Voigtländer Nokton 35/1.4 focusing issues - question

[efix]

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My Nokton 35/1.4 does exhibit the common focusing issues as it seems. Now here's something that baffles me. My particular copy seems to front-focus @ f/1.4 and to back-focus from f/2.8 on. What it does @ f/2 I'm not quite sure - in one test it seemed spot on, in another one it seemed to back-focus.

 

What shall I do? Return it? Have my rangefinder aligned? (Probably not ...) Get a different lens?

 

As it looks right now, I won't get sharp focus at any aperture setting, because focus is always shifted somewhere. This means I can't rely on what the rangefinder shows me as focused at all, which spoils the whole rf experience (at least for me).

 

Also posted to dpreview Leica Talk forum.

[juppdiesel]

Do you have another lens that you can test your camera body with to make sure that the body is adjusted correctly ?

As the body is easy to adjust I would check this first. Only after that I would look at the lens(es).

 

Jari

[efix]

Do you have another lens that you can test your camera body with to make sure that the body is adjusted correctly ?

As the body is easy to adjust I would check this first. Only after that I would look at the lens(es).

 

Jari

 

Sadly I have no other lens to test the M8 with. And I fear sending it to Leica to check and adjust will just bust my funds ... Anyways, as the focusing shift seems to move from front- to back-focus, when I align the rangefinder to be spot-on at f/1.4, shouldn't that then exaggerate the back-focusing problem when stopping down?

[01af]

Now here's something that baffles me. My particular copy seems to front-focus @ f/1.4 and to back-focus from f/2.8 on.

You just found out what aperture-related focus shift is. It's a consequence of spherical aberration. Nearly all lenses exhibit this glitch—some more, some to a lesser (possibly insignificant) degree. It usually is particularly prominent with fast wide-angle lenses.

 

Switching to another copy of the same lens won't make a difference. You've got to learn to live with it. If focus is more or less perfect at f/2 then focus adjustment is about as good as it can get.

[jaapv]

You can have it adjusted to whatever suits your style of shooting. If you shoot mainly wide open, it might be useful to have it spot-on at 1.4, but you will have to remember to compensate your focussing up to 5.6 or so, after that it will be masked by your DOF, if the prints are not too large. In general an acceptable frontfocus @ 1.4 which gradually changes to an acceptable backfocus at medium apertures is the most universal adjustment. As you gain experience with the lens you can lean backward and forward a bit to compensate.

[jaques]

I have one of these also and it seems to consistently front focus wide open.

 

I had heard that adjusting the focus on the flawed version of this lens was difficult?

[Xmas]

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Hi

 

Sell it to some one on fora with a film camera. Think yourself lucky it was not a Leica f/1.4.

 

Buy a slow lens or two slow lenses, from proceedings of sale, again from some one on fora, be happy.

 

Noel

[jamesk8752]

I have one of these also and it seems to consistently front focus wide open.

 

I had heard that adjusting the focus on the flawed version of this lens was difficult?

 

I don't know how difficult the focus adjustment is - it may be a simple shimming operation.

 

I wouldn't consider this to be a "flawed version" of the lens; rather, it is a design constraint and all copies show it. However, they may be set to different focus points to make the shift less objectionable for the user's specific needs/desires.

 

Regards, Jim

[Paul Edwards]

I know this is a basic question and probably self explanatory but when you talk about back focus do you mean the lens actually focuses beyond the point of intended focus ?and this can't be detected in the view finder?

[Xmas]

I know this is a basic question and probably self explanatory but when you talk about back focus do you mean the lens actually focuses beyond the point of intended focus ?and this can't be detected in the view finder?

 

Correct the viewfinder says it is in focus, when you take the shot & expand the chimp screen it is out of focus. You take the shot of a focus target together with a ruler at 45 degrees to lens axis. Review how much offset you have change aperature shoot again...

 

Noel

[jaques]

I wouldn't consider this to be a "flawed version" of the lens

 

I am not sure about this: from what I have read their are flawed versions of this lens. Several reviewers report being sent copies that were way out- and then receiving copies that were spot on.

