Shutter speeds and Time Lapse

[Jim Train]

I am struggling to get my head around my Nizo Pro's time lapse function in regard to shutter speeds and how it detects the light levels.

 

In the manual it says that the intervalometer has settings from ranging from 6fps to 1fpm and that at 6fps the shutter speed is 1/8 and at 1fpm the shutter speed is 1 minute. However, when I turn the intervalometer dial the aperture reading doesn't vary and when I open the film compartment and shoot a few frames, the shutter opens and closes for the same duration regardless of where the intervalometer dial is; the number of frames taken changes fine but the shutter speed appears to remain constant. I am really confused by this and can't think where I am going wrong.

 

I had wanted to shoot a 30 minute sequence using the intervalometer in a room where a reading of 1/4 would be spot on but the camera aperture reading given when in inter mode is the same as when in normal auto 18fps mode which to my mind means that the shutter speed in inter mode is actually 1/40 (the same as 18fps auto mode.) I can't use the Auto Bulb mode for this sequence as the light level in the room would be too high and the Auto B would have run through the entire cart within a matter of minutes.

 

Am I getting something wrong concerning the intervalomter shutter speeds? This has been driving me up the wall all week!

 

Thank you for your time

[Justin Donoghue]

the number of frames taken changes fine but the shutter speed appears to remain constant.

 

you mean that no matter where on the dial you are the shutter speed remains the same? It sounds like the function is not working correctly on your camera. I checked my camera and when I move the dial towards the 6fps the shutter speed speeds up as I can both hear the shutter and see it when I open the film door and look in. My aperture reading doesn't change however. When I switch from 18fps to 25fps and 54fps it does change. It looks to me like you have to 1. use the auto B function or 2. set the frame speed yourself and use the manual aperture control dial? It's not clear in the manual whether the 1fpm to 6fps dial also includes automatic aperture control is it.

Edited July 22, 2010 by Justin Donoghue

[Jim Train]

The frames per minute does speed up and slow down on my camera as I turn the dial i.e. the clicking of the shutter changes speed fine. My issue is that, when you look through the opened film door or listen to the shutter, it is apparent that the length of time the shutter stays open for does not change. You can see that through the film gate that the shutter seems to open and close for the same amount of time when it is set to 1fpm or 6fps. Given what the manual says, when looking through the film gate you should see the shutter stay open for 1 minute when set to 1fpm but that is not the case on my camera.

 

Like I said, all of this leads me to believe that on intervalometer mode, the shutter speed is set and does not vary. The only thing I can think is that the shutter speed change only kicks in when the camera is loaded with film but if that was the case the aperture needle should move when you turn the intervalometer dial to different settings as you would obviously need a much, much smaller aperture if you were letting in anywhere near 1 minutes worth of light (in most situations.)

[Justin Donoghue]

You can see that through the film gate that the shutter seems to open and close for the same amount of time when it is set to 1fpm or 6fps. Given what the manual says, when looking through the film gate you should see the shutter stay open for 1 minute when set to 1fpm but that is not the case on my camera.

 

Don't forget you have to have the orange variable shutter lever pulled back and locked into place also. This leaves the shutter open all the time in between frames which means the shutter interval will change when you rotate the 1fpm - 6fps dial. When you pull back the lever and look into the film compartment you will see the shutter fully open.

[Jim Train]

See I still don't get this. I have just had another read of the manual and if the shutter is to remain open for the entire time lapse (aside from when the frame advances) that must surely means that any footage shot using a slow frame rate of 1 or a few frames per minute would HAVE TO be shot in low light otherwise the footage would be completely overexposed.

 

I mean if you are shooting at 1 fpm seemingly the shutter stays open for 1 minute for each exposed frame, for 2 fpm the shutter stays open for 30 seconds for each exposed frame etc... meaning that when in the (non Auto B) intervalometer mode, you would be better off selecting an aperture yourself that would be suitable. For example, if I wanted to shoot a time lapse at 2 fpm I would need to make sure that I use a very small aperture in moderate to bright conditions otherwise the film will be totally overexposed at a shutter speed of essentially 30 seconds for each shot.

 

Do you get what I am saying? I thought in the inter mode the exposure would always be spot on but now am not sure at all.

 

Has anyone reading this ever shot a time lase of 1 or a few frames per minute in moderate light and if so how did the footage look?

[Jim Train]

To get an idea of what I am referring to concerning shutter speeds and time lapse, you can go to the following Wikipedia Time Lapse explanation and scroll down to the part about "Short Exposure Vs Long Exposure Time Lapse."

