Petri 7s lens swap project

[btgc]

Yesterday arrived Petri 7s w/ 1.8 lens, apparently abused, maybe even more than I expected. From the beginning I planned it only for lens, as I have 2.8 version which works, but honestly, also needs some shutter cleaning.

So I'm going to clean up shutter of 1.8 lens and swap whole lens unit to my old body. That's the project. Not that I need another sub-f2 lensed camera, but....you know, don't you? I think, they both will benefit from merge 😛

 

[charjohncarter]

Great, I have the Pertri 7s with the f 2.8. I works great and when I got it was in better than expected condition. I love the camera top meter.

 

[btgc]

So finally after NY holiday laziness I've reached my tools and removed lens unit from donor camera. After cleaning blades aperture works very smoothly, no hint of dragging.
Opened shutter until mechanism, just to look what's hiding there. Little of old lubricant (I'm against spill-in first aid method) but no bugs or cigarettes, well. Little local naphtha therapy for slow speed mechanism (which worked, but if I were there....) and little bits of oil at shaft of star wheel, two shafts (not very complete method, I know).

f1.8 version has little different charging mechanism (level locates inside body, while f2.8 has it directly under bottom cover), but seems that only configuration differs while sizes and final positions are same - so unit can be swapped into f2.8 body. I yet need to remove top cover on patient camera to check upper configuration of lens unit.

So now I have to swap lens units and solder meter wires. Also releathering look like a next task - unfortunately, Petri used hard material which breaks rather than peels off. Don't want to order online...will look what leather I have locally. Wait, leather isn't good because it absorbs moisture, I guess. OK, will sort out later, for a while it will be Petri "Transplant metal face" 7s 🙂

 

[btgc]

Today I swapped lenses - everything fits!

Diffs in charging mechanism really are not making problems; as I assumed, sizes and dimensions are kept equal for both models.

2.8 model's lens unit has flat surface where release button rests and brass pin to meet release wire in release button - quite common solution. 1.8 has pin or needle machined from same piece of metal, like a bent and pointing up - so it's not flat. Release button sits on this needle and thus brass pin from 2.8 model isn't needed. Had some tough minutes to sort out "extra part" case 🙂

On patient camera leatherette peeled off very nicely, seems that donor were reglued with hard'n'strong glue.

My soldering skills aren't that great, though I managed to connect wires and meter sprung to life. Haven't checked yet if it matches readings from handheld meter.

Just want to revisit aperture blades another time and finally clean up glass - then I'm going to put a roll through old new 7s!

 

[titrisol]

The 1.8 Petri 7s is a good camera
Nice lens, the only think I'm curious is how you transplante the light metering unit????

 

[btgc]

Actually donor's meter seems to be dead - no movement when selenium cell is connected - so basically I hadn't a choice. Meter units seem for my eye the same, so I left what was in patient camera.

Just soldered [resistor]??? which were in 1.8's circuit near meter - they visually differ a little, so I decided to go with native one. Electricity isn't my strong side, yet - I could compare them by multimeter, though.

As for manual camera, I will not worry if on-camera meter will get some assistance from handheld and guessmeter.

 

[btgc]

Another great lesson learned...after assembling bits together, I realized swapped lens is focusing tough compared to old, 2.8 version. Took old lens off helicoid and voila - one wire is connected to different place compared to new lens, I even wondered why it's soldered directly to place where it could spoild movement of inner part of helicoid.

So I'll take new lens off the body and off helicoid, replace one wire as it is on old lens and revisit helicoid if grease has to be renewed.

I should have compared lenses before putting new one on body. Dooh, that 1.8 camera seems to be got some nasty hands on it before me...not that my hands are very handy 🙂 but I try to make it usable.

 

[btgc]

Finally completed this. In fact, had to revisit winding mechanism - sometimes advance lever got stuck. Aha, spring on 2.8 version sometimes can't fully return shutter set bar, so I replaced it with spring from 1.8 version. Now it's snappy.

Cleaned elements, need some bright day to check and adjust RF. Uh, and compare meter to handheld.

Summa summaris - it were fun. Simple camera, easy to work on. Recommend this as first project camera, almost no wires to break off, lots of space under both covers. No big losses if project turns belly up.

Now it should be loaded, though. Hope to get some pics to share.

 

[Sauli Särkkä]

How's this project advancing? I'm a bit of a tinkerer myself, so this sort of project is very interesting to follow. Got any pictures of the teardown/rebuild?

I just picked up a Petri 7S (don't even know which version it is) on eBay to get my hands on my very first & very own rangefinder. I've shot a roll of film through a Mamiya 35-III a few days ago and thought that a nice little rangefinder of my own is just the ticket for little trips here and there, to bring a completely different feeling to the shots that I take.


-Sale

 

[Pompiere]

A 7S 1.8 was my first rangefinder. I didn't know anything about the brand when I bought it, so I got lucky. It was only $15 and just needed the viewfinder cleaned. I have been very pleased with it.

