Carl Hutzler's Blog

Before I bought my first digital camera around 2003, I had a Nikon FE2 and a bunch of prime lenses. I bought the camera with a 50mm lens from Service Photo in Baltimore, used, for about $500 in 1988. I used the camera for 15 years mostly shooting black and white negative film and then slides.

I have a lot of B/W prints from my darkroom. But the slide collection was always hard to view. The projector, screen and inability to simply pull out an image and show someone were always a drag. For years I have been looking for a way to scan the slides cheaply, but the cost to scan 4,500 slides is not even close to approachable. I did not need the highest quality…just something fairly good…good enough for the web. If I really wanted to make a print/enlargement, I always had the original slide and could pay for a drum scan if I wanted.

The idea of putting the slides into a Kodak projector and somehow taking pictures of them with a digital camera was always a thought I had. I even briefly tried to make it work, but quickly ran into a number of issues which stumped me. The slide projector bulb was WAY to bright. Focus was an issue. And even getting decent color balance and contrast was problematic.

Luckily, my father (and mother) have a huge slide collection. My dad was also interested in the same thing – digitizing the slides. He did most of the work but I helped supply equipment, software and some know how on things.

Here is the parts list:

1. Heavily modified Kodak Carousel 4600
2. Custom TTL logic circuitry to drive the slide projector and camera
3. Cheap ebay remote for the Nikon D200
4. Nikon D200
5. Nikon 105mm Macro f/2.5 lens with some small extension tubes
6. Front surface mirror from an old copier machine
7. Custom camera stand
8. Apple MacBook Pro running Nikon Capture
9. AC Power Supply for Nikon D200

After months of on again/off again work and a lot of experimentation, my dad creating a very high quality 10MP slide scanner. It scans a tray of 140 slides in about 4-5 minutes almost completely automatically. Just drop the slide tray onto the projector, seat it by pressing the normal button, reset the TTL circuitry (and make sure the switch is set for 140 or 80 depending on your tray size) and hit the start button. Walk away and come back in 5 minutes and you have 140 digital files.

So how did it all work? The slide projector was modified. The normal bulb was replaced with a small (10w) halogen bulb that ran off of a 12VDC power supply. The bulb illuminated a piece of white diffusion material (paper?) which evenly lit the back of the slide. And the remote control for the slide projector was hard wired to a relay that was connected to the custom TTL circuit which allowed the slide projector to be advanced after a picture was taken. The camera was mounted to a custom mounting stand that could be adjusted very precisely via several finely threaded screws (focus was a key issue). The camera was fitted with a 105 macro lens with about a 1/2″ of extension tubes between lens and camera. The lens was pointed to a first surface mirror at a 45° angle to the projector. This allowed the lens to focus properly without having to be inside the projector for which it was too big anyway. The TTL circuit had options for 80 slides or 140 slides. And it would advance the slide and trigger the camera to take a picture about every 2 seconds.

Focus was a big issue throughout the project. Eventually my father found that shooting with the 105mm macro on f/8 was the best quality. And he also found that the Nikon D200 (at least my camera) was not precisely focusing when viewed on the ground glass…especially with our macro set-up. So he did some testing and eventually just focused by trial and error (I think).

Exposure was simply aperature priority. The lens was not coupled with the camera so it was always stopped down. The meter just set the shutter speed acording to each slide as it dropped. This worked surprisingly well (to me anyway).

I did my entire slide collection in about 3-4 hours last weekend. The only thing I might have changed was seeing if I could tweak the contrast curve for the JPG file conversion in camera. When you scan a slide (or make a slide dupe) you pick up contrast in trhe process. I think maybe a custom contrast curve might have helped with that issue. But even without, the slides are very good.

Exmaple Scan with USM filter applied in Photoshop (click for larger):

Pictures of the set-up below: