ZEISS IKON NETTAR 517/16 Novar-Anastigmat f=75mm 1:6,3 (8,11,16,22) Vario Shutter (B,

[stephane]

:bang: Oh my god !

I have fungus on my lenses !!
I want to clean them up but I don't know how to access the lenses groups. I only manage (unscrewing the front lense) to clean one part of the lenses. But I can't acess the rest of them.

As I see it, my lens is composed of (from front, oustide to back inside folding) :
- Front Lense (which I can unscrew)
- Lens (I cannot unscrew, there seem to be a broken ring holding it tight)
- Shutter
- Diaphragm
- lens (there seem to be a broken ring holding it tight, I see that from the back)
- Mount screw, To unmount the lens with a spanner

So NO, I can't access the part which is close to the diaphragm and shutter...

But will I be able to access every part of the mecanism if I unscrew the back of the lens with a lens spanner ? Or is it pointless and problem generating to do such a thing ?

Has anybody got a clue how to do that ? How to clean my lens ?

Many thanks...

Stéphane (yours, eternally...)

 

[ZeissFan]

The best tool is a spanner wrench to remove the rear element. However, on some of the Novars, the rear element is held in place by a snap spring -- a small piece of very stiff wire that is forced into place. You can usually remove it, but you have to be careful not to chip the lens. It's also a pain to put back into place -- easier with the shutter removed, but then you need a spanner wrench.

To remove the front element, you need to loosen three tiny set screws to remove the lens bezel. Then you can completely unscrew the front group. The middle element might be screwed in or might be held by another snap spring. If you remove the rear group, there is no need to remove the middle. Conversely, if you remove the middle element, there is no need to remove the rear group.

When reassembly, make sure all lenses are reinserted in the proper direction. It's not unusual to put the middle lens in backward because both sides more or less look the same. The rear element should always have the curved surface facing away from the shutter.

Finally, you will need to recollimate the lens to infinity. Otherwise, your focus will be off.

 

[stephane]

How do you "recollimate the lens to infinity" ?

 

[ZeissFan]

Stephane, here's my page, and this is the method that works best for me.

There are others that are quite similar -- and I've come across some pages on the Internet. The only change is that I'm now using a 70-210 zoom at 210mm. It's very accurate.

If your SLR doesn't have a waist-level finder, don't worry it still works, it's just not as convenient. And remember to use the ground glass part of the screen, not the split-image portion.

 

[titrisol]

Your lens is a triplet, with no cemented elements that makes cleaning a bit easier.

You need to take the fron telement, clean it and then take the rear element

To reset infinity, look into the repair tips and notes forum, there is a simple way using a reflex camera

 

[stephane]

Ok ok, I went to Your page, Zeissfan, I saw the technique using the reflex. But I don't understand how I have to proceed with my Nettar to refocus it...

I put the cameras front to front, with a target inside my Nettar, and then ?

What am I suppose to do ?
My Nettar lens has nothing to calibrate it ? The lenses are juste stuck in place with broken rings... So how can I reset infinity on this particular lens ?
Where is supposed to be te "calibrating device" on the Novar lens ? Is there a screw I didn't notice ?

 

[ZeissFan]

The front element should be screwed into the middle element. While peering through the viewfinder of the SLR, rotate the front element until the target is in focus (Step Three). Are you saying that your front element doesn't rotate?

Once infinity focus is set, you replace the distance ring on the lens with the distance ring aligned to the infinity mark.

 

[stephane]

Ok, I get it !! Thank you very much for your patience...

 

[Mike Kovacs]

Does your Nettar have little holes drilled in the rotating front element to accept the set screws from the focus scale?

If your holes are off kilter with your scale when you are at infinity using Zeissfan's SLR method, you will have to try again, this time restarting the threads at a different point. If you marked the point where they came apart in the first place, this can save time, though sometimes you get cameras with previously botched repair jobs.

I've now seen enough posts from Novar lens repairers to know that its very easy to install the middle or rear elements backwards. Take care or you'll get interesting photos, that's for sure!

David Richert kindly hosted a repair article of mine - overhauling a Compur Rapid shutter on a postwar Ikonta 521/16. It may be of some use to you, though its mostly focused on the teardown of the shutter.

http://www.davidrichert.com/zeiss_521_16_compur_rapid_shutter.htm

Don't forget to set your SLR lens to infinity and take care that it doesn't move!

