Joaquín de prada in Opensx70 15minutes

Walking the line

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Take a look at this panel, it’s the latest PCB design I have made, this is my first design candidate for the “product”, and it is, in my opinion, the most advanced electronics ever designed for SX70 operation, an I know what you are thinking “aren’t you that crazy lawyer from Barcelona that knows nothing about electronics?”

Yes, I am, and these four years have been nuts.

I never ever thought I would end up where I am now, heck, not even close. But you know the story, one thing led to another, and then another, and I met Santi, and he had such enthusiasm and eagerness to be part of the project that now I can’t conceive the project without him.

But it’s not only Santi, I feel blessed (I am atheist, but you know what I mean) to have crossed paths with Dave, Hannes, Zane, Michał, and sooo many amazing people. But also many people close to me have been helping me go on, Daniel helped me with the website, and the camera serial number decoder, but mostly Peter that has helped me troubleshoot many issues and dire situations. Of course Cristina with her support and with her talent, sourcing cameras for me.

I want to also mention Georg’s page, “the hackers guide to the SX-70”

I never asked for anything and tried to provide the opportunity to check the project to as many people as could, with more or less success, all I can say is that I don’t regret it, only in the mail I have spent a good chunk of change.

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I have also got a few donations, in PayPal and in cameras, and, I cannot hide it, those mean a lot. I got some cameras donated by Mark Dionne that come from his dad, who was the leader in the shop that designed the SX70. Priceless.

The project, as a whole, calls for a deep understanding of the camera, how it was designed, and unearth as much information as possible. This has got me in touch with the most wonderful people, Polaroid oldtimers, as sharp today as they were 50 years ago, people like Dr. Plummer, Pete Carcia, Alfred Bellows, Mark, the son of Len Dionne.

I am also always looking for documentation, and have found really amazing papers, from the US, to, amazingly in China, but still, I want to think that the best is still waiting to be found.

As of late the super talented Ken Shirriff, who was pivotal in the repair and reverse engineer of the Apollo Guidance Computer (AGC) has agreed, with the help of John McMaster, to photograph and reverse engineer the silicon dies of an original camera. (When people ask me for the reason I want to do it, and what is the practical implications, I always say that none, or close to none whatsoever, but I think in the back of my mind that they haven’t understand what the project is about).

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It is no wonder that theSmithsonian Museum has the electronics of the SX70 on display!

Because these early ceramic PCBs, as fragile as they are, are a thing of beauty

Fire image You can see the laser trimmed resistors.

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I have also contacted the wonderful people at the MIT Museum and Baker Library, that holds what is left of the legendary Polaroid collection. Unfortunately most of the art was sold at Sothebys. Oh well.

Of course, it is also a dream for me to know all the folks in the business, like Jos, Julien, Matt, Jayce and so many more, in fact, at one time I had the delusion that the talented Matt Widmann was going to help me with the dongle…

And then the dongle changed everything

I am big admirer of industrial design. Industrial design is an odd thing, when at its best it’s sort of invisible, things just work, everything thing looks simple. And that is a difficult goal to accomplish. Dieter Rams (thou shalt not say Dieter Rams name in vain), the famous designer of all things Braun wrote the 10 principles of design, like “less is more” (much abused nowadays) and many others. I will post an entry about who did the industrial design of the SX70 and who came with the revolutionary concept of the camera as we know it. You will be surprised.

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So here’s the thing, when Santi came up with the first designs, concepts and renders, and I started posting about them, the perception about the project changed: it was no longer mainly an idea, a project. I was an object, a beautiful desirable object.

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Fire image First 3D printed mock up. Fun fact, I told Santi that we were going to build the dongle “from the outside in”. But as designed, the electronics didn’t fit in this first design.

Those renders were so amazing that I used to call them dongle porn.

So what changed?? I guess the perception of folks about the project, as a product. Now regular people, photographers were asking me when would this be available.

But making a product is a tall order.

Risks and challenges

Of course the dongle enclosure is just the beginning, electronics needs to have approval and certification as a non intentional radiator by the FCC, electronics need to be manufactured at a reasonable cost, need to be programmed. That is a challenge in itself, I got a lot of tips from the book by Polaroid’ engineer Phil Baker.

