Eyepiece Correction Lens for Bronica AE III Viewfinder Prism

Discussion in 'Medium Format Cameras and Accessories' started by jaxon5, Apr 22, 2014.

  1. jaxon5

    jaxon5 Member

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    Hi everyone:

    I own a Bronica ETRSi with an AE III viewfinder prism. The AE III prism is equipped with a standard eyepiece correction lens that has a diopter range of between -2.5 and +0.5. Since purchasing my prism, my eyesight has deteriorated requiring me to (ideally) get Bronica's optional Plus Eyepiece Correction Lens that offers a diopter range of between 0 and +3.

    Unfortunately, despite searching for many months I am unable to locate a Plus Eyepiece Correction Lens; it would seem that they are very rare indeed, and I was, therefore, wondering if anyone had any knowledge or experience with fitting an alternative brand name circular correction lens to the AE III prism viewfinder; and, if so, which brands fit and what worked best.

    Thanks for your help.
     
  2. lxdude

    lxdude Member

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    I don't know what would fit from other brands. I just measured my AEIII eyepiece and got a diameter of 18mm and .75mm pitch. To compare, I checked an eyepiece from a Nikon F2 and got 19mm X .75 pitch.

    I think a good way to go is to take your eyepiece to an optician's and have them make a lens of the diopter you need. They should be able to remove it and install the new one, as it's just a circular spring retainer, but if they won't, any jeweler or camera repair person could do it. The optician can take from the eyepiece lens its actual diopter and make the new one to meet your need. The replacement would be +2.5 diopter different to the standard one. My standard "S" eyepiece lens is a plus diopter (magnifies), but I don't know how much.
     
  3. wiltw

    wiltw Subscriber

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    Keep in mind that the standard eyepiece setting of '0' is actually a non-zero diopter, selected by Bronica to set the apparent viewing distance of the focusing screen and status numbers to about 30-36". (Different manufacturers choose different apparent distances, and I cannot tell you what Bronica chose.) So the optician would need to read the actual diopter value of the standard lens, then add in whatever additional correction you need, to arrive at the replacement lens value.