Jupiter-8 New Style Close-Focus Mod

[Sonnar Brian]

Okay, this one wins the "easiest to modify for close-focus award". I'll post more on it later, but did take pictures. Stuck in the house getting over the Flu...

Removed the close-focus stop-screw, filed down the threads on the mount, reassembled. Done. The close-focus stop screw was slightly longer than the "catch Screw" on the stationary portion of the helical. I used the longer screw for the stationary catch screw, and it ended up being long enough for the infinity stop screw to act as near and far stops.

Filed the threads down for the RF follower to make it into the lens. The result is an inexpensive Sonnar formula lens able to go to ~0.7m with RF coupling and even closer without it.

This is the later Jupiter-8 black lens, where the optics rotate with focus.

I'll edit the pictures and shoot some tests later this week when I'm "recovered". Good way to start a diet and catch up on DVD's. 2009 Star Trek, $5 at Wal-Mart.

 

[paulfish4570]

Glad you are getting over the virus, Brian ...

 

[P. Lynn Miller]

Brian,

Sounds like a good modification, as the Sonnar is a nice portrait lens. Hope you are feeling better soon.

I hope the Nokton 50/1.1 is that easy to modify...

 

[Sonnar Brian]

Easy mod on an inexpensive lens. Paul- this is the lens picked up from you in the trade.

Lynn- anxiously awaiting the F1.1 thread! The Nokton F1.5 was an inspiration. I have a number of focus mounts I'll be looking at for reworking.

 

[paulfish4570]

Excellent. I am glad you found it worthy. I really liked the results I got with it, but without f-stop detents, Mr. Fumblefingers was as likely to move the f-stop ring as the focus ring ...

 

[Sonnar Brian]

I am NOT putting Click Stops in- but if you were going to, probably drill out a small hole in the aperture cone and put click stops in the stand-off ring.

 

[maclaine]

Cool. I have one of these, and frequently find myself in a position where I can't focus close enough. I'm also not that confident in my ability to take apart, muck around, and reassemble my lenses, but this is one I think I can handle. Thanks, Brian!

 

[SteveM(PA)]

Can't wait to do this! Thanks Brian!

 

[nasdak]

Great job Brian,

i'd like to try this mod... do you have a picture of the jupiter 8 model that can be modded this way, so i can buy the good one on ebay ?

thanks !

 

[Sonnar Brian]

I revisited this lens, had to make one change to allow the remaining "far" focus stop to act as both near and far stop.

1: take the optics module out. You are left with the focus mount.
2: Focus the lens until you see the screw under the slot, will appear near infinity. (see pic1)
3: Take out the stop screw under the slot.
4: Unscrew the Helical. Remember where it comes apart: many ways to rethread it.
5: Remove CLOSE Focus screw from the inner portion of the helical. (Pic 2)
6: You will need to make spacer, use a washer, paper, etc, to prevent the first screw from going all the way in. It will be where the failed washer is in Pic 3.

You will have to experiment to get the thickness correct for the remaining stop screw to work as far and near stop.

You will also need to file the threads of the mount down about one thread. This permits the RF follower to keep up with the Cam if using on an RF

 

[Sonnar Brian]

Regular close-focus, on my M8, at F2:

and the New close focus with RF coupling:

Both at F2

 

[Sonnar Brian]

Another set at the new close-focus,

at F2:

at F4:

 

[Sonnar Brian]

So: cheap, easily modified, Sonnar formula lens with RF coupling at 0.7m. Gets even closer on a camera with live-view, like my EP2.

and it is black.

 

[John Robertson]

these lenses have more lives than a cat!!!

 

[Sonnar Brian]

Some of my lenses have had more than one set of glass in them.

My other late-model, black J-8 now has Zeiss glass in it.

 

[ampguy]

amazing Brian, so you're getting coupling down to .7m, but still have some travel closer (with EVF or scale focus?)

That's incredible!

Paul - one reason I think is good for keeping these de-clicked is for potential video use down the road.

 

[randomm]

Just in case you sometimes read these Brian, I wanted to thank you for this inspiration. I managed to close focus modify my new style J8 this morning. Instead of using a single screw though, I drilled another hole at the mark where my M2 cam stopped following the lens and used the original close focus stop screw with some epoxy (I know, naughty, but I don't have tools to cut threads this small). Also managed to re-collimate the lens with some paper shims, so now I have a 0.77m-infinity focusing J8. Perfect. Thank you!

Here you can see the hole for the original position of the screw and the new one. Sorry for bad iphone picture. Hopefully this is of use to someone out there.

Here you can see the focus at its closest setting at 77cm.