Scanning 35mm Slides

And Why Macro Capture Is a Good Choice



120studio.com
April 2013
Updated July 2014


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Digitizing 35mm slides with a DSLR is easier than you think. 

In this article, I walk you through the process, including what gear to choose.


(For additional tips and techniques, please be sure to see my new Film Scanning e-book for the Kindle Reader.)



Article sections:

1.  Flatbed Scanners
2.  Macro Capture:  Primary Considerations
3.  Visual Comparison:  Scan vs. Macro Capture
4.  Choosing Extension Tubes  (Skip this section if you have or plan to get a 1:1 macro lens!)
5.  Choosing a Macro Lens
6.  Don't Forget The Stand!!
7.  Conclusion


Many readers have emailed me and asked about scanning 35mm slides.   What's the most convenient way?  What's the most cost-effective?  What yields the best results without resorting to a drum scan?

I'd been thinking about this problem for a while.  Ready-made scanners have some limitations.  They offer a fair degree of speed and ease of use, but they lack that optimal image quality that most of us seek.   The Nikon Coolscan, which was probably the best of the bunch, was expensive, and now it's not being made or supported anymore. 

The methods we're going to discuss will apply just as well to negatives, and also larger formats such as 120 and 4x5.



Flatbed Scanners


I often use an Epson V500.  It's pretty good for 35mm negatives and better for 120 film.   Unfortunately, the scans of mounted 35mm slides are just a little too blurry for my liking.  The scanner offers no built-in way to adjust the focus height.  The plane of focus is somewhere above the glass of the flatbed, but the exact amount may vary between scanners.  You might get one that focuses better on mounted 35mm slides, but then again you might not.  Since there is only one height of ideal focus for a mounted slide, chances are you won't be one of the lucky ones. 


Messing Around With Height

Since my V500 appears to scan 35mm negatives better than mounted slides, I checked the height of the film holder.  The negative is held more than 0.5 mm, but somewhat less than 1.0 mm, above the glass.  It looks closer to 1.0 mm than 0.5, so it could be 0.8 or 0.9 mm.  Meanwhile, mounted slides seem to be 0.4 to 0.5 millimeters from the glass.  Aha!  That tells me that if you unmount slides and put them right up against the glass, the focus is going to be even worse.  In fact, when I scan photo prints directly against the glass, they do look softer than they should.  Instax Mini photos are already a bit soft, but my Epson V500 makes them look very soft. 

Now, it might seem that if I make shims that are 0.3 to 0.4 mm thick, the mounted 35mm slides should scan better.  A piece of economy-grade printer paper measures 0.095 mm thick, or about 0.1 mm.  Three or four sheets, and we ought to have the right height!   Maybe.

I also measured some black construction paper at 0.21 mm thick.  Two sheets ought to do it, yes?

Actually, no.  I tried raising the height in 0.2 mm increments.  No luck.  Then I tried varying it by 0.1 mm increments (tedious!).  Incredibly, there was no improvement.  None!  (Not long after this test, my well-used scanner decided to quit altogether.  Looks like it's macro capture from here on in!)


How Blurry Scans Can Wear Out Your Hard Drive

It takes a lot of work in "post processing" to sharpen slide scans from a flatbed.  Unsharp masking really brings out the grain and the scan noise patterns, which look like vertical lines.   You have to tweak your favorite noise-reduction algorithm to try to fix that without re-softening the scan.   It's tedious, it's a trade-off, and the bigger scan files put a lot of wear on a hard drive with all that RAM swapping.   (My flatbed actually cost me a hard drive because of this.)

The Epson V700 / 750 allow for height adjustment of the film holders, but realize that this, too, has limitations.  The focus point for "film with film holder" is supposed to be 3mm above the glass, but it could be (say) 2.92 mm, 3.27 mm, 3.32 mm, or some other random number close to three. 

Dealing with height variations is kind of a drag.  Even if you get it right, a flatbed scanner has moving optics.  That means there is going to be a very small amount of "play" there.  It's alright for everyday scanning, but what if you want to make 24"x36" enlargements?    If you have something really special, it's worth it to pay an expert operator to drum-scan your work, but what if you have 200 slides?  


Here's my experience with macro capture, the only realistic "serious" method for most of us.


Macro Capture:  Primary Considerations

1.)  Many so-called "macro" lenses are not 1:1 macro.  That means you will need a set of macro extension tubes to hold the lens farther away from the camera sensor.   Up to a certain point, the farther away you hold the lens, the bigger the magnification.   If you want to avoid a big headache, make sure you read the section "Choosing Extension Tubes", below.  Read it BEFORE you get a set of tubes and put them on your camera!

