Slide copy setup


Slider copier, slide duplicator, digitizing slides

Copying old slides to digital is a time consuming proposition. A number of ways are possible:
- Flatbed scanners
- Dedicated slide scanners
- Copying slides with a camera
- Projecting slides and taking pictures

I had access to a Nikon Coolscan dedicated slide scanner. Despite a firewire connection, scanning was quite slow. I also have an Epson 3490 photo flatbed scanner, which has a slide scanning attachment. It works ok, but is also slow. Further, even though very high scan qualities can be set (in dpi), starting from about 1200 dpi (or thereabouts) the resulting scans only result in increased file sizes, but not increased sharpness. The achieved resolution from that flatbed scanner was less than what a Canon 550D can deliver (with the copy setup shown below). The speed of the scanner is a lot slower than taking images with the Canon.

How to copy with a camera?
A number of possibilities exist:
- Point and shoot cameras can often focus very close, so attachments can be found to mount a slide in front of such a camera without any additional optics, although also versions with a built-in close-up lens (usually around 10 diopters) are available, e.g.:
http://www.ephotozine.com/article/ohnar-digital-duplicator--review-4304
- Slide copy attachments that have built-in lenses and mount often directly to a dSLR camera. Many have a T2 mount, so a T2 to camera mount adapter is needed. E.g., Ohnar and other brands, see http://www.kauserinternational.com/zoomcopierreview.htm
- There are also slide copiers with built-in close-up lenses that attach to dSLR kit lenses to allow slide copying. Again, Ohnar, Opteka and other brands are available, e.g.,
http://opteka.com/slidecopier.aspx

http://srb-photographic.co.uk/slide-copiers-1460-c.asp
http://slidecopier.com/  had quite nice slide holders, but seems now defunct. 

However, none of the options with built-in optics seems to have really high quality optics to achieve optimal image quality. The optics are basically rather simple close-up lenses. Further, reviews of, e.g., the Opteka slide copier on Amazon were not very inspiring about accommodating different slide sizes, e.g., thicker plastic slide frame or glass slides would not fit.
As alternative, slide copiers with bellows and old macro lenses from the film days can be used and adapted to a dSLR. But still, though not expensive, all the parts will still add up, and one has a manual solution in the end, e.g., as shown here:
http://whitemetal.com/pentax/ap_ab_ii/index.htm

What if one has a nice AF macro lens, such as a Canon EF-S 60mm macro for the dSLR? All that is required is a suitable slide holder that goes in front of the macro lens. Something like this:
http://forum.mflenses.com/full-frame-slide-duplicator-for-crop-sensor-t12016.html (even though this is with an old MF lens).
The most convincing description and set-up for copying with a macro lens I found here:
http://www.scantips.com/es-1.html. This uses the Nikon ES-1 slide holder.
This description is very good, and gave all the pointers to make the setup that is shown below, and it also has the information about the extra extension rings.
The Accura slide-holder shown in the previous to last link looked pretty good and more flexible than the Nikon ES-1. It can ever so often be found on ebay under various names, such as Miranda, Accura, Panagor. Use the words "slide copier" or "slide dupliator" to search, and exclude things like Opteka. 

Here is an (expired) example from ebay:

This non-glass containing model (there are other models that have the same holder, but seem to contain a close-up lens) has apparently a Series 6 or 7 thread, which is 44mm/1mm. The original box contains 2 adapters, which seem to adapt to either 46mm or 52mm standard filter threads.

I ordered a Miranda slide duplicator on ebay without clear description, and I was fortunate that the 44mm to 46mm filter adapter was screwed onto it. So, here some images how this adapter looks.

The slide holder section has springs and can accommodate slides of different thicknesses.

 

 

 

 

 

 

The transparent white diffusor on the front is held with springs and can be folded down - perhaps to pass negatives or uncut film roles through it?

There are two adjustment screws: Nr. 1 allows movement of the tubus back and forth for about 2cm, which is useful to adjust magnification. Screw Nr. 2 - when loosened - allows rotation of the unit around its axis. This allows adjustment of the copier into a horizontal position, once it is screwed onto the lens filter threads. The threads at Nr. 3 are the Series threads (44mm/1mm), and Nr. 4 is the adapter ring that goes from Series 7(?) to a 46mm filter thread.


