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Focus problems UGH!


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#1 Mark Sperry

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Posted 29 January 2015 - 10:37 PM

So I've been totally blowing focus a lot more than normal lately at weddings.  Usually when I'm zoomed to telephoto or doing close up work.  It's killing a bunch of my important moments.  I swear everything looks sharp in the finder but the film is like beyond soft.  Could something be out of calibration?  I feel like I know how to recognize an off diopter.  I'm using a Pro814 and a Canon 814 AE.  

 

Would having an overhaul by Du-All here in NYC done potentially fix my focus woes?


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#2 David Cunningham

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Posted 30 January 2015 - 01:46 PM

Are you having this problem with both your Pro814 and your Canon 814 AE?

 

If so, when you do your initial focus, are you doing so zoomed as far in as possible and then pulling back?  This is the best way to pull focus on those cameras.

 

If it's only happening on one camera and not the other, it can definitely be a lens collimation issue on one of them.  If the results are equal with both, I would guess you are focusing wide and then zooming and not noticing the slight increase in softness due to more shallow depth of field.

 

If it's just happening with the Pro814, I would send it back to Pro8mm for a checkup.  It's good to do that once a year or so anyhow to check the take-up torque, etc.  I've never been disappointed with the performance of my referred 814 from Pro8mm or their services for it.


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#3 Josh Gladstone

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Posted 30 January 2015 - 06:57 PM

 You feel like I know how to recognize an off diopter? Why try to recognize it, just make sure it's set properly. Set the lens to infinity, look at something in the far distance, and then make sure that's in focus. If it is, then it probably is a collimation issue.


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#4 David Cunningham

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Posted 31 January 2015 - 09:08 AM

On the 814 the proper way to focus the diopter is the look at something bright but out of focus and adjust the diopter until the center grid is perfectly focused. Now you are perfectly focused on the ground glass.

Then, focus on infinity in something far away. If the focus is off. Something else is off.
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#5 Phil Soheili

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Posted 06 February 2015 - 06:22 AM

Hi,

 

I don't think it could be a diopte problem, because the diopter will only have effect on the viewing of your view finder screen.

You cannot change the focus of a projected image (as on your focus screen) by putting on glasses. - Hope that makes sense to you.

 

I first would try to reproduce the error in a controllable environment - studio, home etc.. if it persists, check if they are always off the same amount.

 

Are no parts of your out of focus pictures in focus or are they in focus maybe on one side yes and on the other no?

(Did you drop the camera or did it get hit recently?)

 

Most probably it is going to be a collimation issue (as has been suggested).

 

If setting your diopter is difficult with a picture on the focusing screen you might as well take your lens off, point the camera to a bright source and focus your diopter to see the grain of the focus screen. It dosn't have anything to do with the "incoming" picture, it just makes it easier for your eyes IF you usually wear glasses for sight.

 

Good luck to you.


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#6 Gregory Irwin

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Posted 06 February 2015 - 10:36 AM

A quick, easy test to see if your eye focus is the same on the film or sensor is to take a sheet of newspaper that has a lot of fine print (no pictures) and draw a red, sharpie line along a row of print in the center of the page by using a straight edge. Rotate the paper so the print and the red line is verticle and mount it flat on a wall or something else stable. Then, with your camera, zoom in to a long lens, wide open and frame up on the paper at an extreme raking angle so you can see very shallow depth of field with the verticle rows of print coming near to far in your frame. Focus on the red line in the center of the frame and you will see the rows of print falling out of focus in front and behind the red line. Roll on this for a few seconds. When you view the results, the red line should be in focus. If not, you will now know that what you see in focus in the finder is not ending up the same on the film or sensor. Big collimation issue and will need to be fixed. Good luck!

G
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