Recent Posts

1

Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by SANDAC on Today at 10:52:06 AM »

The focus stacking technology has changed a lot.  Microstepping stage like that was custom hardware and exceedingly expensive just a few years ago.  I am using Helicon Remote that does not move the camera but only change the focus plane.  It knows about the circle of confusion for a specific camera and can calculate the necessary focus steps and take the pictures.  It is fine for artistic applications, and I think it may be OK for a shallow focus depth with a dozen of so images.  Probably have to re-educate myself about focus stacking technology again.

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Buy, Sell & Trade / Re: Selling Silver Pandas

« Last post by Grip on Today at 08:44:56 AM »

All coins have been sold.

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Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by fwang2450 on Today at 12:52:20 AM »

Mark Goodman has very impressive pictures.  One image is composite of 77 focus stacks!  I wonder whether he manually move the camera or uses focus steps?

It is impossible to do it manually. I believe most people in the US use Stackshot: https://www.cognisys-inc.com/index.php. I use a cheepo version: https://world.taobao.com/item/526008941651.htm?fromSite=main&spm=a312a.7700824.w4004-7594797329.2.moZmTo

4

Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by SANDAC on Today at 12:47:48 AM »

Mark Goodman has very impressive pictures.  One image is composite of 77 focus stacks!  I wonder whether he manually move the camera or uses focus steps?

5

Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by fwang2450 on Yesterday at 11:53:08 PM »

Here is a link to Mark Goodman's review of the Minolta 12.5mm f2 bellows lens: http://coinimaging.com/min12bel.html. Normally it is pretty expensive, but I managed to pick one on eBay for $80.

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Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by fwang2450 on Yesterday at 11:43:59 PM »

Very impressive! is these pictures also taken with the enlarging lens?

The mechanical doubling picture was taken with the Rodagon APO 75 D enlarging lens. The flowline photos were shot with Canon 35mm F2.8 macro bellows lens. 10 pictures were taken for stacking, about 3:1. It is a lot easier with these bellows macro lens to shoot high magnification pictures. I managed to push to 8X with the Minolta 12.5mm F2.0 bellows micro (macro) lens. But going even higher is made difficult by diffraction.

7

Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by SANDAC on Yesterday at 09:31:37 PM »

Very impressive! is these pictures also taken with the enlarging lens?

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Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by fwang2450 on Yesterday at 06:08:47 PM »

Flowlines on the 40th Anniversary commemorative coin.

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Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by fwang2450 on Yesterday at 05:55:47 PM »

Mechanic doubling on a 1977 one Fen coin.

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Chinese Numismatic News, Articles, Books / Re: Chinese Coins: Take Your Best Shot

« Last post by SANDAC on Yesterday at 08:03:45 AM »

I find it easier to take a picture of a coin, rotate 90 degree and take another picture and examine the images on my computer.

This coin has strong diagonal striation lines in the center of the coin.  There are interesting blisters and bumps at the edge of the coin (1-2 o'clock, 3-4 o'clock).