Bokeh modification for Hexanon 57/1.2

[Pontus]

Some people don't mind the special clipped bokeh highlights of the Konica Hexanon 57/1.2 which are caused by the fact that the rear element is in part covered by the lens mechanism. Most people however would prefer perfectly round bokeh highlights when shooting wide open with this lens.

There is an easy fix for those who are using this lens on mirrorless cameras. I haven't done the mod myself (I bought the lens at the left already modified) but it looks easy and reversible. The rear plate that is part of the Konica AR mechanism (which partly covers the rear lens element) can be removed. The result is perfectly round bokeh highlights wide open.

[Jeff Zen]

Thanks for info. Seems like a really good thing! Are there any tutorials online showing how to do this? I would like to know exactly how simple this procedure is.

PS. Just took the back off of mine to see what's what. Looks like you might need to be a professional, or at least an advanced amateur repairman to make this mod. I couldn't do it.

[Dogtag]

[Jeff Zen]

Not a troll, but maybe I'm just challenged.

Couldn't even get the mount plate off on mine. Jammed on somehow.

[Pontus]

[Dogtag]

[Jeff Zen]

[Dogtag]

Oke lets start: You don't have to mark anything!!!
This is what you start with, a blurry picture of a lens

On the top of the lens there are 2 sorts of screws, 3x flathead and 4x philips screws.

First remove the 3x flathead screws on the side of the mount plate. (The green circle):

Then remove the black ring/skirt/hood/thingie:

That's it......
Place the screws back in the black ring/skirt/hood/thingie for safe keeping:

-------------------------------------------------------------------------------next level.
I want to blacken the stainless steel/chrome finish to minimize internal reflections:
You first have to do the above steps or the chrome mount ring will catch the AE latch and you can't get it off.
Remove the 4x philips screws: (in the red circle)

Carefully remove the top plate, why? well because of these:

highlighted in the orange circles are the aperture click springs, small metal bars with underneath them springs --> (bearing) ball. Mine is greased up and staying in place. But if your lens is dry or the springs under too much tension you get flying springs and rods. It's a shame if you loose a good afternoon searching the floor/room/house/vacuum cleaner.
If your aperture is too tight you can add a small drop of handy oil, or just open in up further and clean in completely (but if you're reading this because you needed help in removing the black ring part thingie, stop!!) And if everything works just fine, this is the best advice I can give you :http://www.youtube.com/watch?feature=player_detailpage&v=Kr0tTbTbmVA#t=45

You can now easily paint the ring without any risk to the optics:

You didn't have to mark any thing because it's already marked for you, here's how you reassemble the mount plate. Just align the holes as in the picture: (see red line)

Don't over tighten the screws, it's really not necessary. start with one screw and use the screw hole opposite of the first you did. slowly tighten all screws until the mount plate is secure (just like how you would place a car rim)

NOte:
You might find these:

Not sure what these are, could be against galvanic corrosion or just a simple spacer (I just found one on mine), others might enlighten us

[Jeff Zen]

Thank you Dogtag. Your expertise is well appreciated here. Your close-up photos and step-by-step instructions make everything clear to me. Thanks much for taking the time to do this!