Introduction: 35mm Slide Converter for Cellphone

Picture of 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).

Step 1: Determine the Minimum Focus of Cellphone Camera

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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.


vincent7520 (author)2014-09-21

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 !… ;))

barkergk (author)vincent75202014-09-21

Thanks vincent7520. It get's crazier. Look at my desktop model upgrade.

TimH44 (author)barkergk2015-10-08

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

barkergk (author)vincent75202014-09-22

An addled mind is the rebel's workshop!

Tater Zoid (author)2014-09-18

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.

zigzagchris (author)2014-09-18

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

tj_katopis (author)2017-03-26

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:

JimM307 made it! (author)2016-12-22

Brilliant! I made a few changes to suit my needs. Since most of my photos are in landscape, I cut the slot for the phone 90 degrees to the right so the phone acts as the stand & the slides go in through the top. I also added some black foam weatherstripping to block light from the corners. Works beautifully. Thanks!!!

barkergk (author)JimM3072016-12-22

Cool! Glad it is working for you!

Sabalo made it! (author)2016-08-07

Was looking for a good slide-to0digital converter when I came across this great tutorial last night. I didn't have much at home to work with, so improvised with a soft drink carton, some chopsticks and tape. I hand held my Samsung cell camera and converted 50 slides last night in an hour or so. Thanks for the idea and inspiration!

barkergk (author)Sabalo2016-08-07

Nice job. That is the beauty of Instructables. Gives crative people new ideas.

Sabalo (author)barkergk2016-08-07

Glad I stumbled across it

HarryS24 (author)2015-09-23

Luc Volders made it! (author)2015-03-06


I made it. However I did it with my 3D printer and designed a holder for the phone. At the same time i made a base with leds in it so the slides would be luminated which makes the design usefull for working in the evening etc.

The design is for the Alcatel Pop C7 phone but can be adjusted as all the STL files are available on my webpage:



barkergk (author)Luc Volders2015-03-06

Very nice use of a 3D printer Luc! Glad my Instructable inspired you. That is what this site is all about!

ProDigit (author)2015-01-18

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.

Luc Volders (author)ProDigit2015-03-06

Did it !!!

just look at my webpage:


Bruce P made it! (author)2015-02-23

OK, not exactly like your design but I didn't have any pipe that size. I use a blank page on my laptop fro the back light and I'm getting images better than a low end scanner. Thanks. Now I've got to scan thousands of slides!

marvinsson (author)2014-12-19

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?

barkergk (author)marvinsson2014-12-19

White PVC will work just fine. Sandi it lightly both inside and out and spray paint it flat black.

marvinsson (author)barkergk2014-12-19

Should it be painted inside and out? Is the dark color part of the reason it works?

barkergk (author)marvinsson2014-12-19

it should be black on the inside to minimize reflections and flares.

marvinsson (author)2014-11-19

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?

barkergk (author)marvinsson2014-11-19

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.

duboisvb made it! (author)2014-11-19

Thanks for this. I used 3 inch pac as I have large format slides to do. Also I built a small platform for the iPhone.

barkergk (author)duboisvb2014-11-19

Very nice! Always love adaptation to specific needs.That is what Instructables are all about. Thanks for sharing!

duboisvb (author)duboisvb2014-11-19

i meant PVC not pac.

rondacosta (author)2014-10-05

Hello barkergk,
awesome instructable you came up with.

I have two questions:
Question #1 - I do not have a cellphone, but I have an iPad-2 with front and back cameras.
according to googled specs for that iPad-2 back camera, it can take pictures at 1280 by 720 pixel resolution, or 0.92MP (megapixels). The camera also offers a 5x digital zoom.

Do you have any input on relative quality of results by comparing with the specs of your phone camera? I can't tell what cellphone/camera model you have.

Question #2 - This is open question: can anyone with iPad experience chime in with suggestions to implement this great instructable? May send any input or suggestion to

Thanks for your great idea.

barkergk (author)rondacosta2014-10-05

it should work just fine from the description. just follow the instructions on determining minimum focus. Good luck and keep us posted.

jla181 (author)2014-09-28

C'est une idée géniale, d'une simplicité déroutante mais combien utile.

barkergk (author)jla1812014-09-28

Merci pour ce commentaire !

Je suis heureux que vous l'aimez.

cgosh (author)2014-09-27

I've used two different (expensive) slide scanners with desktop PC's in years past. They were ridiculously slow and all of them are no longer made.

Slides were popular because they took color pictures that used less light than "print" color films, could be push-processed to extraordinary sensitivity (making them as much as 10X more light-sensitive than print film -- great for a telephoto lens at rock concerts), and were much cheaper because you didn't pay for prints on paper. Viewing them was a hassle, but they were the only thing we had for groups before PowerPoint.

Your solution appears to be incredibly faster than the scanners, borders on being free, is simple enough for anyone (who can use a saw) to make, and has better resolution. Check your cellphone camera Settings to find a Macro option.

