News, Tech Tips, Updates
Tele-Vue dioptrx for astigmatism correction fitment photos

Hi All,

Here are some images of a simple adaptation I made to my dioptrx to fit my 45 degree prism.  I simply super glued a stainless steel washer on the back.  I think the hardest part is locating the washer - I happen to have a few extra - if you need one just send me an e-mail.  I use the washer technique to make the whole thing easily reversible in just a few seconds in case you decide to wear your glasses or another photographer will use the camera.  

Photo showing back side of retaining ring removed from the Dioptrx (click photo for larger view):


Photos showing installation after washer is affixed to retaining ring.  You pull the rubber on the prism eyecup outward and slip the retaining ring over it.  Then you fold up the rubber from the 45 degree prism into the retaining ring.  Lastly you hold the Tele-Vue Dioptrx up to the eyepiece and tighten the retaining ring onto the Dioptrx.  Don't tighten all the way tight - leave a little loose such that you can rotate the dioptrx into the correct orientation.


This is what the Dioptrx will look like from the photographers perspective. Overall it works quite well and since the Dioptrx is a bit larger, extends a bit from the prism and has its own eye cup, its actually a bit easier to view through.  I suggest you focus the camera on something brightly lit and then rotate the dioptrx until the image gets sharp.  You will also see the screen lines get sharp too.  As you are getting close, you will see the vertical lines slope to one side or other - they will straighten when its just right and if you go past they will slope the other direction.  So finding the correct setting is pretty easy. Tighten up the retaining ring when you have it correct.


Which power Dioptrx do you need?   Have a look at your prescription for your eyeglasses and find the portion that shows the Cylinder and Axis corrections - that's your astigmatism amount.  Find the one for the eye that you focus with - that's the power of dioptrx you need.  Now if your prescription is mostly astigmatism and you've used a corrective diopter in the eyepiece you may find that you no longer need this.   Or you can order a lower power.  The best set-up is going to be a corrective diopter in the eye-piece that matches your sphere correction value, plus the dioptrx amount for the cylinder amount. Believe me, you'll be surprised by how well you can focus!  I quit using AF after I got this set up for myself. 

TLR pop up magnifiers - Table of available corrective diopters

Table of Corrective Diopters available for pop up magnifiers in the TLR Waist Level Finder

Rolleiflex TLR  2.8FX   4.0 FW and 4.0 FT    (will also fit 2.8 GX, F, 3.5 F and other models with removable WLF)

For some older cameras the label may no longer be visible - you can have an optomatrist read the diopter power and then reference this chart to determine what is installed and what value you need.    * blue item is the standard value

Diopter Labeled Value  Diopter Power Catalog Number
-4.5 9.5 92190.41.009
-3.5 10.5 92190.41.010
-2.5 11.5 92190.41.011
-1.5 12.5 92190.41.012
-0.5 13.5 92190.41.013 *
+ 0.5 14.5 92190.41.014
+ 1.5 15.5 92190.41.015
+ 2.5 16.5 92190.41.016
+ 3.5 17.5 92190.41.017
Diopters, Prisms, Focus screens - getting the best view for accurate focusing

One of the reasons I initially started shooting with the Rolleiflex was for the wonderful viewfinders with are big and bright.   Each Rolleiflex platform has several viewfinder options: on the 6000 series there are 5 finders, on the Hy6 there are four different finders, and 3 for the TLR's.    I like to be in control of the camera as much as possible, and personally rarely use the autofocus features.  When I do use AF, I find that it affects my compositional framing since I tend to center to the subject more.   

Besides the finder choices, another great thing about the Rolleiflex is that DHW-fototechnik offers lots of corrective diopters for their prisms and WLF pop up magnifiers, and they are not too expensive.  (I'm going to list a table of the different corrective diopters very soon.)

My problem is that my eyesight isn't that great and I have an astigmatism too.  That means even with the correct diopter in place, I still can't see really sharp images in the finder without glasses.  I won't bore you all with the effort I went into with building my own custom magnifying finders or experimentation with numerous focusing screens right now (maybe in a later post), but instead will get right to the solution for those of you who have an astigmatism but want to shoot without your glasses.  It's the Televue Dioptrx.   This is a corrective eyepiece for astronomers to fit to their telescopes, but amazingly its about the right size to fit on the 45 degree prism eyecups and also the same diameter of the 3x lupe finders.  Note - I have no affiliation with TeleVue at all.  I am just very happy these exist.  If you know your prescription, you can just select the closest one - they come in .25 diopter increments.  If you are in between, go to the higher value. 

I bought mine from OPT Telescopes but you can get them several places.  Here's a link to their page with the dioptrx.    

These come with a rubber eyecup and have a screw on mount cap that fits over the Rollei 45 degree prism eyecup. You can just remove the rear piece and slip it over the rollei eyecup and then screw in the dioptrx and then as you tighten look through and rotate it such that the angle is correct for your astigmatism (you'll see it get sharp - a little off and things tilt at an angle - way off its blurry).  It will stay on really pretty well.  If you get wild with your Hy6 and hop around like I do, you might want a bit more security.  I ended up gluing a large stainless steel washer on the back of the rear dioptrx cap that had a slightly smaller hole in it and this holds my dioptrx on very well.  I actually have two of these.  The second one is for my lupe finder.  It looks a bit funky but since they are the same diameter - I just use a piece of the blue masking tape around the seam to hold them together.