Focusing The Nokton 50/1.5 Down To 0.7m

[P. Lynn Miller]

I started a discussion about rangefinder 50/1.4 lenses that can focus down to 0.7 metres - Close Focusing 50/1.4 RF Lenses - where the Master Lens Modifier aka Brian Sweeney posted this stroke of genius...

The 50/1.5 Nokton is a screw mount lens. You can back it off a turn in the LTM to M-Mount adapter for closer focus. The actual optics and the RF Cam will move in unison, the actual focus will agree with what the RF indicates. You could make an LTM adapter with a "shim" on it to set the stand-off, and essentially get a hacked dual-range lens.

To which I replied....

Brian,

You are a genius. I was looking at the Nokton 50/1.5 setting on my desk today thinking, if that focused to 0.7m, it would probably be good enough for me.

Just checked... a 3mm, maybe 3.5mm shim would provide enough extension to move the lens to the limit of the rangefinder linkage. I pulled the mount off the back and there seems like there could be enough helical there to modify the lens. Not sure how complicated the modification would be though.

I may fabricate a shim, which would not take long, to at least test performance of the Nokton 50/1.5 down to 0.7m. If the lens holds up at that distance then it may be worth looking at modifying it for 0.7m MFD.

Thanks!

Which brings us to the current state of affairs...

The thickness of a CD/DVD provides enough extension to just 'run-out of rangefinder'. I made a shim of an old DVD and will load the M5 with a roll of Efke 25 soon to check the performance of the Nokton 50/1.5 at distances less than 0.9m. With the shim installed, focus range is about 2.4m to 0.7m.

Since I do not have a digital RF, you will have to wait until I get the film developed and scanned for results. If someone with a digital RF wants to do this quick modification and post some images, that would be great.

 

[Sonnar Brian]

I will give this a try on my M8 later this evening with one of my lenses.

On the question of being parallel enough to the film plane after unscrewing- with the shim, it "should be". Only one way to find out.

This trick will not work with a wide-angle or telephoto lens. The only reason it works with a normal lens is that the RF Cam moves 1:1 with the optics.

"Genious"- I prefer the term "Mad Scientist". I even do the laugh, out loud and involuntarily.

 

[P. Lynn Miller]

Brian,

OK... Mad Scientist it is!

A DVD disc shim should be close to being the same thickness to keep the lens parallel for preliminary testing. It would be easy enough to spin off a spacer/shim of the right thickness from a piece of aluminium tubing if you had a lathe handy.

You should be able to quickly access the performance of the Nokton 50/1.5 with your M8 along with detecting any focus shift as well. Looking forward to seeing your results.

 

[Sonnar Brian]

I should also have realized that the threads will have to be filed down, as Roland did with his Nikkor 5cm F1.4 and I did with my Modified J-3. Early, before coffee. The RF follower of the camera can follow the lens cam only so far before hitting the threads of the lens. So in addition to shimming the adapter, the threads of the lens must be filed to the shape of the adapter's cut-out.

 

[ampguy]

but what will the furthest focus range be after the mod?

 

[Krosya]

I wonder - if it is so doable to make Nokton 50/1.5 focus closer - why didnt Cosina do it to begin with? I have a feeling that it is not as simple with this lens or it would already be done/"fixed" by Cosina. I believe they have to re-design it a lot to be able to focus down to 0.7m. Hope they do it too - as this was the main reason I sold it - otherwise it is a superb lens.

 

[ampguy]

possibly compatibility

possibly compatibility

Probably the same reason Leica didn't adjust their cam and mounts on the 50 lux for 40+ years.

To work on the older cameras including M3s, they only focus to .8 or .9 meters.

Leica probably realized that by the '90s or whenever the E46 version came out, most of their users had moved on to M4s and up which supported .7m focusing.

I wonder - if it is so doable to make Nokton 50/1.5 focus closer - why didnt Cosina do it to begin with? I have a feeling that it is not as simple with this lens or it would already be done/"fixed" by Cosina. I believe they have to re-design it a lot to be able to focus down to 0.7m. Hope they do it too - as this was the main reason I sold it - otherwise it is a superb lens.

 

[Krosya]

Probably the same reason Leica didn't adjust their cam and mounts on the 50 lux for 40+ years.

To work on the older cameras including M3s, they only focus to .8 or .9 meters.

Leica probably realized that by the '90s or whenever the E46 version came out, most of their users had moved on to M4s and up which supported .7m focusing.

Yes - but Nokton was made waaaaay after that time, when most/many people use Leicas, etc that do focus down to 0.7m - why didnt they learn from Leica?. Or did they think at Cosina that if you have a LTM lens one HAS to use it on old body that cant focus to less than 1m.? IMO if they could make it focus down to 0.7m and didnt - thats the stupidest thing they've done. Thats why I think there was another ( mechanical/optical design related) reason why it was not done. After all - LTM Nikkor 5cm/1.4 is an old lens yet can easiy be modified.