2.)  You will need some way to light up the slides uniformly from the back.  A light bulb will produce uneven lighting of the wrong color temperature.   I searched around for plain white glass or white acrylic and was unable to find anything that really would have worked.  Everything I found was either the wrong consistency, was curved, or had some kind of texture that would show up in the photos.  My solution was to get a small, inexpensive light pad (get yours here).   For 8x10 transparencies, you'll need a bigger one.

3.)  You will have to make something to block the light that shines around the slide.  Otherwise the glare will ruin the capture.  A simple solution is to cut a 25x37 mm rectangular "window" in a piece of black construction paper.  Put the paper on the light pad so the light shines through the window, then lay the slide on top of this window.  Or, the other way around if you prefer. 

It doesn't have to be perfect, but make it as straight as you can.



4.)  You will need a way to hold the camera steady and perfectly parallel to the slide.  This is the hardest part.   Everything will have to stay put while you focus the macro lens and take the picture.  Forget shooting handheld;  the focus precision demands a steady support.  The section "Don't Forget The Stand!!" (see below) discusses some ready-made options.  If you make your own, consider how much it costs you to go chasing all over creation for the parts you'll need. 



Visual Comparison:  Scan vs. Macro Capture

Here's a capture of a 35mm slide, scaled down to fit this page.  I added the white rectangle to show the area we're going to enlarge. 



Now, here's a side-by-side comparison of that area, taken from two different methods of image acquisition.  One was a flatbed scan of the mounted slide, the other was macro capture.  What a difference!




The macro capture was done with a 55mm Micro-Nikkor f/2.8 AIS using a couple of cheap extension rings.  Total extension was about 16mm.  (See below for cautions regarding cheap "macro extension ring" sets....)  Just for reference, the macro capture was done at ISO 800, 1/80th of a second, with the lens set on f/5.6.

According to my measurements and screen resolution, the 100% crop would represent actual size if the photo were enlarged almost to 30" x 45".   For 35mm, that's a pretty big enlargement.   And by the way, I made the original photo with a cheap zoom.  I did not use a tripod.  Had I taken the original photo with a better lens and used a tripod, I could get even sharper slides, and thus a better macro capture. 

To get the kind of sharpness improvement you see in the macro capture above, you have to be really good with the focus.  You can get a passable capture by focusing through the viewfinder, but it's better when you switch to "Live View" and zoom all the way in on the view.  Even there, you will probably have to do a few tries to get the ideal focus.  If you do it wrong, it can easily be worse than the flatbed scan.

It's a good idea to use the camera self-timer.  Just a fraction of a millimeter of flexion, and your slide will be out of focus. At these close distances, the plane of focus is very thin. 



Choosing Extension Tubes

(Jump ahead to the next section if you have or plan to get a 1:1 macro lens)

First I'd better mention that the cheapo "extension ring" sets have a tendency to get stuck on the lens.  Sure, you can remove the rings from the camera just fine, but often they will not let go of the lens

If your extension ring gets stuck on the lens, first make sure the whole assembly is removed from the camera.  Then, hold the lens and try pulling on the extension tube barrel while turning it.  Sometimes this will release it.  If it does come off, you might find that the extension tube will no longer hold the lens reliably.  How'd you like to be going along thinking everything is okay, then your cheap extension tube suddenly drops your $400 lens on the pavement?  That's what happens with cheapo extender tubes, for some reason.  They either hold on to your lens like they're brazed there, or else they just nonchalantly let it fall out.   "Oh, you don't want extension tube to weld permanently to your Nikon lens?  Okay, take this!

You would think it's not rocket science to make a lens adapter, but I guess it is.  Metallurgy and precision machining are two things we take for granted in our modern society.  Actually, most cheap lens adapters are made with spring clips.  You're supposed to be able to pull outward and compress the clips, in which case the adapter will release your lens.  Problem is, the spring clips are not exactly NASA-grade alloy.  Sometimes they lose their spring after a couple of uses.  Or maybe one use!

If the extender tubes do stick permanently, keep the lens that way and just use it for macro slide capture.  Otherwise you can sit there trying to figure out how you're going to prevent metal particles getting down in your lens because you had to use an abrasive cutoff wheel to remove the cheap extender rings.  I know of people who have done this. 

Don't waste your time on cheap bellows extensions, either.  Chances are that you will have the same kinds of problems.  (Here again, if you have a lens that you don't ever plan to remove from the adapter, then go for it...)

