How I take pretty coin pictures
Sigma 50mm f/2.8 EX DG Macro Autofocus Lens for Nikon AF
Manfrotto 055XPROB Tripod / 496RC2 Ball head
Long USB cable (USB 2.0 A to Mini-B) for tethered capture
8.5x11 White/Gray card (photo background and to set white-balance).
2 goose-neck lamps with Spiral Compact Fluorescent (23watt / 100 watt equivalent), 5000K
A flat mirror (to level the camera)
Dell Precision Workstation T3500
Dell 27” Monitor
ISO 100 (NO auto-iso)
Aperture priority, f5.6
"PRE" white balance, set using gray/white card, OR if you know the exact temperature of your bulbs, use the "K" setting and select the temp.
AF-S (single servo) focus
Single center focus point above the coin face
Matrix metering mode (The camera bases exposure on the entire frame)
In-camera sharpness set to +9
Exposure Delay Mode set to ON
Increase the exposure by 1/3 to 2/3 stops
Set up the camera on the tripod to shoot directly down onto the surface of the coin. There is no need to exactly level the Tripod, but it doesn't hurt. However, It is critical to level the camera on the ball-head by setting the flat mirror on the table as if it were the coin. Manually set the focus point of the camera to the exact center-point. Move the whole camera on the ball head until the lens aperture opening reflected back from the mirror is shown through the viewfinder to be directly over the selected center focus point, lock the camera in place and set aside the mirror.
Scotch-tape the white-card to the top of table to prevent sliding. Place the coin slab in center of the white-card. Make sure the slab takes up just about all the available vertical real-estate in the viewfinder so you aren't wasting pixels, but there will be a lot of white-space on the left and right side of the coin slab. Adjust the height of the tripod to move the camera closer or further from he coin surface. The lights are arranged around the coin based on type of coin being photographed, knowing optimal light placement will come from trial and error. Connect the long USB cable between the camera and a front USB port on the PC. Open Lightroom and select “tethered-capture”. Take a test photo to make sure tethered connection is made and that the placement of slab is correct to avoid cutting off any part of the coin slab. Check the focus on the top, bottom, left, and right sides of the coin face to make sure the camera was properly leveled. Delete the test photo and prepare to batch process the coins at hand.
The coin slab is placed on white-card and I check placement through viewfinder. (Live view would work too, but I greatly prefer optical viewfinder). I do not re-focus, as pressing the shutter release button in Lightroom will focus for me with each shot, and its already close enough based on the previous coin. Using the mouse, I click the shutter release button, and the camera takes a shot, which pops up on my monitor a few seconds later. I use the "AUTO" upright adjustment tool to make the slab perfectly vertical. I verify the photo is in focus, no parts of the slab are cutoff, and I adjust the lights until I get a representative photo of the coin. I crop the photo tight to the slab, and export using the following basic settings: Resize to fit 2000 pixels on long side, max 2.5 MB, 230 dpi and named appropriately for the coin in question. I repeat for the coins Reverse. Once the pattern is established, many coins can be photographed as needed.
Nikon AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED
I rented this lens and used it for a week along with my normal setup. The 105mm focal length of this lens on my DX camera (vs. a full frame FX Nikon), means that I'm really shooting at 157mm (equivalent). That is deep into telephoto territory. When I remove my 50mm Sigma and replace it with the Nikkor 105mm, both of which are macro lens, the 157mm length gets me a closeup of the coin only, whereas the former gives me a full slab shot. I loved using it and was sad to return it. To summarize my findings, this is a fantastic lens and I want to own it when finances allow. A fixed 50mm and fixed 105mm macro lens combo is the prefect pairing for coin photos.
Before running out and dropping a few thousands dollars on a fancy camera setup for your coin collection, keep in mind a few things. Your existing camera hardware may be just fine to take pictures of your coins, so try fixing your current setup before investing in new gear. $2,000 for a Nikon D7100 and 105mm Nikkor lens is not going to magically fix your bad lighting and bad technique. Try to improve your photos by adding at least two high quality light (not flash). You want something that is 60+ watt equivalent, with a high color rendering index (CRI), ideally a CRI of 85+, with a color temperature between 3000 and 5000 Kelvins (I use 5000K), and something preferably that does not get too hot. LED is perfect in a lot of ways, and as of 2014 they are readily available, affordable, and of high quality, (although I have not yet found a 90+ CRI A19 bulb with a temp of ~5000 and with a high lumen output). For now, I prefer to stick with the tried-and-true CFL. Using a copy-stand or tripod and leveling the camera will fix most of your focus issues. With lots of light and a steady camera, your more than half way there.