Taking The Nokton 50/1.1 Down To 0.7m...

[Todd.Hanz]

Excellent work, wonderful images! Soooo, where can I get me one of those shims 😉.

Todd

 

[ampguy]

Great photos! I agree with the above, that if they shipped this lens focusing at .7m, they'd get a lot of return issues with focusing. Also, as you've shown, close up shows some of the flaws a bit more, although I'd still want one that focused close.

 

[P. Lynn Miller]

...I suspect that manufacturers like lots of room in the helical between close-focus stop and screw apart to prevent wobble...

I ultimately needed a 1.3mm shim to get the Nokton to focus past coupling, there is actually a bit of slack in the focus ring, not enough to ever detect in practical use, but it is there if you really look for it.

Please document the process when you take it apart. Sometimes I go back to review the images taken during disassembly to help re-assemble. "Sometimes", wish I had.

Words of wisdom!

Well done, but like the Noctilux I suspect that most people would not be able to focus this accurately wide open at 0.7m, especially when recomposing. Then people would blame the lens. Limiting the focus to 1m means less chances of people complaining.

There are various SLR lenses that are just as difficult to focus and result in many out-of-focus images. As you would know any movement from the photographer or subject will change the focus point. With apertures of 1.4 or larger, you trip the shutter as soon as you find focus. This is hardly a reason to shorten the focus distance of the Nokton.

...focussing an F1.1 lens on an RF is easier and more accurate than focussing an F1.2 lens on a Manual Focus SLR at 2ft...

One of the main reasons that I keep a rangefinder. When you can no longer focus the M5, it is time to go home.

...the example photo's are in focus using the M5's 0.72x finder...

I am stunned at the accuracy of the M5. I am scared to send if off for a CLA, fearing that it will return not as accurate. The rangefinder has been dead-on. Another subject, but I went and tested a Leica 1.4x viewfinder magnifier the other day, very nice, but at nearly the cost of an M3, I will not be getting one for a while. A modified M3 with a good finder would be very nice.

Excellent work, wonderful images! Soooo, where can I get me one of those shims 😉.

I am hoping to be able to supply spacers at some point. It takes less than 5 minutes to install the spacer. While not as convenient as a full range lens, if you know that you are going to working close, such as a portrait shoot or close quarters at a party or cafe, it would an easy switch that just as easy to reverse.

...close up shows some of the flaws a bit more, although I'd still want one that focused close...

I am curious about the flaws you think have been magnified. I am not implying the Nokton 50/1.1 is perfect, it is not even close to perfect. But compared to my Nikkor 50/1.2 it is amazing and I think it only fair to judge the Nokton with a comparative close-focus images from a Noctilux or similar lens.

While on paper, the difference between focusing at 1.0m and 0.7m seems insignificant, in practice it is a very big different. It is allowing you to get almost 1/3 closer than before. And the depth-of-field when closer than 1m starts to completely disappear, about 1-2mm is all you have to work with when shooting at maximum aperture.

Now back to work...

 

[ferider]

Good work, Lynn. Once you're done, I predict you'll be looking for an M3 🙂

BTW, a 75/1.4 is more shallow than a 50/1.0 at .7m. So it will be usable, carefully ....

 

[P. Lynn Miller]

Here is why I want the Nokton 50/1.1 to close focus...

Leica M5 | Voigtländer Nokton 50mm f1.1 | Efke KB25 | Rodinal 1:25 | 4:00 minutes | 20ºC

While this photo is not in perfect focus, it displays the purpose of owning the Nokton 50/1.1. This little munchkin was in no mind to hold still for a photo, even so I was able to open up the lens to 1.1 and shoot at 1/60sec while using ASA 25 film.

This little fellow's grandfather died very suddenly and his Mum asked me to take some candid photos of him and his Dad. She specifically asked me because I shoot B&W film and my 'style' of photography. The Nokton was more than up to the task.

The more I use this lens... the more I like it.

 

[P. Lynn Miller]

Good work, Lynn. Once you're done, I predict you'll be looking for an M3 🙂

BTW, a 75/1.4 is more shallow than a 50/1.0 at .7m. So it will be usable, carefully ....

Thanks, Roland!

