Lighting techniques for coin photography

[brg5658]

I posted this thread on another coin forum, and I thought a few here might also find it helpful/useful.

 

I have been photographing my coins for the past 4 or so years, and I have found that coin photography is a way to meld together two hobbies that I love. The first 2 to 2.5 years of the process were essentially experimental. I started with a Point and Shoot small Canon camera, and a couple desk lamps with incandescent bulbs. Early on, I also experimented with a light tent (also sometimes called a light box). I noticed improvement over the first 2 years, but I was still not happy with my final images after months of playing around.

 

About 1.5 years ago I was fed up, and wanted to figure out how to get “professional quality” coin images, but didn’t really want to purchase a $1500 macro lens or a new camera. I stumbled upon a coin forum with its own “Coin Photography” sub-forum (this is quite rare among coin forums), and for the first 3-4 months I read every historical thread there related to set-ups, lighting, cameras, copy stands, etc. I finally jumped in and asked some questions, and soon thereafter I had a new way of imaging coins. I purchased a bellows and a couple enlarger lenses (about $90 and $40, respectively) and 3 little lamps from IKEA for $9.99 each (Jansjo lamps). I was seeing big strides in quality, and within 4 months of having this new set-up I was finally at a stage where I was happy with the images I was taking.

 

Ironically, one of the most frustrating and difficult components of coin photography for me (and I think for others) was lighting. I say “ironically” because this also happened to be the least expensive ingredient of the recipe. In my many months of experimentation, I had been doing a lot of things that seemed “intuitive” but were actually the opposite of what I should have been doing. While there is no “magical” advice I can give, and there is no replacement for trial and error (i.e., thousands of practice coin shots), I hope this little bit of advice is at least helpful to a few.

 

Firstly, I want to talk about diffusion of your light source. In essence, I encourage you to minimize diffused light or to avoid diffusion of your light source all together. Related to diffusion of light is the idea of “angle of light source” as compared to the coin. In the following schematic, I have defined the “angle of the lamp” with the pink arc on the left.

 

 

One of the keys to decent coin images is to keep this angle of your light source as high as possible (as close to 90 degrees, and as close to your lens as you can get without throwing reflection on the slab or coin). As the angle of your light source decreases, the more “diffuse” your light appears on the coin surface. You can see in the following set of images how the angle changes the look of the coin. I have shown the left light source, right light source, and both together. This shows how the two light sources at the standard 10-2 positions work together to light the coin’s surface.

 

 

Photographically, a lower angle of light source manifests as a decrease in contrast between high points and low points on the coin, and the overall image appears “flat” and usually lifeless. In terms of the levels histogram (pictured below), you can see that as the angle of the light source decreases, the histogram becomes more compact. In other words, the range between the lightest part of your image and the darkest part of your image decreases. As the angle of your light source increases, the range of lightest and darkest part of the image is much wider.

 

 

The second part of lighting that I just want to touch on is the number of light sources. In all of the images above, I have used lights at the “standard” positions of 10 and 2 (this notation refers to the “clock positions” and is typical among photographers). Two light sources may not always be sufficient to fully light the coin’s surface. The coin I have depicted is about the size of a USA half dollar. You will note that there is a bit of a dark area at the bottom of the coin. In reality, when I am photographing coins larger than about the size of a USA quarter dollar, I generally use three light sources at positions 9-12-3. Some modification of these lighting positions may be necessary for coins with particularly high relief or with designs with devices that may look best if lit from behind or below. Below I show a schematic of the 10-2 and 9-12-13 lighting positions, and the same coin as above lit from a high angle with only 2 lights versus 3 lights.

 

 

 

I hope these illustrations have helped to describe how the lighting angle and number of lights can affect the final image quality. I will just emphasize again, there is no substitute for practice. Over the past 4 years, I have taken more than 10,000 coin images and variables like the metal content (silver, gold, brass, copper, etc.), the surface texture (matte, satin, lustrous, mirrored proof), and toning all modify the way I light a coin. Practice, practice, and practice some more.

