35mm Slide Converter for Cellphone





This image I took of my wife lay unseen for more than 40 years. What other treasures await?

You will need a short length of ABS or PVC pipe, saw, ruler, drill, sand paper (vellum paper and glue optional).

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Step 1: Determine the Minimum Focus of Cellphone Camera

1. Set phone camera to highest resolution.

2. Hold the phone in camera mode over some sharp, printed text.

3. Move the phone up and down to get the clearest, sharpest image at the minimum distance from the print. However, do not sacrifice clarity for minimum distance. Error on the side of clarity.

4. With a ruler, measure the distance from the print to the side of the phone facing the print.

Step 2: Saw Slots in the Pipe for Phone and Slides

1. Obtain a short section of 2 inch (i.d.) ABS pluming pipe. Home Depot sells 2ft lengths for about $4 U.S.

2. No more than a half inch from one end you need to saw a slot for the 35mm slide with a band saw, hacksaw or similar. If you make the slot farther away from the end you may get rounded corners on your image.

3. Remove as many burrs from the cut as possible and test the depth of the slot with a unimportant slide to make sure it is deep enough to allow the slide to be centered.

4. Also make sure the slot is wide enough to accommodate the slide, but snug enough that it doesn't fall out.

5. Measure from the slot you just made the distance of the minimum focus of the camera plus one quarter inch and mark it. The amount of tube you leave beyond the phone slot is at your discretion. I left about and an inch and a half.

6. Saw a slot of similar depth parallel to the first slot and in the same orientation.

7. Make another cut to accommodate the phone thickness. Make sure it is of sufficient depth to allow the phone camera lens to be centered in the tube.

8. Remove the cutout at the attached ends of the cut with a drill if necessary.

9. Remove burrs from the cuts and lightly sand.

Step 3: Check Alignment

1. Make sure a slide and camera lens can be centered in the tube

2. Make adjustments as necessary.

3. At this point you may choose to glue some felt or other material in the phone slot to protect the back from scratches, provided the slot is wide enough for the addition. It is optional however. Keep in mind that smartphones are made to be durable. Screens are made of Gorilla Glass that is highly scratch resistant and the backs a fairly resistant as well.

Step 4: Add a Light Diffusing Transmission or Refecting Screen

Since slide photographs are transparencies designed for projection, light passing through them can change the color and show the light source bulb filaments etc. To avoid this, light must be diffused and softened before passing through. There are two options; adding a transmission diffuser over the tube or a reflector in front of the tube. Vellum Paper is a good choice for the transmission diffuser, readily available and not expensive. You can get a tablet of it for about $6 US at one of the office supply stores. Vellum is desirable because it has a featureless, translucent texture that will not produce mottling in the final image like most copy paper.

1. Place a small line of superglue around the edge of the tube adjacent to the slide slot.

2. Place a square of vellum paper over the end of the tube and press into the glue and let set up.

3. Trim the excess vellum with a razor blade.

4. If you find that with your lighting source a single layer of vellum still produces some unwanted background mottling, you can add another layer or try receiving indirect lighting reflected off a piece of copy paper.

Copy paper should work as a reflection diffuser by itself provided it is a few inches away from the end of the open tube. It can either be mounted in a slotted base or folded at a right angle to rest on the table top.

Step 5: Desktop Stand

With this stable configuration I was able to copy from 4-5 slides per minute.

1. Cut a 3-4 inch section of the same pipe in half lengthwise.

2. Saw a V-notch in the rounded side.

3. Super glue the tube in the "upside down" position so that the slot openings face up.

4. Insert phone UPSIDE DOWN in the slot.

5. Try inserting the slide RIGHT SIDE UP. Depending on the settings on your phone, when you turn your phone right side up after taking the picture the image will rotate 180 degrees so no image rotation will be necessary before saving.

Step 6: Take Picture & Crop

1. Wait for the camera auto focus to adjust and take the picture.

2. Crop image and rotate if necessary. Most cell phone have these camera functionions or it can be exported for further editing.

Step 7: Experiment With Lighting Conditions and Diffusers

Pay special attention to images with a lot of white in them like snow scenes. This is where background lighting artifacts will be most noticeable.

