50Noct, luxasph, Zeiss character and focus

[tom0511]

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Since I am still not happy with my focus I did use the bad weather for some extensive testing.

I had adjusted 1 of my 2 M8s some weeks ago with a hex key to compensate the front focus which most of my lenses show wide open at shorter distances.

Today I found out that this M8 is finde at short distances, but not so fine at longer distances , where it backfocuses now.

So I took the other M8 for my further focus tests.

I shot with 50/1.4asph, 50Noct, 75lux,50Sonnar and 35luxasph at distances: 1,5m, 2m, 3m, 5m, 7m, 40m and fstops from wide open to 5.6.

 

1) What I found to be the case is: closing the fstop the DOF expands more to the back than the front (this should be focus shift) new for me that this seems not only to be the case with the Noct, but also with the other lenses.

2) front focus seems to occur more at shorter distances

 

3) conclusion (and the images seem to proove this) is that if a lens frontfocuses slightly wide open at short distances it will be probably focus nearly perfect at f2.8.

If a lens slightly backfocuses (like me 50asph) the problem is also there if you close the fstop (because as I said the DOF seems to expand more to the back than to the front, even the 50asph shows this tendency)

 

4) Even my 50asph backfocuses only slightly, it destroys even at f5.6 all the IQ advantage compared to the Noct and the 50lux. I also can not back up that then Noctilux gets bad at f5.6 and longer distances. No, in my case it did a pretty good job.

 

5) If a lens is renders slightly softer and less contrasty (like the Sonnar for example) it is not that obvious when focus is not 100% correct. A lens which renders "harder" like the 50asph shows every little front/backfocus.

 

6) I feel like its nearly impossible to have a fast lens on a M8 which focuses 100% at long and short distance and wide open as well as closed down. I think in fil times the film thickness and grain did help to compensate and to get a smoother transition.

With a digital sensor the dof is very small and the transition is not as soft any more and easier to detect.

 

MY final conclusion is to avoid f-stops faster than f2.8 as much as I can (when shooting a digital rangefinder).

My 50asph goes back to Leica a second time.

I will use my Noctilux more often (it also seems to deliever a really nice contrast in the midtones).

If I want an even smoother image with a little less contrast the Zeiss works good.

If the Noctilux was a little smaller and lighter I wouldnt see any need for my 50asph (even if it focused 100% accurate) because I can not see how the Noctilux gets bad stopped down or at longer distances.

 

Cheers, Tom

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[BerndReini]

I also have both the Noctilux and the 50lux aspherical. The 50lux is probably my most used lens on the M8. I use the Noctilux exclusively wide open not because of the softer quality but because the Noctilux exhibits extreme purple fringing in contrasty daylight situations.

[Jamie Roberts]

Interesting results.

 

I have a 50 lux that is perfectly fine at close range, stopped down, and for distant objects.

 

My 35 Lux is essentially the same, though the field of focus shifts, the subject is never out of the field.

 

My 75 Lux (used) backfocussed when I first got it; since my other lenses were fine, I had that lens adjusted. It's fine now.

 

My Noctilux definitely shifts focus as I stop down.

 

Close up and wide open it's in focus; by f2.0 it's a centimeter or so back-focussing, then at f4 the subject area is fine again.

 

At a distance, the backfocus is far less noticable. I'm amazed at how easy it is to focus the Nocti wide open or close to it at 3 - 10 meters.

 

This shift is a well-known property of the Noctilux even on film bodies.

[robertwright]

is it not well known that dof expands about the focal plane in a 1/3-2/3rds manners, iow, you get apparently more dof behind the object because those objects are farther away and you can't tell they are just as out of focus as nearer objects?

 

I think from a pure optical/mathematical standpoint, dof is symmetrical about the focal plane, but in practical terms, as I said above, there will be apparently more behind than in front due to the change in distance/size of objects.

[Jamie Roberts]

Robert--yes, as a rule, you're correct.

 

But certain of the Leica advanced designs *do* focus shift; the field of focus moves from almost back-focussing to almost front-focussing as you go from wide open to moderate apertures.

 

The 35 Lux APSH is, from this forum anyway, the most talked about; on a properly adjusted model at 1.4 close up the subject in focus is right at the front of the field (and if out of adjustment the lens will back-focus); when stopped down to 3.2 the subject is nearly at the back of the focal field.

 

The Nocti is the worst of the lot, no doubt about it. The 50 Lux ASPH suffers the least on my camera.

 

Distance mitigates the issue, but does not get rid of it, especially if the infinity focus is off.

 

After f4, all the Leica lenses I have show the classic 1/3 -- 2/3 split in DOF.

[pelikan1931]

the 0.68 mag ratio and the cropped sensor are not very friendly towards the high speed lens, especially with all those lens using different mounts and being handmade. We will see how the summarits with more uniform parts/mounts go.