As for the M3... not sure. I have spoken to DAG and he and Leica are able to convert the M5 to 0.85x for the price of an M3. My biggest hesitation with the M3 is making sure I get a good view-finder and I will need to have an M3 modified to focus to 0.7m. So I am thinking the best route with the M3 is to find a battered one and send it to CRR for a complete rebuild including a new and modified viewfinder. But the last M3 I owned gave me massive hand cramps after only a short while of using it. Sounds ridiculous, but those couple extra millimetres of width on the M5, allow me to hold the camera more comfortably. But the M3 is a beautiful camera.

Or the other option is to pick-up a Leica 1.4x veiwfinder magnifier, which makes a 0.72x viewfinder 1:1, which is really, really nice.

As for DOF, I am not a fan of shallow DOF photos, it is just a necessary evil when using high-speed lenses at maximum aperture. I am really liking the supposed extra DOF of the Nokton at f1.1.

Thanks!

 

[P. Lynn Miller]

OK... here is a pictorial record of partial disassembly of the Nokton 50/1.1.

WARNING: I ASSUME ABSOLUTELY NO RESPONSIBILITY FOR YOU OR YOUR LENS IF YOU CHOOSE TO ATTEMPT THIS DISASSEMBLY OR MODIFICATION TO YOUR NOKTON 50/1.1, READ AND VIEW AT YOUR OWN RISK!!!

Please ignore the dust on the sensor, I could not be bothered to remove it.

Lens with spacer installed...

The lens mount removed, exposing the 4 small screws that anchor the the internal helical to the lens shroud.... that is the best way to describe it that I know...

With the 4 screws removed, the lens spins freely on the external helical. The shroud and external helical are held together by 4 screws that can be seen here. I had to grind a special screwdriver for these as the slot is so fine and the the screws are held tight with a thread locker, so it takes some effort to remove them. I breathed a very big sigh of relief when the last one came out...

Here you can see the shroud to the left with external helical still mounted on the lens... You can also see the slot cut for the focus stop screw... there are 3 of them. The lens also 'rides' on 3 screws as it extends and retracts... pretty neat set-up...

I have removed the external helical and you can start to see the inner workings of the focusing mechanism...

I will get better close-ups of the various stops, slopes, and index in points in the next round of photos.

I can say with confidence, that I do not think that the Nokton 50/1.1 can be modified without making some new parts and some very big modifications. I will show you why soon...

 

[back alley]

my hands are all sweaty just looking at these preliminary steps...

 

[P. Lynn Miller]

my hands are all sweaty just looking at these preliminary steps...

🙂🙂🙂🙂🙂

Now for some close-ups...

Here is the connection between the focusing ring and focusing helical...

Here is why I am not sure that I can modify the Nokton 50/1.1 to focus to 0.7m...

The focusing range is controlled by 3 slots cut into the focusing mechanism... not sure how to explain this properly. The slots already start and stop very close together. To extend the close-focus limit would cause an overlap of the slots and compromise the strength of the sleeve, if the slot would not actually run into each other.

I am pretty sure that the lens could be made to focus to 0.9m or maybe 0.85m without a compromise, but I am quite certain that 0.7 is out of the question without remaking the sleeve, which could be done by most any competent machinist.

The real question I am now facing... am I willing to risk needing to send my Nokton back to Cosina in a bag as parts to continue any further.

I have some thinking to do... where is the Mad Scientist when you need him...

 

[P. Lynn Miller]

The dilemma...

I am now convinced that the Nokton 50/1.1 can be made to focus continuously from infinity to 0.7m, but it is going to take some head-scratching and extensive machining. A couple of weeks of figuring and tinkering, but I do not really want to be without my Nokton 50/1.1 for that amount of time. That last statement stuns me... it goes to show how much I have come to depend on the Nokton in the past 2 weeks or so... amazing for a lens that I used to hate!

Back on topic... for the time being I reassembled the Nokton and put it back on the M5. I am going to use at the factory limited 1.0m and also with the spacer installed at 0.7m to see how much I really use the Nokton at less than a meter and if it justifies the investment of time, effort and money.

Since this modification to the Nokton 50/1.1 will require me to completely disassemble that lens and make some new parts and etc, I am thinking that I will have the exterior of the lens chromed to match a chrome M5. This will mean getting my hands on another Nokton which I can disassemble and work on for a few weeks.

So time to stop hacking and start taking photos again...

 

[Sonnar Brian]

There is Mad and there is Totally Insane...

