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Diopter focusing on Canon Super 8


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#1 Douglas Hunter

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Posted 19 July 2007 - 01:09 PM

A few weeks ago there was a thread concerning some 1014XL-s test footage, in which a discussion of how to focus the diopter came up, in which one or two rather er, interesting ideas on how this should be done were expressed. Since I was doing a camera test any way and I was curious about the focus on this camera I shot my own focusing test.

There are two ways to focus the diopter on one of these cameras.

method #1: The traditional method: Zoom in on something far away with sharp lines and good tonal contrast. Such as a large store sign. When zoomed all the way in, adjust the diopter until image is sharp and the split image comes together. This is the standard method that most people know and use, and no suprise, it works. The one thing to note is that as you zoom out you will notice the split image that was united when you were zoomed in will split again. This does not signal a need to refocus. your focus on your object is still good.

Method #2: Aim your camera at a bright, tonally even, and evenly lit surface, throw the camera radically out of focus so that the image is a complete blurr. You will still be able to see the split image focusing circles just fine. Adjust the diopter until the split image focusing elements line up perfectly, then lock it down. This is the traditional method of focusing on a camera with a ground glass, you focus until the ground glass is sharp, but I did not think of trying it on this kind of camera until Kenji Luster the A camera operator on my show suggested it.

Both of these methods will get your diopter focused correctly.

When eye focusing these cameras it is important to follow Canon's instructions and to zoom in on your subject to focus, and then zoom out to the image size you want. Do not try to focus without zooming in.

Measured focus:
Perhaps not many super 8 users measure focus, but I did a measured focus test at F5.6 and focus for all witness marks was shapr when I projected the film. Granted this test would have been more accurate if I was more wide open but I was shooting under natural light so its what I could do.
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#2 Alessandro Machi

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Posted 19 July 2007 - 03:04 PM

A few weeks ago there was a thread concerning some 1014XL-s test footage, in which a discussion of how to focus the diopter came up, in which one or two rather er, interesting ideas on how this should be done were expressed. Since I was doing a camera test any way and I was curious about the focus on this camera I shot my own focusing test.

There are two ways to focus the diopter on one of these cameras.

method #1: The traditional method: Zoom in on something far away with sharp lines and good tonal contrast. Such as a large store sign. When zoomed all the way in, adjust the diopter until image is sharp and the split image comes together. This is the standard method that most people know and use, and no suprise, it works. The one thing to note is that as you zoom out you will notice the split image that was united when you were zoomed in will split again. This does not signal a need to refocus. your focus on your object is still good.

Method #2: Aim your camera at a bright, tonally even, and evenly lit surface, throw the camera radically out of focus so that the image is a complete blurr. You will still be able to see the split image focusing circles just fine. Adjust the diopter until the split image focusing elements line up perfectly, then lock it down. This is the traditional method of focusing on a camera with a ground glass, you focus until the ground glass is sharp, but I did not think of trying it on this kind of camera until Kenji Luster the A camera operator on my show suggested it.

Both of these methods will get your diopter focused correctly.

When eye focusing these cameras it is important to follow Canon's instructions and to zoom in on your subject to focus, and then zoom out to the image size you want. Do not try to focus without zooming in.

Measured focus:
Perhaps not many super 8 users measure focus, but I did a measured focus test at F5.6 and focus for all witness marks was sharp when I projected the film. Granted this test would have been more accurate if I was more wide open but I was shooting under natural light so its what I could do.


lol, I think you completely botched the explanation for the first method, which then makes me wonder about the 2nd method as well.
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#3 Douglas Hunter

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Posted 19 July 2007 - 04:09 PM

Right! thanks, I left out two things: First is that when zoomed in all the way on the distant object the lens should be focused at infinity. Second, that the method you suggested in the first thread was totally wrong.

Thanks again for the editorial help!
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#4 Alessandro Machi

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Posted 19 July 2007 - 04:28 PM

Right! thanks, I left out two things: First is that when zoomed in all the way on the distant object the lens should be focused at infinity. Second, that the method you suggested in the first thread was totally wrong.

Thanks again for the editorial help!


Why not find the original thread and give your viewpoint there?
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#5 Jim Simon

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Posted 19 July 2007 - 10:01 PM

The method I was taught is to zoom in, focus the lens, zoom all the way out and adjust the diopter without touching the lens focus.
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#6 Alessandro Machi

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Posted 20 July 2007 - 11:39 AM

:blink:

The method I was taught is to zoom in, focus the lens, zoom all the way out and adjust the diopter without touching the lens focus.


Back focus of the camera is the wild card here.

Besides wanting to set the diopter, we need to also make sure the camera's back focus is correctly set. But since we cannot actually set the back-focus on most Super-8 cameras, the next best thing is to see if after setting the diopter that it actually holds focus from telephoto to wide shot, that's why it's not enough to just set the diopter at telephoto. Your method seems to take into account the backfocus since you are zooming out to the wide position.
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#7 Jim Simon

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Posted 20 July 2007 - 11:59 AM

Your method seems to take into account the backfocus since you are zooming out to the wide position.


Correct. This was why I was taught this method.
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Paralinx LLC

Aerial Filmworks

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Rig Wheels Passport

Metropolis Post

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The Slider

Ritter Battery

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