Slide Duplication How To

Recently I’ve been engaged in conversations at several different forums on duplicating slides using a digital camera. I’ve been using a DSLR and more recently a mirrorless NEX 7 to duplicate my slides for almost five years now, so it occurs to me that it is probably time for me to go ahead and write down exactly what I’ve done and what I’ve learned about the process. So here goes.

There are two basic methods people use to digitize their slides when they feel like doing it themselves. Either they use a scanner of some sort or they use a camera. The most common scanners used are flatbed scanners, which these days render passable reproductions. All flatbed scanners share one trait — their actual scanning resolution is much lower than what they claim. The best flatbed scanners — the Epson V7xx series — deliver scarcely 2400 pixels per inch. Most of your better flatbed scanners are typically around 2000 pixels per inch. I own an Epson 4990, the model that immediately preceded the V700 and V750. It’s an excellent scanner, but its resolution tops out at about 2100 ppi.  This is about half the resolution that you get from a high-end scanner, such as a Nikon Coolscans, the later models of which scan at the level of 4000 ppi. But the Coolscans’ high resolution comes at a price. The later model Coolscans sell at quite a premium — somewhere in the vicinity of $3000US. They do an outstanding job, however, so you’re getting quite a bit of bang for your buck — but it’s still a lot of bucks. Now, what a lot of people do, who have a large quantity of slides to digitize, is they will buy a Coolscan, digitize all their slides, then sell the Coolscan for what they paid for it. That makes a lot of sense, if you can afford the admission price and, perhaps more importantly, if you don’t plan on shooting any more slides. Ever. Well, I’m enough of an anachronism where I’m not gonna say never to shooting slides. Ever. So, the Coolscan is a less attractive option for me.

So what to do if you want the resolution of a Coolscan, but you can’t pay the price. Well, that’s where using a camera to do the scanning comes in. As it so happens, the 24.3 mp sensors used in some digital cameras produce images that are 4000 x 6000 pixels. The 4000 number is the one we’re interested in because it’s the vertical number and that corresponds to the number for the Nikon Coolscans. So this means that a digital camera with a 24.3 mp sensor can rival a Coolscan when it comes to slide duplication.

Actually, if you’ll permit me to spend a bit of time crunching some numbers — the Coolscans are rated at 4000 ppi, pixels per inch. And one inch equals 25.4 millimeters. But a slide’s vertical dimension is 24mm. So that means that the Coolscan is scanning 1.4mm less than an inch on the vertical. Or 1.4/25.4, which equals 5.5% less image. So we multiply 4000 by 0.055 and we get 220, subtract this amount from 4000 and we get 3780. So the Coolscan is actually scanning 35mm slide on the vertical at a resolution of 3780 pixels. It may be scanning at 4000 ppi, but it’s only picking up 3780 of ‘em. Same is true with the horizontal dimension. 1.5 x one inch is 38.1 millimeters, but the slide only has 36mm on the Horizontal, so we can go through the same drill again to show that the Coolscan might be scanning at 4000 ppi, but the slide’s scan will not be a 4000 x 6000 pixel image.  Now with your 24.3 mp camera with its 4000 pixels on the vertical, and with its duplicator set up to take full advantage of this dimension, the image is being duplicated at 4000 pixels, or 220 pixels better than a Coolscan. Cool, eh?

I bought a Sony NEX 7 for a few reasons, but a big one was that it would provide me with duplicates of my slides with a vertical resolution of 4000 pixels. All I had to do was figure out how to get that image into the camera. As it turned out, that was the tricky part. But I managed it.

Next we’ll discuss the gear you’ll need to make duplicates using a digital interchangeable lens camera. There are three basic gear sets that will be used, depending on the camera sensor. Well, actually four, but I don’t have any data on slide duplication using a micro-four-thirds camera, so it will be omitted from this discussion. I’ll concentrate on Full Frame and on APS-C, both the Canon size, which is 1.6x, and the Nikon and Sony size, which is 1.5x. Now, I realize that some of the pro DSLRs have a variety of sensor sizes between APS-C and Full Frame, but I’m ignoring these. Folks with these pro cameras can figure out what they need for themselves. They’re pros, after all. They don’t need me to figure out how to dupe slides.

Full Frame: Full-frame users have it the easiest, but not necessarily the cheapest. All you need for duplicating slides if you have a full frame camera is a set of bellows and a slide duplicator attachment for those bellows, plus a good, sharp, close-focusing lens. I recommend that the bellows/duplicator combination you decide on also has a roll-film stage option. You might not need it now, but the time will likely come when you’ll want to try your hand at duplicating negatives, or scanning unmounted slides. When this day comes, you’ll need that roll film stage.