 

Happy collecting (and photographing)!

 

-Brandon

[HCumberdale]

Excellent information and diagrams here Brandon. It kind of makes me want to try it!!

 

 

[rmpsrpms]

Brandon,

 

Nice work in putting together and describing this information.

 

You've discussed angle to the coin, and clock position, but I'd like to add more "dimensions" to the discussion...

 

You need a 3rd physical dimension to describe light positioning, and in addition to the two you've already mentioned you should add "distance from the coin". With clock position, angle to horizontal, and distance you can uniquely identify a light position in space above the coin.

 

Now, you also mention diffusion, which is actually related to a 4th dimension of coin lighting: "size". Interestingly, size is also related to distance. A given source (eg Jansjo LED) will look "smaller" the farther you move the source away from the coin. At large distances, it will eventually look like a pinpoint source. This increases contrast and thus luster presentation. Moving a source closer to the coin makes it look "bigger" compared with the coin, and this spreads the light out more across the coin, reducing contrast. This is also what happens when you diffuse the source.

 

So here are the relationships:

 

Distance: farther makes the light look smaller

Size: smaller increases contrast

Diffusion: makes the light look bigger at any distance

 

 

[brg5658]

Brandon,

 

Nice work in putting together and describing this information.

 

You've discussed angle to the coin, and clock position, but I'd like to add more "dimensions" to the discussion...

 

You need a 3rd physical dimension to describe light positioning, and in addition to the two you've already mentioned you should add "distance from the coin". With clock position, angle to horizontal, and distance you can uniquely identify a light position in space above the coin.

 

Now, you also mention diffusion, which is actually related to a 4th dimension of coin lighting: "size". Interestingly, size is also related to distance. A given source (eg Jansjo LED) will look "smaller" the farther you move the source away from the coin. At large distances, it will eventually look like a pinpoint source. This increases contrast and thus luster presentation. Moving a source closer to the coin makes it look "bigger" compared with the coin, and this spreads the light out more across the coin, reducing contrast. This is also what happens when you diffuse the source.

 

So here are the relationships:

 

Distance: farther makes the light look smaller

Size: smaller increases contrast

Diffusion: makes the light look bigger at any distance

 

 

Ray, you are completely correct. I have not exhausted the many variables of coin lighting. What I found interesting was the relationship between how a low angle of light seems to approach a coin image very similar to one you would get using a light box or highly diffuse light source. The contrast is extremely limited, and a coin's surface looks flat and dead.

 

When I think of diffusion I guess I more think of a light-tent set-up. Where, essentially you don't have any point sources of light any more, but just a constant ambient light from all directions. Another form of "diffusion" is by applying a cover of sorts physically to your point light source. For example, a tissue, paper towel, white cloth, etc. wrapped around the light source. That sort of diffusion makes the light look bigger, and if still placed at a high angle can still bring out quite a bit of luster on a coin.

 

The angle-variable shots you did on the Coin Community forum recently with the Lincoln Cent prompted this write-up and experimentation of my own. Ray, you have been the single most influential person to my improved coin images. You are a true genius of coin photography!

 

-Brandon

[lehigh96]

What a fantastic thread. I love when two guys who really know about numismatic photography have a discussion.

[BKW]

Thanks for the educational thread Brandon!

[mhomei]

thats awesome..thank you for sharing it

[jpcienkus]

Very informative Brandon and Ray. Thank you.

[Walkerfan]

Awesome Info!! This is something that I hope to become more involved with very soon. Thanks!!

[ArmyBud]

You sure saved me a couple of years of experimenting!! I tried everything but the angle of the light and the position of the camera. I was lighting at an angle (Probably 45 degrees in on two sides thinking it would cancel out shadows. Never worked. Your instruction is excellent....thanks!!!

