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Tungsten negative film & 85 filter


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#1 Damien Dubois

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Posted 14 June 2008 - 01:38 PM

hello,

I get an external minolta 85 filter today for my nizo camera. It's not a 85B filter it's an 85 for 3400° not 3200°.
Do you think it will be ok to shoot some negative tungsten film or should I give it back to the owner and buy a true 85B?
What's the perfect condition to use 85 filter (not the B one) with tungsten film? (Really bright summer light, dawn lite ...)?

On nizo camera (the old grey metal series), the daylight/artificial light selector enable either the internal filter and the photosensor compensation. If I put an external filter on the lens, without selecting daylight not to enable internal filter, it will not compensate the exposure meter.
If I put this external filter on my nizo should I set the light type knob to daylight or artificial light ?
Should I unscrew the internal small crappy filter to change electric sensor setting without adding 2 filters (internal + external) if I put the knob on daylight position to compensate exposure?

I know this topic is often dealt with but with nizo camera it's not posible to put in daylight electric position without enabling the internal filter unless you open the gear and unscrew it.

really thank you in advance for your advices.

Best regards.

Damian
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#2 Michael Lehnert

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Posted 14 June 2008 - 04:11 PM

I can assure you that the 200° Kelvin difference between the Wratten 85 and Wratten 85B is negligible when working both with contemporary color reversal and negative films, even those marked as requiring a specific 85er class.

You will have to use a Wratten 85 whenever you are shooting tungsten cine-film with non-artificial light, i.e. all practical exteriors, plus some interior situations where the primary lightsource is sunlight (e.g. sunlight falling in through the window, lighting up the room, with only minor punctual artificial lights to posit hightlights on the set). Zenith-related or colour-temperature-varying differences of the sunlight at hand is negligible, too.

If you put the filter selection switch into daylight, the internal Wratten 85 (which by the way is a very good and sealed gelatine product, much better than the reputation they have among the Super 8 crowd..!) will engage. If you have your front filter on as well, you will unnecessarily double the colour effect from the daylight conversion effect, you might also loose 1/3 f-stop at least. If you remove the internal filter, then this doubling effect will be gone, and the exposure meter will be set right for usage with your front filter.

If you don't engage the filter selection swith to daylight, but use the front filter only, you should compensate for 2/3 f-stop manually due to the Nizo's wiring, either via the handy exposure meter compensation dial that Nizo big-bodied and sound cameras have (not sure about some small-bodied models - I think the Nizo 116 lacks it, but I might remember that incorrectly now -- what model do you have anyway :) ?). That would sort out your problem

Puh, I hope I didn't forget anything here in my hurry (saturday night, sorry, will have to leave now). If so, I might post again or someone will eventually chime in, too.

Cheers,

-Michael
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#3 Damien Dubois

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Posted 14 June 2008 - 10:31 PM

Thanks a lot Michael, I will follow your advice. I will use my external 85 filter for "daylight" conditions. I will also remove the internal filter (maybe 1 or 2 screw to remove on my nizo 801..) to compensate the exposure without doubling the color effect with 2 filters engaged.
That's really kind to reply so fast.

Regards

damian
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#4 Jim Carlile

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Posted 15 June 2008 - 03:38 AM

If the negative film is from Kodak, it's supplied in a notchless cartridge, which means the filter pin will be pressed in and the Nizo's internal 85 filter is automatically withdrawn, no matter what. So you have to use an external 85. There's no other choice.

If it's V200, then Kodak speed-notches this film for ASA 160. But with its notchless cartridge, the withdrawn filter pin also acts as a daylight film sensor, which means that the meter will be keyed to the lower ASA of the cartridge speed-notch-- which is ASA 100. This means V200 will be exposed at ASA 100. This is exactly how they handle the new Plus-X

But these silent Nizos will only read up to ASA 160, so any higher film speed will be read as ASA 100 as well. That means V500 will also be set at ASA 100.

Now the Nizo-- unlike any other camera-- here tell has a very unusual feature. If you slide the filter switch back to 'tungsten' or bulb, the meter will be set at the higher ASA of the speed-notch, which is ASA 160. If it's set to 'daylight', it will toggle back to ASA 100.

The reason for this is so that these Nizos could read the 'newer' daylight high-speed films like Ektachrome 'G' or Tri-X. With other cameras that only read speeds up to ASA 160, the 'daylight' notchless cartridges will trigger the lower ASA 100 speed, giving an incorrect reading.

Now some cameras will read these high-speed daylight films correctly, because Kodak speed-notches them at ASA 250-- which these cameras will detecty -- and the notchless daylight cartridge will key the meter to the lower ASA of that particular speed-notch, which is ASA 160.

That's how Kodak sets the correct ASA for these films (if you look closely at Tri-X, you'll notice it's speed-notched at ASA 250, even though it's an ASA 200 film. That sets the camera to ASA 160, which Kodak prefers. There is no ASA 200 speed indice in super 8.)

So, the rule is, if it's Kodak negative (V200,) a super 8's automatic meter will be set to ASA 100 and no internal filter no matter what. If it's a silver body Nizo, you can toggle to ASA 160 just by setting the filter switch to 'bulb.'
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#5 Michael Lehnert

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Posted 15 June 2008 - 04:05 AM

As a relevant follow-up to Jim's post, esp. when shooting V-200 (i.e. 7217), I suggest going through this post of mine here about further issues related to exposure index measuring, as well as how the matter of film latitude works out in light of that, and the additional parameter that is the accuracy of the exposure meter in the camera, as even CLA factory setting might be peculiar.

CLICK ME:
<a href="
http://www.cinematography.com/forum2004/index.php?s=&showtopic=26346&view=findpost&p=200888" target="_blank">http://www.cinematography.com/forum2004/in...st&p=200888</a>


The post hyperlinked above specifically deals with Bauer cameras, which have straightforward default settings (mostly found in other Super 8 cameras other than those with the Multi-Pin system of all Nizo and some Canon sound cameras), where the notch sensing either leads to reading EI 25 D / 40 T or EI 100 D / 160 T, and the filter switch does exactly what it says, without cancellation function. All Nizo cameras are quite complex in that respect, and dare I say unnecessarily sophisticated. Nevertheless no reason to shun them, as they are quite rightly well ranked in the Top Camera Guide in the pinned FAQ here.

I know that all this reading in this thread might make Super 8 camera gear look like unrealiable patchwork thingies from hell, but actually they aren't, and dealing with built-in lightmetering techniques in Normal 16 handheld cameras or Super 16 shoulder cameras, even 35mm gear from the 1970s that had the luxury of built-in exposure meters, isn't that different. That's why Super 8 is such a great format to become originally acquainted-with in cinematography (and it sure still costs less than 16!).
And we havn't even started about using external incident or spotmeters... in set-light conditions.
So my message to all third-party newbie readers: Don't Panic!

As long as you don't save at the wrong end and shoot some test reels based on a worked-out or documented process (so that you know what the settings were for each take), everything will become very clear and easy to understand. Going through a RED menu is much more challenging.

-Michael
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#6 Jim Carlile

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Posted 17 June 2008 - 02:16 AM

As far as it goes with what conversion filter you need, here's a great color temperature nomograph to play around with:

http://micro.magnet....raph/index.html

Your source light is at the top, the film's color temperature rating is at the bottom. Set one (say the bottom for the film you're using) and then slide the top one to whatever light source you have. The middle line goes to the required filter.

You can play around with it to see exactly what the difference is between an 85 A, B, or C, or what it takes to need an 81.
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