Digitizing Slides to DVD: Which Way to Go?

If you’re like a lot of folks who used to shoot slides, or perhaps you still do, you probably have a large collection by now. Perhaps you’re worried about emulsion degradation and want to archive them. Perhaps you just want the convenience of having them in digital format so they can be enhanced or transferred more easily. But when it comes to deciding how to deal with all your slides, perhaps you’re somewhat confused as to the best way to proceed. In this case, this article will give you the perspective to make it easier for you to decide what exactly to do.

Before we go any further, it’s probably a good idea for you to make a decision based on the quantity of slides you own. If you own fewer than 1,000 or so, and don’t plan on adding to your collection, then the most cost-effective way to proceed, not just in terms of dollars but also in terms of time spent, most likely will be to send them out to a service and have them scanned to CD or DVD. If you have more than 1,000, or if you would just prefer to do things yourself, then read on. In this discussion, we will concentrate on three technologies that will give you the most bang for the buck: a flat bed scanner, a dedicated film scanner, and a slide duplicator used with a digital SLR camera.

Transferring Your Slides to DVD Using a Flat Bed Scanner

Epson Perfection 4990

Your average flatbed scanner is a device that works essentially the same as the scanning section of a photocopier. An image is placed onto a glass plate and a light and lens passes slowly under the plate in very tiny increments. For relatively recent-technology scanners, these recorded increments, referred to as “pixels” or “dots,” can be anywhere from 2400 per inch to 4800 per inch and even higher. We’ll use the term “pixels per inch” or simply “ppi” for short when we discuss image resolution here, and we’ll want to be using a scanner for our slide scans that has a maximum optical resolution capability of at least 2400 ppi. Some scanners list two resolutions, for example, 4800 x 9600 ppi. It is the smaller of the two numbers we will pay attention to, since that is the limiting value. We will disregard interpolated resolution, since it adds nothing but bloat to an image.

To scan slides, the scanner must also have film scanning capability. The primary difference between a film-capable scanner and one that isn’t is that the film-capable scanner has an additional light in its cover, which is activated when film is scanned. This extra light is necessary because film must be back-lit when scanned. Since the scanner’s lens is inside the scanner body, the light inside the body, being next to the lens, cannot be used to back-light the film. Thus there must be a light in the cover. Most scanners that can scan 35mm film can also scan 35mm slides. But make sure of this before you buy, if you haven’t purchased one yet.

A slide film-capable scanner will come with at least two film holders, one for negatives or unmounted slides, and one for mounted slides. We’ll be using the holder for mounted slides. If you are thinking about buying a used scanner, make sure that the film holders are included in the price. Also it’s a real good idea to test out a used scanner first and make sure the top light comes on before finalizing the deal. Some older scanners use SCSI connectors. Be aware that, unless your computer already has one, you will have to purchase a SCSI adapter card for your computer in order to run a SCSI scanner. Native support for SCSI among modern operating systems is limited, so you will be dependent upon finding a card with the right set of drivers for your OS. For example, Adaptec, one of the most respected names in the SCSI world, shows at their website that their 2930CU adapter card, an excellent all-around performer, has drivers for all recent Microsoft operating systems. Plus the card also comes in a flavor with Apple Macintosh support. Also, if you buy used, visit the scanner’s company website, where you should be able to download an operating manual and the latest software revisions for the scanner to operate in tandem with your PC.

Setting up your scanner

Now it’s time to set up the scanner so it will operate with our computer. Follow the instruction manual for this. There may be a procedure you should follow regarding when to turn on the scanner with respect to installation of the software. With my scanner, for example, the software should be installed first before the scanner is turned on, then the scanner is turned on, then the software is booted. Also the scanner should be synchronized with the image processing software you use via a TWAIN driver. Most decent image processing packages support the TWAIN protocol, which is an applications programming interface (API) that allows communication between imaging devices and software that support it. If your image processing software supports TWAIN (and it should) then when you click on the scanner icon in the software, it will actually boot the scanner’s software. Then after the scan is complete, the image is loaded into your image processing software.