It’s been my experience, from back in the day when film was the only choice, that a 50mm lens works well when duplicating slides with a bellows. I have been able to dial in exactly a 1:1 duplication ratio with a 50mm. I’m not sure if a longer focal length lens can be dialed in similarly. Perhaps not. Everything has to coincide. Focus has to come at the right spot at the right magnification and there’s not a whole lot of variability with this. So because of my own experiences, I recommend you use a 50mm (or so) lens with your bellows.  There are quite a few excellent quality 50mm (or so) macro lenses available. Your decision will likely be a result of the brand of bellows you obtain and/or the brand of camera you use and/or whether or not you’ll need to use an adapter to hook up the bellows to your camera. I chose Nikon for my macro lens and bellows because I felt this provided me with maximum flexibility. Actually, I had already owned a 55mm f/3.5 Micro Nikkor lens, and for my EOS DSLR I’d already owned a Nikon-EOS adapter, so I just decided to stay with Nikon for the bellows. I could have just as easily gone with another brand and used adapters, but this was the most elegant solution for me. When I bought my NEX 7, one of the first things I did was buy a Nikon-NEX adapter for it, so I was set.

Yeah, I was set — only problem was with either my EOS DSLR or my NEX, being APS-C cameras, I wasn’t able to dial in a 1:1 ratio with my bellows using any combination of lens and/or extension that I own.  So, maybe one day when I get a Sony A7 or another full frame digital, I’ll be able to use my Nikon bellows and slide duplicator. Until then, using the bellows is still an option, but only if I am interested in doing crops of my slides. Which actually occurs somewhat often.

So at any rate, if you have a full frame digital camera, whether a DSLR or a mirrorless, such as the Sony A7-series, you’ll most likely want to go the bellows route with a 50mm (or so) lens and a slide duplicator (of course) with roll film stage (preferred). Cost? Well, you can browse eBay to get a good idea of cost, but figure somewhere around $250-300 and up for a good setup that includes the bellows with duplicator and a macro lens.

Canon 1.6x APS-C: I’ve found that the reproduction ratio I get with my Canon DSLR is just different enough from that which I get with my NEX that the two deserve different configurations.

canon aps-c with dupe assy

Canon 1.6x APS-C DSLR with Slide Duplicator Assembly

Please refer to the image showing the arrangement of adapters and tubes that I use for a 1.6x crop body Canon. I have a fairly large collection of adapters and tubes and extensions and teleconverterss. I’ve tried all combinations and permutations of the gear I own and I’ve arrived at this configuration as the best I could manage. It gives me just slightly less than 1:1, meaning there’s just a bit of unused area left over — but it isn’t much, probably less than 5%. Horizontally it translates into maybe 1-2mm of movement leeway I have to position a slide before I start cropping off an edge. This is as good as it gets, I’m figuring — at least with the gear I have at my disposal it is. Now, I’m not saying that this is the only way to do it, but I am saying that this is the best way I know how.

The components of this dupe rig are as follows:

  • One set of cheapo extension tubes (I use tube #1 and the two bayonet pieces)
  • Opteka (or equivalent) slide duplicator tube, stripped
  • Slide Stage
  • Roll Film Stage (not shown, optional but strongly recommended)
  • Nikon 55mm f/3.5 Micro Nikkor (any 50mm macro lens should work)
  • Appropriate adapter for your camera

The big sort of wild card in this setup is the dupe tube — I’m showing it as the Opteka (brand) tube that I’ve stripped. By “stripped” I mean that I’ve removed all the stuff that it came with. Out of the box, this tube has a correction element inside so that the lens being used will focus closely enough, plus it had a slide holder at the end.  The tube is threaded at one end in 52mm. The idea behind this “digital” slide duplicator was that you would screw it into the front of a lens, probably most commonly a zoom, which would allow you to dial in a 1:1 ratio easily,  and that then the lens would autofocus on the slide and you ‘d point the assembly toward a light source and fire away. The Opteka tube rotates, which is necessary because every time your camera autofocuses, the tube rotates with the lens, and you have to reposition it again so it’s properly aligned (annoying, but consumer grade AF zooms with non-rotating front elements ae not common). My Opteka came with a 52mm to 55mm adapter, which provided some flexibility. The latest iteration of this duplicator is that it is now available in a range of diameters, from 46mm to 62mm (I think?). Well, for me, 52mm is just right because that’s the filter size of my 55/3.5 Micro.  So anyway, I stripped down this tube so all I had left was a tube with 52mm threads on one end and a flange on the other. That’s all I wanted out of this setup. Unfortunately, to get this  flanged tube with built-in rotation, it cost me over $50 for the whole duplicator setup.