 

Here: http://en.wikipedia.org/wiki/Time-lapse

[Justin Donoghue]

See I still don't get this. I have just had another read of the manual and if the shutter is to remain open for the entire time lapse (aside from when the frame advances) that must surely means that any footage shot using a slow frame rate of 1 or a few frames per minute would HAVE TO be shot in low light otherwise the footage would be completely overexposed.

 

I mean if you are shooting at 1 fpm seemingly the shutter stays open for 1 minute for each exposed frame, for 2 fpm the shutter stays open for 30 seconds for each exposed frame etc... meaning that when in the (non Auto B) intervalometer mode, you would be better off selecting an aperture yourself that would be suitable. For example, if I wanted to shoot a time lapse at 2 fpm I would need to make sure that I use a very small aperture in moderate to bright conditions otherwise the film will be totally overexposed at a shutter speed of essentially 30 seconds for each shot.

 

Do you get what I am saying? I thought in the inter mode the exposure would always be spot on but now am not sure at all.

 

Has anyone reading this ever shot a time lase of 1 or a few frames per minute in moderate light and if so how did the footage look?

 

Yeah I get what you're saying. I suppose the feature works best in auto mode and in very low light conditions where you're not too bothered about how much footage you're using etc.The 1fpm is obviously to be used in seriously low light and don't forget at the time most people would be using 40T film which required plenty of light to expose so 1fpm may be reasonable. It looks like in order to get your desired result you'll have to take an external light meter reading and manually set you're f-stop based on the shutter speed e.g. 1/8 sec @6fps. If the light is consistant then it should be ok. Good luck.

Edited July 23, 2010 by Justin Donoghue

[Jim Train]

Thanks! Have a family party coming up so am going to shot a cart of time lapse tests.

 

Out of curiosity what happens if you shot in Auto B mode or using the intervalometer mode with the shutter NOT in the fully open position? Have you ever done this intentionally or by accident?

[Justin Donoghue]

Thanks! Have a family party coming up so am going to shot a cart of time lapse tests.

 

Out of curiosity what happens if you shot in Auto B mode or using the intervalometer mode with the shutter NOT in the fully open position? Have you ever done this intentionally or by accident?

 

I have actually....and the result was under exposed time lapse.

 

Shooting test footage is the best way to figure it all out. That way you have proof of what works and there's no speculation.

Edited July 24, 2010 by Justin Donoghue

[Jim Train]

Thank you for all your help!

[Alessandro Machi]

There is no way that 6 frames per second equals 1/8th of a second per frame in this instance. More likely the shutter speed is around 1/10th to 1/12, 1/8th of a second exposure per frame is just too fast as the camera could not possibly run 6 frames per second while staying open for 1/8th of a second per each exposure.

 

When you factor in the time it takes to move each frame of film and the time the shutter needs to be closed before the film is advanced, all that won't happen in just one second.

 

As stated earlier by Justin, sliding the orange lever to the right all the way basically reverses the intervalometer function. Instead of staying open for a fraction of a second between a set interval, the shutter stays open the entire interval until the frame is advanced.

 

The shutter speed for non-time exposure intervalometer work (aka time-exposure time-lapse) is controlled by the films per second film rate speed dial, a very clever extra feature that is almost impossible to find in either 16mm or 35mm if my prior research in this area has been correct. I generally recommend keeping the filming speed at the slower speed settings since the motor is being revved up every time the film is advanced, probably saves on power consumption as well.

 

The time to use the higher film speed dial setting for time exposure work would be for faster time-exposure work that would occur during low light daylight time, like early morning or late afternoon, when you might want to do time-exposure but at multiple frames per second. The basic difference between time-exposure or intervalometer if you are running a few frames per second is the time-exposure will actually be adjusting the frame rate as the lighting values change whereas the intervalometer will keep shooting at the same speed and shutter rate per second.

[Jim Train]

My understanding is that when the shutter is held open for the time lapse function on say... 6fps, the film advance rate combined for all 6 frames during the second equates to somewhere close to 2/8's of a second which is why Nizo have stated that in intervalometer mode a setting of 6fps gives a shutter speed of 1/8. I thought that made sense but made I am wrong in my assumption that the film advance per second in this example would add up to 2/8's.

 

For judging correct exposures a shutter speed of 1/10 ro 1/8 won't make a catastrophic difference and so I plan on shooting some tests with different exposure levels to try to suss out once and for all what the likely shutter speed rate are.

 

I will report back once I have the transfer.