coinimaging.com Blog

After the book went to press, I figured out that one statement I make in there is not quite true. I will fix it for further editions of the book, but I figure that I will head off things off and explain the correction here.

The error is on pg. 120. I describe the distribution of the depth of field as being a little deeper on the side of the camera from the focus plane. That is not correct and the depth of field at macro distance is almost equal on either side of the focus plane.

The depth of field for normal picture taking is typically deeper on the object side of the focus plane (away form the camera) and the distribution tends towards equal on either side as the magnification increases.

I have seen online statements suggesting that the depth of field can get larger on the camera side above 1:1 magnification, but when I plug the numbers into the depth of field equations, I see no way that it can. I will stick to “nearly equal” until proven otherwise.

My own suggestion of putting the sharp focus on the relief somewhere in the middle between the high point and the fields remains accurate. I even prefer to put the sharp focus closer to the fields as I prefer the fields to be sharpest. The picture seems to look the sharpest to me when the fields are razor sharp.

My apologies. Mark.

After a long wait and a lot of work, the finished book has finally arrived at the publisher (Zyrus Press). I presume that will mean that copies will soon be available from me or your favorite bookseller.

I am always looking to improve my writing/book, if you have any wants or suggestions for a future edition (should that come to be), let me know. 

For Immediate Release

June 2008

News media contact:

Uriah Cho, for Zyrus Press, (888) 622-7823

* Electronic file of cover image, description and other information available upon request

New Book Teaches Techniques and Tips on How to Photograph Coins

            (Irvine, CA) – As the use of the Internet and electronic visual media becomes more of a vital part of the coin industry, photographing coins, either raw or slabbed, has become an increasing concern with collectors and dealers. How do I get a good detailed image of this coin? What are the tools I need? Do I need to purchase any expensive equipment? What kind of lighting should I use? What techniques can I use to produce a good image of this coin?

In Numismatic Photography (published by Zyrus Press), Mark Goodman teaches the reader in an easy-to-read and visually rich guidebook format on how to image quality photos of coins with your digital camera. Whether you are using a digital camera for the first time or you already have experience in other fields of photography, Goodman addresses typical problems faced by the photographer, recommends ways of improvements and offers specific tips and techniques for raw and slabbed coins.

“[Mark] Goodman’s first numismatic book is an impressive addition to the coin collector’s arsenal of knowledge… Numismatic Photography is recommended for anyone interested in making better coin photos, or in learning how these images are made.”

–Roger Burdette, Author of the Renaissance of American Coinage series

Some of the chapters included are Imaging Concepts, Color and Luster, High Contrast Coins, Low Contrast Coins, Toned Coins, Special Imaging Techniques and Image Presentation, among others. The book also includes two appendices: a Troubleshooting Guide and General Rules for Coin Photography.

Releasing on July 15^th, look for copies of Numismatic Photography in bookstores nationwide, your local coin shop, or Amazon.com. You can also order from Zyrus Press by mailing to PO Box 17810, Irvine, California 92623, calling (888) 622-7823, or online at www.zyruspress.com.

Numismatic Photography Releases on July 15^th!

Published by Zyrus Press, Inc. of Irvine, California (www.zyruspress.com)

Publication Date: July 2008

Binding / Size: Paperback / 7×10

Pages: 160

Photos / Illustrations: 300+ full color images

ISBN: 978-1-933990-09-5

Suggested Retail Price: $29.95

I am told that the book should be arriving on 7/15 from the printer. The images below show what the final front and back covers will look like. It was pointed out to me recently that there are a couple problems with the covers.

1) The reflected image on the lens should be reversed: Well, maybe the coin is reversed, like a brockage or something. Didn’t think of that did you?

2) The lens on the front is a zoom lens: That isn’t really a problem since with a few minor add-ons a zoom lens can make a usable macro lens. So there.

The back cover is my actual setup. I am sitting in front of and to the right of the picture at this very moment.

I have been told that the book has been delivered to the printer, which means about 8-9 weeks until release. It has been a long slow process, but the final product should be worth it.

I just finished adding a new a larger image gallery to my website. At present there are over 1000 images online in several galleries. Go to my main website www.coinimaging.com and click on “gallery” and then click on “gallery 2.0″.

After initial experimentation into using a microscope objective as a supermacro lens, I can tell you that they do indeed work and quite well at that. It does require some adapters and various do-dads to work well on an SLR but it isn’t terribly difficult or expensive. My initial setup cost all of about $300. and I think that it can be done significantly cheaper. I need to do some more experimentation before I can give good advice on that.

The images obtained are very sharp. I haven’t directly measured the magnification yet but it will probably be variable from the 4:1 to 7:1 range. The image below was shot with a 4x objective with about 20cm of extension (distance from the objective to the detector).