Next, let’s select some slides and get started with the scanning process. For starting out, choose slides that are well exposed and sharply focused. Check that the slides are free of dust. If they have a bit of dust on them, you have two basic methods of cleaning them: you can use a very soft brush and lightly brush the dust off, or you can use “canned air,” which is simply an aerosol can of air used for cleaning lenses, slides and negatives, and can be purchased at camera stores. Sometimes using both works best. You really want to check your slides for dust before scanning them because if you don’t, you can end up spending way too much time in your imaging software getting rid of the scanned dust motes.

Make sure the scanner’s glass is clean. Place the slide carrier on the scanner glass, aligning it with the alignment marks. Then place the slides face down inside the openings in the slide carrier. Close the scanner cover.

Now we need to set up your scanner software for slides. There should be a selection with choices labeled something like “reflective” and “transparency.” Chose transparency. Then there should be another selection for “positive” and “negative.” Chose positive. There should also be a selection you can make regarding scanner resolution. I recommend you select at least 2400 ppi, but I do not recommend that you select a resolution higher than the highest optical resolution of your scanner. For example, my scanner’s maximum optical resolution is 4800 ppi, but it has an interpolated resolution capability of up to 19200. Interpolation is simulated resolution created by the software, and has no use for our purposes. Your software will offer other adjustments as well, but for now, I recommend you leave this to “auto” or just go with what the software recommends. You can explore these capabilities later.

The next step is to do a preview scan. This gives you a basic set of images you can use to determine exactly where and how much of an image you want to scan. Your software may automate the selection process for you, or you may have to manually determine exactly the size of the scanned image. I actually prefer the manual method, but whatever you feel most comfortable with, that’s what you should do. Once you’ve selected the images you want to scan, your software should have some means of your specifying that you want only a single image scanned at a time or multiple images. Go ahead and set it for multiple images, since this is the most efficient use of your time, and select the image areas for more than one slide.

Next, after every thing is set, click on “Scan.” At higher image resolutions this can take a while—perhaps as much as three to four minutes per image. So if you’ve selected several images to be scanned, now is a good time to take a break.

Once the scanning is complete, close the scanner software. You should have one or more images in your imaging software. At this point, there are a great many things you can do to adjust and enhance your images and a discussion of them is well beyond the scope of this article. In fact, we aren’t going to do any of them. Remember, these are archives, and you want to maintain a maximum amount of original information with an archived photo. If you start making changes to the original file and save the changed version as your archive, then the original information is gone. The day may come when you wish you still had the unchanged original, but it won’t be available. You’ll have to scan the slide again. Also, since we want to keep the maximum amount of information, the image format we select becomes important. For our purposes, we will chose a non-“lossy” image format, such as .tif or .png. The .jpg format is quite a bit more compact than the others, but at a cost—.jpg is a “lossy” format, meaning that image information is permanently lost. Not good for an archive.

When you save your slide images, I recommend that you rename them to something that will make sense to you. Instead of going with a default, which often will look something like “IMG_2547.TIF,” for example, try renaming it into something understandable, like “Alex 5th birthday.tif.” At some future date, when you’re combing through your archive looking for a particular image, it will be much easier to find what you want.

At a later date, you can go back and do some post-processing to your images, saving the post-processed files in a separate archive. If you’re like me, you’ll find that, as you do this more and more, you will get better at the process and you’ll find that your early attempts were often too heavy-handed. This is a pretty clear demonstration as to why the originals should be archived unaltered.