Attaching the slide copier to the lens


Working distance: To get the right working distance from a 35mm slide to the front of the Canon EF-S 60mm macro lens requires more than the minimal 1:1 working distance (which is 90mm for the 60mm macro), because of the crop factor the slide is 1.6x larger than the sensor. An advantage of using a crop sized sensor is that one has the possibility to enlarge the center of the slide up to 1.6x, if desired. The actual required working distance to get the slide frame filling the crop sensor is about 128 to 130mm (depending a bit on the frame used for the slide).
Connecting to the lens: Connecting the slide holder to the lens is done first using a 52mm to 46mm step-down ring (ebay). Further, a 52mm extension tube/ring was ordered from ebay. However, once delivered, it turned out that the tube was one of the cheap mechanical macro extension tubes commonly found on ebay that have 7mm, 14mm, and 28mm rings with screw threads, and a male and a female lens mount, respectively, that screw onto the rings. The screw thread size of these rings is a 52mm filter thread, but the lens mount that came with it was alas not a Canon. [It would have been nice, if one could have used them also as simple macro extension tubes. Similar types of simple macro tubes exist for Canon mount, but these seem to have a thread diameter of 60mm (info from a dpreview poster), so would require different sets of step-up and down adapters.] The extended Miranda copier, adapter ring, and extension tube rings provide the required working distance for coping 35mm slides as shown below.

The Miranda slide holder, the adapter rings, and the extension tubes assembled and mounted on a Canon 550D provide the required working distance for coping 35mm slides.

The system now has full autofocus and aperture control, so slight differences in slide position/curvature etc. are easily taken care of. As mentioned already by Wayne Fulton (scantips), such a set-up is not really subject to hand-shake, the camera can be held in the hand with long shutter speeds and produces sharp results.

 

Note: with other macro lenses the length of the tubes to get the right working distance would need to be adjusted. The new Canon EF-S 35mm macro would obviously need less extension due to the shorter working distance.

Lighting and exposure

Slides, like Kodakchrome capture reportedly about 5-6 stops of dynamic range. The actual exposed slide, however, can contain a much wider dynamic range, i.e. the darkest and brightest areas are more than 6 stops apart. Tests shoots of a clear/white slide versus a totally black slide (exposing the white slide to grey, and when shooting the black slide adjusting the exposure until it was about the same grey level as the white slide) required about 11 f-stops of exposure adjustment, showing the dynamic range that the emulsion of a slide can have (Wikipedia reports 12 stops). This needs to be taken into account when copying as it is close to the limits of dynamic range of a dSLR (as of 2012) and careful exposure is needed. To copy slides, it seems to work ok to hold it against a window. However, for reproducible results, i.e. white balance, even illumination, etc., a set-up with flash or another constant light source should be best. Here an Canon 430 EXII is used with an extension cord (ebay). With this set-up it is better to have the flash illuminate the slide with an angle from the side. Straight-on illumination into the camera from the back of the slide does result in some unevenness - the diffusor is not completely sufficient to diffuse the light completely.


Other slide copier links

http://www.photosolve.com/main/product/xtendaslide/index.html offer slide holders without glass for many distances.

http://www.andromeda.com/people/ddyer/photo/slide-transfer.html has different tests
http://www.scantips.com/projectorslidecopier.pdf shows how to convert a slide project to copy slide with project and camera.
http://babryce.com/slidedigitizer.html how to use a slide project to copy slide with a camera.
http://www.pbase.com/pganzel/basic_stamp_projector_camera_controller yet another slide projector slide copier set-up.
http://www.photosolve.com/main/product/xtendaslide/index.html a present day tube and slider copier attachment commercial product with different holders.
http://www.covingtoninnovations.com/dslr/SLIDEDIG/index.html comparison of different methods (scanner, camera), but old - 2006
http://www.digicaminfo.btinternet.co.uk/diyfilmcopying.htm comparison of scanner versus digital camera copying, detailed, nice