 

 

Leica Camera AG - Photography - Summarit-M Lenses

[tom0511]

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Robert--yes, as a rule, you're correct.

 

But certain of the Leica advanced designs *do* focus shift; the field of focus moves from almost back-focussing to almost front-focussing as you go from wide open to moderate apertures.

 

The 35 Lux APSH is, from this forum anyway, the most talked about; on a properly adjusted model at 1.4 close up the subject in focus is right at the front of the field (and if out of adjustment the lens will back-focus); when stopped down to 3.2 the subject is nearly at the back of the focal field.

 

The Nocti is the worst of the lot, no doubt about it. The 50 Lux ASPH suffers the least on my camera.

 

Distance mitigates the issue, but does not get rid of it, especially if the infinity focus is off.

 

After f4, all the Leica lenses I have show the classic 1/3 -- 2/3 split in DOF.

 

Jamie, are you sure? In my case the lenses do show front focus wide open and closing the f-stop they move towards focus plane being more in the back.

[tom0511]

I decided to write a letter to Leica about all this and I hope they come up with a good suggestion to get my stuff going.

Thanks for all the feedback. As much as I love the Leica M gear I am evaluating if I should not go with an AF system for low light - fast lenses photography.

I am still hoping they get my problems sorted out.

Regards, Tom

[rosuna]

... but because the Noctilux exhibits extreme purple fringing in contrasty daylight situations.

 

That is true. It is the worse problem with the Noctilux. My copy hasn't the 6-bit code. Is your copy coded?

[BerndReini]

Yes, it's coded. I got it as my 30% off lens brand new from Leica. I'm thankful that it doesn't backfocus and I love this lens. It really is special, but by no means a replacement for the 50lux.

[rosuna]

Yes, it's coded. I got it as my 30% off lens brand new from Leica. I'm thankful that it doesn't backfocus and I love this lens. It really is special, but by no means a replacement for the 50lux.

 

I though the camera could apply color aberrations correction algorithms, like the vignetting correction algorithms (Hasselblad does it). Now I know it isn't the case, and coding the lens will not resolve this problem.

 

I also have the Summilux-M 35mm ASPH. It is one stop slower, but you can used it with shorter exposition times. Even more, the 35mm provides the same FoV than a 50mm lens on film Ms. Therefore, the 35mm lens is the more versatile low light lens I have. The strong point of the Noctilux is the interesting fingerprint it has. Finally, I have the 75mm Summilux, maybe the most difficult lens to handle (for me).

 

I like the Noctilux lens anyway.

[Eoin]

I decided to write a letter to Leica about all this and I hope they come up with a good suggestion to get my stuff going.

Thanks for all the feedback. As much as I love the Leica M gear I am evaluating if I should not go with an AF system for low light - fast lenses photography.

I am still hoping they get my problems sorted out.

Regards, Tom

 

Tom,

 

Funny you should say this, I've just done the same thing regarding a brand new 50 Summilux Asph I've received today, the lens can't focus correctly at any aperture or distance. If Leica require my body back for a record 4th time I'll not be a happy man, that would make it 4 months back in Solms in a year, perhaps a record!. It's so funny it's sad, I had tried a friends 50 Summilux Asph and found it perfect on my M8 and based on my trials I decided it was the one to replace my Noctilux. I found a new one in Scotland, chrome no less and went with that on friday, I received it today and put it on my camera just to check and wham, not a sharp image at any distance below f:/8. I checked my other lenses 28, 50, 75 & 90 Summicrons and they are all perfect.

 

I'm just getting so tired of this, paying good money for something brand new and it won't even work straight out of the box. Sorry to rant on, I'm just pissed off. I'd be interested to hear what they say to you, perhaps we can compare notes.

 

Aside from that, I'm still enjoying my M8 almost 1 year in despite being in solms for 3 months. Oh bugger!

[Jamie Roberts]

Jamie, are you sure? In my case the lenses do show front focus wide open and closing the f-stop they move towards focus plane being more in the back.

 

Yes, so if they're all actually front-focussing wide open close up it sounds to me like the RF needs a tiny tweak (again, the Nocti should be bang on at f1.0, if a little soft).

 

All warnings here apply: YMMV etc... I'd let DAG in the US or Kindermann in Canada have a look and let them fix it.

 

I have to say that having all my M lenses act predictably means I have better low-light fast focus than any AF system I've ever tried.

[tom0511]

Tom,

 

Funny you should say this, I've just done the same thing regarding a brand new 50 Summilux Asph I've received today, the lens can't focus correctly at any aperture or distance. If Leica require my body back for a record 4th time I'll not be a happy man, that would make it 4 months back in Solms in a year, perhaps a record!. It's so funny it's sad, I had tried a friends 50 Summilux Asph and found it perfect on my M8 and based on my trials I decided it was the one to replace my Noctilux. I found a new one in Scotland, chrome no less and went with that on friday, I received it today and put it on my camera just to check and wham, not a sharp image at any distance below f:/8. I checked my other lenses 28, 50, 75 & 90 Summicrons and they are all perfect.

