The Learning Curve: Rookie With Nikon Camera, Linux Control Software.

As this forum has been a tremendous help to me, I thought I would document my adventures in coin photography for the benefit of other camera rookies. I am not a proficient photographer, so hopefully this thread will help to bridge the gap between true beginner and (I hope someday) an adequate coin photographer.

For two years, I have been using a very basic setup of an iPad with a clip-on magnifier, a clip-on macro lens, a DIY tiny axial box, a lampstand with a daylight LED bulb, and a LED bar flashlight wrapped in facial tissue for diffusion. Eventually, I exhausted the accuracy and picture capabilities of that very cheap setup. Marv was kind enough to gift me with a real USB microscope to examine tiny coin details. However, given that I am now acquiring more expensive variety coins which I wish to document and possibly sell, I decided to jump the shark to a camera setup. I have always admired Zurie's coin photos, so I took the pragmatic approach of simply asking him what he uses and then buying the same thing: a Nikon D90 camera body with a Nikkor 105mm AF lens.

I asked a bunch of questions about lenses here before buying a 105mm lens. The upshot of those discussions is that you want the 105mm lens because it gives you some more working space from the coin, which is important for lighting. I haven't even begun working with real lighting yet, but it's apparent that mastering lighting is crucial for good pictures.

I do not yet have a copy stand. I plan to build a basic one using a DIY video blueprint from YouTube--a hefty wood base, a pipe from Home Depot, and a pro-grade socket and clamp assembly. My testing setup is a workhorse with a C-clamp camera socket, and a stack of textbooks below. The socket is made for super light cameras, so I just have the camera basically hanging from the clamp and resting against the workhorse with a towel to cushion it.

It took me a moment to figure out how to set the entire assembly into manual mode. For the AF 105mm, there is a selector ring on the lens barrel (which is different from the A/M selector switch that I have used on other cameras). The D90 camera body needs to be set into M as the camera mode on the selector wheel, and also have the A/M switch on the front body set to M. The manuals all warn that a mismatch between A and M on the body vs. lens can cause serious motor problems, so pay attention.

For software, I am using a Linux Mint laptop with the Entangle sofware. It connects to the camera via a USB cable. The live view on the software is rudimentary, definitely not enough to fine-tune focus. There are many selector drop-downs, although some of them don't do anything. The two settings that really confounded me were f-stop and lighting profile. I kept clicking through different f-stops, which the software allowed, but infuriatingly the photos never changed. Turns out, in Manual mode you need to hand-turn the aperture selector on the lens. The camera will only respond to the software aperture setting in AutoFocus mode. Entangle will happily let you select all sorts of different f-stops, but just to repeat, that does zero in Manual lens mode. The lighting profile was also puzzling. All my pictures were turning out dim, shadowy, and bluish. Turns out that the color profile was set to Tungsten, which is some kind of artsy filter. Switching to normal Daylight made all the photos look like the preview. The final default setting that I changed was a NEF+JPEG to just taking a single JPEG photo. The Entangle software automatically offloads the image from the Nikon D90 in tethered mode and puts it in your target folder, which is convenient.

For lighting, I am still waving around the white LED bar flashlight wrapped in tissues. These pictures also involve some indirect sunlight in the office. After some poking, my test photo settings were: ISO 640, shutter 1/100, aperture 5.6. This 1940 Mercury dime test photo was the result:



While the photo doesn't surpass even the images taken with my iPad setup, this is a reasonably accurate image to the coin. I am finding it challenging to get all the edges of the coins into focus, which I think might be a depth of field challenge. Possibly the coins are not perfectly square to the camera, or vice versa.

My next steps will be figuring out the proper ISO/aperture/shutter combinations for acceptable photos (daylight, axial, dark room with hand light), and then onwards to lighting and the DIY copy stand.