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Slide Copying with the Konica Minolta 5D
For quite a while now I've been trying to come up with a good way to digitize my collection of almost 8,000 35mm slides. The reason I want this is to have a convenient way of cataloging, locating, enjoying, and sharing them. Light boxes, loupes, projectors, and screens are all cumbersome to deal with, so the slides mostly sit in their boxes and hardly anyone, including me, ever looks at them anymore; and they're impossible to share with people in other locations.
I've owned a film scanner for many years, and it works well for careful digitizing of important images. But I recognized immediately that the time and effort required to scan that number of slides with a typical scanner like mine would be mind-boggling, so I looked at faster digitizing solutions. I considered approaches such as an auto-loading scanner, or a flatbed scanner that can scan a 'sheet' of slides in one pass. I thought about projecting slides on a wall and re-photographing them with a digital camera. I also thought about outsourcing the whole job, but I found the cost prohibitively expensive and the idea of sending my slides away too risky. The solution I chose was to custom build a slide copier for use with the Konica Minolta 5D and 50mm f/2.8 Macro lens.
Like most current digital SLRs, the 5D has an APS-sized sensor. This means that my macro setup needs to accommodate a magnification ratio of about 1:1.5 or 0.67x. With the more typical slide copying magnification of 1:1, the image on the sensor would only include the central area of the slide. After some experimentation, this is what I built:
The illumination source can be just about any type of light. I use a small 40-watt tungsten bulb.
In addition to the stuff at the left, I also made an alignment slide by drawing lines on a piece of wax paper stuck into a slide mount. The alignment slide helps in getting everything lined up and centered before I start shooting.
The slide copier is made of bits and pieces of other items - the stage section of an old macro stand, a piece of a flash bracket, a Minolta AB-III focusing rail, some foam core material, and a clip-on gooseneck lamp. Everything is mounted on an old spare tripod for easy portability. The basic requirements of the apparatus are:1) the slide has to be held securely in the frame and kept in good alignment; 2) the frame should allow for some left-right, up-down, and rotational adjustment; 3) there must be a light diffuser and a light source behind the cutout; 4) the mount must hold the camera and lens at a specific distance from the cutout, and allow for some magnification and focusing adjustments.
Here's what I do when I'm ready to copy slides: 1) attach the camera and lens, and put the alignment slide in the frame; 2) turn on the camera and the backlight and focus on the alignment slide; 3) adjust the frame so that the slide is centered, confirm that the magnification is where I want it, and make any necessary fine adjustments; 4) set the camera controls to my standard slide copying settings (see below); 5) grab a slide, brush/blow the dust off, and drop it in the holder; 6) take a shot, check the LCD image and histogram, and adjust and re-shoot as necessary; 7) when I get the result I want, remove the slide and repeat from step 5.
I usually begin with these settings: ISO 100; manual focus; manual exposure at f/11 and 1/10 second; Tungsten white balance; Natural color mode; contrast -2; saturation 0; sharpness +2. I shoot high resolution fine JPG files, just as I do for all of my normal work.
For the best results, I check the LCD and histogram with every slide. Dark scenes often require much longer exposure times, and some slides look better with a higher contrast setting. I rarely change anything other than shutter speed or contrast. Although the front of the slide is exposed to ambient room light, I keep the lighting low and have not encountered any problems with that.
Below are some sample images that I made to compare a copy done in the camera to a scan from my Minolta Scan Dual II film scanner. The Niagara Falls scene was shot on Kodachrome in 1978. I scanned the slide at the film scanner's highest hardware resolution of 2820 dpi and then downsampled it to match the resolution of the image made with the 5D. Both images needed post processing and sharpening in Photoshop to make them look as good as possible. However, I did no dust cleanup on either of them.
The scanner is certainly capable of better overall results due to its higher resolution (about 10mp) and wide dynamic range. But I find that the camera produces more accurate color without intervention. When a carefully copied and corrected image is compared to a carefully scanned and corrected image that has been scaled down to the same resolution, the differences are minor.
Scanned and downsampled version:
Copied version, 100% crop:
Scanned and downsampled version, 100% crop:
I'm very happy with the results. I can get perfectly usable 6 megapixel versions of my slides this way, much faster than I could by scanning. These are more than adequate for cataloging and sharing, and they can also produce good small prints (although I would still prefer a film scanner for any important printing projects). Something I can't get with this method is Digital ICE dust removal, but I understand that ICE doesn't work so well with Kodachrome anyway. I have found the Polaroid Dust and Scratch Removal utility to be very helpful in this regard.
Text and images © 2006-2012 Ray Lemieux