wolves3012
Veteran
This post is intended to allow a DIY-er to adjust the RF on a FED or Zorki. The information can be found elsewhere on the net but I thought it might be useful here, where it's a common question.
First of all, be sure the RF is out, rather than a lens-fault being the cause. It's normal for small horizontal-alignment differences to exist between lenses, partly due to QC issues and partly due to wear in a lens' cam or helicals.
There are two steps to adjusting the RF, vertical alignment and horizontal alignment. Usually, vertical doesn't need correcting but if it does, always do that first since it *does* throw the horizontal off. If you adjust the vertical, you *will* need to do the horizontal afterwards!
Vertical adjustment:
All models have a circular prism in front of the RF window. On most models, there's a bezel around this, which is removed for access. On all the Zorki 3 and 4 models there is no bezel and the top plate must be removed for access. On FED 4 and 5 models the nameplate slides off, against a flat spring - careful not to lose it! Once you have access to the prism, look closely and you'll see either 2 flats or 2 notches (the innermost ones) just around the window. These are used to rotate the prism until alignment is correct, using tweezers or thin-nosed pliers. If the prism won't turn, put a drop of methylated spirit on the prism face, so it soaks the periphery - shellac is used to lock the prism and this will soften it (note: lighter fluid will not disolve shellac!). If the prism is loose, lock it after adjustment, with something non-permanent.
Horizontal adjustment:
There are two means of adjustment, infinity is by a tiny screw hidden near the VF window and close-up is by altering the RF sensor tip. First gain access to the screw. Most models have one short, fat screw next to the VF window on the top cover and the adjustment screw is behind this. On Zorki 5 and 6 models it is actually one of the nameplate screws that hides the adjuster. On FED 4 and 5 models it is behind the nameplate, removed as above.
Once you have access to the screw, a very small screwdriver is needed. Put the standard lens on and turn it to infinity. Adjust the screw until the images coincide: use a target that is *at least* a couple of hundred metres away (tip: the moon or a star at night is the ultimate "infinity" target). The screw turns left-for right, meaning that turning the screw left (anticlockwise) moves the RF image right and vice-versa (I have a vague recollection that this may be reversed on the long-base models, Zorki 5 and 6 and FED 2, so move it slightly and check).
Now check close focus, using a target placed exactly 1m from the film plane (a few mm in front of the camera back). If close-focus is wrong, take off the lens and use a pair of snipe-nose pliers to alter the position of the RF tip. Bear in mind this WILL upset the infinity setting so don't go for perfection yet. Turning the sensor tip so that it is flatter-on will move the RF image to the right for a given lens-distance setting. This is the same direction as focussing the lens closer, meaning that the RF image was too far left on the 1m target with the lens set to the 1m mark. The reverse logic is true (unsurprisingly).
Now comes the fun part! Adjusting the sensor tip will have upset the infinity alignment. Adjusting the infinity upsets the close-focus. You need to repeat the adjustments, a little at a time, so as to fine-tune to the point where both ends of the scale are correct. Make a note of your adjustments, to be sure you're not going the wrong way and making things worse!
When you're done, don't forget to replace any bezels, screws and covers.
First of all, be sure the RF is out, rather than a lens-fault being the cause. It's normal for small horizontal-alignment differences to exist between lenses, partly due to QC issues and partly due to wear in a lens' cam or helicals.
There are two steps to adjusting the RF, vertical alignment and horizontal alignment. Usually, vertical doesn't need correcting but if it does, always do that first since it *does* throw the horizontal off. If you adjust the vertical, you *will* need to do the horizontal afterwards!
Vertical adjustment:
All models have a circular prism in front of the RF window. On most models, there's a bezel around this, which is removed for access. On all the Zorki 3 and 4 models there is no bezel and the top plate must be removed for access. On FED 4 and 5 models the nameplate slides off, against a flat spring - careful not to lose it! Once you have access to the prism, look closely and you'll see either 2 flats or 2 notches (the innermost ones) just around the window. These are used to rotate the prism until alignment is correct, using tweezers or thin-nosed pliers. If the prism won't turn, put a drop of methylated spirit on the prism face, so it soaks the periphery - shellac is used to lock the prism and this will soften it (note: lighter fluid will not disolve shellac!). If the prism is loose, lock it after adjustment, with something non-permanent.
Horizontal adjustment:
There are two means of adjustment, infinity is by a tiny screw hidden near the VF window and close-up is by altering the RF sensor tip. First gain access to the screw. Most models have one short, fat screw next to the VF window on the top cover and the adjustment screw is behind this. On Zorki 5 and 6 models it is actually one of the nameplate screws that hides the adjuster. On FED 4 and 5 models it is behind the nameplate, removed as above.
Once you have access to the screw, a very small screwdriver is needed. Put the standard lens on and turn it to infinity. Adjust the screw until the images coincide: use a target that is *at least* a couple of hundred metres away (tip: the moon or a star at night is the ultimate "infinity" target). The screw turns left-for right, meaning that turning the screw left (anticlockwise) moves the RF image right and vice-versa (I have a vague recollection that this may be reversed on the long-base models, Zorki 5 and 6 and FED 2, so move it slightly and check).
Now check close focus, using a target placed exactly 1m from the film plane (a few mm in front of the camera back). If close-focus is wrong, take off the lens and use a pair of snipe-nose pliers to alter the position of the RF tip. Bear in mind this WILL upset the infinity setting so don't go for perfection yet. Turning the sensor tip so that it is flatter-on will move the RF image to the right for a given lens-distance setting. This is the same direction as focussing the lens closer, meaning that the RF image was too far left on the 1m target with the lens set to the 1m mark. The reverse logic is true (unsurprisingly).
Now comes the fun part! Adjusting the sensor tip will have upset the infinity alignment. Adjusting the infinity upsets the close-focus. You need to repeat the adjustments, a little at a time, so as to fine-tune to the point where both ends of the scale are correct. Make a note of your adjustments, to be sure you're not going the wrong way and making things worse!
When you're done, don't forget to replace any bezels, screws and covers.
