Speed Ramping and Exposure in the 4008zm2

Post by **bakanosaru** » Sun Jun 19, 2005 3:54 am

I'm trying to do some evenly exposed speed ramping in my zmII.

In the past I've used the variable shutter to control the exposure, which really hasn't worked that well as one can't tell how much to open or close it as it has no markings.

Has anyone had any success with speed ramping on a zm2.
Perhaps with a service the auto exposure will be up to the task (at present I don't think it will).

Any advice for producing an evenly exposed frame throughout the process?

thanks

Post by **mathis** » Sun Jun 19, 2005 9:51 am

Working auto-exposure with the motor is the method of choice I guess.

Alex · Post by **Alex** » Sun Jun 19, 2005 6:24 pm

Why did you decide to try the variable shutter rather than the f-stop wheel?

Auto exposure makes the most sense. If you are a machinist, you might be able to figure out how to make an actual physical connection between the speed dial and the f-stop wheel, as the speed dial turns x-amount, the f-stop would be turned an equivalent amount. Probably next to impossible to manually do it.

Some company won an Oscar 20 years ago for designing a system to match exposures with film ramping for 35mm cameras, but in Super-8, the auto-exposure feature should suffice and do the same thing.

Post by **bakanosaru** » Mon Jun 20, 2005 9:48 am

I used the shutter control because the reglomatic autoexposure on my 4008 seems a bit sluggish, I don't know if this is a feature of all 4008's or if it would be fixed with a lube and adjustment by Bjorn. :roll:
(I presume it would get better but not be as perfect as for example the speedy autoexposure of a canon 1014xls.)

Sure I could adjust the aperture while ramping the fps but this is pretty difficult.

If anyone has some actual experience with ramping on the 4008 I'd love to hear it.

Alex · Post by **Alex** » Mon Jun 20, 2005 2:01 pm

bakanosaru wrote:I used the shutter control because the reglomatic autoexposure on my 4008 seems a bit sluggish, I don't know if this is a feature of all 4008's or if it would be fixed with a lube and adjustment by Bjorn. :roll:
(I presume it would get better but not be as perfect as for example the speedy autoexposure of a canon 1014xls.)

Sure I could adjust the aperture while ramping the fps but this is pretty difficult.

If anyone has some actual experience with ramping on the 4008 I'd love to hear it.

Consistent sluggishness can be useful. If you feel the f-stop in autoexposure mode reacts too slowly, but is consistent, that would mean your image is perhaps being underexposed by lets say 1-stop as you ramp. I have three suggestions, probably all flawed, but something to try if you are bored.

Idea #1. You can do a tradeoff via the ASA wheel, adjust the wheel by 2/3 of a stop so when you start ramping you will go from 2/3 of a stop overexposed to only 1/3 of a stop underexposed as you finish your ramp.
Since the autoexposure is sluggish, there probably will be a backend backlash that will return the exposure to 2/3 over. Still might be fun to try.

Idea #2. Use an external power supply. The draw on that little camera battery may be too great for both slow motion and auto-exposure control to work as effectively as a more powerful (but same voltage and wired the same way) external battery.

Idea #3. Think of the f-stop ring as a focus ring. Calculate the amount of f-stop change that should be occuring during your ramping, time your ramping time, and then rack the f-stop wheel equal to the amount you have calculated you will need during the speed ramping. You'll probably need an assistant since it will be difficult to look through the viewfinder and know how much you have actually moved the f-stop wheel, while also having to turn the speed dial.

Post by **fastwind** » Mon Jun 20, 2005 6:16 pm

No matter if you shoot Super 8 or 35mm, you loose one stop of light for
each time the frame rate doubles.

24fps = no loss

48fps = open up one stop

There is no light loss when starting at 18/24 and going lower.
Hope this helps.

Alex · Post by **Alex** » Mon Jun 20, 2005 7:25 pm

My previous explanation assumed ramping up, but it's just as likely one could be ramping down as you state.

Some Beaulieu's can go from 2 frames per second to 70 frames per second, or 70 frames per second down to 2 frames per second. 2-4-8-16-32-64-70 FPS represents approximately a 5 and 1/3 f-stop shift.

Post by **jean** » Mon Jun 20, 2005 8:45 pm

I've done that with one of my 4008 than was not taken apart, and it diod just fine. I changed the speed gently from 2 fps to 18fps, and the exposure was fine and the effect funny. I suggest to invest some feet of k40 and try it..

Or b/w stock and send it to a lab, you'll have the results much faster.

Post by **Uppsala BildTeknik** » Tue Jun 21, 2005 12:43 am

Anyone shot with 70 fps with a 4008?
How are the results? Is the registration still good?

Post by **bakanosaru** » Tue Jun 21, 2005 3:11 am

What I find with autoexposure is that it picks the exposure for the initial fps fine and then does almost nothing until I get to 70fps when the reglomatic kicks in and zooms around to full open.

Post by **mathis** » Tue Jun 21, 2005 8:57 am

Uppsala BildTeknik wrote:Anyone shot with 70 fps with a 4008?
How are the results? Is the registration still good?

Yes! I shoot a lot at 70fps, thatÃ‚Â´s why I bought this baby.

Post by **Uppsala BildTeknik** » Tue Jun 21, 2005 9:25 am

Cool, then I will try the 4008.
I was not sure if IÃ‚Â´d use my 4008 or my ZC1000 (it can do 72 fps), but if the registration is good with the 4008 I will use it (I have more Super8 film to shoot).

Post by **gurra83** » Wed Jun 22, 2005 2:37 am

I did shoot some test film (K40) last week with up to 80 fps on my 4008 ZM4.

Will be reciving the footage next week i think. Hopefully i got something out of it.