Anyone tried or use the CV 35mm Nokton on the M8?

[martinb]

Do any of you use the CV 35mm f/1.2 Nokton on the M8? or have you tried it? Does is block the 35mm framelines without hood?
I'm looking for a high speed lens for the M8 and both the 35mm Summilux ASPH and 50mm Noctilux are very expensive. The Nokton isn't exactly cheap either, but considering f/1.2 speed it is pretty cheap.

[gravastar]

Yes, I use it and am quite impressed. It has low flare at full aperture with light sources in the picture. It blocks about 5-7% of the 35mm frame with no lens hood. It's supplied with a tubular hood that has a scalloped front but a larger vented one (like leica) is available that doesn't block much more than no hood if you don't mind viewing through the cutout.

There is however a potential problem with this lens on the M8, some people have experienced it to a varying degree others not. There are two protective fins that protrude from the back of the lens which can foul the inside of the M8 and prevent focus at infinity, it's all a question of tolerances. Inside the "throat" of the M8 are two semi-circular cut outs which have a small ridge at the back of them. Depending on the alignment of the inside of the M8 with the lens axis the fins can catch on this ridge. Some people have had no problems, others have found slight resistance and have forced the lens to infinity without apparent damage. In my case the misalignment was large enough not to risk this. I solved the problem by machining off the back corners of the fins at 45 degrees. Not so easy, the fins are steel.

So I think it's important to very gently check for focus at infinity before you buy. First make sure the lens is focused to it's closest distance before mounting it on the M8 though.

Bob.

[bradreiman]

i have one and really like it. creamy

[martinb]

Thanks Robert! Sounds like it blocks about the same amount of the 35mm framelines as the 28mm ultron blocks the 28mm framelines.
Regarding the problem you mentions, I can't try or have a look at the lens before buying..

[mike prevette]

Bob,

Tell us more about the machining. I'm really interested in this lens, and have thought about doing the same thing. I have the 40mm 1.4 nokton. I love it, it's the smallest 1.4 lens available in M mount. But a snitch wider and a snitch faster would always be nice.

_mike

[sps]

I actually have one that is maybe 4 weeks old. I mounted it on the M7 but it hasn't even left the house. Cards not filled in. All packaging material.

I bought it b4 I found a 35 Summilux Asph that is now stuck to my m8. I doubt I'll ever use it. Any interest?

[sean_reid]

Hi Martin,

I have a test copy of that lens here right now. As Bob said, the shroud at the rear of the lens contacts a tab inside the M8 when the lens is focused near and at infinity. There should be ways around that for anyone who isn't squeemish...<G> Otherwise, the lens works fine on the M8.

Cheers,

Sean

[pelikan1931]

is this the shroud?

[martinb]

Thanks for all the answers. Don't know if I would dare to buy it, if I don't know for sure that it will work properly.

[MP3]

Hi, anybody here can show us some photos taken with this lens with great creamy bokeh?

Cheers
Matthew

[sean_reid]

Pelikan,

Yes, that is the shroud.

Cheers,

Sean

[jlancasterd]

Originally Posted by gravastar

Depending on the alignment of the inside of the M8 with the lens axis the fins can catch on this ridge. Some people have had no problems, others have found slight resistance and have forced the lens to infinity without apparent damage. In my case the misalignment was large enough not to risk this. I solved the problem by machining off the back corners of the fins at 45 degrees. Not so easy, the fins are steel.
Bob.

Bob - How close to infinity would it focus before you machined off the fins?

[mike prevette]

I just ordered this lens from Stephen at Cameraquest. I've been thinking about it for months, and this thread pushed me over the edge. I have no problem tenting off the back of the lens and shaving those suckers down with a dremel and a hand file.

_mke

[rvaubel]

Originally Posted by mike prevette

I just ordered this lens from Stephen at Cameraquest. I've been thinking about it for months, and this thread pushed me over the edge. I have no problem tenting off the back of the lens and shaving those suckers down with a dremel and a hand file.

_mke

Why don't you take some before and after pictures. I am pretty handy with a dremel but I wouldn't mind if someone else did the R&D on the stock removal

Rex

[mike prevette]

Will do for sure.

[gravastar]

Originally Posted by jlancasterd

Bob - How close to infinity would it focus before you machined off the fins?

Mine started to bind about half way between 5 metres and infinity.

To machine down the fins I first removed the 6 screws holding the bayonet ring and then remove the ring and back cover. The screws have a narrow slot so you need a high quality engineering screwdriver with a width almost the diameter of the screws.

If you focus the lens to it's closest distance the outer shroud retracts giving better access to the two inner prongs which need to be machined down. I was going to turn the lens in a lathe to reduce the diameter of the last few mm of the prongs but decided against this. The prongs are fairly hard steel and I think it would be a bumpy ride. Instead I ground off the outer edges of the prongs to a 45 degree chamfer. I found that to give sufficiennt clearance.

The most time consuming part of the whole operation was the sealing and protection of the rear of the lens and barrel. I used surgical tape for most of the sealing. I cut a circular disk of tape equal to the diameter of the rear element and attached it adhesive to adhesive to another strip of tape. This was placed across the back element to protect it. I then covered as much as possible of the rear section, including the rear element and lens barrel with tape making sure there were no gaps. It's easier if you use small overlapping sections of tape which butt right up to the rear lens cell. I used a roll of cardboard to protect the rest of the barrel. The idea of using surgical tape is the adhesive is very sticky and traps debris. Small gaps between the fins and lens cell were filled with plasticene type compound.

The lens was centered in a lathe chuck and a grinding wheel at 45 deg. used to chamfer the fin edges as the lens was turned by hand.

Afterwards while holding the rear of the lens downwards I blew off as much as the debris as possible and still holding the lens downwards very slowly pulled off the surgical tape. The sealing putty was then removed. Don't forget to scrub and wash your hands before reassembling the lens. Optics and carborundum don't mix!

I don't have a before picture but have included an after where you can see the 45 deg. chamfer.

Finally I painted the fins with matt black acrylic before reassembling. As usual ****** at your own risk ******

Bob.

[MP3]

gravastar, you brave craftman. Pls go out take some beautiful closeup and infinity shots with your newly operated baby =) and share with us.

Cheers
Matthew