Very interesting answer from Leica on 35mm 1.4

[tashley]

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If you don't have a backup camera, then 6 weeks is a very real risk... What I might do myself (if I cannot think of a proper way to adjust the eccentric on the arm) is to bite the bullet and send the camera to one of the independents who do this kind of work. There is one in Holland, one in Germany and one in Italy, and probably more. With a proper arrangement, it would probably take less than a week, although it would not be free.

 

 

Thanks Carsten and Jono,

 

I have had a long phone call with an extremely helpful and well-informed chappie at Solms about this, having emailed him some samples. He has tested the same lens that I tested, and many others, and had exactly the same result.

 

The reason is that the 35 lux has no floating element unlike the 50 lux, and on an M8 when viewed at 100%, my findings will be replicated on any correctly calibrated RF with any correctly manufactured 35 lux, as long as the test is rigorous, which mine and Solms' were. In fact, anyone who runs a rigorous test with the above conditions met will, I am now convinced, find the same.

 

So it seems that this is just a fact of the design constraints of the lens. The 35 'cron will do the same but less so, whereas for example the 28 elmarit won't at all.

 

I'm satisfied with this now, and confident that it is true. I just have to decide whether to forgo ownership of a Leitz 35mm and the amazing sharpness you can get when the focus 'happens', learning how to front focus it at different apertures and subjects to distance by differing degrees - or whether to make some other choice.

 

BTW I also learned that something else I noticed is true, which is that there is a zone between the edge and the centre where the image will be slightly less sharp (but still pretty good!) at certain distances and F stops.

 

I thank all who have helped me think this one through!

 

Best

 

Tim

[carstenw]

I meant that I would have my M8 rangefinder adjusted to the lens, not the lens to the camera. The M8, as all Ms, has two horizontal rangefinder adjustments, one for the entire range (the little wheel), and one for near-infinity balance (the arm). I suspect that the 35 Lux and the latter rangefinder adjustment are at opposite ends of their respective tolerances, and thus lead to your results. I am still assuming that others who claim not to have this problem are actually right in saying so. I do not have the 35 Lux myself.

 

Actually, I suppose there is a way to test if what I am hypothesising is correct: does your M8 + 35 Lux focus perfectly wide open both at 1m and at infinity, with the rangefinder being dead on? Note that infinity has to be tested on something very far away, ie. several kilometres. A point light source on a distant building at night from a hill is perhaps the easiest to see.

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[Jamie Roberts]

Tim, when I get some time over the weekend I'll try to reproduce your tests and post some results.

 

I'm with Carsten here--but just by way of my experience getting this lens to focus predictably wide open and close up.

 

But your absolutely right: without rigorously testing there's no telling what's going on.

[tashley]

I meant that I would have my M8 rangefinder adjusted to the lens, not the lens to the camera. The M8, as all Ms, has two horizontal rangefinder adjustments, one for the entire range (the little wheel), and one for near-infinity balance (the arm). I suspect that the 35 Lux and the latter rangefinder adjustment are at opposite ends of their respective tolerances, and thus lead to your results. I am still assuming that others who claim not to have this problem are actually right in saying so. I do not have the 35 Lux myself.

 

Actually, I suppose there is a way to test if what I am hypothesising is correct: does your M8 + 35 Lux focus perfectly wide open both at 1m and at infinity, with the rangefinder being dead on? Note that infinity has to be tested on something very far away, ie. several kilometres. A point light source on a distant building at night from a hill is perhaps the easiest to see.

 

 

Hi Carsten and thank you for all your advice on this. I understand what you're saying here but as I have now returned both lenses to Solms I can't test that. Images in my library that fulfill your requirement are hard to track down due to the lack of EXIF on aperture used.

 

In any event I am loath to adjust the RF since it is so spot-on with everything else! But I do think that your hypothesis is likely correct and that those few who seem to have 35 luxes that do retain focus throughout the F range likely have an RF adjustment which allows for it, just!

 

I await Jamie's results with great interest!

 

Tim

[tashley]

Tim, when I get some time over the weekend I'll try to reproduce your tests and post some results.