 

[ampguy]

Right

Right

I agree, that it would have been much better for us if both Leica and CV allowed their lens to focus as close as possible, as soon as possible.

It would messy up their data sheets, they'd have to specify for min. focus capability *if your camera is capable but it sure would be nice to have the E43 luxes focus in a bit closer. Nokton too.

Yes - but Nokton was made waaaaay after that time, when most/many people use Leicas, etc that do focus down to 0.7m - why didnt they learn from Leica?. Or did they think at Cosina that if you have a LTM lens one HAS to use it on old body that cant focus to less than 1m.? IMO if they could make it focus down to 0.7m and didnt - thats the stupidest thing they've done. Thats why I think there was another ( mechanical/optical design related) reason why it was not done. After all - LTM Nikkor 5cm/1.4 is an old lens yet can easiy be modified.

 

[P. Lynn Miller]

I should also have realized that the threads will have to be filed down, as Roland did with his Nikkor 5cm F1.4 and I did with my Modified J-3. Early, before coffee. The RF follower of the camera can follow the lens cam only so far before hitting the threads of the lens. So in addition to shimming the adapter, the threads of the lens must be filed to the shape of the adapter's cut-out.

Brian,

I have disassembled the back of the Nokton 50/1.5 and there is a milled stop at 0.9m to prevent the lens from focusing closer. After I determine whether the lens will perform at 0.7m, I will work out if the lens is worth the aggravation to make the modification.

And yes, the mount will have to be filed to let the RF follower contact the cam past 0.9mm

As for why Cosina did not make the Nokton focus closer, my original thinking was they limited the Nokton to 0.9m because of being a LTM lens and the mount would need to have a notch cut in it to all the RF follower maintain contact with the cam and this is just not done on a factory lens. But the Color-Skopar 50/2.5 focuses to 0.75 and Cosina did cut a notch in the mount to ensure with would work with bodies the focus down to 0.75m.

This is my biggest gripe with Cosina, we all know that they are capable of producing world-class optics, but sometimes they just seem to make illogical short-cuts. Why doesn't the Nokton 50/1.1 focus to 0.7m? JUst because Leica was too lazy to make the Noctilux f0.95 to focus to 0.7m was not a reason for Cosina to not make the effort.

Nikon/Nikkor has been making floating element lenses since 1970, long before the convenience of CAD/CAM. I would be happy to pay 50% or 100% more for the Nokton 50/1.1 if it focused to 0.7m.

Enough ranting... have a film to develop.

 

[Sonnar Brian]

The Leica M2 button rewind will focus to 0.7m.

My M3 will focus to ~0.7m.

I just tried the Summarit in LTM on the M8, and could unscrew it 1 full turn and have the RF pickup wheel of the M8 follow the Cam. The Summarit has thin threads. The images were in focus looing at the screen, pixel-peeping. I have a spare Summarit focus mount- I might go ahead and cut the threads.

This hack is for a pseudo Dual range lens. Put it on the shimmed adapter for close ups, will probably get out to at least 6ft. Put it on a normal adapter for 3ft to infinity.

Also: I know how to make the Jupiter-3 focus closer than my 0.8m hack. I could get it to 0.7m. Next time I pick up a cheap J-3, I'll try it.

My Canon P will get into ~0.8m with the modified J-3.

 

[ampguy]

wow

wow

sounds like a lot of effort to get a lens to go from .7m to 6 feet, then need to switch adapters to go back to beyond 6 feet.

I can understand modding to increase min. focus and still get infinity, but I realize that will need some helical machining or more.

The Leica M2 button rewind will focus to 0.7m.

My M3 will focus to ~0.7m.

I just tried the Summarit in LTM on the M8, and could unscrew it 1 full turn and have the RF pickup wheel of the M8 follow the Cam. The Summarit has thin threads. The images were in focus looing at the screen, pixel-peeping. I have a spare Summarit focus mount- I might go ahead and cut the threads.

This hack is for a pseudo Dual range lens. Put it on the shimmed adapter for close ups, will probably get out to at least 6ft. Put it on a normal adapter for 3ft to infinity.

Also: I know how to make the Jupiter-3 focus closer than my 0.8m hack. I could get it to 0.7m. Next time I pick up a cheap J-3, I'll try it.

My Canon P will get into ~0.8m with the modified J-3.