If you don't want to trash your lens, there are two real options for macro.

The first option is to get a good set of tubes.   Forget all the re-branded generic ones, unless you have a lens from which you never plan to remove the rings.  Even the Vivitar set, which is usually pretty good, can sometimes jam up on your lens.  Furthermore, if you try to use a lens with an electronically-controlled aperture (typical for modern kit lenses), you'll be stuck at f/22, which is a diffraction disaster for digital cameras.  You'll need to use something wider to get better detail.

Realistically, you're looking at $200 for a good set of extender tubes that (A.) won't get stuck, and (B.) can work with electronically-controlled lenses.

For Nikon cameras, a lot of people buy the Kenko extension tube set.   There's also a set for Canon EOS cameras. These may not be perfect, but at least they don't jam like the cheaper ones.  The Kenko tubes will work with electronically-controlled (DX and G) lenses.  The drawback is that the whole assembly has some play in it.  Not as much as you get with the really cheap tubes, but it's there. This can make it tricky to maintain the perfect focus necessary to capture slides.   This is all the more reason why your camera and lens should be oriented vertically, looking down, so that gravity keeps everything parallel (see "Don't Forget The Stand!!", below).

There's another, possibly bigger reason to skip extension tubes altogether. That is, corner sharpness. However, the use of extension tubes with a macro lens such as the Micro Nikkor 55 is generally OK. The real problem starts when you try to use a non-macro lens with the tubes. The 50mm Nikkor Series E "pancake" has incredible sharpness at the center... but not in the corners when you use an extension tube. Again, the main purpose of using an extension tube is to bring a less-than 1:1 macro lens up to 1:1 magnification.

By the way, if you're instead thinking of buying the Nikon-made PK13 extension tube, make sure you realize that it does not support lens electronics.  That means it will not work with lenses that don't have an aperture ring.  The PK-13 works great with the 55mm Micro Nikkor, though.  If you have that combo, you might consider getting the Nikon ES-1 Slide Copy Adapter.  Yes, it's a little finicky, but not nearly as bad as the ultra-makeshift rig I used to do the macro capture for this article.  With these three things and a Nikon DSLR, you have pretty much everything you need for slide capture, except a light source.  (Canon owners, you could still use these same three items if you get a Nikon-to-Canon lens adapter, such as this one or maybe this one.)

If you have a Canon DSLR, I highly recommend you get the real Canon tubes.  They're so expensive that you're better off buying them individually.   I'd go right for the Canon EF 25 II extension tube (get it here).   Canon tubes now cost about two or three times what they should, but that's the way the whole camera industry has been going lately.  This tube has a total extension length of about 32mm, which means that if you set your zoom lens to a focal length of about 32mm this will give you 1:1 macro.  Here's the equation, if you feel like doing some math:

       (Extension length) / (Focal Length)  =  Magnification

Many people use DX or APS-C digital cameras, so the apparent magnification is greater because of the crop factor.  1x macro would be perfect for capturing a 35mm slide if you're using a full-frame DSLR, but on a DX/APS-C camera, you really need only 0.67x to have it fill the frame. 

     32 / f = 0.67
    
     32 / 0.67 = f

     f = 48

That means when using the Canon EF 25 II, which has a total extension length of about 32mm, you'd want a lens with a focal length of about 48mm on your APS-C camera.   The 18-55 kit lens can do this, obviously, but it's not really sharp enough for macro capture. Instead I'd get the 50mm 1.8.   The Canon-made extension tubes are designed to work with the lens electronics, which is another reason to go for the Canon and skip the cheaper tubes. 

If you look at the equation, you might notice that as the focal length goes up, the magnification goes down.   That means extension tubes are a waste of time with long lenses.   The 18-55mm kit lens provides just about about the ideal range of focal lengths for extension tubes.



The second option is to buy a macro lens that can do 1:1 magnification without needing extender tubes.  This is the option I recommend.




Choosing a Macro Lens


Magnification

If you have a full-frame DSLR, just get a macro lens that can do 1:1 macro.  That's 1x magnification.

If you have a "crop sensor" camera (DX or APS-C), that same 1:1 lens would give you an effective 1.5:1.  That's an apparent magnification of 1.5x.  This happens because of the crop factor of the smaller sensor.  

For crop-sensor DSLR's, all you'll really need is a macro lens that can natively do at least 1:1.5, or 0.67x magnification.  When you fit that lens to an APS-C or DX camera, you'll get an apparent 1:1.

