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Full-frame slide duplicator for crop-sensor
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PostPosted: Thu Oct 30, 2008 1:58 am    Post subject: Full-frame slide duplicator for crop-sensor Reply with quote

I have a flatbed scanner, but I am very dissatisfied with the results and especially with the very slow scanning.

I was inspired by this group to look at slide duplicators as an alternative. There are plenty of these available, leftovers from the last age of photography. They look very attractive because on a DSLR they promise almost instant duplication.

However, for a crop sensor DSLR they have a big disdvantage. Most of them are actually fixed-focus macro lenses designed to give a full 35mm frame 1:1 reproduction of a slide - or on the "zoom" versions, more than 1:1. With a crop-sensor DSLR we want LESS than 1:1, because we want to fill the smaller DSLR frame with the whole slide image. If we use one of the regular duplicators we will end up cropping the slides. This might be OK for some things, but as one of my objectives is to get real wide angle results out of my wide angle lenses, I might as well just use these on my DSLR.

I found this very interesting item -

This setup is from the camera end - a 20mm M42 extension ring, the Super-Takumar 35/3.5, a 49mm->SeriesVI adapter, and the Accura duplicator.

This is an Accura "Variable Magnification Duplicator". Instead of having a fixed-focus lens, this is just a slide holder that fits an existing lens. This allows all sorts of adjustments with bellows or extension rings, and the use of any lens. In this case I used my Takumar 35/3.5, but I also tried it with my Takumar 55/1.8. Both work, but the 35mm requires less extension on both sides of the lens, and gives the same results.

Some test shots - this is a 30-year old Ektachrome, not perfectly focused, but typical of old snapshots -

Scanned on my Canon 8400 flatbed at 2400dpi -

Copied on the duplicator (6MP on my Pentax K100D)

The duplicator shot was underexposed, and I bumped up the contrast, losing shadow detail. There is also probably less tonal range. But I do get the whole slide- in this case maybe a little more than the whole.

Scanner crop -

duplicator crop -

It looks like the ability to capture detail is about the same, though the exposure needs to be carefully calibrated. It is MUCH faster though ! Not perfect so far, but I think its promising.

PostPosted: Thu Oct 30, 2008 10:41 am    Post subject: Reply with quote

That's a great ingenious idea Luis! I don't have one of those duplicators - I've been trying to use a Pentax slide copier unit on bellows, but it's optimised for a 35mm camera and the bellows force the camera too far away from the slide. I've worked out a way of mounting the slide copier unit directly to the camera without using the bellows rail. It's very simple and works perfectly but I can't finish it until my neighbour returns from holiday to let me borrow his lathe again. Smile

About the under-exposure, what light source did you use behind the slide? After trying various lamps and windows I'm beginning to think a flash unit might be best.

PostPosted: Thu Oct 30, 2008 11:04 am    Post subject: Reply with quote

I have one of those duplicators - for Nikon.
Unfortunately I don't seem to be able to find the slide holder for it. I need to search more for it.

PostPosted: Thu Oct 30, 2008 11:32 am    Post subject: Reply with quote

I had the same idea but my problem is that I don't have nor film holder nor slide holder Sad I've found even the device to light the slide/film form behind : an old dia projector from which I took off the front lens.

PostPosted: Thu Oct 30, 2008 11:41 am    Post subject: Reply with quote

I picked up an old Spiratone slide duplicator off of eBay cheap & used that on a Nikon D70s with acceptable results in many cases. Main problem being dust on the slides was a pain to remove in post processing. You need to clean them off really good before you duplicate them...

PostPosted: Thu Oct 30, 2008 11:55 am    Post subject: Reply with quote

I managed to use the scan holders to keep the film firm, some diffuse light behind and the camera with a lens on a bellow on a tripod, centering the tripod to the frame and move the bellow to get the right focus, then one just have to keep note where the holder is placed and swap the slides around.

Mostly slide copier need the slides to be framed while mines are still in rolls of 3-4.

PostPosted: Thu Oct 30, 2008 11:56 am    Post subject: Reply with quote

I had the same idea .... Some time ago, I won a Praktica and a few lenses. Amongst them was a Prinz zoom slide duplicator.

What I did was to remove the slide holder, fix it on a PVC tube fitted at the other end with a filter thread.

I screw it at the end of a 50mm and mount the lens with an extension ring ...

Still need to find a way to use that duplicator for negative ... maybe a 6x6 slide glass to hold the neg could do the trick ...