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Using an enlarger lens and a Sony a6500 to copy negatives

This is very much a work in progress. I've assembled a collection of components and examined the feasibility, but not done any proper testing. Hopefully you will find it interesting.

I have a large collection of negatives and transparencies dating back to the early 1960s, and I have scanned quite a number of them using an Epson 4990 Photo flatbed scanner. The results are OK, particularly for 120 film, but not so great for 35 mm. Sadly the film related section of the scanner failed recently, possibly due to overwork or maybe just old age, so I was interested in finding an alternative.

If you have a good macro lens read no further, but if, like me, you don't possess a macro lens, then what is the next best thing? Well possibly an old enlarger lens. They were designed to provide the best possible resolution over a flat surface ( the negative) and project onto another flat surface (photo paper), both at close quarters, so, theoretically, they should be well suited to scanning.

There are drawbacks. First, enlarger lenses don't include a means of focusing, they rely upon the helical mount or bellows within the enlarger for that purpose. Secondly they tend to come with very none standard (these days) screw mounts.

If you are rich and famous you will be able to afford a set of focusing bellows, probably the best solution, but if, like me, you are not wealthy and, not to mention intrinsically parsimonious, you need to find an alternative solution. Fortunately help is at hand in the shape of a cheap as chips focusing M42 thread  helicoid - cost £22.

You can get around the lens thread issue by purchasing an M42 to whatever thread your enlarger lens happens to be, adapter.  In my case M39 - cost £1.25

Here's a photo showing you the required kit (click for a larger photo)

From the left along the top row we have a Minolta Rokkor 50 mm f4.5 enlarger lens, a Kecay 15-26 mm focusing helicoid and an M42 20 mm extension tube. Bottom row, an M39 to M42 adapter and an M42 to Sony E fit adapter.

This is what it looks like on the camera

The next task is to provide some clean white back light for your negatives or transparencies and a means of supporting the camera.  Here's where I have got to so far...

Here you see an old  home made lightbox with, at present, a rather yellow light source. The 35 mm negatives are held flat using the negative holder from my scanner. That from the enlarger might be better. The camera is mounted on a Manfrotto tripod with an old pistol grip head. 

I have successfully focused negatives using this arrangement, a 20 mm extension tube provides about the correct separation to fill the frame. In use you raise the tripod stem to get approximate focus and then use the helicoid to home in on the detail. 

Edit - Experience has shown that 20 mm is too long, it brings the lens too close to the negative and you can't capture all of it. My smallest extension tube is 11 mm, and that is a wee bit short, so that focus is achieved too far away from the negative. You get the entire negative, but you need to crop in camera. 

To make this work I need to find a whiter LED light source and a means of ensuring that the camera and negative are reasonably parallel, maybe by using a spirit level. Switch off the background lights and bingo, a solution.

If you wish to scan larger negatives you will probably need a 75 mm lens, every good photographer's home used to have both 50 mm and 75 mm enlarger lenses.

Moving on, I've now acquired a LED light source courtesy of B&Q - a £6 Mains powered bulkhead wall light and the first scan is seen below.

Edit - I am seeing a black band traversing across the screen when using this light source. This is making focusing more difficult and it sometimes appears on the image in camera.

The 1940 vintage  mid Tyne Ferry Tyne Princess

Actual pixels crop

Latest setup.  Custom made stand with switched light source, 75 mm Rokkor enlarger lens and full set of extension tubes 11 + 20 + 30 = 61 mm, together with the helicoid focusing adapter. A spirit level is used to align the lens and a precision steel 35 mm negative carrier from the enlarger.

I've changed the tripod head from a pistol grip to an old three axis unit, as it is much easier to adjust the three axes independently when aligning the camera.

This arrangement does appear to allow a better correspondence between the size of the negative and the image captured on the sensor than with the 50 mm lens. Incidentally, take away the extension tubes and the remaining combination of Olympus to Sony adapter and the focusing helicoid makes for a cracking 75 mm lens for distance work!

The problem with banding referred to above is much reduced if the lens is stopped down.

Edit 20-3-19 - comments about banding and problems with 20 mm extension tube

Edit 21-3-19  New setup with 75 lens and custom stand


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