When you have finished scanning your slides, the next step is to burn the images to DVD. A standard DVD will hold 4.7 gigabytes of information. A typical high-resolution .png or .tif image file can easily range in size from 20 to 80 megabytes. So doing the math, we’re looking at approximately between 58 and 235 images per DVD. Before you rush out and buy a stack of DVDs, though, ask yourself—how long do you want your archived images to last? Be aware that cheaper DVDs can be problematic when it comes to longevity. I have read numerous reports of DVDs failing two years or less after they were burned. So you’re better off spending a bit more for your archive DVDs. As to which you should buy, I recommend you do a bit of online research. A few favorites will quickly emerge. The inventor of the DVD format was Taiyo Yuden (now JVC), and has long been recognized as the manufacturer of the best DVDs. Taiyo Yuden DVDs have appeared under other brand names also, most commonly Verbatim. There are also DVDs that are designed specifically to be archival, called “gold” DVDs, and which are claimed by their manufacturers to last more than 100 years. Gold DVDs sell for a healthy premium, but if your archive is important to you, the extra expense may be worth it. Also, do not buy DVD-RWs. Because of their composition, they are not really suitable for archival use. In general, DVD+R format is more stable than DVD-R, so if your burner supports +R, this will be the better way to go.

Computer operating systems such as Windows come with the capability to burn DVDs these days, but I would rather use a stand-alone product. There are many to choose from. I use a couple of freeware applications, and they do a fine job. Do an internet search for free DVD-burning software and you should find one that will do what you need.

After you’ve burned your DVD, use a permanent marker, like a Sharpie, to record the DVD’s general contents. Be sure to date it. Store the DVDs upright in plastic cases in cool, dark, dry areas. Follow these guidelines, and they should last you for many years to come.

Using a Dedicated Film Scanner

Plustek 7600i Dedicated Film Scanner

Nowadays you can find a variety of dedicated film scanners in a variety of price ranges. Not too long ago, only high-end film scanners were available and cost thousands of dollars. These days you can find inexpensive consumer models for well under $100. But as is all too often the case, you get what you pay for. The cheap ones do a barely acceptable job. They typically provide claimed resolutions of 2592 x 1680 pixels, equivalent to a 5 megapixel camera. This amounts to 1680 ppi, which is significantly lower than what can be obtained with an average flat-bed scanner. Models exist in price ranges closer to good flatbed scanners, however, and they have much higher claimed image resolutions—typically closer to 2400 ppi, some as high as around 3800 ppi. It is also possible to buy on the used market dedicated film scanners that formerly sold for thousands new but now sell for “only” hundreds. Sometimes these are a good deal, sometimes not. One must closely examine the specifications, make sure the used scanner is complete with all accessories including film holders, and one must also find out how the scanner connects to a computer. Many use the SCSI interface, so keep in mind what I wrote about SCSI above.

Installation of a dedicated scanner is very straight-forward. Most all of the modern ones hook up to a computer using a USB 2.0 cable. Software is typically provided, and even the cheap scanners are TWAIN compliant, which means you can boot the scanner’s software from within your imaging software and transfer the scanned images directly into it. Follow the directions regarding loading slides into the holders and starting up the scanner. Then it’s a matter of getting familiar with the scanner’s software, choosing the images you want to scan, executing the scan process, and then waiting for it to finish.

Once your images have finished being scanned into your imaging software, follow the steps I outlined previously for flatbed scanners, starting at the paragraph above that begins with “Once the scanning is complete, close the scanner software.”

Transferring Slides to DVD Using a Digital Single Lens Reflex Camera and a Slide Duplicator

In recent years, “digital” slide duplicators have become quite popular. The advantages to using one are several if you already own a good digital single lens reflex camera (DSLR). The images are typically quite sharp, well exposed, and the focus is precise if your camera’s autofocus capability is being used. It is also much faster taking duplicates than scanning images. Your typical high-resolution scan may take from two to four minutes. A slide duplicate takes maybe 1/125 second.

Digital slide duplicators are quite ingenious in the way they work, and are also quite reasonably priced. They are “digital” in the sense that they were designed to be used with digital cameras, although there is nothing inherently digital about them. Consisting of a tube with threads on one end and a slide holder on the other with a correcting lens inside the tube, they are designed to screw onto the front of a camera zoom lens, and take advantage of the lens’s zoom capabilities to crop the slide image. The internal lens is typically well corrected and renders a respectably sharp image. There are a couple of caveats to bear in mind, however: you must have a camera lens with the necessary focal length and it must be able to focus down to about 2 feet or so. Obviously, the better quality the camera lens, the better quality your slide duplicates will be.

