Hack 91 Copy Slides with Your Digicam

Dedicated slide scanners can be expensive and more than a little tedious to use. The digicam you already own might be your best bet for digitizing some of your favorite slides .

I have a lifetime of slides neatly tucked away in my closet, and I know it would take two lifetimes to properly clean, preview, scan, correct, and archive my legacy image collection. But wait! What about using a digicam to copy all those images?

Previously, the preferred method was to enslave yourself to an ergonomic chair in front of a dedicated slide copier that was connected to your computer. Nikon, Minolta, Microtek, and Polaroid all have competent units.

Inexpensive flatbeds with transparency units in the lid don't do nearly as good a job as the dedicated slide copiers. Agfa, Epson, and Microtek make more expensive flatbeds that do better. The inexpensive units are not only cumbersome and time-consuming . They also don't have the resolution for small formats, such as 35mm, nor do they capture the density range that can hide in a slide. You're really better off renting time on a dedicated slide scanner.

This brings us back to using a digicam for this project. Before getting too excited, let's examine some of the potential drawbacks:

Compressed density range

Most digicams ( prosumer digital SLRs are the exception) capture 8-bit channels (the amount of image information recorded by the device). Even inexpensive scanners usually do better, and the best scanners capture 16 bits per channel. So, expect to lose some shadow and highlight detail, much as you would when you're copying film to film.

No inline image correction

There's nothing quite like scanning a faded slide and seeing it pop back to life with no scratches on your monitor. Many dedicated slide scanners have advanced software that analyzes the image and tries to fix its imperfections during the scanning process. That's not going to happen in your digicam. Expect to spend some time correcting color and cleaning up scratches.

Lower resolution

Dedicated scanners know they're working with 35mm images that are destined to be enlarged substantially, so they offer very fine resolution (4,000 ppi) to capture huge files. Your digicam isn't going to do any worse than it does with anything else it shoots, but it won't approach the level of detail that a dedicated scanner delivers.

Interpolated color

Scanners can move down the image, reading RGB at their leisure to create a full red, green, and blue sampling for each pixel (even sampling the same pixel up to 16 times to eliminate noise). Digicams capture the image in a fraction of a second, interpolating two of the three colors for every pixel.

Okay, so now your hopes are somewhat deflated. Don't give up yet. Copying slides with digicams also presents a few advantages:

• You can load several slides or negatives at a time, copying a roll of film in just a few minutes.

• Those compact file sizes are also an advantage. They're perfect for viewing on-screen and printing in standard sizes. What else do you need?

• The quality, I've found, is just fine. For important pictures, there are a few tricks you can perform to optimize the capture. And you can always resort to a dedicated scanner for the problem slides that need extra attention.

8.7.1 Using the Right Camera

This entire hack hinges on having the right digicam. Not every model is capable of capturing a tiny 35mm frame. First, your camera must have a Macro mode. Second, it has to capture a sharp image, corner to corner, with no lens distortion. Third, it has to get pretty close to the subject. Sometimes, that means adding a close-up converter lens.

One sure sign that your digicam is capable of copying slides is if the manufacturer offers a slide-copying adapter. If so, you're in business.

I don't want to discourage you from rigging up an attachment to hold a slide in perfect alignment to any digicam's sensor plane. The US$40 Happenstance (http://www.steves-digicams.com/happenstance.html) is a simple device with which you mount your slide against a translucent piece of plastic and photograph it in Macro mode. I found that adding a little duct tape around the side, to keep ambient light from hitting the front of the slide, improved results.

If you have a digital SLR, you can adapt an old film slide adapter [Hack #12] . This system is cheap and works well. The only drawback is that most digital SLRs have more magnification than their traditional 35mm brethren, so your adapted 35mm slide adapter won't copy full frame. You will have to do some cropping, whether you want to or not.

Beyond that, some people have even built rigs with nothing more than a paper cup and rubber band. Put the slide in the paper cup so that the light shines through the bottom of the cup, illuminating the slide, and use a rubber band to attach the whole thing to your camera. Crude, yes. But in a pinch you can get a decent image out of it.

That said, I prefer to use the manufacturer's device for copying slides with my digicam. I need every advantage I can get.

8.7.2 Coolpix 990 with Slide Copier

When I want to copy film with a digicam, I use a Nikon Coolpix 990 with the US$80 Nikon Slide Copying Adapter (ES-E28). The Coolpix's Macro capability sets it apart from many other digicams, and the slide copier takes full advantage of it.