 

[Pablito]

Even with frame lines that move to compensate for parallax, the view from the finder is quite different from what the lens sees when you are that close. Frankly, if I am going to be shooting close I will use an slr that can go much closer than any RF lens. As a project, just to see if it can be done, I guess it's a challenge to do this modification. From the point of view of a photographer, I don't get it. But that's just me.

 

[P. Lynn Miller]

I just pulled the negatives from the tank and the results look promising. I will try to get some scans posted later today.

For the Nokton 50/1.5, making it a dual-range lens is very simple. Machine a shim the correct thickness, between 2.5 and 3mm(still not sure, the battery died in my digital micrometer), use the lens over its normal focusing range, infinity to 0.9, when you need to get up close and personal, spin the lens off the LTM adapter, pop on the shim, spin the lens back on, and you are good down to about 0.65m(at least that is about where the M5 is uncoupling) and out to about 2.5m, which perfect for a portrait shoot or close quarters such as a pub or dinner party. No modification needed to the lens or adapter.

I am going to have shim made up in the next day or two. If someone else wants one, let me know.

 

[Keith]

From one meter to .7 doesn't really stir my blood sorry and wouldn't be worth the effort from my angle!

A bit like teaching your cat to bark occasionally ... usefull for scaring off the odd intruder but it's still a cat!

😛

 

[ampguy]

very cool!

very cool!

kinda like poppin' on some wheel spacers to pimp your ride, then poppin' them off for normal driving ... 😉

I just pulled the negatives from the tank and the results look promising. I will try to get some scans posted later today.

For the Nokton 50/1.5, making it a dual-range lens is very simple. Machine a shim the correct thickness, between 2.5 and 3mm(still not sure, the battery died in my digital micrometer), use the lens over its normal focusing range, infinity to 0.9, when you need to get up close and personal, spin the lens off the LTM adapter, pop on the shim, spin the lens back on, and you are good down to about 0.65m(at least that is about where the M5 is uncoupling) and out to about 2.5m, which perfect for a portrait shoot or close quarters such as a pub or dinner party. No modification needed to the lens or adapter.

I am going to have shim made up in the next day or two. If someone else wants one, let me know.

 

[P. Lynn Miller]

The thickness of the shim needed to take the Nokton 50/1.5 to 0.7m is 1.1mm. I am having one made today by a machinist friend.

Having a Nokton 50/1.5 that will focus to 0.7m will make for a very versatile, fast 50mm for general RF use. If I am planning for tight head and shoulder portraits, I will use an F with the Nikkor 105/2.5 or or the Micro-Nikkor 105/2.8 for macro work, or any of the other dozen or so Nikkor's that I have.

It seems that the only RF 50/1.4 lens that will focus to 0.7m is the Summilux or a modified LTM Nikkor 50/1.4, a modified Nokton would be an economical alternative.

Having abit of fun and why not?

 

[raid]

I often mis-type Brian's name as Brain.
Mybe it is an omen?

 

[ampguy]

what would be really cool ...

what would be really cool ...

is if you replaced the shim with a light proof inner baffle tube, then put 4 angled mini-hydraulic pumps around the lens base, triggered by sync'd stepper motors, then with a flick of a button or switch you could go from close focus mode to normal mode, maybe put a little bounce in the movement for effect !!

Take it down to E. LA and do some street shootin' !

The thickness of the shim needed to take the Nokton 50/1.5 to 0.7m is 1.1mm. I am having one made today by a machinist friend.

Having a Nokton 50/1.5 that will focus to 0.7m will make for a very versatile, fast 50mm for general RF use. If I am planning for tight head and shoulder portraits, I will use an F with the Nikkor 105/2.5 or or the Micro-Nikkor 105/2.8 for macro work, or any of the other dozen or so Nikkor's that I have.

It seems that the only RF 50/1.4 lens that will focus to 0.7m is the Summilux or a modified LTM Nikkor 50/1.4, a modified Nokton would be an economical alternative.

Having abit of fun and why not?

 

[Keith]

The thickness of the shim needed to take the Nokton 50/1.5 to 0.7m is 1.1mm. I am having one made today by a machinist friend.

Having a Nokton 50/1.5 that will focus to 0.7m will make for a very versatile, fast 50mm for general RF use. If I am planning for tight head and shoulder portraits, I will use an F with the Nikkor 105/2.5 or or the Micro-Nikkor 105/2.8 for macro work, or any of the other dozen or so Nikkor's that I have.

It seems that the only RF 50/1.4 lens that will focus to 0.7m is the Summilux or a modified LTM Nikkor 50/1.4, a modified Nokton would be an economical alternative.

Having abit of fun and why not?

Speaking of fun ... I'm off to play with the Norita! 😀


edit ... and I meant to add ... I'm wondering if this mod would work on the Canon f1.2 ... Brian?