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How Will My Nizo Handle ISOs It Can't Read?


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#1 Mark Sperry

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Posted 26 July 2011 - 03:54 PM

So I have a Nizo 481 Macro, which as you may or may not know has a CdS meter that will read up to ISO 100D or 160T. First of all, why are their different sensitivity levels for tungsten and daylight?

I just got a roll of 100D back (pro8mm HD transfer) and it looks freaking fantastic IMHO. The internal meter did a great job, as well as Pro8mm doing the transfer and making everything looking consistant.

Now I'd like to start using higher speed emulsions, but tri-x is just out of the reach of the camera's meter. Does anyone know how the internal light meter will read this cartridge? Will it think of it as 160 or just revert to some default setting? Can I rely on this reading at all? I have an external Sekonic L-558 (non-cine) and I could use this. However it assumes a shutter angle of 180, while my Nizo is 150. And it doesn't have my shutter speed, which is probably somewhere around 1/65th at 24fps/1/43 at 18fps.

If only these cameras would just allow you to manually set the ASA it would save a lot of headache!

Any suggestions for metering these films? Should I just use my incident meter at the box speeds, and try to compensate in manual mode on my camera?

What Super 8 cameras can meter these speeds? Is it worth upgrading?

I have a photography background and I'm getting into Super 8 now for my wedding photography business, and because I've always wanted to since I was a kid.

Thanks!
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#2 Martin Baumgarten

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Posted 27 July 2011 - 11:37 AM

The NIZO 481 Macro is a great camera. One of the drawbacks to it and many other Super 8mm cameras (especially many made after about 1974) is that they were only made to read the standard filmspeeds for mainly KODACHROME 40A and EKTACHROME 160A/G. However, they could still use films such as the discontinued PLUS-X 7276 (ISO 50) & PLUS-X 7265 (ISO 100), and TRI-X 7278 & 7266 (both ISO 200). The relative film exposure latitude will allow use of these films in your NIZO 481m.

DAYLIGHT and TUNGSTEN differences are/were intended for shooting under either situation with and without the builtin Daylight Conversion Orange filter which was made primarily for using Color Tungsten filmstocks. Virtually all Super 8mm Color Reversal films made during the heyday of Super 8mm, were Tungsten films. That way, the filmer could shoot in both daylight and tungsten lighting, with only ONE filmstock. It often meant having to use photoflood lamps for dark indoor filming. The Wratten #85 Daylight Conversion Filter lowered the effective filmspeed since the filter absorbs light of course....thus the reason for different Daylight and Tungsten ratings for each given filmstock. This can also be applied to using B&W films.......but these days KODAK doesn't notch the cartridges for Filter use....BUT you can do so yourself IF you want to take advantage of that builtin orange filter which works GREAT for B&W films shot in daytime. Saves having to put a filter on the camera lens, and it lowers the filmspeed by a third, thus allowing easier use of TRI-X in brighter light since it will be effectively ISO 130 instead of 200, and if you use the Variable Shutter you can drop that to HALF, thus ISO (E.I) 65.

As long as your builtin exposure meter is accurate, you can still take advantage of it for films outside of the camera's exposure indexing range. Note I didn't say exposure range...since the meter, IF it had been calibrated to read the other cartridge notches, would've been fine and easy to use of course. Anyhow, so what you'd do here for example if you were using say, ISO 400 or 500, is take an exposure reading, knowing that the maximum filmspeed notch the camera can read is ISO/ASA 160.....then adjust the exposure setting in the viewfinder display via setting the camera to Manual Exposure Control with the necessary exposure bias that you need. Thus, if the meter display shows/reads F/5.6 (at the max ISO of 160) and you're using say the new VISION-3 ISO 500 film, you know that ISO 500 divided by ISO 160 is about 3 (close enough here) so you would factor that in as 1.5 Stops, so your NEW exposure setting would be set at the mark between F/8 and F/11. You would use this similar methodology for any other films.

For a more accurate exposure rendering for TRI-X 7266 if you don't want to live with the film latitude range at ISO 160, then using the above example, take a reading and if it's F/5.6 for ISO 160 then for ISO 200 it would be a little bit higher, or a smaller F-Stop opening.....thus about 1/3 Stop setting past F/5.6 in the direction of F/8. It's not much of a difference, but that's how you would do this. I recommend metering via a gray card or other similar value to find your exposure range, and then factor in any considerations you need for what your subject matter is; light, dark, contrasty etc.

The NIZO 481m has a variable notch lever that reads the notches up to that ISO 160. Why they didn't go higher is beyond me, but BRAUN did so on the sound cameras. Frustrating when the CHINON made cameras such as the GAF ST-xxx series and higher all read from ASA 16 to ASA 640 (Daylight & Tungsten films considered in this range). That all notwithstanding, it's possible to have the camera's exposure meter modified so it would read higher or have an external potentiometer adjustment made for Under/Over Exposure value changes, but that might or might not be worth the hassle; only you can assess that. A guy in Europe was making such modifications to various cameras back when we all had the exposure situation with the EK64T filmstock.....going under the name of Adams64. Not sure if he's still doing this.

If you wish to meter using an INCIDENT Exposure Meter setting, first calibrate your hand held meter to the camera's meter (if the camera meter works fine of course). For example; using a gray card, white card or similar solid toned material for metering and regularity.......meter with the camera at it's Maximum ISO 160 reading, or whatever other useable cartridge the camera will read okay. Then read with your handheld meter but set at the REFLECTIVE setting (not incident) and read off the card, and adjust the ISO setting until the meter is correct, thus matching the camera. Take note of the ISO change compared to the NIZO S-481m, and you'll see the deviation. The camera of course, is metering thru the lens and has the shutter angle and beamsplitter light loss all calculated into its exposure reading. You need to have your handheld light meter setup in agreement. Now, you can use the light meter set to INCIDENT setting, since you know the deviation you will have to set the ISO at so it agrees with the camera. IF for some reason, you do not have a Reflective setting on your meter, and it's truly ONLY and INCIDENT Meter.....then do this: place a thin walled white stryofoam coffee cup or drink cup over the camera lens and face it into the light falling on it and take a meter reading. Then take your Incident meter reading as well, and compare the two readings. Then, take a reading with the camera off of an 18% Gray Card and compare that to the plastic cup "incident" meter reading you did with the camera. Compare BOTH readings to the one from your hand held INCIDENT Meter reading. IF using Negative films in the camera, bias the exposure to the slight over-exposure side based on those TWO camera readings, NOW factoring in the difference to your hand held INCIDENT Light Meter. For example: IF the NIZO S-481m gave you a reading of F/8 off the gray card, and a reading of F/11 using the cup method.......use the middle range setting for most shots until you've done a test roll for reference for future filming. Otherwise, use the F/8 setting to calibrate your INCIDENT Meter by changing the ISO so that it does read F/8...and use that for Negative films or all films until you've done tests to see if you need to make other exposure changes for lighter or darker subject matter. FOR REVERSAL films, use the middle or higher setting of F/8 & 1/2 or F/11, until you've made your test film.

The TEST FILM is important, since it will visually let you know exactly how much to compensate for, for either NEGATIVE or REVERSAL films, and under what lighting.....so you can make NOTES and then always be able to factor that bias into your hand held INCIDENT Light Meter from then on.

It's all easier than it sounds here in text writing of course, but you do have to specific in how you conduct your tests. At the very least, if unable to do an actual film test, you'll be in the ballpark exposure wise for most situations. Hope this helps.
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