MOORMAN AND MOTION BLUR

[Chris Bristow]

Does anyone know the shutter speed of Mary Moorman's polaroid? I thought she was at 1/50th and Zapruder at 1/40th. I'm asking because I don't see any motion blur from the limo or the background in the Moorman photo. Zapruder shows much more motion blur at 313 and he was far from the limo. Moorman was right next to it and had to pan much faster than Zapruder. It is if the limo was barely moving or stopped, imagine that.

[Bill Miller]

Zapruder filmed at 18 frames per second (shutter opens and closes with each frame) and had both motion blur and panning blur within his images.

Moorman took her photo in reaction to the head shot and with the car barely moving. The car is determined moving because the emblem in the middle of the hub caps are blurred from being in motion/turning at a much faster rate than the car is moving forward.

Edited February 18, 2017 by Bill Miller

[Chris Bristow]

Thanks Bill, Zapruder was 18 fps but the shutter speed was 1/40 I believe. That determines the amount of motion blur. You said the car was barley moving in Moorman's photo but  Zapruder 313 is the same moment in time or very close, so the limo speed must be the same in both Zapruder and Moorman. I was looking at the side of the white wall to determine motion blur which looks pretty sharp, So I am wondering about the shutter speed of Moorman's camera

[Alistair Briggs]

This might be of use - a link to the specifications of the type of camera that Moorman used...

http://www.copweb.be/Moorman Camera.htm

[Chris Bristow]

44 minutes ago, Alistair Briggs said:

This might be of use - a link to the specifications of the type of camera that Moorman used...

http://www.copweb.be/Moorman Camera.htm

Bingo, thanks Alistair. It says "Shutter: 2-speed everset rotary-leaf design; 1/25 and 1/100 plus Bulb". I assume plus bulb means 1/100 with the flash working. So hers was even slower than Zapruders and still blurred less.

[Alistair Briggs]

7 minutes ago, Chris Bristow said:

Bingo, thanks Alistair. It says "Shutter: 2-speed everset rotary-leaf design; 1/25 and 1/100 plus Bulb". I assume plus bulb means 1/100 with the flash working. So hers was even slower than Zapruders and still blurred less.

Happy to be of assistance.

What about the aperture? What affect does that have?

Just to ask, is it fair to compare the amount of blur seen in Zapruder and the amount of blur seen in Moorman seen as the former is filming and the latter is merely taking a photo?

Regards

 

 

[Chris Bristow]

Alistair, I know the wider the aperture the more spherical aberration and the focus softens. That should cause an overall blurring and turn round objects into oval ones. I would guess lengthening the depth of field would soften the focus in other ways too  but not sure about how that would work. The difference with motion/panning blur in this case is that horizontal line of blur that denotes the motion.
As far as the difference between still photography and motion the only real difference I can think of is the shutter and aperture, otherwise each frame is like a still photo. At least nothing that will affect the motion blur that I can think of. Would like to hear an expert weigh in on it though. 
 

[Bill Miller]

2 hours ago, Alistair Briggs said:

Happy to be of assistance.

What about the aperture? What affect does that have?

Just to ask, is it fair to compare the amount of blur seen in Zapruder and the amount of blur seen in Moorman seen as the former is filming and the latter is merely taking a photo?

Regards

Zapruder suffered from severe Vertigo and was constantly moving as he stood atop of the pedestal trying to pivot with the limos line of travel. Mary was pointing her camera as the limo had just passed he and was much steadier in her holding of the camera.

[Bill Miller]

4 hours ago, Chris Bristow said:

Thanks Bill, Zapruder was 18 fps but the shutter speed was 1/40 I believe. That determines the amount of motion blur. You said the car was barley moving in Moorman's photo but  Zapruder 313 is the same moment in time or very close, so the limo speed must be the same in both Zapruder and Moorman. I was looking at the side of the white wall to determine motion blur which looks pretty sharp, So I am wondering about the shutter speed of Moorman's camera

Zapruder was always struggling to keep his balance. The limo was moving left to right in his field of view. (Z313)

Moorman had Kennedy just past her location and moving away with Mary not being shaky with the holding of her camera.

 

Edited February 19, 2017 by Bill Miller

[Sandy Larsen]

14 hours ago, Bill Miller said:

Moorman took her photo in reaction to the head shot and with the car barely moving.

Huh? Wasn't the limo moving the same speed for Moorman as we see it moving in Zapruder?

Or do you consider the speed we see in Zapruder to be "barely moving?"

 

[Sandy Larsen]

1 hour ago, Bill Miller said:

Zapruder was always struggling to keep his balance.

Thankfully there are plenty of frames that are steady to choose from.

Here's an odd thing I've noticed:

Z309:

 

Z308:

 

These two frames are only one frame apart. And it is clear that Zapruder is following the limo quite well given that there isn't much motion blur on it in either frame.

But for some reason the motion blur on the spectators of Z308 is much worse than it is on the spectators of Z309.

How can that be explained?

Edited February 19, 2017 by Sandy Larsen

[Chris Bristow]

Whenever the limo has no motion blur the camera was not unsteady or it jiggled just right. Either way we can determine the motion blur in those frames because the witness' will show all the blur caused by following the limo.

Sandy I don't know if Zapruder had auto focus back then but maybe it shifted a bit from 308 to 309.

Edited February 19, 2017 by Chris Bristow

[Sandy Larsen]

33 minutes ago, Chris Bristow said:

Sandy I don't know if Zapruder had auto focus back then but maybe it shifted a bit from 308 to 309.

But that is horizontal motion blur. Or at least primarily so.

Yet it's not normal motion blur. It looks like double vision. It can most easily be seen by looking at the hands of the woman in red... she has two left hands.

It's as though the shutter opened, the camera was jerked very slightly horizontally to a new position, and then the shutter closed. But that can't be what happened because it would have resulted in double vision of the limo as well. It is selective jerk blur! LOL

(Actually I have a hypothesis I'm working on that might explain it. My hypothesis has to do with a method that may have been used to increase the apparent velocity of the limo, right at around Z313, where witnesses said the limo slowed down.)

[Chris Bristow]

Sandy, I thought the auto focus may add a bit to the overall focus.
I have noticed many times that double images appear where I expect blur. Like many frames of the Stemmons sign poles. Brighter images or things at varying distances may have something to do with why some images blur and others double, but it is weird. 
Your hypothesis has to do with something other than missing frames or matte work on the limo? 

[Sandy Larsen]

1 minute ago, Chris Bristow said:

Sandy, I thought the auto focus may add a bit to the overall focus.
I have noticed many times that double images appear where I expect blur. Like many frames of the Stemmons sign poles. Brighter images or things at varying distances may have something to do with why some images blur and others double, but it is weird. 
Your hypothesis has to do with something other than missing frames or matte work on the limo? 

My hypothesis has to do with removing frames to speed up the limo. (Which I know is not an original idea. It's the details of the process that have to do with the motion blur we've been talking about.) At this point I'm not sure that what I'm thinking of is even feasible. I need to study it more.