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#1 Mark Oliver

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Posted 06 March 2009 - 11:08 AM

Hi all,

I have a query regarding the AutoB function on my super-8 Nizo. I planned to do a bit of experimenting, but insights before I start would be great to save on time and money where possible.

First off, I’m new to all this so please forgive me if some of my questions are daft!

The first thing I don’t get is: AutoB is designed to automatically work out the correct exposure time right? But isn’t that what the simple auto / manual exposure knob allows you to do?

Next, should you always lock the red lever to the half mark when using AutoB? Is there any application where you might want to be on AutoB but keep the red lever fully open? (I guess there are instances where you’d want to do this, otherwise why would the function be split into two actions on the camera?)

3) I’ve heard that AutoB is great to use with daylight stock at night, if you want to create traces (eg, ghostly figures walking past buildings, or the famous streaking car lights) – is this correct?

Lastly, any other general comments on AutoB would be very well received.

Thanks all,

Mark
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#2 Alessandro Machi

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Posted 07 March 2009 - 04:21 PM

Auto-B is a different function than regular exposure because instead of fractions of seconds that is normally associated with regular daytime filming, one is dealing in the realm of seconds.

Auto-B is simply giving you a chance to make night time exteriors come to life in a vibrant and colorful way. If used indoors, Auto-B can increase the sensitivity of your camera by an incredible amount, with the trade off being blurriness if your camera is not tripod mounted or there is movement within in the shot. However, if you were at the back of a church shooting a wide shot from up above, Auto-B would allow you to both kick up the f-stop a bit, to say, F-4, while still gaining a brighter picture by using a much slower exposure time. Since most people aren't moving, the images should still be useful.

I have done all of my time-exposures with the Eumig 800 series cameras until very recently, when I used a Nizo Special. However, I barely used the Nizo Special and have not gotten that footage back yet in a transferred form. I cannot recall what the difference is between turning the lever half way or all the way.
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#3 Matt Kemp

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Posted 15 March 2009 - 09:10 PM

The red lever on the side of the Nizo controls the variable shutter angle. When locked at the halfway position, the shutter angle is slightly reduced (you can see this by looking at the gate through the back of the camera with the film door open, and pointing the camera at a bright light source while moving the lever). This reduced exposure time, and can be used as a kind of ND filter in too-bright conditions.
With the lever locked all the way back, the shutter angle is significantly increased, and much more light is let in. When used together at night with AutomB (which automatically calculates how much exposure time is needed for each frame to be properly exposed), you can create streaks of light. I've attached a picture from some tests I did a while ago.

If you shoot with AutomB without locking the lever all the way back, the effect is much more strobey than streaky.

Hope that helps, good luck with the filming.
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#4 Will Cummock

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Posted 19 March 2009 - 10:14 AM

i've never used autom b with the lever half way back, i'm pretty sure it isn't designed to work like that. for reliable time exposures always lock the lever fully back, this will lock the shutter open even when the camera isn't running so do beware of flash frames.

if you don't lock the shutter open autom b should work fine, but in most cases it doesn't. the strobe effect seems to happen when the shutter frequently fails to lock open. different nizos seem to behave differently in this respect, battery level is also a factor i've heard.

the strobe thing can be used to good effect- i discovered this in a fortuitous single cart comp accident:



the shots in question are just after 2 minutes in case you don't want to watch the whole 3 mins.


will
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