35mm Summilux f1.4 ASPH Front Focus

[jaymz007]

HI
I have been reading on the forums that you can just the m8 for lens that have focus problems. Is this a wise thing to do?
My 35 lux non 6 bit ---front focuses.
But my 50 summilux ASPH 6bit ---focuses fine.

Next question is if I just my m8 for the 35mm lux than will my 50 lux still focus the same or will my 50 lux focus get thrown off.

What is the best way to fix this 35mm lux?

Thanks in advance.
Jaymz

 

[ecliffordsmith]

Hi Jay,

The only truly user adjustable tuning you can do is to the cameras rangefinder infinity setting.

Before doing this I think you need to be certain about exactly what is going on.

The Leica 35mm Summilux and to a lesser extent Summicron exhibit focus shift by design. In the later lens this can be so trivial as not to matter at all.

I would suggest that you first confirm what your 35mm lens is actually doing. Is the lens front focusing consistently at all apertures? I understand that the optimal setup to achieve focus via the rangefinder with this lens is to have Leica or DAG adjust the lens so the focus is at the front of depth of field wide open so that as the focus shifts backwards as you stop down you remain within the depth of field limits. If you have a focus shift then adjusting the infinity setting of the rangefinder will not help you.

With your 50mm lens at what distance do objects align at infinity? Do you for example so an aligned image of a distant object? Do you reach infinity in the rangefinder when the lens is set to it or do you go beyond it? This is what you will be altering by changing the infinity setting.

 

[jaymz007]

Well I just did a focus test by tapeing a ruler on the wall and at an angle I took some shot first at 1.4 focused on the number 18 but when I look at the image number 19 is the focus point. At f2.0 the focus point looks like 18.5. At f2.8 the focus point seems to be spot on. and at f4 it seems to be okay.
This really bothers me because I shoot mostly wide open.
I know this lens has a focus shift problem but that is not what I am referring to. I want to have the focus spot on at 1.4 and then if it does shift its okay because reading Steve Huff's web site about the focus shift in these lenses I can live with but at F1.4 my images look out of focus. I don't like that.
Please help.

 

[ecliffordsmith]

Hi Jay,

Are you doing these tests on a tripod? The reason I ask is that I have been through the whole exercise myself and found that you really need to control the test environment.

On the assumption that the lower numbers are at a closer distance than the higher ones you appear to describe back focus wide open as the point of critical focus is behind where focus was indicated with the rangefinder. As you stop down things seem to improve and this could be down simply to the increased depth of field. If that is all true then you do not seem to have a major amount of focus shift.

You could adjust the infinity setting in the camera to make 1.4 perfect with your camera but if the lens is out instead of the camera you are basically making the rangefinder calibration incorrect because the lens is incorrect. This may not be a problem if you only use that camera/lens combination but you could just move the focus problem to your 50mm lens.

Does you rangefinder align at infinity?

 

[jaymz007]

yes it was done on a tripod if you pm me your email I can send you the pics and you can take a look at it and see.

 

[jaymz007]

How do I check the alignment at infinity?

 

[ecliffordsmith]

Hi Jay,

Sorry, I am not being very clear. All I mean to say is that with your lenses mounted if you look at a scene with a distant object at what point of focus on the lens does the rangefinder provide a completely aligned image? A distant tower is ideal as an unbroken line is easy to detect. The thing to check is that you do not each infinity too early and that you do not go beyond infinity. You should have a perfectly aligned object in the rangefinder.

 

[Bob]

Send the lens to DAG.
The infinity focus adjustment is a bit touchy, and although it can be done at home, I would recommend that you send your body and the lens in question to DAG and ask him to check and adjust as appropriate. He will tell you if the body needed any. If it did, then send in the lens that now looks ok.
Almost all lenses shift focus as they are stopped down from full open to minimum, and it usually is not a problem if the point of focus remains within the depth of field. Some lenses are more difficult to adjust than others, and DAG may give you adjustment options after he inspects your particular lens.
Since the 35 lux has a reputation for back-focusing as it is stopped down, sometimes a slight degree of front focus may be required wide open so that images are sharp at f/2. Check your focus test images at one stop intervals from full open down to about f/8 and see how the point of sharpest focus moves around.
-bob

 

[skolapper]

35mm Summilux f1 4 ASPH Front Focus

If youre able to see your shots immediately, like on a computer, take some practice shots of individual stars until you have pinpoint stars. Without being able to see the shot, you wont know exactly how close to focus you are. You cant just set to infinity, it is in fact usually a bit backed off of infinity, and the camera display is not clear enough for accurate focus. The only reliable way I have ever found is displayed full screen after the shot, then adjust focus and shoot again until you have nice, sharp stars.

 

[Paratom]

I also would recoimmend not to mess with the M8 and the Allen Key.
You might improve your camera for one lens but then you might mess it up for others. I did it and finally set my M8 to Leica for re-adjustment.
Rather send the 35lux to Leica and tell them how you wamt it calibrated (for f1.4)
Personally I have never managed to get totally reliable focus at various f-stops with the 35asph-lux and the Noctilux, even though mine have been calibrated by Leica together with my camera.
I rather use the 28asph and the 50asph, those 2 just work great regarding focus.
Kind of sad since I really like the drawing of the 35lux asph.
Cheers, Tom

 

[jaymz007]

Well Thanks everyone for the advices.
I just decided to take a chance and adjust the infinity focus on my own and I got pretty good results.
I took a 75mm Summicron ASPH APO lens that Leica fully checked out before sending it to me and using that lens I adjusted the infinity focus and the close distance with it. I went on checking focus for my 50mm lux and 35 lux and everything now is spot on with the focus.
the 35 lux does have a slight focus shift stopping down but nothing I can't live with. The 50 seems to be fine and the 75 is sharp sharp.