 

I'm with Carsten here--but just by way of my experience getting this lens to focus predictably wide open and close up.

 

But your absolutely right: without rigorously testing there's no telling what's going on.

 

 

Hi Jamie,

 

I'd dearly love to hear the results of this test if you do get a chance to run it!

 

Thanks for all you help here!

 

Tim

[Jamie Roberts]

Tim--don't worry; I'll post it right here.

[ho_co]

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Tim--

Thanks very much for this thread. It may be that Leica is learning that there are new constraints to consider for lens design with digital sensors, and you've enlightened us by keeping us posted in your discovery process.

 

Thanks very much for your superb Venice pictures. It's a little hard for me to imagine the same person who made those pictures also finding such hard-edged problems with this lens. But of course, that stands to reason: You want the lens to work predictably in order to make such images.

 

Thanks very much for proper use of the word "loath" in http://www.leica-camera-user.com/digital-forum/17699-very-interesting-answer-leica-35mm-1-a-4.html#post188307. I don't know how it is in other regions, but in the US the verb often gets used in place of the adjective.

 

Sincere thanks on all three points.

 

--HC

[tashley]

Tim--

Thanks very much for this thread. It may be that Leica is learning that there are new constraints to consider for lens design with digital sensors, and you've enlightened us by keeping us posted in your discovery process.

 

Thanks very much for your superb Venice pictures. It's a little hard for me to imagine the same person who made those pictures also finding such hard-edged problems with this lens. But of course, that stands to reason: You want the lens to work predictably in order to make such images.

 

Thanks very much for proper use of the word "loath" in http://www.leica-camera-user.com/digital-forum/17699-very-interesting-answer-leica-35mm-1-a-4.html#post188307. I don't know how it is in other regions, but in the US the verb often gets used in place of the adjective.

 

Sincere thanks on all three points.

 

--HC

 

Ho Co, that made me giggle - I used 'loath' that way without thinking either a) twice or that it could give someone pleasure. Glad to be of service!

 

You're right about the answer to the apparent contradiction between the Venice shots and my requirements from a lens. I like OOF stuff as much as anyone, but really prefer to choose the moment myself! The 35 lux was responsible for a surprisingly high proportion of the Venice shots but that's because I was in effect bracket focusing, aware that there was an issue. You should have seen the shots I didn't post...

 

;-)

 

Tim

[Jamie Roberts]

Tim,

 

Well, I'm loath to post this, but I just reproduced your test (well, not as aesthetically nice, but you know what I mean).

 

I'm happy to say that the focus point on my 35 stays in focus throughout its aperture range; I'm sorry to say that this makes more of a mystery for you, though (so I'm sorry, in a way!). Maybe it's the chrome lens. Dunno.

 

On the plus side, you now know that focussing a 35 1.4 reliably is certainly possible. I'll post the 100% crops tomorrow.

[sergiolov]

Thanks Carsten and Jono,

 

I have had a long phone call with an extremely helpful and well-informed chappie at Solms about this, having emailed him some samples. He has tested the same lens that I tested, and many others, and had exactly the same result.

 

The reason is that the 35 lux has no floating element unlike the 50 lux, and on an M8 when viewed at 100%, my findings will be replicated on any correctly calibrated RF with any correctly manufactured 35 lux, as long as the test is rigorous, which mine and Solms' were. In fact, anyone who runs a rigorous test with the above conditions met will, I am now convinced, find the same.

 

So it seems that this is just a fact of the design constraints of the lens. The 35 'cron will do the same but less so, whereas for example the 28 elmarit won't at all.

 

I'm satisfied with this now, and confident that it is true. I just have to decide whether to forgo ownership of a Leitz 35mm and the amazing sharpness you can get when the focus 'happens', learning how to front focus it at different apertures and subjects to distance by differing degrees - or whether to make some other choice.

 

BTW I also learned that something else I noticed is true, which is that there is a zone between the edge and the centre where the image will be slightly less sharp (but still pretty good!) at certain distances and F stops.

 

I thank all who have helped me think this one through!