 

I'm just getting so tired of this, paying good money for something brand new and it won't even work straight out of the box. Sorry to rant on, I'm just pissed off. I'd be interested to hear what they say to you, perhaps we can compare notes.

 

Aside from that, I'm still enjoying my M8 almost 1 year in despite being in solms for 3 months. Oh bugger!

 

I called Leica today to ask for a contact person to send my mail, I sent my mail and I got called back by Leica 3 hours later. They suggest to me to send my M8 + my 50lux plus the Noct in and are confident to get it fixed. They also said they can fix it and that lenses which show focus shift are usually calibrated to focus correct wide open.

I am surprized in a positive way how fast Leica responded and they gave me the feeling that they want to fix my problem.

I think in the end the Noctilux will hopefully be fixed for focusing good wide open, the 50/1.4asph seems notto show focus shift-so once its adjusted to your camer ot should work at every f-stop.

I will send in my stuff in the next days and hope that it wont take too long.

Best Regards, tom

 

Dont give up

[BerndReini]

Before you send your lens and M8 on the looong journey to Solms, please try tweaking your rangefinder with a 2mm allen key. There are instructional posts about this and it worked like a charm for me. I also did this adjustment for my friend and again great. You will notice that the 50s in general focus a little further back than the 75s and 35s. If you take a tape measure and focus at a number about 1m away with all your lenses, you should be able to tweak your rangefinder with the allen key to a happy medium point that works for all your lenses. It is easy to do and might just save you a long wait for your camera and i am convinced that you can do a better job adjusting the rangefinder for yourself than Leica could.

Good luck, and let me know if you need any advice with this.

[tom0511]

Before you send your lens and M8 on the looong journey to Solms, please try tweaking your rangefinder with a 2mm allen key. There are instructional posts about this and it worked like a charm for me. I also did this adjustment for my friend and again great. You will notice that the 50s in general focus a little further back than the 75s and 35s. If you take a tape measure and focus at a number about 1m away with all your lenses, you should be able to tweak your rangefinder with the allen key to a happy medium point that works for all your lenses. It is easy to do and might just save you a long wait for your camera and i am convinced that you can do a better job adjusting the rangefinder for yourself than Leica could.

Good luck, and let me know if you need any advice with this.

 

Bernd I did that with one of my M8s, the front focus is minimized at shorter distances, however now it looks like on this body at longer distances the lenses show backfocus.

As discussed in another thread the 2mm Allen key adjustment seems to influence close focus and far focus in a different way and in my case did not lead to a better overall focusing. Short distance was improved but long distance focusing is off now.

I decided to not touch the rangefinder of my second M8 myself.

Best Regards,

Tom

[Jack_Flesher]

My experiece is identical to Jamies re the 35 and 50 Lux, but exactly reversed on the Noct and the 75 Lux. In my case, my particular Noct does not FS, at least excessively when wide open and closer in (E60 pin hood version). It is dead on wide open in the 1 - 3 meter range, then does start to BF slightly after that. Stopped down beyond f2.8 it FF's slightly in the 1 -3 meter range (by maybe 1 cm) but then is on after 3 meters to infinity. In all, a pretty ideal situation for lens that fast.

 

With my 75, it is dead-on wide open at 2 - 4 meters, but BF's by about 2 - 3 cm at closest focus wide open and FF's slightly, getting significant after about 10 meters (like 0.5 m off at 10 m). Stopping down doesn't improve the closest focus much, so I adjust when using it there, which is rarely. However, stopping down to 2.8 or higher does clear up the longer distance focus shift. Again a pretty good situation for a fast lens, though the close focus thing is problematic. The good news is when I'm wanting to focus at MFD wide open with the 75, it's usually a static subject so I can chimp and confirm...

 

Sidebar --- the more I use the 75 Lux, the more I *hate* the framelines... This lens may go an the auction-block soon. Frankly, I don't even use the Nocti that much so it may go too.

 

Cheers,

[pelikan1931]

hope M9 will be a full sensor body with viewfinder back to 0.72. the current 0.68 is not that friendly towards the f1 and f1.4 lens.

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Hallo,

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[Jamie Roberts]

{snipped}

Sidebar --- the more I use the 75 Lux, the more I *hate* the framelines... This lens may go an the auction-block soon. Frankly, I don't even use the Nocti that much so it may go too.

 

Jack, I so agree on the framelines. Though the 75 is great, I'm surprised at how much using it is coloured by the weirdness in the framelines there. I don't have this issue with other lenses, just the 75.

 

So hopefully the M9 will rectify this

[michaelstokes]

Eoin, what method/process did you use to check the focus?? I have a 35mm and 50mm Lux that I would like to check.