Being continuously suggested to do a Kickstarter I have to say that I would never ever do that. But I also have to recognize that bringing such product to the market is very expensive.

But that, of course, it’s only one side of the issue, cameras need to be refurbish and calibrated to the highest standards, and I mean the highest. I can spend years researching the cameras, the different hardware iterations, how to improve them, how to make them quick for another fifty years, but all that research has to be done by technicians that love the craft and with the highest standards.

A new era

I dream of a new era in SX70 refurbishing, where all cameras have a new PCB, and dual ISO capabilities, and not only that, but dongle compatibility, so that, you know that you can have manual control at any time, just by purchasing the dongle at any time.

An era with new calibration tools that make cameras run to the highest specs possible.

Fire image Fire image Fire image An era that sets a before and after in the SX70 world. These are captures from the Eames office film about SX70

We need to operate on the conservator’s code, making sure that the cameras will work for generations to come. As Dr. Land said, optimism is a moral duty.


Many people may wonder where did I get my inspiration for the project, was I inspired by project M or X or Z? And the answer may surprise you. Of course I knew that this could be technically archived, it had been done and I had it, yes, it was expensive, but it worked. In my mind it had a terrible flaw, it had to have a PC flash compatible connector to sync flash in manual speeds, and at full f.8, without hardware modifications.

But before I go on, I want to say that what truly inspired me was Phyvine, he started a project to manually control the SX70 with a replacement of the dark/light wheel.

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He has been truly amazing, and we discussed a few times our own inroads into SX70.

Seeing this project truly inspired me, and I felt that I could accomplish something similar to what he did.


This is a picture of my first dongle, it is from October 18th 2017: no nonsense f.8 flash from day one, no need for external self timer, and multiple exposures.

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Fire image Nuff said.

Still to this day no camera does full f.8 flash on manual speeds, or for that matter fill in flash. A lot was learned when the alpha supplement was unearthed.

You stop leading when you have a de-facto monopoly and there are no competitors to drive your product. When you can set your prices absurly high, just because there’s no alternative.

What is my favorite SX70?

Phil Baker, a young engineer at the time the SX70 was under development noticed that the ground glass wasn’t good enough for focusing, especially under low light conditions, when flash was used. He explains this amazing story in his book “From concept to consumer” (By the way, I learned a lot from this book and I highly recommend it)

The problem was the clever compensation system devised for the flash by the Polaroid engineers. If you got your focus off, your flash picture was going to be blown or too dark. In daylight that wasn’t a problem. So Phil presented the solution to Dr. Land that reluctantly accepted it. But with one condition: it had to be off center.

So back to my favorite flavor of SX70, I like alphas, I like chrome, I like tripod and straps, and I also couldn’t live without the focusing aid. Zero interest in a manual focusing camera without the focusing circle (so many puns here, and so much intended)

Of course, covers have to be tan.

Fire image Is she a Polaroid girl?

Keeping it original

This drives us to the phylosophical question of when does the SX70 stop being “original” and becomes something else.

For me the answer is easy, as a collector I love to have original artifacts, early original cameras, odd versions etc, as original as possible. BUT, as a photographer I want a camera that just works, with the film we have now and in a reliable and repeatable way.

That brings me to the question of the auto exposure: I struggled with that for quite a while, but then Dave, while in the shower, came up with the most brilliant idea: light to frequency.

The way exposure works on all SX70s up until the SLR680 is called integration. Every camera has a capacitor, imagine the capacitor as a bucket and the water as the light. A slow film needs more light thus a bigger bucket, a faster film needs a smaller bucket than fills much faster. With Dave’s idea the bucket size is a number, I call it the magic number. So the light sensor has a beat, the more light it sees the faster it goes, so now the size of the bucket is a number. Lots of light, reaches the count very fast, say 10ms, but very little light and it might take a while to reach the counter. This, of course, works for much longer exposures than the original electronics.

Walking the line

So it is quite clear that I owe a lot to the community, the current generation of software is second to none, thanks to the awesome coding by Zane, sonar evolved with Hannes help and his impatience, Dave’s ideas, etc…

I feel, in a way that I am betraying the project, but at the same time I think it has to be done, as in totally new PCBs design, of course with a lot of what I learned, but going a few steps forward, seeking electronic compliance, and across the board camera compatibility. Peter is also writing a new software, looking for reliability (not that the current isn’t) but maybe going beyond the original specs, both hardware and software, like the dongle with the Attiny microcontroller, that costs less than a dollar when the Dallas costs more than 4 dollars. Because now the approach of not taking into account the cost of the parts is something that we can’t afford. Costs have to be brought down without compromising quality.

