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 Replies: 12 / Views: 1,454 |
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Pillar of the Community
United States
972 Posts |
Found this setup in my price range. anyone know about these. Does 40mm mean I have to be real close? or would an 85mm be better?   |
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Pillar of the Community
 United States
3933 Posts |
85mm would be much better. You'll be practically right on top of small coins with the 40mm.Even with 85mm you'll be very close.
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Pillar of the Community
 United States
972 Posts |
will the standard lens it comes with work or do I need to switch to a macro? AF-S DX NIKKOR 18-140mm f/3.5-5.6G ED VR lens  |
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Pillar of the Community
United States
3933 Posts |
The 18-140mm won't do well for coins. Its maximum magnification is 0.23x at 1.5ft closest focus distance. Even a Dollar, at 38mm diameter, requires ~0.37x to nearly fill the sensor frame. The 18-140mm will only fill ~8.7mm out of the ~15mm sensor height. You need a lens that can go up to 1x magnification in order to fill the sensor with smallest US coins, so a macro lens of some kind is a must. Personally, I'd recommend going with an enlarging lens with helicoid, which will cost you a lot less than a dedicated macro lens. Edited to add: here's a link to Ken Rockwell's review of the 18-140mm where I found the 0.23x magnification data: https://www.kenrockwell.com/nikon/18-140mm.htmEdited by rmpsrpms
10/21/2021 5:18 pm
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Bedrock of the Community
United States
17524 Posts |
Agree, a macro would offer better results. Don't neglect your lighting solution.
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Pillar of the Community
United States
972 Posts |
so either a dedicated this is only 85mm  or with helicoid how does the helicoid work? what is an enlarging lens? Edited by bishftl
10/21/2021 10:08 pm
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Pillar of the Community
United States
3933 Posts |
If you Google "what is an enlarging lens?" you get quite a few good hits, and related searches. Here is one of the hits for "Adapting enlarger lenses". This page shows the lens and helicoid in an animation to show how it works: https://www.dpreview.com/forums/thread/4235814 Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Bedrock of the Community
United States
17524 Posts |
If you live near a reputable, full service camera/photography store, you may be able to rent a lens or two to try them out.
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Pillar of the Community
United States
972 Posts |
here's some info on what I have now. and a couple test pics with 2 led.    Edited by bishftl
10/22/2021 8:30 pm
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Pillar of the Community
United States
3933 Posts |
It's hard to tell how well it will work. The minimum focus distance is not a useful metric, since it does not tell you the magnification. A shorter lens with same magnification will have a shorter minimum focus distance, yet may have lower magnification, so is less useful for coins. All you can do is experiment.
If what you have now is working for you, then no need to buy anything new.
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Pillar of the Community
United States
972 Posts |
my current camera is failing, been glitchy for a while now. shuts off on it's own. click on menu and it moves all around on it's own without even touching the buttons. time for an upgrade. last question, I promise. I don't know anything about cameras and focal lengths etc. i have the 28" copy stand with 2 super bright diffused LEDs.  will this lens be enough to do the job or do I need a 105mm. I'm going to try axial lighting as well.   |
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Pillar of the Community
United States
3933 Posts |
The 105mm would require more working distance. I think either the 85mm or 105mm would work with that copy stand for full range of coin sizes.
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Pillar of the Community
United States
972 Posts |
thanks for all the help, everyone.
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Replies: 12 / Views: 1,454 |
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Posted 10/20/2021 11:47 pm
