Nokton 35mm 1.4 II focus all over the place.

[Bliz]

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Hello, I recently aquired a M10R to go alongside my two film Ms. I own a VM Nokton Classic 35mm version 2 which always seemed reasonably sharp and in focus on film, on the m10r it seems to backfocus quite a bit at every distance and won’t focus sharply at infinity even at f8/f11, if I focus through live view I can achieve focus and it turns out i have to focus closer than the supposed distance for it to be in focus. It is especially off around f4. On the same camera I have a few other lenses that seem to work fine (35 cron asph v1, 35 biogon c, 21mm skopar f4, 50mm nokton asph).

I would just think the lens calibration is off, but I don’t get why the same problem doesn’t seem to be there on film. I’ll try to attach a couple of examples.

The b&w church pic is a crop from a picture on my m4 shot on superpan200. The electricity pylon is on the m10 focusing through the RF and then on LV at f4, the glass jar is focusing on the top of the jar at f4, focus falls clearly behind. Edit. Oops I noticed I couldn’t upload the glass jar shot, will try again when the forum allows me to.

Now the question is, is it a matter of lens calibration? Is it worth/possible to have it fixed?

 

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Edited March 21 by Bliz

[jaapv]

As film has a thickness focus is far less critical than digital. However, I would check with my dealer whether the lens or the camera body (or both) is out of adjustment. 

[Bliz]

So it is probably made way more noticeable by the digital sensor? A shame, i liked the lens and got it second hand a while ago.

Here’s the glass candle pic for focus at about 1.5m, for what it’s worth.

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[jaapv]

These things are easy adjusted by a third party repair shop specializing on Leica. See the list on this forum. It would be a shame to struggle to use it. And it may be the camera. Check it with a lens that is known to be correct. Come to think of it may be neither. You bought a high resolution camera. Those pose sharpness problems for some users. The high resolution exaggerates unsharpness through camera shake and/ or minimal focus errors. They are far more demanding in handholding and focus techniques without, IMO, offering a significant improvement in IQ for most photographic situations. 

[Bliz]

17 minutes ago, jaapv said:

The high resolution exaggerates unsharpness through camera shake and/ or minimal focus errors.

Yes i know and you are right, but the lens focus is slightly off at infinity on a tripod too, as seen on the electricity pole pics. As I stated the other lenses i own seem to focus just fine on my m10r, I’ll look around for a shop and try to understand if having the lens adjusted for digital makes sense from an economical pov.

Edited March 21 by Bliz

[TomB_tx]

The Nokton 35 1.4 is also one of my favorite lenses, both in the ver I and ver II forms. The RF focus on both of mine is very good on both M9 & M10 with the lens wide open at f1.4. Both versions have some shift in the focus plane as they are stopped down, but while the ver I was quite significant, ver II is much improved. On my ver II it can be seen mostly at f4, as depth of field compensates for the shift when stopped down more. That said, the shift in focus as stopped down is to the rear, where your lens/body combination is showing front focus at f4.

I'd suggest you first test focus with the lens wide open, then try it at different f-stops to see what the effects are.

If could certainly be either lens or body, or maybe a bit of both. Focus calibration has some tolerance, and sometimes a body may be at one side of tolerance while the lens is at the other side of its tolerance - so its the combination that causes the visible issue.

I have several Voigtlander lenses, and usually their calibration is very good. But I recently bought 2  50 f1.5 lenses (one for my son) and focus was perfect on one and enough off on the other that I sent it for calibration.

Likewise I have several M bodies (mainly film) and careful testing will show slight variations in their focus calibration, but not enough to cause me problems - but I did have to adjust a used M6 with .85 VF, which showed me how touchy it is to adjust it "close enough."

But I seldom "pixel-peep" at high magnification, so if the picture looks good at normal viewing distance it's good for me.

[Bliz]

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8 minutes ago, TomB_tx said:

I'd suggest you first test focus with the lens wide open

wide open it is quite a bit better in fact, not perfect but better than f4.

Edited March 21 by Bliz

[lct]

1 hour ago, Bliz said:

Now the question is, is it a matter of lens calibration?

If you had a version 1 of this lens i would think of focus shift my SC v1 was suffering from but my SC v2 shows none at any focus distance so i suspect it is a matter of sample variation. I would ask a good repair shop as suggested above.

[Keith (M)]

Example from my Classic II SC at f4 with M10M using the rangefinder.  Can't say I have ever noticed any focus issues at any aperture on either M10M or M11.  Given its combination of f1.4, lightweight and diminutive size it has become something of a 35mm favourite.  Is there a dealer etc in your area where you can have the lens focus accuracy checked?

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[caranatar]

Stupid question maybe but are you certain it's the version ii?

[Bliz]

7 minutes ago, caranatar said:

Stupid question maybe but are you certain it's the version ii?

Yes, it’s written on the front of the lens, and the aperture tabs are different on I and II. I got the lens from MPB btw.

 

34 minutes ago, Keith (M) said:

Is there a dealer etc in your area where you can have the lens focus accuracy checked?

Yes there is a Leica dealer in a city relatively close to me, I’ll reach out to them to have the lens checked because I really enjoy the form factor of the nokton classic and when I focus through live view the lens is able to be remarkably sharp on digital too.

Edited March 21 by Bliz

[oldwino]

9 hours ago, Bliz said:

Yes, it’s written on the front of the lens, and the aperture tabs are different on I and II. I got the lens from MPB btw.

 

Yes there is a Leica dealer in a city relatively close to me, I’ll reach out to them to have the lens checked because I really enjoy the form factor of the nokton classic and when I focus through live view the lens is able to be remarkably sharp on digital too.

Don’t MPB offer a warranty?

[Bliz]

4 hours ago, oldwino said:

Don’t MPB offer a warranty?

Yes but I had the lens for more than 6 months. Anyway after some more thorough testing I think the camera might be at fault, it is just less noticeable with other lenses but it more or less always front focus a bit. It would give me an actually easier solution, just adjust the cam a tiny bit.

Edited March 22 by Bliz