Now it seems to me that you might be able to save some money here if  you use an old 52mm filter, some PVC pipe and a piece of flat plastic, about 1/8″ thick. Remove the glass from the filter (if you have a lens spanner then you can use it to unthread the retaining ring; if you don’t, just knock the glass out). 52mm is almost exactly 2″. So take the filter down to your friendly neighborhood Big Box Store and dig through their PVC stuff to see if you can find something in the range of 2″ that will fit in or around that filter. Doesn’t have to be precise, just close. If close, you can use some silicone seal to stick the two pieces together. If a more snug fit, well, silicone seal will still work, but so will other, more conventional types of glue.  Ideally, you’ll want to find two pieces of PVC — one to fit the filter, and another to fit around the first piece like a sleeve, so it can rotate the way the Opteka does. Reason for this is not because of a rotating lens front element (because with my Nikkor at least, it does not rotate), but because  you can’t count on the filter threading down onto the lens such that the slide holder will be perfectly aligned. You’ll want to be able to tweak this, and the best way I can think of is if you can have one piece of the PVC fit over the other. The Opteka tube is made so that it can be rotated easily, but this is the cheap route, so we’ve got to do it ourselves. I recommend that you do not glue these two pieces of PVC together, although I suppose you could once you got everything properly centered.  You’ll want the total length of this two-piece section to be 3-1/4″ long. Why? Because that’s how long my  Opteka tube is, that’s why.  Then for the flange, we’re going to need a flat piece of plastic, about 1/8″ thick, that you’re going to have to drill a hole into, same diameter, or close to it, as the tube, then glue these two pieces together. As for the flange dimensions I recommend that you do not trim it down until you’ve obtained a slide duplicator stage. Take your dimensions from the stage and trim this piece accordingly.

Whether you choose to buy a pre-made duplicator and strip it, or make your own, the resultant assembly should work well and give you almost exact 1:1 duplicates.

NEX and Nikon 1.5x APS-C: The 0.1 difference in magnification ends up making a pretty bid difference in the adapter. Now, you can use the above adapter for a NEX or Nikon APS-C camera, but instead of losing about 5% or less of the image, you’ll be losing closer to 20% of the image. Yep, just that little bit of difference in magnification makes quite a bit of difference in the size of the image.

nex7 dupe assy

NEX 7 with slide duplication assembly for 1.5x APS-C

Referring to the photo, you’ll see the following are required for this duplication assembly:

  • Opteka “Digital” slide duplicator (or equivalent), stripped
  • Nikon K-5 tube from Extension Tube Set K
  • Nikon BR-2 and BR-3 Rings
  • Nikon TC-14B 1.4x Teleconverter
  • Slide Stage
  • Roll Film Stage (not shown, optional but strongly recommended)
  • Nikon-NEX adapter
  • Nikon 55mm f/3.5 Micro-Nikkor lens

As you can see from the equipment list, this is quite a bit more complicated than the detail list for the Canon. The upside is that this configuration will give you almost exactly a 1:1 ratio — actually it’s just a tiny bit more than 1:1. You’ll end up cropping 1 to 2 mm from the Horizontal of the slide. It’s been my experience that I can live with this very small amount of crop. If not, then I can always go with the EOS configuration — I’ll get the entire image, but I’ll be giving up about 20% of the resolution, which may or may not matter in the ultimate scheme of things.

Everything I wrote about the Opteka tube and building your own above applies equally here.  Most everything else is fairly self explanatory. I was fortunate enough to have quite an assortment of Nikon adapters and extensions and teleconverters such that I was able to cobble together this setup from parts on hand. Now, there may be a more elegant way to achieve 1:1 with a 1.5x crop body camera, but I can assure you, I tried every combination at my disposal, and finally decided on the above as the best solution to the problem. If you have a better, more efficient, or less complex way, I’d like to hear from you.

Now, of course, I’m not insisting that you use Nikon. This just so happens to be the best assortment of adapters, etc., that I have on hand, so naturally that’s what I used. There is an advantage to going with Nikon, and that is that its accessories are usually fairly easy to come by, whereas with other brands, you might be waiting a while before you come across the item you need.

Lighting: Let’s discuss briefly the lighting we’re going to use for slide duplication. Some people prefer natural light, others prefer artificial. I use both, but there are limits.

With natural light you have to be careful about the light’s color. Mid-day is best. Early morning and late afterrnoon light has much more yellow and orange in it. If your camera is good at white balancing, then this might not be an issue, but not all cameras are all that good at light balancing, I’ve discovered.  Which is why I recommend mid-day or close to it. Additionally, you don’t want to point your dupe rig at a blue sky. This is just asking too much of your camera’s white balance. Instead, you can use a reflector. A piece of white posteboard makes a great reflector. Arrange the posterboard such that it’s reflecting the sunlight and then point your dupe rig at the posterboard.

