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digitizing slides with enlarger lens
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PostPosted: Thu May 17, 2018 8:30 am    Post subject: digitizing slides with enlarger lens Reply with quote

I decited to shoot some slides again. I also want to digitize them. So I could buy a dedicated slide scanner but I believe its much cheaper to use my Nex or Alpha 7 to do the job.
My plan is to mount the camera on a tripod looking down on to my desk where the slide will be placed on a tracing light board.
All I need is a sufficient macro lens and a focussing helicoid.
I though of getting myself a Leitz Focotar 4.5/50 ; a M42/Nex helicoid and a M39/M42 adapter.
Does someone know how much extension the 50mm enlarger lens needs to reach 1:2~1:1 ratio?
- I need to know to choose the matching focussing helicoid.

What do you think about my idea?

best regards


Timo


PostPosted: Thu May 17, 2018 11:35 am    Post subject: Reply with quote

For a simple lens, infinity focus is reached with the lens 1 focal length from the sensor & 1:1 is reached with the lens two focal lengths from the sensor.
This generally isn't too far from the mark with enlarging lenses.
So I would expect one of the 30-90 helicoids on a short adapter should give you the right sort of range.


PostPosted: Thu May 17, 2018 3:10 pm    Post subject: Reply with quote

It's a good idea. You can even use some multi-shoot HDR software to get better details in the shadows/highlights zones (slides are quite contrasty...).
Focotar is a very good lens. I'll recommend the copy/repro-lenses, as well (for example Rodenstock APO-Rodagon D 75mm f/4, which is optimised for 1/1 magnification).
You can use any m42/Nex focussing helicoid but get some M42 extension rings, as well - they are very cheap and you can couple some of them to get the correct extension for slides-copying with the helicoid (for 1/1 magnification - 2x the FL).
A good light source for slide-copying is the screen of a tablet with a white document opened, if placed at a distance behind the slide (out of the DOF zone of the lens).


PostPosted: Fri May 18, 2018 10:50 pm    Post subject: Reply with quote

You can have good result with simple techniques like this one I like a lot

https://nikonrumors.com/2018/04/21/copying-photographic-film-with-the-nikon-d810-and-a-shoe-box.aspx/


PostPosted: Sat May 19, 2018 1:22 pm    Post subject: Reply with quote

I've been using a Canon 50/1.8 LTM(like the Serenar, but doesn't say it) on a Vintage Novoflex Bellows, I chose it because the slide copy hood fits the lens perfectly.

About the extension, it will depend on the lens, it's not really about getting 1:1, it's about fitting the slide within the FOV of the lens, and I prefer to error on the side of capturing a bit of the holder and cropping it out later, I also had some Super Slides to scan(127 format) which don't fit my slide copy mount, so I adjusted it for best fit.


PostPosted: Sat May 19, 2018 1:59 pm    Post subject: Reply with quote

I use the Nikkor 55mm f2.8 micro (AIs), combined with the PK13 extension tube and the Nikon ES-1 slide copier attachment (52mm thread for easy attachment to the lens filter thread). Only minor focus adjustment needed when one first sets up, then can pop new slides in and out in rapid succession. I use this setup on a Sony A7r, with the appropriate adapter. Very nice results.


PostPosted: Sun May 20, 2018 5:28 am    Post subject: Rodenstock + Olympus Reply with quote




Digital focussing screens are not particularly good, even when labelled as manual focus, so I use this outit tethered to a laptop to get a better focussing view than through the Olympus magnifier. The Olympus bellows unit, like the Novoflex ones has interchangeable camera-side mounts and another bellows between the lens and the slide\negative holder.

The enlarger lens is perfectly adequate except for difficulties with adjusting the aperture: in order to fit the front bellows, the clamping device also clamps the aperture ring.

This setup works much faster than the slide scanner, but the Vuescan software seems to provide better control for difficult originals than camera raw+photoshop.

p.