You’ll want to use a DSLR that has at least 5 megapixels resolution, since this is typically what images are scanned at when you send them out to have it done. The way I see it, if you will be doing the duplicates yourself, you should expect yours to be at least as good as what are commercially available. Your lens must focus down to about two feet, and it must have a focal length that will enable you to take full-frame duplicates. DSLRs use a variety of sensor sizes which affect the way lens focal lengths magnify an image. For an APS-C sized sensor, which is found in many cameras made by most major camera manufacturers, the necessary focal length is about 71mm, whereas for a full-frame sensor, which is the same size as a 35mm image, the necessary focal length is a few millimeters under 50mm. Because of these uncommon focal lengths, zoom lenses work best.

Proper exposure and light balance is critical, as is optimum lens performance. All three factors are closely linked when duplicating slides. There are two basic ways of obtaining proper exposure when shooting slides—using the camera’s meter in a natural light setting, or using a photo strobe or flash. Regardless which method you use, you will want the slides to receive enough light so that the camera’s lens aperture will be working within its “sweet spot,” which for most lenses is between f/5.6 and f/11. You also want to set your DSLR’s ISO value to a low number—ISO 100 at most. This insures that a minimum of image “noise” is transferred to the image.

Shooting your duplicates using natural light is the easiest and cheapest method. All you need is a piece of white poster board and a little cooperation from the sun. If it’s a sunny day, you’ll want to shoot your duplicates between the hours of 10am and 2pm or so. The reason for this is the light balance I mentioned above. Much earlier in the morning or later in the evening and the ambient light color will take on a progressively yellower cast, which will taint the color of your duplicates. Many DSLRs have an auto white balance feature, but it is not always as accurate as it should be, so it’s best not to have to depend on it.

Set your camera’s program setting to Aperture Priority mode and, for now, let’s set the lens aperture value to f/8. Then point your camera with a slide in the duplicator at the white poster board. Don’t worry about the shutter speed. Because the duplicator is mounted directly to the lens, even if the shutter speed is too slow for hand-held photography a little bit of camera shake won’t transfer to the image.

If it happens to be overcast outside, things become even easier. For starters, the time of day is not as critical, since the gray skies tend to absorb the sun’s yellow light that happens earlier and later than mid-day. So all you need to do is set your camera to the same settings as above, point it at the overcast skies and click away. Gray skies are great for shooting slide duplicates. Gray is a perfectly neutral color and will not change the natural color balance of your slides at all.

The advantages of using a photo strobe or flash is that it provides a consistent light source in terms of color balance and brightness. But it can get expensive. Dedicated strobes can easily cost several hundreds of dollars apiece. Plus, if you want to have your camera synchronize itself with the flash so it will provide auto exposure with through-the-lens (TTL) metering while the flash is off the camera, you will need a special off-camera module and cabling, and these items are not cheap either. Not all DSLRs support the TTL metering of off-camera modules, however. Something you need to check into.

The alternative to this is to use a flash that can be set to manual mode and which preferably has variable power settings. Manual flashes are priced much more reasonably than dedicated flashes. You will still need an off-camera adapter and cabling, but an expensive TTL adapter and cabling won’t be required. Using a manual flash, the proper exposure can be determined through trial and error by varying the flash’s power setting or the distance from the flash to the camera if it doesn’t have variable power settings, and using the camera’s review feature to confirm. Once it’s set you shouldn’t need to change it.

To shoot with a photo flash, mount the flash so that it’s pointed directly at the camera. If using a manual flash, measure the distance between the camera and flash and adjust your exposure accordingly. Then lock in these values by locating both the flash and the camera on tripods or stands or what have you, and fire away.