This idea is what Instructables are all about. Also, great that you showed your early prototype; that encourages others to see how to get their own ideas moving along. Thank you. Next, I'm headed for the plumbing department . . .

barkergk (author)cgosh2014-09-27

Thanks for the comment. My original intent was simply a proof of concept. I was actually astonished at the results. I didn't really consider making it into an Instructable until a friend insisted I do so. Glad he did. I am happy to help others beat the system so to speak.

ajoyraman (author)2014-09-25

Great Idea ! and thanks for the other posts regarding super 8.

David Catriel (author)2014-09-24

Amazing! Need to see if I can adapt this idea for photos.

kentek (author)2014-09-21

This is a great solution. I have boxes of 35mm slides.

But, how would you use a similar solution to digitize Super 8 film? I have even more Super 8 stashed away awaiting digitizing.

I would think one would need a reel-to-reel mechanism and stepper motor to sync the 30fpm to the iPhone cine camera.

Something to think about.

barkergk (author)kentek2014-09-24

Pretty easy if you have a working projector. Barring that it gets exponentially more involved. I converted all of my super 8mm by projecting very close to a small white screen and pointing a video camera at it.

kentek (author)barkergk2014-09-24

But don't you get some distortion as you will be at an angle with the vid cam?

What if you recorded from the back of the white screen (if see through)?

In your process how is the the quality of digitized version?

I have an old Eunig (I think that is name) but it is 220V so I need a converter.

BTW: There is a group inventing a Super8 cartridge that record digital in a Super8 cam. Can't wait to get one as i have 3 working Super 8 cams.

barkergk (author)kentek2014-09-24

There is a little angle distortion, but if you put the camera as close as possible to the projector lens it is minimal. If you record from the back of the screen then everything would be reversed. Not sure how you would correct that with movie film. I digitized over three hours of old movies this way about five years ago and it was quite satisfactory.

alcurb (author)kentek2014-09-24

I suspect it would work well for super 8 if the slot is cut for that size, but the phone camera might not have a sharp-enough macro that can go in that much at any decent resolution. Perhaps a magnifying glass (double-convex) between the film and the camera might do the trick. The lens should have a much bigger diameter than the diameter of the camera lens to avoid picking up edge distortions.

I wonder if the camera can be placed in movie mode and you simply slide the film through the slot by hand. Then open the resulting movie file in an editing program to separate the frames digitally. There is no doubt that would be tedious work. Your idea of using a reel-to-reel mech with stepper motor is a time-saver if you can get the frame alignment perfect every time.

alcurb (author)2014-09-24

Brilliant solution. This would make a great Kickstarter project which would include adapters that work with virtually any kind of phone. The adapter might have set screws for adjusting XYZ positioning so that you can perfectly align the phone camera lens to the slide.

barkergk (author)alcurb2014-09-24

Thanks alcurb. What I have found with just my phone is that because the slide image is considerably smaller than the camera screen is that perfect alignment is not critical. As long as the image axis is straight it can be off center since it is going to be cropped anyway.

vvvieira (author)2014-09-24

Splendid idea; unfortunately, my slide collection is already digital, with the help of a professional scanner. But it surely will be helpful in the future - I'm sure I'll build one to lie around and used when needed.

As for the Super 8 film: my collection (Super 8 but also Regular 8 - is already converted to digital, thanks for a guy that works on a TV station! In fact, it's much easier that way, but for a time I thought of creating a mechanism to do that. It envolved the use of step motors, a discarded projetor, LED lighting and diffusers, a CCD camera, and software to transform the JPGs of individual frames into a movie.

Afterwards, you will still need specialized software, as old Regular-8 movies were filmed at 16 fps.

Eh Lie Us! (author)2014-09-23

This is great. thanks for sharing. I find a lot of discarded slides and negatives in my work and I always try and squint to see if I can make out the image. This might be a way to give them a 2nd life! Advice on negatives?

barkergk (author)Eh Lie Us!2014-09-23

There is an android app called HELMUT Film scanner that supposedly will turn negatives into positives. I have never used it.

Jetpack5 (author)barkergk2014-09-23

You can invert the colors from the negatives pretty easily in most picture editors on your desktop or laptop computer. Probably there are photo editors that will invert the colors also, and that's all you need.

Twinmum (author)2014-09-23

This is brilliant, thank you. I have quite a few old slides that would cost too much to get them all printed up, but not so many that I could justify the cost of a converter. Off to show my handy man hubby what I'd like him to make for me :-)

barkergk (author)Twinmum2014-09-23

Nice! Keep us posted.

HonestY1 (author)2014-09-23


Elect_Rick_Carr (author)2014-09-21

What an awesome idea! I'm a former art professor and sometimes have students contact me, asking, "Hey, do you still have a photo of that piece I made in your class?" Up until now, I had to take their slide to Walgreens and pay to have it transferred to a CD. Thanks for this great instructable, best one ever in my opinion! By the way, I'll use drafting mylar instead of vellum, it's tear resistant.

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