This is not really a problem, though.  When you buy a "1:1 macro" lens, that number refers to the highest magnification it can do:  in other words, 1x.   The same lens can do 0.67x if you want it to;  simply move the object farther away and re-focus.   You can go below the rated magnification for a macro lens, but you can't go above it without extender rings.  Just as an example, if you had a Micro-Nikkor 55mm lens, you'd still have to use extender rings, because that lens has a maximum magnification of 1:2.1, or about 0.48x.  The apparent magnification if you fitted that lens on an APS-C camera would still be only 1:1.4, or about 0.71x.

Some Lenses

If you don't anticipate using the macro lens for other kinds of macro work, you won't need one with an extended working distance.   For crop-sensor Canon DSLR's, I would consider the Canon EF-S 60mm macro.   You can use it as a portrait lens when you're not doing slide capture, but just keep in mind that it doesn't have image stabilization. The Canon has good bokeh (Tamron's 60mm macro is better though). 

Nikon users can get the Nikon 60mm f/2.8G AF-D lens, available through this link.  This is an excellent lens that will work on full-frame (FX) or crop (DX) sensors. On a DX-format camera such as the D7000, D5300, etc., it makes a great portrait lens, since the apparent focal length is 90mm. However, if you want to save some money and don't care about autofocus (which you won't use for macro capture anyway), go for the Nikon 60mm f/2.8D AF, available through this link. (Actually, the AF-D will autofocus on the higher-end Nikon DSLR's such as the D810 and D7100;  just not the entry- or mid-level models such as the D5300.)

There's also the Micro Nikkor 105mm f/2.8G VR macro lens.   As I've found with the Canon 100mm, this focal length is just about perfect for macro capture, and I also use the 100mm macro for all-around photography and portraits.  If you can budget the 105mm, get the 105 instead of the 60mm.  Either of them will work on both FX and DX Nikons.

There's also the Tamron AF 60mm f/2.0 SP Di II, a 1:1 macro lens made only for APS-C / DX cameras.  Tamron's model number on this is G005.  The 60mm SP Di II, like the Canon 60mm macro, doesn't have image stabilization.  You can pick up the Canon EF-S mount version here or the Nikon-mount version here.  If you have a Sony DSLR, your version is here.  If you're after bokeh, this Tamron 60mm macro lens is actually better than the Canon 60.  It should be, since it costs more.

If you want the 90mm Tamron, which will also work on full-frame DSLR's, you could go for the SP model with VC ("vibration compensation").  Canon-mount version here;  Nikon here;  Sony here.  The Sony-mount version has no VC.  Tamron's model number on this lens is F004. 

If slide capture were all I planned to do with the lens, I'd actually go for the Tamron model 272E.  That's the classic AF 90mm f/2.8 Di SP.  (The name says "A/M", for "Auto / Manual focus", but you can manual-focus with the other lenses, too...)  This version, like the 60mm lenses, has no image stabilization.  For slide capture you don't need to spend the extra $250, since you should be using steady supports anyway.  Canon-mount version is here, Nikon-mount version here, Sony here.  This is a very popular lens model, so they also make it for Pentax DSLR's (get it here).

The 60mm and 90mm Tamrons have a short working distance for 1:1 macro.  This makes them a somewhat poor choice  for use on butterflies or other critters, which will want to fly away when you get that close.   What the Tamrons do have going for them is nice bokeh.  These make good portrait lenses when you're not using them for slide capture.



Best Macro Lens for Nikon DSLR's


If your budget can accommodate it, just go for the Micro Nikkor 105mm f/2.8G

           



Best Macro Lenses for Canon DSLR's


If you're a Canon DSLR user and you want the absolute best, go for the Canon EF 100mm f/2.8L IS USM macro.  This has the best, sharpest image quality, which will give you the best in slide capture.  At a street price of about $1050, it's not cheap, but at least if you buy this lens you won't be constantly thinking there's some better macro lens around the next corner.   

The 100mm f/2.8L macro has a working distance of 5.9 inches (even more with an APS-C camera), meaning that you're not stuck using it on slides and postage stamps.  

If you don't care about image stabilization, which is not usually used for macro anyway, here's what I would do.  Head straight for the non-L 100mm f/2.8 USM macro lens.  Read my review here, or get your lens through this link.  It has L-quality optics, but it's about four-hundred dollars less than the actual "L" version. 

If you're looking to build the ultimate slide capture device, you'll know you're using the best optics, instead of messing around with extender tubes that have play in them.  The only big drawback to the EF 100mm lens is that when you fit it to an APS-C camera, it acts like a 150 or 160mm lens.  Then again, you may find that desirable.  One day I saw some unusual wildlife that was far away.  The 100mm Canon macro on a Rebel T3 offered the longest reach I had at that moment.  160mm effective focal length was sure better than 70 or 80.