Compare the results between the reflection screen and transmission screen.

When editing the image, auto lighting adjust may NOT be the best option.

Step 8: Original Paper Tube Version

My original "proof of concept" made from a wrapping paper tube and packing foam. Actually works pretty well, but is no less work to construct and less durable than my ABS pipe versions.

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88 Discussions


5 years ago on Introduction

Only on instruct able can you find people crazy enough for beautiful solutions ! …


So much for the $200 + scanners offers by Hp, Canon, Epson, Brother et al.

More brilliant even : a no tech alternative to the low tech idea ? What one could ask more ???

As SnazzyBot says : put it in the tech contest : wil all will vote for you !… ;))

3 replies

Reply 4 years ago

Is there a link for a desktop model different from this one?

Tater Zoid

5 years ago

What a great idea. I pulled 20 slide carousels out of a dumpster years ago and have been meaning to digitize them. This will surely save me tons of money.


5 years ago on Introduction

dig this. Actually worked this summer converting slides to images but our machine was $3000+


4 years ago

In step. 5 you say to make a cut at the focal distance plus 1/4". Is this just to be on the safe side?

2 replies

Reply 18 days ago

Probably: you can focus out past the minimum focal length, but not closer (if you cut too close).


Reply 4 years ago

Yes! If you are a little over your auto focus will adjust. If you measured wrong and make the slots too close together you are out of luck. I would also that you don't want to have too much of the tube beyond the slot for the slide or you could get some rounded corners in your images. Let us know how it turns out.


Question 3 months ago on Step 8

Thank you for an excellent Instructable!
I am confused on just one point:
"6. Saw a slot of similar depth parallel to the first slot and in the same orientation.”
I’m sure the fault is mine
(having suffered a brain injury some time ago)
but this instruction seems to have no context.
Where would this cut be made, please, and for what purpose?
Thanks for your patience and assistance.

1 answer

Answer 18 days ago

I will try!

Step 2 has you cut a thin slot at one end of the tube. That's where you will put in the slide that you are going to scan.

So Step 6 is making a slot for your phone to go in, so the camera can "see" the slide. The step is very terse, and each word in important:
1. The second slot must be the same depth as the first slot so that you don't cut all the way through the tube!
2. The phone's slot must be parallel to the slide's slot so that the image is not warped (narrowed into a trapezoid, usually, called keystoning).
3. The "same orientation" means that you start both of the cuts from the same side of the tube, so that "up" will be the same for the camera and the slide. (If they aren't oriented the same way, you may trim off the corners of the image. And even if you somehow end perfectly upside down, you'd need to rotate the scan in software.)

I hope that's helpful!


3 months ago

Do you think I could modify this set up to use with DSLR?


3 months ago

Great Instructable! I was looking to purchase a slide scanner, and ran across your instructions! Fantastic. One thing I saw someone else mention is that a blank document on your laptop makes a good even light source. Thanks for posting this!


Question 11 months ago

Is normal room lighting sufficient, or do I need a light source at the end of the tube? Do you use flash on phone?


11 months ago

Question: Will your device work equally well with normal 35mm slides, and Kodachrome? I have some of both to scan.


2 years ago

This and some of the other commenters' solutions are really great, thanks for posting! On the measurement Step 1, could you recommend the closest distance from the camera lens to the slide? I would like to hold close to fill the frame with the image as much as possible. On my iPhone 6 it seems that around 8.1cm is as close as I can go before the camera is no longer able to focus (not a scientific measurement). Is there a way to get closer? Would love to eliminate cropping altogether. Here's my little DIY with DSLR I used for 1000’s of my dad’s old slides, from my blog: http://www.tjkatopis.com/new-blog/process-for-digitizing-photographic-slides


4 years ago

It would be cool, to create a 3d print model. A lot of people have 3d printers nowadays, and most cellphones have a pretty much equal minimal focal distance.
adjusting it, as well as the slide, is just a matter of changing a few variables, or opening the picture in a CAD editor and moving the slot around.

1 reply

4 years ago on Introduction

My home center doesn't carry ABS in short lengths. Will PVC (white schedule 40) work? Is the color critical to performance or just cosmetic?