50mm f1.4 - aperture blades stuck

[cleo7613]

Hi,
my apologies if this is dealt with elsewhere - searched in vain. I'm new to the forum - just acquired my first Nikon S2 in beautiful condition. My thanks to this community for being such an excellent resource...
The lens has the aperture stuck in the closed position - can anyone advise me how I go about disassembling this lens to free the blades?
many thanks for your help,
Carl

 

[OldNick]

I suspect it is not for the faint hearted to deal with. I have beautiful Schneider lens for Exacta that stuck wide open and was told it could not be repaired. Of course, this was an SLR lens that stopped down when the shutter release was pressed, so this added another mechanism.

Jim N.

 

[Sonnar Brian]

Look at the back of the lens, there is a retaining ring that unscrews. If you can't get it by hand, a rubber mousepad or cork should work. Once the lens module is out, it simply unscrews by hand. Keep track of the order of things. Hopefully it is just the metal tab used to make the click stops. Mine was badly bent and prevented the mechanism from working.

 

[dreamsandart]

May be oil on the aperture blades which can freeze the lens aperture ring. Don't force it! Send it in for a CLA and everything should be fine for many years to come.

 

[cleo7613]

Thanks for the replies...

Brian,
I removed the rear ring - cork, thanks - lifted off the rear barrell section, removed the thin brass ring - and then...?
The rear lens - this is part of an assembly that unscrews from the remaining lens body? - under this is the aperture assembly?
thanks for your help
Carl

 

[Sonnar Brian]

That brass ring is the shim. Save it!

The front section of the lens unscrews, exposing the aperture blades. That front section also comes apart into two sections.

Consider this an Advertisement for Thomas Tomosey's book on Nikon Repair. Worked for me!

This is from his section on the Nikkor 5cm F2, but it is close enough for the F1.4 lens.

 

[cleo7613]

Many thanks for all your help Brian.

Rubber kitchen gloves, lighter fuel, tweezers and $3 micro screwdriver... and a little help from forum brethren!

Aperture blades tumbled out... thought I was in trouble - but all cleaned and reset. Lens now 100% gorgeous again.

Not only did I get to fix the problem but more importantly admire the beautiful engineering and watchlike precision circa 1956...

My best regards Carl

 

[Sonnar Brian]

Well done! Not too many DIY repairers get all those blades back into the lens!

 

[VinceC]

I'll second that "well done." I tried a similar kitchen-table repair about 15 years ago and never did get the blades back in. I ended up using the lens as a parts lens and maginfying loupe.

 

[cleo7613]

Thanks for the words of encouragement!

If anyone's in a similar position - I'd be glad to explain how I got the blades back in... after a good night's rest and contemplation of the quote I received from a repair shop...
Carl

 

[ZeissFan]

The construction of the early Nikon RF lenses are pretty much identical to the Carl Zeiss lenses for the Contax RF. Glad to hear you were able to reset the aperture blades -- that is a task that requires time and patience.

 

[dexdog]

Yes, quite an accomplishment getting all the blades back in position. I did that once on a 50/2 Sonnar, and it took me about 3 hours and 3 inches of tequila. Those last one or two that have to go in place are very difficult.

 

[VinceC]

>>The construction of the early Nikon RF lenses are pretty much identical to the Carl Zeiss lenses for the Contax RF.<<

I have always appreciated the click-stops on the Nikkor lenses compared to the Zeiss ones. I think the very earliest few thousand Nikkors, from 1949-'50, didn't have click-stops. But those are rare-bird collectibles, not user lenses.