 

[btgc]

I'm still at mid of the first roll.

I had a devils etch to disassemble lens again to clean ISO/ASA ring because it turned hardly. During this I accidentally tore wire which comes out from back side of lens barrel. So to fix this I'd have to again remove lens assy and open back of the lens.
Anyway meter isn't very accurate so I don't hesitate to do this.

Another major issue for me is viewfinder. Currently my eyes are on diet - I'm wearing little weaker glasses as they need (to adopt) and while I can focus Yashicas - both Lynxes and Electro, Petri has too small and too weak patch. With full-strength glasses it were no problem.

 

[john_van_v]

Summa summaris - it were fun. Simple camera, easy to work on. Recommend this as first project camera, almost no wires to break off, lots of space under both covers. No big losses if project turns belly up.

Cool, my first rangefinder is a 7S. An obsessed collector named weird collector said it was his favorite, so I bid.

Actually I have two, both dysfunctional.

The 1.8 is mint, probably because it broke early on. Shutter works only when the lens is focused on infinity, and the lens is a bit loose (any suggestions?)

The meter is actually the best I own, an exactly the average of all my other cameras combined and divided. The viewfinder is also the best.

The 2.8 isn't great but works, and I have the telephoto and wide angle lens add ons.

I just saw a light blue snake skin 7S on Ebay, and it is pretty cool looking.

How does the lens compare, say with Yashica's RF Yashinons, in your opinion?

 

[Doug]

Interesting project, btgc! I admire your adventuresome spirit in using donor parts to get the rig operating. From what I recall reading, the 1.8 lens is a better one than the 2.8, so maybe you have a better camera now as well as one that works.

I have my father's 7S and wide/long add-on kit that he bought new in Japan years ago. It still works fine.

 

[Sauli Särkkä]

The 7S seems to have a common problem of loosening retaining rings. Open up the camera back and you'll see that the lens assembly is held onto the body by a single retaining ring.Two or three are visible, the inner one(s) encase the rear lens group, the outermost one hold the lens assy to the body.

That pink 7S image is from here: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280329729772


-Sale

 

[btgc]

Thanks all! Film from 1.8 is finished, though not souped yet.

The 1.8 is mint, probably because it broke early on. Shutter works only when the lens is focused on infinity, and the lens is a bit loose (any suggestions?)

Only reason I can think about is that release lever is most extended of lens when focused at inf. So probably release rod isn't catching lever when lens set at close distances. Like Sauli suggests, check retaining ring from film chamber. I'm pretty sure it's easy fix anyway. If you like it, bringt it to some competent repair shop or tinkerer you'd trust.

 

[Sauli Särkkä]

I actually had a similar problem with a 7S II that wouldn't advance properly when winding a single wind + the shutter was a little problematic. The film advance lever had to be slightly nudged after the first wind to set the shutter and get things rolling. I found that one rod inside the bottom of the camera had been slightly bent, so I carefully bent the end of the rod into position once more. This bend plus a quick touch to the shutter with isopropanol plus tightening of the retaining ring made the camera functional again.


-Sale

 

[btgc]

Woohoo, today got back souped film! I've flickred two pics - and I think it's really really nice lens.

 

[Sauli Särkkä]

Congratulations, that's great 🙂

The 1.8 lens is an excellent piece of optics, I agree. I have a pretty beat-up 7S 1.8 that I repaired that also gave me a handful of nice shots. Perhaps I'll finish restoring it one day.


-Sale

 

[john_van_v]

Thanks for this info. The retaining ring description seems to fit my camera. I am guessing that my camera had this problem early on, and this prevented it from being used, making it otherwise "mint"

I have found that its light meter reads the exact average of all my other lightmeters, meaning it is "spot on"

Another super sexy 7s is on ebay. I wondered if the skins are available now die cut, but after a failed search I concluded that the seller is cutting his own skins.

This is a very nice picture, btgc !!

 

[Jack Conrad]

[/quote]

This is a very nice picture, btgc !!

[/quote]

Wow! I agree... that IS a very nice picture, btgc.

My respect for your observations and knowledge pertaining to these fixed lens rangefinders continues to grow. Thanks.

By the way, I just found a Petri 7s yesterday locally for $10, and honestly didn't really think it had a functional meter.
But when I got it home and played with it a bit discovered the camera seems to be working great, so I have it loaded now and will be testing it out. It sits very nice in the hand and I even like the "clunk" sound of the film advance.

Here's a quote from Wikipedia on the Petri 7S.

"the Petri 7S Circle-Eye System coupled rangefinder, leaf-shuttered model, that was used by some professionals in the Sixties, and that was so well built that this model is still used by enthusiasts today and has a following around it amongst street photographer artists. This was followed by the very successful Petri 7S 11 in 1966 . Both models had colour corrected lenses."

Ha! So now I own and am a self designated member of the select club of the special Petri 7S "cult" street camera classic. Way Cool....😛