What kind of screwdriver can I use to fix this Zenobia focus ring?

The focus ring on my Zenobia became lose all of a sudden and it feels like the outside ring doesn't move the lens / doesn't focus at all.

Pics and videos here.

But the screw is so small! I would love to know how I can take it apart (as in, which screwdriver I need) and how I can recalibrate to make sure I put it back together properly.

This is a huge bummer because it's one of my main cameras and now I have to fix it before I can use it again

It looks like the lens is moving in and out, ie focusing

Vessel Precision Screwdriver Set TD-56 ought to work nicely. Although you could also use a regular metric screwdriver, JIS-types are generally a better fit for Japanese products.

I see that the front trim ring with the writing is not rotating with the focus ring, and presumably it should.

It is likely that the focus ring is held onto the barrel of the front lens group by those 3 setscrews with pointed tips digging into the lens barrel. Use the right size flathead screwdriver (the Vessel set , or a good driver like Wiha or Wera of the right size. Cheap so-called jewelers' screwdrivers can make it worse).

You can then probably back out the screws enough to gently pull off the focus ring without actually taking the screws all the way out. Look for the divots in the lens barrel, that will tell you where the ring was originally lined up. With the focus ring off, you can turn the lens barrel by hand, if it's very stiff, that's probably why the ring came loose and it should be cleaned and relubed. If it's not stiff, then the screws may have just backed out enough over 60 years to let go.

There may be a 3-way ambiguity about how to position the focus ring screws if they are distributed symmetrically. The lens group may screw in a little further past infinity; if so then screw it it out a little beyond the furthest-in point and figure out where infinity lines up with the focus mark and the screws line up with the divots. If not, you may have to pick a position and then do focus tests with a groundglass or on film.

Most, it not all, products of Asian origin that I’ve encountered with screws using cruciform drive sockets use JIS (Japan Institute of Standards) geometry. They are not compatible with Phillips drive sockets.

In the following article there are 10 different cruciform drives listed under “Cruciform drives.”

Two more are listed under “combination.”

Phillips and JIS B 1012 drives are discussed in detail further down in the article. It’s worth reading to get a better understanding of the differences and to appreciate the importance of using only the correct size and type of tool for each socket type.

https://en.wikipedia.org/wiki/List_of_screw_drives

I got one of these recently. It is pretty nice.

Ian C said:

Most, it not all, products of Asian origin that I’ve encountered with screws using cruciform drive sockets use JIS (Japan Institute of Standards) geometry. They are not compatible with Phillips drive sockets.

In the following article there are 10 different cruciform drives listed under “Cruciform drives.”

Two more are listed under “combination.”

Phillips and JIS B 1012 drives are discussed in detail further down in the article. It’s worth reading to get a better understanding of the differences and to appreciate the importance of using only the correct size and type of tool for each socket type.

https://en.wikipedia.org/wiki/List_of_screw_drives

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The OP's pictures at the imgur link clearly show slotted screw heads.

Yup, that’s a slotted screw head. I use the Wera small screwdrivers and like them a lot. Duckduckgo won’t let me copy and paste the Amazon link, but hrere’s the info: “Wera 345270 1.5 mm-4mm 6 pc. Kraftform Precision Slotted Metric Screwdriver Set” for $23.18. Well made and very useful for those small screws.

Tel said:

Yup, that’s a slotted screw head. I use the Wera small screwdrivers and like them a lot. Duckduckgo won’t let me copy and paste the Amazon link, but hrere’s the info: “Wera 345270 1.5 mm-4mm 6 pc. Kraftform Precision Slotted Metric Screwdriver Set” for $23.18. Well made and very useful for those small screws.

Click to expand...

Could you measure the width in metric units, of the smallest flat head screwdriver of this kit?
I feel like I need the screwdriver on top of the photo here but it looks much smaller than the one you gave me the reference for?
Now this set costs $42 but if I just need the top screwdriver I wish I could buy just that

IDK where I got this, only that it was a few months ago or so and didn't cost anywhere close to $42.

It's well suited for working on lenses etc.

Edit: looks like it can be had for around $10 on amazon.

If you have trouble keeping hold of tiny screws, a small ball of BluTack will hold them in place on the end of the screwdriver.

fabulousrice said:

Could you measure the width in metric units, of the smallest flat head screwdriver of this kit?
I feel like I need the screwdriver on top of the photo here but it looks much smaller than the one you gave me the reference for?
Now this set costs $42 but if I just need the top screwdriver I wish I could buy just that

Click to expand...

Can’t tell from that photo. The blade width in mm is printed on the handle of the Wera screwdrivers but I can’t read it in this photo. Bottom line, though, is you don’t need a 12-screwdriver set. Buy a smaller set for half the price and it’ll be useful. To be certain, measure the slot on your camera’s screw the long way and you’ll know what size you need.

Just go to Home Depot or any hardware store. They will have small screwdrivers.

You will have to verify infinity focus before you tighten that ring back down.