The Nikon adapter is a bulky but lightweight cylinder that screws into the lens thread, as shown in Figure 8-17. It has slots on both sides to slip in either the double-slide holder (which lets you leave the slides in their mounts) or the six-negative film-strip holder. The adapter holds them in place with a strong metal spring. The front of the adapter is a piece of milky Plexiglas that diffuses the light source.

Figure 8-17. My Nikon 990 setup

In addition to sliding the holder back and forth, you can adjust the two-piece barrel up and down and change the angle of rotation. You can use a set screw to fix any adjustments you make.

Unlike some rigs I've seen, the Nikon adapter does not permit any ambient light to fall on the front of the slide. Not only is it enclosed , but it's also black inside. So the only light that hits the lens is transmitted through the slide.

You'll also need a tripod and your camera's power adapter. You want the camera to stay on while you reload the holders, and you don't want it sliding around as you shoot.

Finally, get a can of compressed air, preferably the environment-friendly kind that doesn't use CC and HCFC. Shooting this close greatly magnifies imperfections, such as scratches and dust, so cleanliness is a big issue. Just a couple shots of air on both sides of each slide or negative strip will help deliver clean images.

8.7.3 Technique with the Coolpix

Fortunately, no elaborate studio lighting is required. I've happily used nothing but sunlight as my light source. For night work, I've used my 16" 18" portable light table with two short, fluorescent tubes of certainly the wrong degrees Kelvin. I've also used a soft box. Anything that provides bright, even illumination to the diffused white plastic will work, but I do balance the light by setting a custom white balance while no slide is mounted. I even do that for sunlight so that the color cast of the slide itself isn't a factor.

If you use sunlight, remember that it moves. Make sure shadows don't fall across your setup as the day passes . I just take a look at the front of the adapter every time I reload it.

This kind of work is best done in Manual recording mode. Aperture Priority mode lets you choose a sharp f-stop (between f-4 and f-5 for this lens). You can adjust exposure for underexposed or overexposed slides by using the EV setting, which changes the shutter speed.

Manual focus is also worth considering. Once you've found focus, it won't change. Automatic focus systems that are based on contrast detection can be confused by flat subjects such as seascapes.

The next trick is to align the slides to the sensor. Since the adapter screws into the lens mount on the camera, I reset the alignment every time I attach the adapter.

With a loaded film holder positioned in the adapter, use the zoom control to display a nice, tight crop in the LCD, as shown in Figure 8-18. Take a shot and pull the card out of the camera. Then take a look at it in your image-editing program. Did you get the whole image? Is it too low or too high? Is it square? Make any necessary adjustments and continue testing until you get the alignment right.

Figure 8-18. The slide in the LCD viewfinder, ready for capture

Then, it's just a matter of loading the holder, blasting both sides of the slide with air, slipping each slide into the adapter, and firing the shutter for each image.

8.7.4 Extending the Density Range

While your digicam captures only eight bits per channel, this setup is ideal for bracketing two 8-bit captures that can later be blended into a single 16-bit image in Photoshop. This technique can greatly extend the dynamic range of images that have a lot of contrast.

Take at least two shots of any difficult image: one underexposed and the other slightly overexposed. You aren't limited to two, of course. I've taken as many as five.

Open each image in Photoshop and convert it into a 16-bit image. Use the Blend Exposures plug-in from Reindeer Graphics' Optipix suite (http://www.reindeergraphics.com) to create one 16-bit image whose tonal range and contrast provide the best of both images. When you're happy with the blend, save the image as an 8-bit channel image with the detail intact.

8.7.5 Copying Color Negatives

Color negatives are a special case. There's a great deal of misinformation about them, especially on how to handle the orange you see. It's important to understand that the orange tint you see when looking at a color negative is not equally distributed in the highlights and shadows, so you should not simply mask out orange from the image.

Shoot the negative normally (with a custom white balance) and convert it using custom curves in an image-editing program. You can batch your curves to apply to whole rolls at a time. If manipulating curves sounds too tricky, you might consider LaserSoft Imaging's NegaFix, part of their SilverFast Ai package (http://www.silverfast.com).

8.7.6 Final Thoughts

With the right equipment, it's easy, quick, and inexpensive to get pleasing results when copying slides and negatives with your digicam. But the real thrill is having digital access to all your old images, many of which might never have been printed, were perhaps given away, or have been forgotten.

If you can't spend the rest of your life scanning every slide in your collection, the next best thing is to copy your favorites with a digicam.

Mike Pasini