When focusing if I move (slide) the image slightly to the right

[bab]

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Tried over one hundred shots today, the only way I achieve perfect focus is when I move the registration slightly to the right in a horizontally image. If I focus the subject as one would normally the point of focus is behind my intended point. Ex. When I use the focus test chart at a 45 degree angle the parrellex throws me off and I can't seem to focus. Then when I focus straight on I have to register the IMAGE slightly to the right to get it on focus point that I intended. If I focus on a ruler on the number 6 the number 7 and 8 are in focus and 6 is not.

 

When I read I usually wear 1.25 correction lenses

 

My question is do I need a diopter or is the camera or lens 35mm1.4 coded lux out of alignment. (I am using the leica 1.25 magnifier)

[sparkie]

..or could be the rangefinder in the camera is off

[sparkie]

if you have several lenses and do a focus test and all lenses back or front focus, likelihood then is the camera RF is out. if one lens is back/front focusing then its probably the lens. if you only have one lens and one camera then it gets tricky as there is no point of reference/elimination

[bab]

here is a pic of what i mean

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[bab]

Yea that right just on lens currently

[nscali]

I have found that when the lens is wide open it focusses perfectly, at least for the first 2 f stops of the lens (starting from wide open).

After that, the point of focus is softer. The effect is worse on some lenses (like the summilux 50 or summicron 35) yet barely noticeable on others.

Like you, if you shift the focus alignment to the right your point of focus becomes sharper.

My understanding is that this is focus shift and is simply a characteristic of the camera, used with older designed lenses. The very new lenses are flatter, which are more compatible with the flat sensor of the M8.

I have recreated this problem on 3 seperate M8 bodies, using many lenses, all of which were uncoded. I find it almost impossible to believe that the reangefinder could have been out on all the bodies.

Try testing with the lens wide open. Put it on a tripod, use aperture priority, focus at one point, then take several shots, each time stopping down. See what happens.

I would be interested to hear about your results.

Nicky

[sparkie]

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sorry, just read you usually wear 1.25 correction lenses when reading. this adds another variable to the mix!

[sparkie]

yea, the focus shoft has been discussed in one of tim ashley's posts regarding the 35/1.4 ASPH. happens when stopping down. i personally havent tested for this on my lenses.

[bab]

shot this at f2 but i will run the test now for you on a tripod!

[bab]

here are the test photos starting at f1.4 focus on the 6" mark on the ruler then slightly shifted to the right as looking through the finder.

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[nscali]

Definately out of focus at all fstops.

Notice, that the sharpest image was around f2-f2.8 (your shifted one) and then it degrades after that anyway.

Do you have another lens to test?

You may well need a diopter.

Nicky

[ho_co]

Barry--

I'm thoroughly confused (not that that is new! ).

 

You say you focus and then "slide the image slightly to the right."

 

How do you slide the image? Do you slide the camera? If so, how do you do that on a tripod? If you have to pick up the tripod and move it, then there's no test because the tripod is in a new location.

 

In some of the images it looks as if you've rotated the camera a few degrees to the right, which would introduce other changes (among others, shifting the focus plane) and invalidate the focus test.

 

And the f/2.8 picture (unshifted) is completely unsharp--looks as if the tripod got bumped.

 

If I understand what you are doing (rotating the camera after focusing), the result you are seeing is due to the lens's spherical aberration, which causes edges to focus at a different distance than center. Tim Ashley and the forum pretty well explored the matter in an almost interminable earlier thread about the same lens.

 

Testing with a focus chart seems unwise to me, particularly if you introduce anomalies by moving the camera after focusing.

 

Do you get what you want when you just take pictures? If not, the focus chart may be of interest; but better would be having the body and lens tested by a competent repair facility. The other suggestion made above--try other lenses--may give a better understanding of whether you have a problem with one lens or with all. The latter case might indicate the need for a rangefinder adjustment.

 

 

It seems to me that the question of whether you need an eyepiece diopter is unrelated.

 

How easy is it for you to focus? If you struggle to line up the rangefinder images, you may need a diopter. But the M8 image is projected to the equivalent of 2m as I recall, so it would need the same correction you use for normal situations, not for reading.

 

--HC

[Chuck Hatcher]

Assuming you see well enough to see the rangefinder patch clearly in the viewfinder, a diopter correction won't help the problem. I would make one recommendation regarding the focus chart and that is to draw a thin vertical line crossing the center focus line to assist focusing. I find it somewhat difficult to focus on a horizontal line compared to a vertical one. When doing the test, focus only once, and try not to move anything else as you change the aperture for the subsequent shots.

 

Also, if you aren't using the self timer for your test shots, definitely do so. A couple of seconds delay gives time for vibrations from pressing the shutter button to subside. More important with a shaky tripod, but always a good idea.

 

With one lens and one body to test it will be a little difficult to determine which one is the culprit. With the lens focus ring set to infinity, and viewing an object a long way in the distance, does the object appear focused in the viewfinder?

[d_brown]

Barry:

 

Your 35 Lux exhibits the same backfocus problem as the two I have. "Shifting" of the focus is simply compensating for the lens elements being misaligned with the focsing mount. I have one 35 Lux which has been in Solms going on four months. I am told it is on the way back now. Whether they shimed it to correct the problem, or simply say it is within tolerance, remains to be seen. I have another 35 Lux, a 35 Cron, a 50 Lux and a Nocti which are all in NJ now to be shimmed. They promised a reasonable turnaround, but we will soon know what "reasonable" is and whether they actually fix the problem or just say they are "within tolerance".

