The polaroid lighten/darken wheel

So I saw a polaroid sx-70 one step rainbow type camera at a yard sale the other day for $4 and said what the hell, and bought it. Picked up a flash unit for it (the corresponding "Q" flash that was built for this camera) for another $10 and a pack of impossible colour film. Looking at impossible's website, their film is 160 iso and not 70 iso as the cameras light meter is calibrated for. It's suggested to turn the lighten/darken wheel one third into the darken area to compensate. Then I start shooting and all hell breaks loose. Things seem mostly underexposed.

So, first of all, does anybody know if the "exposure wheel" on the front of the camera, which is divided into 6 segments (three lighten, three darken) correspond to actual stops? like does one segment equal one stop or is it simply some random amount unique to polaroid? I shot a photo of my daughter with her back to the sun and lightened it by three "segments" to help keep her from silhouetting out. Definitely didn't get the result I thought I would. Given they recommend moving the lighten darken wheel 1/3 into the dark section to compensate for the doubling of the film sensitivity stated in my first paragraph, it would suggest that each individual segment on that exposure comp wheel would be one stop. Opening up three stops should have provided a better exposure of my daughters face than the near silhouette I did get.

Also, I'm finding the flash difficult to judge. Full disclosure- I'm not really well versed in the use of a flash. All my photography to date is pretty much natural light. That being said, impossible recommends the use of a flash with their sx70 film and instax won't even let you disable it on the majority of their cameras. So off I go, flash in hand. I'm outdoors on a bright day and take a photo of my kids. About 5 feet from them, everything set to "middle position" on the flash and camera for those lighten/darken options. My kids came out well exposed but the background at 4pm looked like it was 9 o'clock at night. The sky was dark (very strange), the foliage immediately behind them (maybe 5-6 feet from the camera and within the flashes stated range) was underexposed and very dark. Again, looking like it was late at night. My subjects were front lit by the sun.

So does anybody know the stop difference per segment of the cameras in body lighten/darken/exposure compensation wheel? Does anybody know the stop difference between the neutral, lighten and darken slider on Polaroid's "Q" flash?
Any tips for using the camera in general? I know impossible's film is still fairly experimental but I'd like to make sure the fault isn't with me before I start faulting the film for every missed shot.

The SX70 has a cult following, googeling it will bring up tons of mods for it including some electronics mods if you dare.

What I do remember, was experimenting with ND filters over the lens as well as removing or adding the ND filters over the CDS sensor to adjust for Fujji film of the day... not sure of ASA or details since it was a very long time ago.

have fun.
Are you going to do some of that smear artsy stuff that was very popular with these polaroids?

BTW since these were selling for a dime a dozen, they were a good source of mirrors for MF cameras. They are top quality mirrors too.

I'd have to pull my SX-70 out to talk specifically about ticks marks, but I believe that a 'full throw' either direction is about 1 1/3 stops. I have found the Impossible film, both B&W and color, tricky because results seem to rely heavily on scene lighting. Be sure to shield the film from direct light as it exits the camera.

Alan9940 said:

I'd have to pull my SX-70 out to talk specifically about ticks marks, but I believe that a 'full throw' either direction is about 1 1/3 stops. I have found the Impossible film, both B&W and color, tricky because results seem to rely heavily on scene lighting. Be sure to shield the film from direct light as it exits the camera.

Click to expand...

My experience so far is lighting is very tricky to deal with. So you think a full throw in either direction is 1 1/3 stops? That could explain why my photo silhouetted even with what I thought was a 3 stop compensation. Otherwise yes, I've been following their "best practices" by cleaning my rollers, I installed their frog tongue and I shield it from light, wait the 30-40 min, etc... Thanks!

paul ron said:

The SX70 has a cult following, googeling it will bring up tons of mods for it including some electronics mods if you dare.

What I do remember, was experimenting with ND filters over the lens as well as removing or adding the ND filters over the CDS sensor to adjust for Fujji film of the day... not sure of ASA or details since it was a very long time ago.
have fun.
Are you going to do some of that smear artsy stuff that was very popular with these polaroids?
BTW since these were selling for a dime a dozen, they were a good source of mirrors for MF cameras. They are top quality mirrors too.

Click to expand...

I like your idea of using nd filters. I should be able to trick the light meter to compensate for even more than what the exposure wheel seems capable of. I probably won't do too much with smearing the polaroids. I'm realy just dabbling with this camera for nostalgia's sake.

On top of the differences between Polaroid film and Impossible, the camera is many years old so the calibration of the auto exposure may be way off. Experimentation is the order of the day, which can get expensive.

Lee Rust said:

On top of the differences between Polaroid film and Impossible, the camera is many years old so the calibration of the auto exposure may be way off. Experimentation is the order of the day, which can get expensive.

Click to expand...

oh well. something to help me avoid doing any real work!

I may have some ND filter sheets left in my closet if you want to play with that?
It would be nice to know where you are from in your profile so I have an idea what postage might be?

pm your address and I can mail it to you.

paul ron said:

I may have some ND filter sheets left in my closet if you want to play with that?
It would be nice to know where you are from in your profile so I have an idea what postage might be?

pm your address and I can mail it to you.

Click to expand...

I'll update my profile for sure. In fact, I should really subscribe too. Should have done that a while ago really... That being said, I have a few ND filters for my 35mm cameras so while I appreciate the very generous offer, it's not necessary. Thanks very much though!

ND filters are very useful as well as color filters for the B&W film. I have a set of gel filters mounted in old Calumet filter holders that I use for medium and large format. For the SX-70, if there isn't any wind to speak of I just set the filter on the front camera edge below the lens and lean it back against the camera body. Works great! If you poke around the web you'll find many instances of homemade filter holders, too.

Have fun!

I have a reasonable amount of experience with the SX-70 and impossible film and I'm sometimes still surprised by the results.

First, regarding the exposure dial, on my SX-70 (an original folding one, not a solid frame model) I would say the tick marks are one f-stop. I can get the exposure of a given test subject to be very dark to very light. When I use Impossible film, I move the dial one half tick mark into the "darken" zone (this should be one half stop underexposure). This has given me the best and most consistent results.

Still, one thing that is very obvious is that highlights just bloom and produce an aura effect. If I compensate and try to make it darker, the whole photo is too dark. It definitely requires experimentation. By the way, as soon as the photo's ejected, I keep it in total darkness for one hour. This is for film manufactured in early 2016 (the "pastel box", not the earlier white box). Actually, I'm sure the older white box film didn't blow the highlights - it seemed lower in contrast.

It's hard to say whether your exposure dial works the same way - I'm afraid you'll have to experiment. It's expensive, but once you've got an idea of how to set the exposure, you can get nice results.

I'm not very familiar with how the L/D control in the SX70 and 600 cameras worked, but I do know that the ColorPack (folding) series used a progressive ND filter in front of a CdS cell for control of autoexposure.

All of them had electronic components that changed value with age, causing incorrect exposures, usually toward underexposure, sometimes in cameras less than ten years old. In some cases, turning the L/D control all the way towards Lighten (+2 stops) still rendered dark pictures.