Shooting duplicates with your DSLR is about as difficult as falling off a log, but there are still a few things you should know. First, just about every autofocus zoom lens made has a front element that rotates. So this means that, as your lens autofocuses for each slide, it will rotate the slide, most likely positioning it such that it isn’t perfectly straight in relation to the camera’s image frame. Fortunately, the slide holder rotates, so you can adjust the slide’s position after the lens has focused on the image. Sometimes it takes a few tries before the slide is lined up, even though it looks correct when looking through the viewfinder. This problem occurs because the viewfinder doesn’t provide you with 100% of the actual image frame—it can be as low as 90%. So it’s best to check the image using your camera’s image review feature to confirm alignment.

You will find no doubt that your camera will insist on refocusing with each new image, causing you to have to align each slide. This can get very annoying after a few images, and as a practical matter, it isn’t necessary. Remember, we’re shooting at f/8 to start with, which not only provides the lens’s best performance setting, but which also provides sufficient depth-of-field such that minor focusing variances won’t matter. You can check this for yourself: let your lens autofocus on a slide, check it for focusing accuracy with the camera’s review function, then set the lens to “manual” and shoot another slide without adjusting focus. Then check it’s sharpness, zooming all the way in to maximum magnification. There should be no difference in focusing sharpness between the two images. So, once you have the focusing ring set, as long as you don’t move it, you shouldn’t have to re-focus.

Once you have shot duplicates of your slides, use your camera’s software to load the images onto your computer. Then you can call them up as needed into your image processing software. From this point on, follow the directions given starting with the paragraph that begins with “Once the scanning is complete, close the scanner software.”

Macro Bellows with Slide Copier Attachment

The above rig is the old school route for duplicating slides, and if you have a full-frame DSLR, it’s still the best. It consists of a macro bellows and a macro lens with a slide copier attached to the front. Some slide copiers also come with a roll-film stage, which makes it easier to shoot duplicates of film strips. This setup allows you the ability to take not only 1:1 duplicates but you can crop portions of the slides also, if desired. It bears mentioning that not all current DSLR manufacturers produce bellows for their camera systems, although chances are they did in the past. Let’s take Canon as an example, since their EOS DSLRs are so popular. Canon has not offered a bellows system since they were producing their FD line of manual focus lenses. And the FD mount is incompatible with the EOS mount. It is possible to get an adapter that will allow one to use FD lenses on EOS cameras, but if the adapter does not use a corrective lens, infinity focus is lost. If it does use a corrective lens, the image quality is degraded. So Canon users are kind of stuck. Now, in the case of macro work, such as using bellows for duplicating slides, one will not be as concerned about infinity focus, so such an adapter may not matter. In which case, a Canon user can use the Canon Bellows FL or the later FD Auto Bellows and then a Canon-mount macro lens. But one can also buy an adapter that will allow one to mount another make of lens to an EOS body, such as Nikon, Pentax, Olympus, and others, and with these adapters, infinity focus is retained. If one goes this route, then one can buy a set of bellows to fit one of these cameras along with a macro lens in the same mount. The advantage to the latter route is that the lens can be used for more general-purpose photography on the EOS camera, since infinity focus is retained. Adapting other makes of vintage manual focus lenses to be used on DSLRs is something that is becoming increasingly popular amongst the photographic community. I’m certainly an advocate.

When it comes to a few other makes of cameras, such as Pentax or Nikon, no adapters would be needed to use bellows and macro lenses since these manufacturers have not changed their lens mounts. With others, such as Sony (formerly Minolta), there is no backward compatibility so the adapter route will have to be used.

My own slide duplicating rig is something of a hybrid. I’ve adapted the duplicating tube from a digital slide duplicator to the slide stage off an old duplicator. The tube screws into an old 55mm macro lens, and the macro lens sits in front of a short extension tube. This combination provides me with almost exactly a 1:1 image size for my duplicates. Works great, and it’s fast to use.

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