 

[stephane]

ZEISS IKON NETTAR 517/16 Novar-Anastigmat f=75mm 1:6,3 (8,11,16,22) Vario Shutter (B,25,75,200)

😛

Mike Kovacs, the page you made about the Ikonta 521/16 lens/shutter servicing is absolutly great !

I did already unmount the lenses to clean them up, and did put them back so I am going to refocus them this afternoon... My front lens has the 3 screw made to lock the lens so I can regulate the focus (and it is really out of focus now !!). I am also going to "re-oil" the shutter... I bought lens spanners recently, I think it will help me... Great !!


Just a little note about "putting the lens the right way"...

Composition from inside camera to outside camera :
back lens
shutter & diaphragm
middle lens
front lens

On this Nettar, the middle lens is beveled on the front side to receive the broken ring that keeps it tight. The beveled part as long as the side of the lens are painted black. So I think this is an easy reference point to put it the right way.

😀

 

[Mike Kovacs]

The Vario shutter ought to be a whole lot simpler than the Compur Rapid. No slow speeds to stick, though oil/debris on the blades could make it run sluggishly. Look on Dan Mitchell's site for more details on different shutter makes, though without much "handholding". I really targeted my article towards beginners.

http://daniel.mitchell.name/cameras/index.html

The Vario is a simplification of the Prontor-S shutter, which he does have photos of.

The one in the article was a friend's Ikonta 521/16, but here is a shot of mine, ca. 1938 vintage, and of course was restored to prime shooting condition. Its a wonderful 6x6 folder that fits in a jacket pocket with a tack sharp, uncoated Tessar lens.

 

[stephane]

wOw !

You have very interesting adresses !

I have to wait for my lens spanner (bought on eBay) To arrive home before I proceed with a full expertize of my vario shutter.

At the time being I had access to the shutter mecanism thanks to these pages, and it seems ok. Anyway I am going to clean and lube the parts... Do you have an advice for the kind of oil, grease or lube I should use ? And an adress to get it from ?

I am doin my personnal webpage. When it is done, I will put photos of the Vario shutter (and probably of my other foldings shutters and lenses...) on it with helping tips to help others 😉 !! I will give the adress to those interested...

 

[ZeissFan]

To lube the helicals, I use some Nye moly instrument grease 750A from Micro-Tools. What I do is clean the helicals with lighter fluid and remove all of the old grease. That's very important.

You can also use lighter fluid to remove the grease that gets onto the lens. Then clean after with optical cleaner. If you're in the U.S., Eckerd drug store sells a very large bottle for a few dollars. This stuff is excellent.

Once everything is clean, I put three small dots of lube on the helicals and screw it back together. Work the lens back and forth and few times so it spreads evenly.

 

[stephane]

Mmmm... Lighter fuel is alcohol. In France, I can probably buy a large amount (1liter) of burning alcohol for a cheap price.... Alcohol dissolves greases and oils...

What do you think of the use of :
- White spirit
- Acetone
- demineralized water
- degrip-oil (brand and product...)

 

[ZeissFan]

Acetone will work -- just be careful not to drip it on other things, especially plastic. I would think kerosene would work -- usual cautions apply.

 

[Mike Kovacs]

Lighter fluid is not alcohol, its "naptha". Alcohol will probably not dissolve that grease. Acetone one must be extremely careful with as it will also attack some paints.

I use lighter fluid to remove the excess grease but recently learned a new tip - #0000 steel wool rubbed carefully in the threads (I masked the lenses in my Super Ikonta", followed by dishwasher soap, rinsing in tap water, then distilled water, then blotted dry. After it was all dry, I cleaned the optics and regrease with either Schwinn synthetic bicycle grease (light damping) or Dow Corning High Vacuum Grease (heavy damping) which my students use in the lab. Both are synthetic and will not migrate or outgas products onto the glass. There are many options for grease but choose one that does not migrate or your lens and shutter will be covered in oil in a few years time.

The steel wool makes a huge difference but it is a little messy, and you sure don't want to rub little pieces of steel when you clean the lens so take care. It is hands down the best when you have a helical free of glass, e.g. on a Contax rangefinder. On my Super Ikonta, the helical had a rough spot that made using the focus wheel difficult, now it is as smooth as butter with light damping grease.

I would go for a heavier damped action on a scale focus so you don't bump it. The Super Ikonta uses the wheel focus so heavy makes it too hard to turn the lens.