Bud

[ldhair]

Great thread. This makes me think of the quality of images about 12 years back. Very few could post anything that was very good. Today after so many have taken the time to teach others, we see many more great images.

 

Thanks to all you guys for taking the time.

[physics-fan3.14]

Very useful information. How did I miss this thread when it was originally posted?

 

As you should expect - I have a few questions:

 

1. Are you still using a point-and-shoot Canon? That is what I have, so I'm trying to figure out just how good my pictures can get without spending a bunch on a new camera.

 

2. Talk to me about the copy stand you are using. I think this is a purchase I need to make, and want to know what I should buy.

 

3. When you use 3 lights, why did you choose 9-12-3 instead of a more uniform 4-8-12? Could you post pictures taken with lights at these two different orientations, so I can see what effect that has?

 

4. What exposure settings do you find most useful (f-stop, aperture, ISO, etc)?

 

5. How do your settings and light positions change for business strike vs. proof (or prooflike ) coins?

[coinman_23885]

I don't have anything really to contribute, other than to say thank you for creating such an informative thread. It has been immensely useful. Like Physics, I would love to know your thoughts in regards to his questions numbered 1 and 3.

[brg5658]

Jason, see my replies below:

 

1. Are you still using a point-and-shoot Canon? That is what I have, so I'm trying to figure out just how good my pictures can get without spending a bunch on a new camera.

 

I have not used a Point and Shoot for almost 2 years. I shoot with a Canon T2i, with a bellows, and enlarger/duplicating lenses. I found I was highly limited in what I wanted to accomplish in terms of quality and sharpness using my Canon point and shoot. As such, I got some good advice, and went the route of an entry level DSLR with a great sensor, and the bellow+lens setup which is significantly less expensive, and in my opinion, much more flexible than a fixed focal length macro lens.

 

 

2. Talk to me about the copy stand you are using. I think this is a purchase I need to make, and want to know what I should buy.

 

I do have a copy stand, but it's not a really expensive one. I believe it was $60-70. The reason why I didn't spend big bucks on one is because my bellows has a built in focus-rail; thus, my copy stand is at a fixed height and I haven't moved it for 2 years. I don't have any particular advice regarding brand, as anything that is sturdy will do.

 

 

3. When you use 3 lights, why did you choose 9-12-3 instead of a more uniform 4-8-12? Could you post pictures taken with lights at these two different orientations, so I can see what effect that has?

 

You can use any positions for the lights that illuminate the coin's surfaces fully. I would not recommend 4-8-12, as it rarely looks "normal" to light a coin's surface from below -- lots of coins have faces on them, and lighting the face from below the chin simply looks odd. If you wanted to set the lights 120 degrees apart, I'd go with the standard 10-2 positions, and add a light at 6 o'clock as a filler light. As I noted in my initial write up, there is no magical positioning for lights. Positions of 10-2 and 9-12-3 are only where I start, and I am constantly moving the light positions real-time to light a particular coin appropriately (I can see real-time what the lighting changes look like through the Live-View screen on the camera).

 

 

4. What exposure settings do you find most useful (f-stop, aperture, ISO, etc)?

 

My camera is set to ISO 100, Aperture Priority, and the duplicating/enlarger lenses I use are never stopped down further than f/5.6. Using aperture priority means you don't have to mess around with exposure times, as the camera can figure out for itself what is appropriate for proper exposure. By the way, f-stop is the same thing as aperture...your question made me think you might think they are different concepts?

 

 

5. How do your settings and light positions change for business strike vs. proof (or prooflike ) coins?

 

Experiment. Again, no magical formula. You just have to practice. Trial and error is your friend. For proofs with high cameo contrast, I do pull the lights back a little bit from the coins, so as to avoid direct blown out glare spots. But, some glassy look can be pleasing for proof coins. Regarding prooflike coins, that's a realm you'll have to experiment with on your own.