[jamesk8752]

I am not sure about this: from what I have read their are flawed versions of this lens. Several reviewers report being sent copies that were way out- and then receiving copies that were spot on.

 

Perhaps I misspoke or was misunderstood - I meant that I believe that the "flaw" is most likely in the basic design; different copies may have different focus points depending on how they were calibrated, but all probably suffer from it. Depending on the aperture at which the focusing is calibrated and how carefully one looks at the images, this may or may not be perceived as a problem. My opinion, anyway...

 

Regards, Jim

[ezc203]

It's funny how I read about a lot of complains about this particular lens, but mine has been a stellar performer. Never really liked how the Cosina lenses pulls color, but for low-light Tri-X stuff, the 35/1.4 is a gem.

 

Admittedly, I rarely (RARELY) shoot above 2.8 with the lens, but so far have not experienced any focus shift problems. Maybe I have a rare, good copy of the lens?

[ezc203]

I should also add I have never done any "tests" with my lens, all conclusions were drawn from day-to-day use.

[khiromu]

Don't test lenses unless you see problem from your real life example. When you test, you are most likely to find something you don't like. Then, suddenly, your real life example becomes unacceptable.

[vafa]

I purchased this lens a few months ago and it back focused. I sent it back for an exchange and the new one had the same problem. I think this is typical of this lens.

I find this lens to have a low contrast, which makes the focus issue appear even worse.

I kept my lens since it costs a fraction of the leica.

[efix]

I purchased this lens a few months ago and it back focused. I sent it back for an exchange and the new one had the same problem. I think this is typical of this lens.

I find this lens to have a low contrast, which makes the focus issue appear even worse.

I kept my lens since it costs a fraction of the leica.

 

Yes, it's not the greatest performer, but absolutely bang-for-the-buck, and since I'm using it on an M8, I always process the pix until they look good to me.

 

I'm considering comparing a pre-asph (2nd or 3rd gen) 35 'cron - if I should be able to get hold of one for a reasonable price - against the Nokton, and keep which one I like best overall.

 

Oh, and by the way, front focusing was indeed related with my M8's rangefinder being slightly misaligned. It's now spot on at infinity, and spot on with the Nokton at f/1.4 and f/1.7. Shift sets in already (!) at f/2, but compensating is no big deal soon as you know how much to compensate at which aperture setting (i. e. in my case slightly to the right at f/2, some more at f/2.8 and by 5.6 dof will catch up with shift).

[jaques]

Don't test lenses unless you see problem from your real life example. When you test, you are most likely to find something you don't like. Then, suddenly, your real life example becomes unacceptable.

 

I wish I had read this brilliant advice before I tested my Nokton.... when I first got it I loved it- small and fast- well built- good looking- the perfect 35- photos looked good as well.. a summilux for a 10th of the price.

 

Then I tested it- found the focus out- and now I find the real life examples unacceptable.

 

From now on I will not test my lenses unless I am sure they are way out- and it is affecting my shots.

[Guest mc_k]

Don't test lenses unless you see problem from your real life example. When you test, you are most likely to find something you don't like. Then, suddenly, your real life example becomes unacceptable.

 

I'm sure this is true, and the converse, too. Probably many focus tests are biased by the tester's expectations.

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[efix]

Don't test lenses unless you see problem from your real life example. When you test, you are most likely to find something you don't like. Then, suddenly, your real life example becomes unacceptable.

 

Well, the problem is I WAS seeing problems in real-life examples, as I often shoot inside with available light, for which I need the f/1.4. I couldn't get any sharp portraits, so I started wondering. f/1.4 is spot on now, but everything else is off. Still possible both lens AND rangefinder are misaligned, but at least I get in focus what I'm focusing on now at my most used aperture setting. And in bright daylight, when shooting f/2.8 onwards, I just turn the focusing ring for a few degrees and then focus is correct.

 

I'm going to try to get a better lens, but if I can't find one, I'll stick with this and try to learn to live with its quirks.