APO Lenses for Coin Imaging posted by The Artist's Collection

[CSJournals-migration]

Regular camera lenses produce chromatic aberration:Red, Yellow & Blue do not

focus equally on the CCD sensor.

 

Apochromatic lenses, like BRG might use, focus the many varied color rays of

light together on the CCD sensor plane. Regular lenses not and therefore produce image distortion.

 

It would then seem beneficial for accurate coin color rendition to use an APO

lens.

 

This would include types of copy camera lenses as well as film enlarging

lenses and specialized apochromats made for cameras.

 

The lower curls on this Morgan Dollar have a magenta tint which is the earmark of chromatic aberration.

 

See more journals by The Artist's Collection

[Iowa Silver Baron Bammer]

I have heard about these lenses. But on my coins, I find that making sure the white balance setting on my camera is set for the type of bulbs being used, along with color adjustment in Microsoft Picture It! Premium 10 takes care of all of it.

 

I also have a book entitled "Numismatic Photography" by Mark Goodman. I really recommend this book to anyone who would like to take nice pictures of their coins. In it, he shows how proper lighting and lighting position can dramatically help out our photos. And he doesn't include the above types of lenses.

 

I am not trying to belittle the suggestions here, but rather point a way to possibly get good photos without worrying about extra lenses.

 

Iowa Silver Baron

[brg5658]

Actually, Mark Goodman has tested many of the enlarger and duplicating lenses used by some of us numismatic photographers. You can find his write-ups and analysis on his website here. In particular, he has tested the lens that I (and many others) use here.

 

As Mark himself notes in his write-up, the "APO" part of the Rodagon 1:1 75mm lens is not a true apochromat. There is still some abberation, particularly outside of its optimal magnification of 1:1. The main reasons why I use enlarger lenses or duplicating lenses are the following:

 

1. The prices are much more affordable and the quality truly rivals that of very expensive macro lenses.

 

2. The flexibility of enlarger/duplicating lenses for covering magnification ranges from 0.3:1 up through 4:1 or even more is hard to beat with a typical macro lens. This is particularly useful for variety attribution images or super-close-up photography.

 

3. I really like shooting with a bellows set up. It affords flexibility for keeping the lens far away from the coin (which means flexibility for placing your lights high). With a bellows set up, enlarger/duplicating lenses are natural lens to use.

 

4. The enlarger/duplicating lenses are specifically manufactured to maintain a flat field. What that means is that your images (in theory) are in focus from corner to corner of the frame. Modern expensive macros can compete with this characteristic, but for coin photography this is something you really desire. The optics are optimized for photographing a flat object at a fixed distance.

 

In summary, I have some $15-30 enlarger lenses that can compete with macro lenses that cost $600 or more. That's impressive to me!

 

-Brandon