The Route of "The Queen Of The Valley"

[Flintlock76]

Maybe some of you have seen this before, but I was fooling around on the YouTube as I usually do and blundered into this one.

DON'T  let anyone ever tell you steam couldn't MOVE!  This is 33 minutes starting with some high-speed action on the Jersey Central in the Jersey City area, and you'll be amazed at what you see.  Shot on 8mm B&W, quality could be better but it's an amazing watch just the same.  Someone should do some serious restoration on this footage.

So have fun everyone!

https://www.youtube.com/watch?v=t3eqnW5H2ac  

[timz]

Wonder if 8 mm could look that good.

[Flintlock76]

It's 8mm all right.  16mm would be a lot sharper.  However, movie cameras and film weren't cheap, so if an 8mm camera was all that railfan could afford who are we to judge?  He may not have used the best-quality film either.  I'm just glad he was there to get what he did. 

In the right hands restored 8mm can look as good as this.

https://www.youtube.com/watch?v=_BfIILYpsD8   

Which is darn near what 16mm looks like.

[Overmod]

timz

Wonder if 8 mm could look that good.

Part of this may be that some 8mm 'pro-grade' equipment was made; not everything was cheap consumer 'snapshot' quality, especially in the early days of the stock format.  When the resolution is emulsion-limited rather than due to cheap or wrongly-designed optics, you can get remarkably good images from the small size (think Minox for example).

I am tempted to say, not from experience, that processing makes a big difference, especially if the film had to be 'pushed' to allow higher shutter speed at aperture giving adequate depth of field...

[KennethBR]

It should be 8mm, mostly the same to the equipment I currently use.

[timz]

Movie cameras could change shutter speed?

Offhand guess: depth of field for train scenes would be plenty good enough at f/1, on an 8 mm camera.

[Overmod]

timz

Movie cameras could change shutter speed?

Good ones can.  Perhaps I should have said 'exposure time per frame' which is what speed of a focal-plane shutter translates into.

If I recall correctly the approach is derived from a rotating-blade design.  A typical focal-plane shutter is actually two shutters that are synchronized, one opening a path to the film and the other closing it, so a slit passes across the face of the frame that exposes a given area only for a given time (equivalent to a mechanical device that could reveal the whole frame for the equivalent time and then cover it again, which would be difficult to build for film (the closest I know being a variant of DLP) but possible with electronics.)  In something like a good SLR these are thin curtains moving in a straight line quickly, driven by spring machinery, and they are 'cocked' as part of frame advance.  This could certainly be done at up to 24fps for a small frame size but wear, vibration and noise would be high, especially in conjunction with film advance and locking that must take place in the same relatively brief interval.

One alternative is to use a rotating shutter, which in its simplest version  has a proportional slit cut in it and does not suffer from 'starting and stopping' inertia or the need to reverse direction (think OC vs. RC poppet valve drive to appreciate some of the mechanical points).  You can cut this slit asymmetrically so each area on the film will be exposed an equal amount in one 'traversal'.  It quickly follows that a single 'disc' of larger diameter can have multiple slits and be coordinated with periodic film pulldown.

Variable exposure in this design can be done by analogy with the focal-plane shutter by using two discs with slots that can be offset from each other; this preserving the synchronous coordination of rotary-disc speed with transport but controlling the exposure across the locked frame as for a still camera.

That the effective shutter speed can be very short is seen in things like the 'wagon wheel illusion' where clear images of an object like a spoked wheel do not show 'motion blur' (as a camera mimicking the human perceptive system might record) but only a stroboscopic capture at whatever the frame rate is, but with each exposure 'fast' enough to prevent frame distortion (most people are familiar with the effect in older focal-plane camera images where a fast car or train appears to be 'leaning forward'; this is because as the shutters are moving the slit, the image may also be moving relative to the film so its capture is shifted progressively...)  In general that kind of distortion is more objectionable than strobing, particularly in pan shots where the camera, not the subjects, do the rapid 'moving', and so we have to compromise.