   


Don't Forget the Stand!!

To perform the original macro test, I used some hardware that wasn't designed for cameras.  It was kind of precarious.  The test rig didn't hold the camera very well, so it introduced way too much play.  It's a wonder I was able to get a good slide capture at all.  

What's really needed is a "copy stand" or "macro stand".  (For this purpose you won't need the lighting kit.)  I strongly recommend that you don't skimp here.  The macro stand is actually your most important component, next to the lens and camera.  You will be adjusting the camera up and down a lot more than you might expect.  When you have to refocus a macro lens, the amount of your view that's filled by the slide will change.  Sometimes you have to move the camera half a dozen times, refocusing each time, to get the correct 1:1 view of a slide.  When you're not filling up the screen with the 35mm slide, you're sacrificing resolution and detail.  This is where a good copystand is indispensable.


Skip The Cheapo Stands

I would recommend skipping the $35 stands altogether.  About the lowest-priced copy stand worth considering for the task is this one, but only if you have a lightweight camera.  I mention it for those looking to get started for the smallest investment. Thing is, such a track usually ends up costing more in the long run. If you still want semi-cheap but reasonably good, get this stand instead.

The weak link in macro stands is the right-angle mount for the camera.  That's also the part that matters most.  The cheap ones have more wobble.  Another weak link is the gear mechanism.  Either of these can cause unwanted "play" that translates to a poor-quality slide capture.

Look to the $100 to $200 range for semi-serious use.  Most of these are larger than the $25-$50 stands.   With the larger stands you may have to set your light pad on a stack of books to get the slide close enough to the macro lens.  It's actually better to get a larger stand than necessary, in case you get a bigger macro lens down the road.  How would you like to order a stand and find out the post is not tall enough for your camera / lens combo?

One word of caution:  an angled upright post will cause you some frustration.  Every time you move the camera up or down, the slide will have to be re-centered beneath the camera.  This is not a complete wash, though, because once you get a routine going, you will know exactly how high to position the camera and where to place the slide / negative.  Take note that even most of the top-end models have an angled post.   The reason they do this is so the post won't be in the field of view when the camera is elevated.  An angled post allows you to put the camera out over the center of larger documents.  (For capture of 35mm and 120 size transparencies, this feature isn't really necessary.)

              

The Albinar High Load copy stand is probably the best deal.  I have a full review here.

If you want the highest build quality and think you'll be using the heaviest camera / lens combos at some point, choose a super heavy-duty copy stand.  While there are copy stands that go for $2,500 or more, these have features such as tilting camera mount, built-in light pad base, etc.   Just know that the real pro quality starts around $500.  

The Kaiser 205510 ("RS 1") is not cheap, but then again you get what you pay for.  You can get it here.  That's a rather sizeable chunk of change for a stand, but you will find it's got the performance for serious work.  Everything is better:  better gear mechanism, better hold, and a solid camera mount.  

Another one in this range is the Beseler CS-21.  Film enthusiasts should all be familiar with that name.  Their copy stand has the same upright design as some of their enlargers.

                    

There is also the Kaiser 205511.  The camera mount assembly allows for forward adjustment of the camera.   

If you're serious about macro photography and slide capture, it's absolutely worth it to purchase a good copy stand.  Since you're basically making a "scanner" here, keep in mind that a good stand also allows you to "scan" documents, large format negatives & transparencies, and, yes, photographic prints.   This will get rid of the problem of blurred scans, which you get from a cheap flatbed scanner whose optimum point of focus is a couple of millimeters above the glass! 

(Speaking of which:  don't forget to put anti-Newton glass over your bigger negatives and transparencies to keep everything in the plane of focus.)

Figure on these basic elements: 

Light pad:  $50 to $100
Entry-level DSLR:  $400-$600
High-quality 1:1 macro lens: $400-$800
High-quality copy stand:  $500-$600

Total investment:  $1,350 to $2,100

That's better than spending $1,000+ on a used drum scanner that might not even work, and for which you may not even be able to get replacement parts.  (And last I checked, some drum scanners were three-hundred grand....)


Conclusion

This has been a look at the gear and some of the methods for macro-scanning film. 

My new Film Scanning e-book, available for purchase now, has even more information.  It contains advanced scanning and color-processing methods to help you unlock more of the potential from your film.

If you found this article helpful, please help me out by purchasing your photo gear (or anything else) through any of the links on this site.

Thanks for reading!




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