Using a smart phone as a slide scanner

Pitlamp

Well-known member
I've been asked to give a few pointers as to how I managed to scan slides using my iPhone.
You need a light source (more details below) and various supports.
It really was a bodge - but if you know the key aspects you can set this up yourself easily, in a number of ways:

* The slide must not be laid directly on the light source, otherwise imperfections / dust etc on the light source will be in focus and appear on the scan result.
* The light source must be diffused, to ensure even lighting. You can buy small white LED lit plates but I used a variable brightness bright LED dive torch with a bit of white polythene bag over it (acting as a diffuser) with the light from it bounced upwards off a plain white seet of paper a few centimetres below the slide.
* The plane of the slide must be exactly the same as the plane of the smartphone, otherwise only part of the scanned slide will be in focus.
* The smart phone needs to be far enough away from the slide to ensure pin sharp focus. If this means the slide doesn't fill the field of view on the smart phone screen then just zoom in and adjust until you're happy with the field of view, or crop the scan later using Photoshop-style software.
* If bouncing light like I did, the light source needs to be below the slide or otherwise screened from it, to avoid any light reflection off the upper surface of the slide.
* There are videos on You Tube which give suggested methods; one of the slightly more involved ones is here:
I suggest you use this as a guide to understand the principles if you can't be bothered to make the stand as shown in this video.
* It's possible to buy custom stands for smart phone scanning from Amazon etc; the prices vary from fairly cheap upwards.

What I did was as follows (but now I know smart phone scanning works I may make something a bit more sophisticated in future). I'm sure readers will easily find improvements to this; it was my first go and really just an experiement.

1. Lay a sheet of clean white paper on a flat surface, in a room with low light levels (to minimse reflected light from the slide's upper surface).
2. Use two small rectangular objects a few centimetres apart to support the slide above the paper.
3. Place two larger rectangular objects either side of the supported slide (in my case a pair of "Al Fez" couscous boxes) to support a rectangle of hardboard or MDF. (The latter is placed off centre on the larger supports so that the camera lens can be perpendicularly over the slide.)
4. Lay the smart phone on the hardboard with the camera lens end overhanging it, such that the lens is directly over the slide to be scanned. Remember, the smart phone must be far enough above the slide to focus properly.
5. Shine the diffused light from the torch down onto the white paper from the side but at as high an angle as possible.
6. If the slide is slightly too dark or light, adjust the brightness and / or angle of the dive torch beam to compensate. (The reflected light method described here allows this, whereas a white LED lit plate below a slide may not.)
7. Make small adjustments to the smart phone camera's field of view until the desired area of the slide fills the smart phone screen. (Hint - if, like me, you hate using computer software to manipulate images, this offers an excellent method of "analogue cropping".)
8. Press the smart phone camera's shutter button as gently as possible to avoid disturbing the set up.

I did say it was a real bodge . . . !
But it does seem to work; below is an example taken from a slide that wasn't brilliant itself; the stalagmite is not in focus on the original and the photograph was slightly too dark and grainy. It's not perfect and I'm sure I can do better with practice; that was just my first go.

Have a play and see what you can do. Once you know it works you may like to spend £25 upwards on a proper stand obtained from Amazon or wherever. Best of luck!

Sample_smartphone_slide_scan(1).jpeg
 

ChrisJC

Well-known member
Two comments:
1. You might be able to make a convenient backlight with something like this:

2. The image looks as if the 'phone has done a fair bit of 'digital helping'. A sort of smudge effect. I've seen it before on digital photographs from a phone and am never entirely sure if it makes images like this better or worse. I suspect it's not something the user has any control over though.

Chris.
 

Edwardov

Member
I actually did this at Christmas for family photos using my caving headlamp, a cheese stand, white plastic and my iphone. It was all I had at the time!
 

mrodoc

Well-known member
I had forgotten how to do it although it does work so thanks for the reminder. I have a slide scanner but it helps with 120 negs.
 

Pitlamp

Well-known member
Go on then; who is going to be the first to identify the caver in that picture above? When he died on 8th September 2016 he was 74. But I'm sure plenty of folk remember him as one of the Dales' greatest characters.
 

JAA

Active member
@Pitlamp might it be worth trying the phones timer setting to avoid any slightly “wobble” caused by pressing the shutter button? I believe folk do that when using tripods so the effect of pressing has 10 seconds to dissipate before it takes the pic?
Ace result in that photo!
 

Fulk

Well-known member
Inspired by the above, I just tried making digital copies of a few slides simply using a camera – in this case, a TG6, which has a close-up setting. I put the slides on a light box, tried taking the pictures at 100 ISO, but found that they were marred by camera shake, so I tried upping the speed to 400 ISO. First results are quite promising; when I've got my time to faff, I might try using a lower ISO and a tripod along with the self-timer.
Anyway, here are a couple of examples:
 

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As well as using the timer setting to avoid wobble, you can get cheap and effective Bluetooth shutter release gadgets for smartphones too.
 
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