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Lens distance markings?


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#1 Mark Williams

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Posted 08 January 2006 - 07:08 AM

OK.. I know.. I should set up each lens to a wall chart to find out the exact position for correct focus..

But WHY arent there exact Markings on the lens? I certainly dont want to paint little marks in SO if say I wanted to focus at 5feet I have measured the distance and now I want to focus using only the lens markings because I have a video assist hogging the viewfinder.. Is there a method?

Would I set the focus at the beginning of the Number 5 the middle of the Number 5 or the end? A trivial question perhaps.. But maybe there is a method being used when they print the numbers on?
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#2 Stephen Williams

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Posted 08 January 2006 - 07:25 AM

OK.. I know.. I should set up each lens to a wall chart to find out the exact position for correct focus..

But WHY arent there exact Markings on the lens? I certainly dont want to paint little marks in SO if say I wanted to focus at 5feet I have measured the distance and now I want to focus using only the lens markings because I have a video assist hogging the viewfinder.. Is there a method?

Would I set the focus at the beginning of the Number 5 the middle of the Number 5 or the end? A trivial question perhaps.. But maybe there is a method being used when they print the numbers on?


Hi,

In the middle of the no!

It is important to check the flange focal length of the camera, and that the lenses are collimated. When the camera and lenses are properly set up, then marks are more accurate than eye focus, with wide angle lenses, and at wide stops.

Stephen
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#3 Mark Williams

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Posted 08 January 2006 - 07:48 AM

Hi,

In the middle of the no!

It is important to check the flange focal length of the camera, and that the lenses are collimated. When the camera and lenses are properly set up, then marks are more accurate than eye focus, with wide angle lenses, and at wide stops.

Stephen


I assumed it was the middle but then I thought well 18" or 10 feet Numbers?

Would the Middle of that be between the Digits or in the Middle of the entire number.. Or even the middle of the first Number .. Without clear direction I wondered if I was missing something? Anyway thought it was worth asking... SO Just the Middle of any Number and not between digits ect..

Thanks :)
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#4 Stephen Williams

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Posted 08 January 2006 - 08:04 AM

I assumed it was the middle but then I thought well 18" or 10 feet Numbers?

Would the Middle of that be between the Digits or in the Middle of the entire number.. Or even the middle of the first Number .. Without clear direction I wondered if I was missing something? Anyway thought it was worth asking... SO Just the Middle of any Number and not between digits ect..

Thanks :)


Hi,

There is not that much between the two. Remember somebody had to mark the lens in the first place! Your Superspeeds may well have some slight backlash as they are 20+years old!

Stephen
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#5 Mark Williams

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Posted 08 January 2006 - 08:31 AM

Hi,

There is not that much between the two. Remember somebody had to mark the lens in the first place! Your Superspeeds may well have some slight backlash as they are 20+years old!

Stephen


I wasnt planning on doing any focus pulling with this BL Although I guess the Blimp housing could be marked for focus pulling using the Zoom lens Bet thatd be just as good..

Is their a test I can do for backlash perhaps just feel if there is any loose movement?
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#6 Stephen Williams

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Posted 08 January 2006 - 10:38 AM

I wasnt planning on doing any focus pulling with this BL Although I guess the Blimp housing could be marked for focus pulling using the Zoom lens Bet thatd be just as good..

Is their a test I can do for backlash perhaps just feel if there is any loose movement?


Hi,

Feel it, and see it in close ups through the eyepiece.

Stephen
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