 

A few posters here evidently have 35 Luxes which do focus properly, but I suspect many have badly adjusted lenses, whether they realize it or not. The older Leitz lenses were very well shimmed. The newer ones seem to be made with much looser tolerances and Leica seems not so concerned with maintining the quality levels that got them their reputation.

 

When my lenses are returned, I'll post the results. If they aren't fixed, I will be pi**ed and have a lot to say in my posts. But one way or another they WILL get fixed. $15,000.00 invested in lenses that are not usable is not Leica quality!

 

As for your problem, you can either learn to judge how much "shifting right" it takes to compensate for your lens and get better results that you get now, or you can send your lens to NJ and hope they fix it. I wish you well!

 

Dale

[ho_co]

I would make one recommendation regarding the focus chart and that is to draw a thin vertical line crossing the center focus line to assist focusing.

Chuck--

Barry has already beat you: He turned the camera to vertical so that the dark line crosses the rangefinder patch properly for easy focus. Both easier and more exact than trying to focus on the crosspoint of a broad and a narrow line! Nothing wrong with your suggestion, just extra doing without added accuracy.

 

 

"Shifting" of the focus is simply compensating for the lens elements being misaligned with the focsing mount.

Dale--

This isn't misalignment of any sort. It looks like spherical aberration.

 

 

Barry--

Check the tediously long thread started by Tim Ashley about his 35/1.4 (http://www.leica-camera-user.com/digital-forum/17699-very-interesting-answer-leica-35mm-1-a.html). There are several different tests and illustrations suggested by different forum members which would give you some insight to where the problem lies in this case.

 

--HC

[bab]

When I say shifting to the right I mean I move the focus knob so the Image shifts out of alignment to the right.

 

1. the focusing window only works level straight on, if the camera is tilted down you get parrelex and for me a vertical line looks like it runs ne to sw so when you look through your view finder the images which are supposed to line up instead form a elongated "X" so what part of the "X" at its intersection do i consider in focus?

 

2. I never moved the camera while on the tripod for any of the shots only the aperture and the focus.

 

When I am focusing on someone eye I want the eye in sharp focus not their ears or their shirt collar.

 

Maybe a dealer of Leica will let me experiment with some of their lenses in stock.

[ho_co]

When I say shifting to the right I mean I move the focus knob so the Image shifts out of alignment to the right.

Then you mean that you first focus and then refocus, throwing the rangefinder image out of focus? Since there are two rangefinder images, when the rangefinder is not lined up, one of them will be to the right and the other will be to the left. You described a situation of back-focus, so I suppose you turn the focus ring to focus a little closer than the distance indicated by the rangefinder?

 

the focusing window only works level straight on, if the camera is tilted down you get parrelex and for me a vertical line looks like it runs ne to sw so when you look through your view finder the images which are supposed to line up instead form a elongated "X" so what part of the "X" at its intersection do i consider in focus?

As I said above, trying to focus on an X is more difficult than what you seem to be doing. You are using the camera in vertical position, aren't you, in the same orientation in which you show the chart? That's the only reliable way to work with this chart and a rangefinder camera. But it sounds as if you have astigmatism, so you might want to have your eyes checked for glasses. If you have astigmatism (as I do), then all the correction must be in your eyeglasses; diopter correctiion lenses won't help. But notice that none of your images show the focus chart square to the camera. All the pictures show it leaning to the left, so you have the same question now: Which part of the dark line do I focus on, the near side or the far side?--They should obviously both be the same distance.

 

I never moved the camera while on the tripod for any of the shots only the aperture and the focus.

That may have been your intent, but it doesn't look that way to me. Again, the first images for f/2.8 and f/4 show nothing sharp on the page to my eye. And sometimes the red pen is in the image, sometimes it isn't, implying rotation of the camera. If these are not identical crops in all cases, then the test is meaningless. (And I have to say I don't understand why the ruler is there, since the test chart lying at 45° is intended to be more accurate. Nothing wrong with the duplication, I just don't see its usefulness.)

 

Maybe a dealer of Leica will let me experiment with some of their lenses in stock.

Excellent idea! That would be a good way for you to check exactly where the problem lies. And again I suggest that you check out the thread that I mentioned on this topic. It looks to me as if what you are seeing here is the same matter Tim discussed with Leica. You could save yourself time and worry by seeing whether your question has already been answered there. Leica made some specific suggestions of lenses that don't show focus shift to the same degree.

 

Good luck!

 

--HC

[carstenw]

Perhaps this suggestion will strike some as heretical, but if you use only this lens anyway, why not tweak the wheel so that it focuses correctly? When/if you one day get a second lens, you can examine where the problem really is.

[B&W]

Perhaps this suggestion will strike some as heretical, but if you use only this lens anyway, why not tweak the wheel so that it focuses correctly? When/if you one day get a second lens, you can examine where the problem really is.

 

How do you tweak the wheel?

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Hallo,

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[stunsworth]

Do you notice the problem in 'real world' shooting?