was taken with my standard setup, but instead of the 75ARD1 I used a Nikon CF Plan 4x 0.13 objective. I also used a new Director I built just for the purpose, with a tiny tip that fits nicely between the coin and objective even though there is only 14mm working distance...Ray
Pillar of the Community
United States
3057 Posts
 Posted 02/14/2012  12:44 am  Show Profile Bookmark this reply Add aladinslamp to your friends list Get a Link to this Reply
Very very nice Ray, and as always your research on lighting really shines! I was going to guess the missing E86 lenses your collecting...G
Valued Member
United States
489 Posts
 Posted 02/14/2012  12:44 am  Show Profile Check brg5658's eBay Listings Bookmark this reply Add brg5658 to your friends list Get a Link to this Reply

Quote:
Nikon CF Plan 4x 0.13 objective


Care to expand on what this is and what all of the "jargon" means?
Pillar of the Community
United States
2037 Posts
 Posted 02/14/2012  12:55 am  Show Profile Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Sorry, I love acronyms and jargon...

This is a microscope objective. Basically I attached a microscope objective to the bellows and made a mini-microscope out of it.

CF = Color Free, ie requires no color correction from the rest of optical system
4x is the optimized magnification
0.13 is the NA or Numerical Aperture. You can convert to effective aperture by calculating Feff = M/2*NA. So the effective aperture of this beast is f15, which is not bad at 4x. You can convert back to infinity aperture to compare to a normal lens by calculating Finf=Feff/(1+M) or Fin=3 for this lens.

Pillar of the Community
United States
3057 Posts
 Posted 02/14/2012  12:57 am  Show Profile Bookmark this reply Add aladinslamp to your friends list Get a Link to this Reply
some times MATH has its virtue, and to many its out of this world LOL......I need to travel space...
Valued Member
United States
489 Posts
 Posted 02/14/2012  01:06 am  Show Profile Check brg5658's eBay Listings Bookmark this reply Add brg5658 to your friends list Get a Link to this Reply
Ray, thanks for the detailed information -- I love jargon too, and I even love formulas more! Now, care to explain any of the details about how one attaches such a "lens" to a bellows? Are there standard threads for such lenses and/or adapters? Is this in the pricing ball park of a Printing Nikkor or an EL-Nikkor 80mm? -- or somewhere in between?
Pillar of the Community
United States
2037 Posts
 Posted 02/14/2012  01:17 am  Show Profile Bookmark this reply Add rmpsrpms to your friends list Get a Link to this Reply
Most of these objectives are "RMS" thread, which is 20mm in diameter. You can get RMS adapters to fit onto M42 bellows that are either flat or tapered (which are really cool looking) and you can also get RMS to 52mm reversing adapters for objectives that are "infinity" corrected (another discussion entirely). A lot of optical systems used RMS, and in fact the smaller Nikon Macro-Nikkors used RMS threads. So it's not terribly difficult to adapt, and if you have M42 bellows you are in great shape.

The gold standard for 4x objectives is the Nikon Plan Apo 4x 0.2. These will cost you at least $1k if you can find one. The one I bought is not an Apo and only has NA 0.13, but still does pretty well. I bought it on eBay for $125.

I have a few "run of the mill" 4x 0.1 objectives in the mail to test. I am not sure if they will give that great a result since their Feff=20, but they were cheap and I wanted to find out how good an image they can produce.
Valued Member
United States
489 Posts
 Posted 02/14/2012  01:30 am  Show Profile Check brg5658's eBay Listings Bookmark this reply Add brg5658 to your friends list Get a Link to this Reply
Very cool. The first thing I noticed on your image was that it was ridiculously sharp and the DOF was immense for that magnification. I figured possibly a 28 f/2.8 lens, as you'd be able to get to 4x and if you left it wide open you'd be shooting at Feff = 2.8(4+1) = f/15. Nonetheless, this is a whole new world of lenses for super-mag coin images. I love reading your posts! Thanks for all the info!
-Brandon
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