 

Best

 

Tim

 

 

Hi Tim

I insist that there is absolutely no reason not to keep your wonderful summilux, and that the informed person at Solms is not so informed.

For the lens to stay within focus range at all distances, it must be regulated to frontfocus a little at full aperture, to compensate for the focus shift closing it, and this is a very simple adjustment to perform either on the lens or the camera,wichever apply.

The accurate test that follows, notwhistanding the fact that it is performed with the cron asph, is largely applicable to the general case, being performed at 70cm against your at 1m,so obtaining the same starting depth of field at full aperture.

(all can be said against Leica, but not that theyr engineers designed and put on the market a lens that is by project unable to focus correctly. Quality control is another matter)

Images are from f2 to f8

Best regards,

Sergio

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[marknorton]

Where can you find this template? It looks much better than my effort to use a spirit level rule which was too reflective.

[sergiolov]

Where can you find this template? It looks much better than my effort to use a spirit level rule which was too reflective.

 

Find it here

Nikon D70 Focus Chart

Sergio

[marknorton]

Thanks, looks very helpful...

[tashley]

Hi Tim

I insist that there is absolutely no reason not to keep your wonderful summilux, and that the informed person at Solms is not so informed.

For the lens to stay within focus range at all distances, it must be regulated to frontfocus a little at full aperture, to compensate for the focus shift closing it, and this is a very simple adjustment to perform either on the lens or the camera,wichever apply.

The accurate test that follows, notwhistanding the fact that it is performed with the cron asph, is largely applicable to the general case, being performed at 70cm against your at 1m,so obtaining the same starting depth of field at full aperture.

(all can be said against Leica, but not that theyr engineers designed and put on the market a lens that is by project unable to focus correctly. Quality control is another matter)

Images are from f2 to f8

Best regards,

Sergio

 

Hi Sergio,

 

That really is interesting and thanks for shooting and posting it. The guy from Solms did say that the 'lux was significantly more affected than the cron so I'm still (politely) a bit uncertain. Both my lenses have been returned but if the adjustment is that easy I'd love to have it done. How is it done? But would it not then fail to achieve perfect focus at F1.4?

 

Yours head-scratchingly,

 

Tim

[tashley]

Tim,

 

Well, I'm loath to post this, but I just reproduced your test (well, not as aesthetically nice, but you know what I mean).

 

I'm happy to say that the focus point on my 35 stays in focus throughout its aperture range; I'm sorry to say that this makes more of a mystery for you, though (so I'm sorry, in a way!). Maybe it's the chrome lens. Dunno.

 

On the plus side, you now know that focussing a 35 1.4 reliably is certainly possible. I'll post the 100% crops tomorrow.

 

 

Thank you Jamie, this is much appreciated. Not sure what to conclude but the possibilities seem to be

 

1) that the nice chap from Solms was really trying but had missed the point or

2) that your RF is slightly front focussing or

3) your example of the lens is slightly front focussing

 

You would know if it were 2) and if it were 3) it wouldn't focus exactly wide open. So not sure, unless yours is a slightly different version of the lens? Mine were both black ASPH.

 

The plot thickens and the mystery grows. Hmmm!

 

Tim

[sergiolov]

Tim,

let's wait for Jamie's test, it should bring to a conclusion.

Sergio

[ChrisC]

Find it here

Nikon D70 Focus Chart

Sergio

 

Sergio - Alas, the download appears to have been withdrawn.

 

..................................Chris

[Bill Sievers]

One of the advantages of a digital camera is the ability to chimp and adjust the results in a controlled or studio environment. In candid or street conditions its gonna be hit or miss.

 

That D70 article is interesting reading.

[marknorton]

Chris, it's there, and as William says, interesting reading. I'm going to re-do my test on my 35/1.4.

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[mjh]

For the lens to stay within focus range at all distances, it must be regulated to frontfocus a little at full aperture, to compensate for the focus shift closing it, and this is a very simple adjustment to perform either on the lens or the camera,wichever apply.

This entails compromising focusing accuracy at f1.4, where it is most critical – not an acceptable solution in my view.