That is quite a mechanism, looks more like the cams you would find in a zoom lens. They wanted that lens to move smoothly and not wobble. With the pitch chosen for the helical, it looks like the minimum focus is near a limit. As I am looking at it, machining a part with thinner cams and guide pins with smaller diameter heads would be required.

As Scotty would say, "Cap'n, I've taken it down to 0.8m and the Structural Integrity Field is Collapsing, we have to Back Off".

 

[Mister E]

Of course the modified lens can be used at 1M, but an unmodified lens cannot be used closer. Focussing an F1.1 lens on an RF is easier and more accurate than focussing an F1.2 lens on a Manual Focus SLR at 2ft. People have been doing that for many years.

How so? I can see the exact point of focus no mater how far of center it is.

 

[Sonnar Brian]

Because you rely on "just your eyesight" for feedback, and not the rangefinder mechanism. The Rangefinder is a sophisticated mechanism designed to help you focus precisely. SLR's are better for focal lengths ~135mm and above, where the magnification provided by the lens to the groundglass exceeds the RF's accuracy.

I use 55/1.2's on my F2AS and F2SB. I have an easier time focusing the 50/0.95 on the Canon 7.

 

[P. Lynn Miller]

Brian,

You are right... it is more like a cam system that you would find in zoom. Are you telling me that this is a better system than a threaded helical?

The optic cell moves on 6 guide pins, 3 in longitudinal slots for extension and 3 in the pitched slots that are actually the main 'helical'. There are two secondary helicals of traditional thread type... one on the focus ring and one on the shroud.

The lens only needs 1.3mm of additional extensions which is by my estimate 15° to 20° of rotation on the focusing ring, a total of about 120° focus ring rotation.

If I can commit a lens to be completely disassembled and studied, I think I can modify it without a huge amount of work.

Maybe I will just bolt the Nokton 50/1.5 to the M5 and commit the Nokton 50/1.1 to the workbench for a few weeks.

Mad... or Totally Insane... or just Sheer Stubbornness... I hate to back away from a challenge.

 

[P. Lynn Miller]

How so? I can see the exact point of focus no matter how far of center it is.

Nathan,

I agree that I like using a full matte screen in my Nikon F's so I can focus anywhere in the viewfinder, but as I chronologically advance my eyes are not able to give the precision needed to focus a f1.2 lenses in low or no light any more. So while I would rather use an SLR for usability, I would rather have the negative in focus even if I have to keep the subject dead-center to do so.

You are fortunate to have younger eyes.

 

[Sonnar Brian]

Guide pins and guide rails produce steady and repeatable motion. It looks like Cosina "pulled out the stops" to get a steady and repeatable motion with this lens. It really is beautiful.

I want one.

 

[P. Lynn Miller]

Guide pins and guide rails produce steady and repeatable motion. It looks like Cosina "pulled out the stops" to get a steady and repeatable motion with this lens. It really is beautiful.

I want one.

You made me smile with this statement - "It really is beautiful" - you really are the Mad Gearhead Scientist!

I wish Cosina would pulled the stops out a little further and made the Nokton to focus all the way down to 0.7m... then it truly would be a beautiful thing... that and make in silver.

 

[ferider]

Totally different question, Lynn: looks like the brass ring (with wrench slots) can be used for lens/RF infinity alignment/calibration, correct ?

 

[Krosya]

Brian,

You are right... it is more like a cam system that you would find in zoom. Are you telling me that this is a better system than a threaded helical?

The optic cell moves on 6 guide pins, 3 in longitudinal slots for extension and 3 in the pitched slots that are actually the main 'helical'. There are two secondary helicals of traditional thread type... one on the focus ring and one on the shroud.

The lens only needs 1.3mm of additional extensions which is by my estimate 15° to 20° of rotation on the focusing ring, a total of about 120° focus ring rotation.

If I can commit a lens to be completely disassembled and studied, I think I can modify it without a huge amount of work.

Maybe I will just bolt the Nokton 50/1.5 to the M5 and commit the Nokton 50/1.1 to the workbench for a few weeks.

Mad... or Totally Insane... or just Sheer Stubbornness... I hate to back away from a challenge.

You are a Brave Man! I have worked on many lenses and cameras, yet I could never do this to my M-Hexanon 50/1.2 to see if I can make it focus closer than 0.9m, however tempting it may be. 😉

 

[Mister E]

For some reason I cannot see any of the pictures in this thread.