I need to do some more experimentation to see what objectives work and what won’t (I think that they will all work fine, but I don’t know).

I got a “finished” copy of the book for edit. I have to read through it and fix any mistakes and send it back. I really like the layout. It has been a long slow process and it is finally getting near the end. After they fix what needs fixing, they send it back to me for a final edit and then it will go to the printers.

Hopefully you will find the wait worthwhile.

I was playing around with the whole stacked lens concept and decided to see what would happen when using my 55mm lens with a 28mm reversed lens. I discovered the problem that I have seen referred to as “vignetting.” Vignetting is when the image doesn’t fill the all of the detecter and you end up seeing the aperture. This results in an image in the center with a black surround as seen below.

I believe vignetting to be related to the size of the image presented by the reversed lens and the size of the image expected by the primary lens. In this case the 55mm lens is relatively wide angle and because of this, it “sees” at a wider angle than the size of the image presented by the reversed lens. I believe this to be the reason why longer focal length lenses are used as the primary lens. They see at a narrower angle field of view and thus will see only the image presented by the reversed lens. Now I may be totally off base on this, but it seems like a reasonable explanation. Bring me down gently if I am way off.

One way to minimize the vignetting is to open up the aperture on both lenses. The top image was done with both lenses wide open (f2.8 on both). The image below was shot with both lenses at f8. The vignetting in this instance is much worse. The problem with opening the apertures is that you will lose some sharpness.

I am just glad that my 200mm with either a 55mm or 28mm works fine. I don’t have a 100mm lens to test for this issues, but I would bet that it will be better than the 55mm as a primary lens.

I am always looking for a better way to take close-up images. I have pushed the various techniques (bellows, reversed lenses) about as far as I can and have found that the image quality starts to suffer. The images at high magnification just aren’t as sharp as I would like. Todays technique is to use stacked lenses.

For this technique you start out with a longer focal length macro lens. I have a Nikon 200mm macro that I will use, but a 100mm macro lens will also work. This lens attaches to the camera normally. To this lens you attach a “macro coupler” to the filter threads. This is just a small piece of aluminum with filter threads on both sides. It cost about $7. They come in a few convenient sizes, but may not match the threading for your lens.

My 200mm requires a 62mm filter. To remedy this I bought a $7 62mm to 52mm step-down ring. Attach the step-down ring to the lens and the connect the macro coupler (52mm to 52mm) to it. Now you have filter threads that will screw onto another lens (which will be reversed). The second lens is a shorter focal length lens. It does not have to be a macro lens or even one made for your camera since you are attaching it by the filter threads. The shorter the focal length, the more magnification you will get.

The magnification that you get is roughly equal to the longer focal length over the shorter focal length. So for my 200mm coupled to my 55mm lens, it would be 200/55 or about 4. This means about 4x life size on the detecter. Since the detecter of most digital cameras is smaller than a 35mm frame you will get a little extra. The camera and coupled lenses are shown below.

To use the coupled lens you need to do a couple things. First, I had to set the focus on the 200mm lens to the closest focus. Move the lenses toward the coin until things start to come into focus. One you have the focus relatively close by moving the camera up and down, you can fine tune the focus with the smaller lens (55mm in my case). Set the aperture to the sharpest setting on the small lens (f8 for my 55mm) and set the aperture on the big lens to its sharpest setting (f10 in the case of my 200mm macro).

You won’t have much depth of field at higher magnification, so you set the focus on the surface you want sharp. Sometimes setting the focus in between the fields and the relief will also work well and get everything in decent focus. but there isn’t a lot of wiggle room with focus. Now you are ready to shoot.

I set the lights at a low angle and back them away from the camera so the light is a little softer. I also tried out an Ott light on its side about 8 inches away which worked well. With the softer low-angle lighting, it will require a fairly long exposure, so make sure that your camera is steady.

The first picture is an uncropped image using the 55mm and the 200mm. I also took a picture of a ruler to figure out the magnification. The mag on with the 55mm turned out to be about 4.6:1 (field of view is about 5mm wide). This image is very sharp up to the highest zoom. The image below is resized by a large degree and looks really good blown up.

The next image was done the a 28mm lens coupled to the 200mm lens. The magnification on this image works out to be about 9.1:1 (field of view about 2.6 mm wide). From what I have read, this is pushing toward the upper limits of magnification for SLR lenses. This image is starting to show color fringes (extra red and green pixels, seen best when zoomed up), but is still relatively sharp.

 So far this seems to be the best way to get high magnification images that I have seen. Sometime I will compare all of the different methods for sharpness and quality. I do have one more thing to try first though - using a microscope objective. Got this idea from a fellow collector who pointed me toward a website that shows snowflake images using this method.