I like artificial light for its flexibility and control. I prefer the kind of flash that has fractional output in manual mode so that I can set it to 1/8 or 1/16.  Currently I use either  a Canon 540EZ or a Nikon SB24. Both of these are powerful flashes, so I set them to 1/16 in manual. When I trigger them, I usually hold the front of the dupe rig between 12 and 18 inches away from the flash. Depends on the exposure I’m after. Sometimes I’ll located the rig even farther back.

I attach the flash to a stand and trigger it using either a sync cord with adapters or I use a slave module to trigger it using the small on-board flash on my camera. There are advantages and disadvantages to these methods. When I trigger the flash with it connected to my camera with a sync cord, the camera doesn’t know there’s a flash connected, so I have to use Manual mode. I set the shutter speed to 1/60 and I leave the lens’s aperture set to f/8. If I forget to do this and leave the camera set to, say, Aperture priority, yes, the flash goes off when I press the shutter release, but the shutter times out according to whatever light value is entering the camera, which could be several seconds. Now the disadvantage to having the camera set to Manual is that the display doesn’t show anything unless I’m in a high ambient light environment, which is usually not the case. So I have to switch to Aperture priority, which allows the display to light up so I can see what I’m shooting. This allows me to line up the next slide, and tweak the focus, if necessary. Then I have to switch back to Manual to take the photo. Lather, Rinse, Repeat.

The other option is to use the on board flash to trigger a slave module that I’ve attached to the flash. The advantage to this is that I can leave the camera set to Aperture priority, which makes the  workflow smoother. The only real disadvantage I’ve run into is, because I’m having to use the onboard flash on every exposure, the battery drain is increased. There is also the occasional episode where my 30-year-old (or more) slave module may occasionally flake out, requiring me to tweak it a bit to bring it back to life.

Raw or JPG? I shoot raw for one big reason: you have greater control over the image than when it is fixed to a particular file format. This is particularly true with exposure, color, and saturation.  Sharpness and contrast can also be accomplished in raw mode, which has less of a deleterious effect on the image. Some raw image converters even have noise adjustments.

Here’s an example from some recent dupe sessions: it is not unusual when I’m duping an image for it to turn out somewhat too dark for my liking, even though it looked perfectly fine when I took the image. Using the EV control I can add (or subtract when overexposed) steps of brightness to the image that simply are not possible once it has been saved as a .jpg (or .tif or .png, or whatever).  Same is true with color or white balance and saturation. It’s just more subtle and natural looking when the adjustments are made on the raw file. And of course, even after saving the raw file with the new settings, you can always go back and put the raw file back to the way it was originally. You cannot do that with a file saved in one of the popular given file formats. However, it is my understanding that both Photoshop and Paintshop Pro have native file formats that will recall changes made to the original after the file has been saved, much the same as raw files. Photoshop’s files in native format are saved with a .psd  extension and Paintshop Pro’s are saved as a.pspimage file.

Sourcing The Parts: These days, I tend to look on eBay first when I’m after something that might be a bit odd or uncommon — or even popular, far as that goes. But if you have an APS-C camera there are a few parts you’re gonna need that will be found easiest on eBay. The slide stage, for example, the kind that is best for this project, which has the spring clips that hold it against a flange, is most easily found on eBay. Look for a zoom slide duplicator — these most often have the slide stages held on by the spring clips. You can usually pick up a zoom slide duplicator for cheap, often less than $10.  Zoom slide duplicators are cool tools, but even when zoomed all the way in, they’ll be cropping your images. Remove the slide stage and set the zoom tube aside; add the slide stage to your pile of goodies.  You’ll also want to keep your eyes open for a roll film stage. These are less common, but they do show up on eBay from time to time. I picked up a Spiratone one on eBay for $7. Fortunately it has the spring clips and the hinged white plastic diffuser, same as on the slide stage.  I also bought a Chinese set of Nikon extension tubes for less than $10 on eBay, and all the miscellaneous adapters and tubes and extensions I now own — most came from eBay, a few came from a local camera store that was blowing out its old used stuff. I picked up the set of K extension tubes and the BR rings from the local camera shop, actually, along with a PK-3 and a PN-1 extension tube (I didn’t use them in these rigs, but they were part of the haul, which is why I mention them). The Nikon Extension Tube Set K is important because it has 52mm thread, so the tube I used threaded right into the adapter and the lens.  You can buy 52mm extension sets on eBay, but they tend to be very expensive. The Nikon Set K is usually much cheaper.  The TC14B came from eBay, as did the adapters for Nikon to EOS and Nikon to NEX. I’ve found that if I just  use extension instead of the TC14B, the image fills about 90%  of the viewfinder. Not bad, but not as good as you’ll get with the TC-14B. But if you don’t want to spend the money for a TC-14B, extension tubes are much cheaper and you can end up with a decent dupe at 90% (or so) of maximum.


Leave a Reply