Changing EOS-3 focusing screens to Ec screens requires you to switch CFn-0?!?!?!

Discussion in 'Canon EOS' started by j._d._mcgee, Jan 9, 2003.

  1. I believe I have made a huge mistake. I switched out my standard
    focusing screen that came with my EOS-3 about ten months ago, I put
    in a Ec-B center split image screen. I DID NOT know that you had to
    change Custom Function 0 to the 1 setting to obtain a standard
    exposure with any Ec screen.

    I have been shooting for all this time and apparently my shots have
    been a bit over or underexposed (which one?) Some of the some odd 45
    rolls I took in that time period did look a bit overexposed, an
    uncomfortable number of them. However, most of the pics look fine.
    I suppose since I used mostly print film I was able to squeeze by
    but chee, that's insain. They don't say anything about CFn-0-1 in
    the little instruction sheet for the focusing screen.

    Has anyone else been this stupid and not realized they did this? If
    you changed your default focusing screen be sure this Custom Func.
    is set to 1! How much of a difference does it make? How much is it
    under or overexposing all your pictures. Should I feel bad, about
    some of the more blatant mis-metered photos I took in this time
    period? Canon should have made this more of a WARNING, it is only
    mentioned once in the whole manual and it is easily looked over
    considering it is custom function 0, zero I mean what is that
    anyway? Its not mentioned in the focusing screen paper, when it
    should be in RED letters. Thanks for any opinions and help.
  2. "Canon should have made this more of a WARNING"

    So, you didn't notice the "CF 0" reminder on the focusing screen frame when you changed the screen?
  3. Ec-N and Ec-R are the bright (New Laser Matte) screens (EOS 3 standard and EOS 1NRS standard respectively). Other Ec series screens are darker (Laser Matte), such as the Ec-CIII (EOS 1V standard screen). I use an Ec-CIII in my EOS 3 for the greater focus "snap" of the laser matte screen compared to the new laser matte Ec-N.

    Since Canon put a reminder on the focus-screen frame, which you couldn't possibly miss in the process of changing the screen, then it would seem that the onus is on you.

    The reason that CF-0 is not mentioned in the instructions for Ec-B is that Ec-B pre-dates the EOS 3 by around 10 years. The brighter New Laser Matte Ec screens came in with Ec-R on the EOS 1NRS and continue with Ec-N on the EOS 3. The EOS 1 was released long before the New Laser Matte screens, and this is when Ec-B was released. Since CF-0 did not exist at that time, since the New Laser Matte screens did not, and we can assume that canon's engineers are not blessed with precognition (otherwise presumably the EOS 1V would have been released at the very start of EOS system, along with IS DO lenses), it is reasonable that they did not include mention of it in the instructions. For what it's worth, newer focusing screens, such as Ec-CIII DO mention CF-0 in the instructions.

    Canon may even have updated the instructions for the other Ec series screens, but focusing screens aren't exactly large-volume sale items, and so there are likely a great many out there unsold which were produced before CF-0 was introduced (obviously this can not apply to newer screens, such as Ec-N and Ec-CIII). Thus the instructions are out of date. It isn't reasonable to expect canon to go around all the shops that might or might not have this old stock and put new instructions into them.

    Also, page 133 of the EOS 3 user manual, entitled "Interchanging the Focusing Screen" makes very clear the need to set CF-0 appropriately for the screen in use. In fact, that entire page is dedicated to the need to change the CF, rather than detailing the actual process of changing the screen, which is only covered in the focusing screen instructions.

    Also bear in mind on the exposure issue that you can not use evaluative or centre-spot metering modes. Presumably partial metering is also affected. You can only rely on centre-weighted average or off-centre spot metering readings to be accurate within the usual bounds.
  4. First of all I did not know that there was SUPPOSED to be a notice printed on the focusing screen frame as my EOS-3 DOES NOT HAVE "CF-0" Printed anywhere on the frame. I see what you are saying now that I requested to look at a friends EOS-3 screen just a few moments ago. I suppose that would make my camera defective considering the notice is not painted on mine. I just put the default screen that came with the camera back in and I am selling my split to that friend. That's too much trouble just for the split prism.

    SECONDLY you will notice there are several editions of the EOS-3 manual. After doing some research since I made my post, I have a extremely early version "Current as of July 1998" not September 98 or October 2000 like some of the others I have asked to look at this evening of various EOS-3 owners I know. In this early version, or misprinted version there is no "whole page" dedicated to CF-0 in my manual, plain and simple, I have it right here in front of me and I can read. The only mention is on the page where the other CFs begin and it is easy to overlook.
  5. My manual is of the September 1998 variety. Since your manual does not have this information, and your camera does not either, then obviously it was not apparent that CF-0 needed to be changed.

    However, with revisions to the camera, the manual and the instructions of more recent focusing screens, the issue appears resolved.
  6. This seems to be a deeper issue than I realized. Apparently the two are related; the camera body and the manual itself. I suppose this particular EOS-3 may be in a rare batch of very early models or just plain that .01% of defective models that get by inspection and onto the shelves. The manual on the same respects seems to have been on a short run at the canon presses. Weird.
  7. BTW For what its worth my manual also was binded incorrectly with very little glue so the pages just fall out. I haven't lost any though. Perhaps another reason for revision.

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