Fire image Same form factor but new electronics for the dongle.

We are also developing new tools much in the way Polaroid had when manufacturing the cameras.

So is openSX70 dead? Absolutely positively not, it’s there and is going to be the sandbox for experimenting and improving all things SX70, without the high bar of the “product” standards.

The space in the upper right corner

(If you know you know). We are going for it. Once we have set our goals of an honest product, based on innovation and true love for the camera, admiration for Dr. Edwin Lands talent, constant investigation, just because, yes, because that is our goal, because the “product” is a byproduct, then we can do fun stuff, and we have plenty ideas, original ideas, and, just to name a few, different colour dongles, wooden skins, skins made out of materials that you would never think of. But we will go way further, think of a dongle made out of a aluminium block with a CNC, or, why not, maybe wood.

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This is going to be really fun.

And by the way, the 4-layer and .6mm PCBs, once verified and tested will be compatible with all cameras, meaning you will have your manual sonar if you fancy. The first working manual sonar cameras were accomplished in 2019, with focus by wire. That is innovation. And by the way, the 4-layer and .6mm PCBs, once verified and tested will be compatible with all cameras, meaning you will have your manual sonar if you fancy. The first working manual sonar cameras were accomplished in 2019, with focus by wire. That is innovation.

The book

I love those Leica books, with pictures of the cameras. Yes, highly fetichistic.

I feel that the SX70 deserves such a book, the story of the camera, as a design process, as a series of prototypes, as a story to be told.

There’s enough “art” books, and I love them, but this book (coffee table please) has to be done, and, in time for its 50th birthday in 2023.

SX70 is an icon of American ingenuity, a revolutionary object.

Last month I had the privilege of having a long Zoom conference with Ron Fierstein. He s one of the lawyers that won the Polaroid vs Kodak patent trial. His book is, in my opinion, one of the best informed about SX70.

He revealed to me, that, while researching for the book at Baker Library in Harvard, there was an item just labeled “coffee table”, out of no logical reason he asked the curator for that item, only to reveal that those were pictures, SX70 pictures of him with Dr. Land. I am ever so grateful to Mr. Fierstein for taking the time of talking to me for a while.

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I hope one day to be able to visit MIT museum and Baker Library in Cambridge, COVID-19 permitting.

Oh, and I would also like to feature some of the amazing custom jobs done with the SX70, I think this kind of jobs are an art in itself.


Yes, I know, I know,, I could do phone app, Bluetooth, WIFI, and pretend that is the greatest thing ever, but, that would easy, and that, in my opinion doesn’t make for a better SX70. I n fact it’s a cheap trick. Manual aperture control, and things like that, rooted on the deep understanding of the camera operation: that is what this is all about. And doesn’t mean that I won’t do it in the future.

The other day I was wondering what would happen if we slowed down the motor while ejection, how would that affect the picture and it’s “artistic” qualities so to speak. I am also seriously considering that speeding the shutter by means of the pneumatic valve might have benefits in picture taking.

Back in the day, the objective was to have clear sharp pictures, with the famous “inefficient shutter” but maybe nowadays having a faster shutter speed renders more bokeh (no serious post about photography should end without using that word), and that might be a desirable result for modern photographers that seek that creative edge.

I also want to say that I am amazed at the SX70 “scene” it seems that even though Matt has retired from the business there is a new generation of young folks doing amazing work, like Jeremy, Ivan, Dennis, and many more. But also there’s companies pushing the art of refurbishing to the next level, reaching standards never seen before, not even back in the day. That is why I feel we are in the best moment for the SX70, heck, even the film is pretty darn good.

I also want to mention the sweet moment these cameras have regarding accessories, like i-type batteries by Rezivot, PolaStudio, Helicord camera, and many more, some DIY, but still awesome.

Take all this with a grain of salt cos’ who I am to say, you know, I am just a guy.

The “product” has not yet a name, because all the names I have come up with, my lawyers think that will get me in trouble. Ideas welcome.

Please post your opinions, they matter to me.