Using the Zone System with Polaroid SX-70 Film, Part 1

[@joaquindeprada]

Hey, amazing video, thank you for making it. I am an SX70 lover and a zone system lover, so this really made me happy. I have so much to say, but let me start by saying that the maximum shutter speed the SX70 can do is 1/178th or something like that, so it would be technically more accurate to speak EV regarding SX70, and I started like that but I finally gave in to speeds at f.8 equivalent. When at fast speeds the SX70 is quite unreliable, the difference between 1ms and 2ms is a huge difference. I have found a way to make the shutter/aperture system about 4x faster, I am still experimenting with this. SLR670S cheats at higher speeds, take the same manual 1/2000 picture on an sunny day, first in a normal fashion, next covering with dark tape the eye sensor window. I was astonished when I found out this. I was measuring speeds on the MiNT and they were so different every time that I was going crazy, then (I think it was 33ms) and on they were rock steady. I was thinking about ways to influence the development of the picture, like using temperature while developing. I am also thinking about doing slow expulsion, running the motor slower via PWM. I have also implemented some rudimentary aperture control. My name is Joaquin de Prada and I run the OpenSX70 project. Again amazing work!

[@WalkClickMake]

Hi Joachim. Thanks for your interest! I have been following your OpenSX70 project. In particular, I enjoyed your research on the way the shutter/aperture mechanism works and, as a result, I always feel uneasy about referring to a constant f/8 aperture on the MiNT SLR670-S, knowing that it may actually be shooting at a smaller aperture in some cases. All I can determine is that, after using the camera for a year in manual mode (using the MiNT Time Machine attachment), using f/8 to set my exposure seems reliable and consistent. It would be great if your work managed to gain control over the aperture setting. Even a consistent f/11 and f/16 would be helpful. I like your idea of using temperature control or slower/faster ejection to control development. That would offer something similar to N+1/N-1 development with conventional film. So far, my 'accidental' experiments while shooting at too high or low a temp does lower the contrast and film speed but also introduces physical defects due to (it seems) poor distribution of the chemistry as the film is elected. Perhaps applying mild heat or cold after ejection might work? Hmmm...something to try!

[@joaquindeprada]

@@WalkClickMake I think really early cameras had some sort of heating element connected (somehow seen in the Eames movie). This probably means that they were not sure about the film reliability. Another factor with the “new” film is the effect of shielding or not shielding on ejection. The new opacification process is nowhere near the original. I always have this though that if they presented the current film to Dr. Land he would throw them out of his office! Oh and it’s JoaQUin ;-)

[@Freakydile]

Thank yu for this most informative video!!! Looking forward to part 2. Regards from Belgium!!!

[@WalkClickMake]

Thanks Axel! Part Two should arrive next Thursday.

[@edwardferry8247]

One has to admire the sheer eccentricity of the endeavour.

[@WalkClickMake]

Agreed. One has to be slightly mad to work with Polaroid in 2023!

[@rancosteel]

How do you calibrate an external lightmeter with the compensation dial?

[@gd70]

Excellent! Great job! Thanks! Keep posting great videos like this.

[@WalkClickMake]

Thanks. There's more to come!

[@nutterbutter66]

Awesome! I just got my SX-70 and always trying to learn more :)

[@WalkClickMake]

Thanks. Hope you find my videos useful!

[@alexbrambilla]

Well done! Thank you!

[@WalkClickMake]

Glad it was helpful!

[@gatsbye53]

Great video. Thank you!

[@WalkClickMake]

Glad you liked it!

[@bigbadbyrnes]

I feel like I’m getting a PhD level education, surely this will be helpful. I just got an SX70 electronics modified to shoot 600 film, but all these principles apply.

[@WalkClickMake]

Thanks! Have fun with your new camera.

[@naforul]

Amazing...

[@WalkClickMake]

Thank you! Cheers!

[@pirata00001]

You could mention in the first minute that you own a modified SX70 and your video does not apply to the regular camera.

[@WalkClickMake]

Thanks Andre. Sometimes I get too carried away with the details.

[@beanclap]

how much money did you spend on film on this video alone-?

[@WalkClickMake]

A lot. Likely 5-6 film packs. But it was a learning experience and I'm pretty sure I (and others) could now complete a set of zone photos with a single pack, as I mention towards the end of Part 1.

[@bilonggrisimmeri]

This is wrong!! Zone system worked with "high silver loading" emulsions, such as on glass plates. Modern emulsions contain the minimum amount of silver halide to achieve a given D-Max, and are developed to Unity. No amount of extended development will SIGNIFICANTLY increase negative contrast, tonal range, shadow detail or D-Max. You can REDUCE neg contrast by over-exposing and under developing. That's it. I have a non Mint SX-70, so it shoots at f8 only, varying just the shutter's speed. I recommend either using a light meter to measure scene brightness range, accepting just a few stops of range, or using the same smart phone to test shoot. This gives some idea of your scene contrast, once you learn how to interpret it. You still won't get perfect pictures every time, but it helps.

[@WalkClickMake]

The Zone System process I described does not talk about altering development time, which is impossible with Polaroid materials. What I describe is a means of using shutter speeds-and perhaps a neutral density filter-to pre-visualise where the dark tones (eg Zone 3) and light tones (eg Zone 7) will fall (given the limited dynamic range of Polaroid SX-70) and choose the best shutter speed setting based on that. Which is more or less what you are saying at the end of your comment. Varying contrast by using N+ or N- development (which can also involve varying the developer dilution as well development time) only works with sheet film. I used to do this all the time with 4x5 film sheets. It will also work with roll film but, of course, all frames on the roll must be developed to the same contrast.

[@bilonggrisimmeri]

@@WalkClickMake In that case, we agree to disagree. You showed us Ansel Adams's book, to start with, hence my initial comment. Ansel Adams himself did in fact say what I wrote about silver halide loading not being found on modern films. I even capitalised the word "significantly". Since my SX-70 is not the Mint modified one, there's no way to tell shutter speed. It's light meter is crude, not TTL even, so no wonder exposure is unpredictable. Despite this, I've taken several 100 pictures with it. Right now I have some of the new 600 film to try. I may get the new £600 iType model, despite its not being an SLR. To me it looks a bit cheap and nasty though.

[@WalkClickMake]

@@bilonggrisimmeri I don't have the new Polaroid I-2 but the few reviews I have seen suggest it's a good camera. It ups the ante with aperture as well as shutter speed control (although only in full-stop increments it seems). It is much less expensive than any Mint camera so, if you are willing to give up the TTL viewfinder and the original SX-70's form factor, I would consider buying it.

[@bilonggrisimmeri]

@@WalkClickMake Yes, on YT it looks OK, if very bulky non-folding design. Wex may be stocking it, and I need to hold it in my hand, to see build quality. For now, I will use my 1980s SX-70 autofocus, to see if Polaroid is still useful to me. Since one Polaroid 600 photo costs £2.27, dud shots are now a real issue, whereas in the past the film cost much less, allowing for inflation. There's no 100% reliable way to get perfect exposure with that crude SX-70 magic eye meter.