Railfan Technology > Slide Projector to DSLR Digitizing

Seeing a need to more quickly digitize slides at the CNWHS Archives that I volunteer at, I created a setup for digitizing slides using a DSLR and slide projector.  I like the quality and really like the speed - upwards of 750 slides per hour can be digitized.  If you count loading the carousels and dusting, it works out to about 300 slides per hour.  This makes what is otherwise a long task more managable.

Here is page that describes this more. http://www.yardoffice.com/archives/howto/slideshootingdslr.html

1. The setup
2. Cropped, resized scan
3. 1:1 pixel crop showing the resolution

Jeff Eggert

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Wow - that is an impressive setup.
The results look great.
Thanks for showing how you did it.
Gary

Does the projector light shine directly into the camera lens between changes from one slide to te next?

Greg Stadter
Phoenix, AZ

E25 Wrote:
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> Does the projector light shine directly into the
> camera lens between changes from one slide to te
> next?

The slide projector has a black "flap" or piece of plastic that blocks light coming out while the slide changes.  It seem instantaneous.

Jeff Eggert

I'd be interested to see the same transparency as a high quality scan. Looks like the contrast in the sample is really high, much like a dupe slide.

trainjunkie Wrote:
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> I'd be interested to see the same transparency as
> a high quality scan. Looks like the contrast in
> the sample is really high, much like a dupe slide.

Yes, the contrast is high, that is my lack of skills using slide film, probably a poor choice in example.  I rarely shot slide film, normally I shot color negatives.

Here is a better sample, taken by John Luckfield, part of my collection.  The Plustek scan is at 3600 dpi, the DSLR at 3980 dpi.  I'm sure if I tweaked the lighting and color in both cases I could get them to a closer match.  These are only sized down for posting here.

1. Plustek 7600
2. DSLR - Projector
3. 1:1 Comparison

Jeff Eggert

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The images from the D-SLR are not bad. We've had a number of versions of this discussion here, using either a slide projector to project the image and a D-SLR to capture it, or a D-SLR with a slide duplication attachment. The results are usually about the same. The digital image from a high-end scanner is generally better than from the D-SLR, regardless of how it's used. The true test is to digitize a few less-than-perfect or poorly exposed slides using both a scanner and a D-SLR duplication set-up and see which ones prevail. It's generally the scanner. They just have superior D-MAX.

I still prefer the flatter image from the scanner but for a quick way to digitize film, the camera image is not a bad compromise. Certainly an acceptable way to build a digital catalog and images for low-res internet posting. But for prints or lithographic reproduction I'd want to start with a scanned image.

How is the slide projector modified?

pennsy3750 Wrote:
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> How is the slide projector modified?

The lens is removed and the light module is pretty much gutted with an 5000K, high CRI LED bulb put in its place.  The high CRI bulb provides better color reproduction than a typical off the shelf bulb at the store.

Jeff Eggert

blueflag Wrote:
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> The lens is removed and the light module is pretty
> much gutted with an 5000K, high CRI LED bulb put
> in its place

So, am I correct in thinking that the primary purpose of the slide projector is the carousel feed?  If I'm interpreting the above correctly (which I might not be), one could build a similar contraption without a slide projector and just use the bulb in a box, and just live with loading one slide at a time?

pennsy3750 Wrote:
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> So, am I correct in thinking that the primary
> purpose of the slide projector is the carousel
> feed?  If I'm interpreting the above correctly
> (which I might not be), one could build a similar
> contraption without a slide projector and just use
> the bulb in a box, and just live with loading one
> slide at a time?

The primary purpose is for feed speed.  They make slide duplication attachments for a lens with a light and slide holder.  But, I doubt you can run 80 slides through a single slide setup in 6 minutes.  In theory, a team of three people (2 dusting slides, loading & unloading carousels, 1 digitizing) could knock out upwards of 5,000 slides in an 8 hour work day at an archives or similar.

The projector with a carousel (a stack loader would work too if the projector accepts one), is really just using an already well designed piece of hardware to do that job, reliably shuffle slides infront of a light source.

Jeff Eggert

I built the wood frame, just like seen in Railfan Mag. Fan vibration seems to be an issue. I put the projector on the kitchen table and mounted the camera on a tripod. Helped a bunch. 
Anyone interested, crop body and I use the 100mm fixed macro with an adapter to the digital body. Stock bulb but a piece of heavy gloss paper over the lens produced even light. Straight from mag article. You can do slight cropping and a bunch of exposure compensation. I've darkened light slides and lightened dark ones to suit my taste.
Yes on stack loader. But it doesn't seem to seat them evenly like the carousel. I sat and ran a bunch of purchased slides through it to see. Seems you have to baby sit the exposures account the different exposed film colors. Would be easier to run a group of the same roll. Exposures being more even. Bouncing around is a little more work. 
Now I have to start cleaning slides. Think it was worth it. The lens was a Canon, $37 and I had the crop body as my backup.
Had everything else. Still wish I could reduce the vibration with out modifications to the fan circuit.