35 sumilux asph in focus just at f1.4...plese help

[pomwan17]

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my 8.2 and 35lux asph have a sharp focus just at f1.4.

But other than that since f2 it happen to back focus around 2" or 3".

Can i adjust by my self like this thread below.

 

thank

 

http://www.l-camera-forum.com/leica-forum/leica-m9-forum/115034-rangefinderproblems-new-m9s-6.html

[jaapv]

No you cannot. This lens has focus shift. That means that focus will change as you stop it down. By slightly getting it to the far side of the tolerance span at 1.4 the effect can be migitated, but it cannot be eliminated. Send it to Leica and ask them to adjust it to your use. It is virtually impossible to adjust a lens yourself. You need the correct shims to do it, plus the equipment and expertise. If you start doing it yourself on the camera it will be off for all other lenses, if not out of tolerance at all distances.

[luigi bertolotti]

Welcome to the forum !! It's a very well known issue, and as Jaap said there is nothing yo do about: that's the reason for this year they made a new version with a floating back group (even if , to be honest, I haven't yet seen a test which proves the problem solved... but deliveries probably have just started...).

Anyway... why having a 35 1,4 if you don't use it frequently wide open ? I mean, if I were you I'd keep the lens as it is: having a lens well sharp at 1,4 is a good value... and probably from 5,6 on the focus shift is decently compensated by depth of field

[efix]

It's a very well known issue, and as Jaap said there is nothing yo do about: that's the reason for this year they made a new version with a floating back group (even if , to be honest, I haven't yet seen a test which proves the problem solved... but deliveries probably have just started...).

 

The NEW Leica 35 Summilux ASPH 1.4 Lens Review | STEVE HUFF PHOTOS

 

"I saw no shift at all in this test shot. Each shot was done on a tripod and the focus was set once before the first shot. If there is shift here, it’s not visible to my eyes. The 1.4 shot is sharp as is the F5.6 shot. (...) So my conclusion is that this lens will not give any focus shift issues in real world images as I have not seen it at all. I was told by another Leica shooter who is also testing this lens that there is a teeny bit of shift still present in this lens if you shoot a ruler but honestly, I I only care if it shows up in real images. Bottom line? When taking real photos there will be no visible focus shift with this lens. If shooting rulers or newspapers, then maybe there will be some microscopic shift but if so, it would be MILES better than the old version."

[luigi bertolotti]

Yup, thanks for the link... I forgot that also Steven's tests exist...

[Ario Arioldi]

I have tne new Summilux since the end of July, and I'have not detected any focus shift.

Very nice lens, indeed.

Cheers,

Ario

[zlatkob]

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Sean Reid's review of the new lens has very good test shots comparing the old and new 35/1.4. As I recall, the new lens is not perfect, but a clear improvement, and solves the problem for all practical purposes.

[ho_co]

pom, the others' comments are all on target. I'd add just one thing: If you send the lens to Leica and tell them it doesn't work on the M8.2, they may be able to adjust it to improve its performance.

 

That is, some of the earlier 35 Summiluxes showed more of the 'problem' than others. Leica used the focus shift to help make the lens sharp wide open. Usually, depth of field covers the residual error. But on some of the lenses, the focus shift became too wide.

 

You say the focus is out two or three inches. Whether that's bad depends on the distance. I'd say at twenty feet, that's not bad; but at four feet, it might be.

 

Have you tested it with a test chart? You are using a tripod, aren't you?

 

The focus should be exact wide open, as Luigi said. The depth of field should then cover the focus shift as you stop down.

 

If you're sure that's not happening, send it to Leica to have them check it.

[Ario Arioldi]

Both the camera rangefinder and the lens are calibrated within certain tolerances. If the combined effect of the calibration tolerances set your system (camera+lens) on the backfocus side (even if still acceptable at f/1.4) it is most likely that by closing down to f/2 through f/4 the focus shif will show up.

If on the contrary the starting point is on the front focus side, the increasing depth of field will probably compensate the focus shift when closing down.

Cheers,

Ario