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Focusing Issues


Googaliser

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After a day of shooting in perfect weather down in Australia, I was saddened to find that many of the day's best shots seemed to be marginally out of focus. I'm not typically a pixel peeper - but I have a sharp eye for critical focus - and I was left underwhelmed. As the new wisdom dictates - I manually focussed where possible, although the shots with issues were on-the-whole autofocus shots.

I am used to a very high keeper rate using an M9/Noct 0.95 and also the Hassy H3D50 with HCD 100mm - so I am reasonably experienced when it comes to focussing technique. Something was wrong.

Today, I became a dreaded pixel peeper and set up some targets and shot off a tripod. This is what I found:

 

Using the S2/70mm I found that the camera consistently focusses approx 2 inches behind the target at a range of 10 feet. Obviously most noticeable at f2.5 - but even at f5.6 the target isn't yet in focus (as one would expect given the very narrow DOF at this range).

 

As for manual focussing - success at narrow DOF really is dependent on the subject detail. I intend to place an order for the split-screen accessory to aid with MF.

 

In the meantime, my S2 will be going back to Leica to have this investigated. The AF for close range photography is essentially useless. My Hassy in AF mode was spot-on at these ranges - so the 'just manually focus' argument doesn't work for me.

 

Back to the trusty M9 for now.

 

Rgds

Edited by Googaliser
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Well, if someone has to break the silence....

 

i also had concerns about focussing, not with the 70mm but with the 180.

 

I didn't do as rigorous a test as the OP, but eventually came to the conclusion that it was generally operator error failing to appreciate just how narrow the plane of focus can be.

 

I also believe that the last firmware update seems to have addressed this problem. Either that or I am rising up the learning curve because I have had no problems with the 180 since upgrading.

 

There was a thread on dpreview (I think?) about focussing issues, but I can't track it down now.

 

Cheers

 

 

 

Ed

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I did some more testing today using different targets and the S35mm also. I struggle to let these things rest - I desperately want this to be a case of user error since I have a couple of projects this month and next and would be mighty upset if instead the camera was on a workbench in Germany.

The results are infuriatingly inconsistent. I would still wager that the S2 is on average focussing behind the targets - but one or two were spot on. This for me, is the most annoying of issues. Is it me or the camera ? I'm in the field so this testing takes up valuable time. My MacBook Pro (top spec 17" only a year ago) - chokes on the S2 files - 1:1 zooms take about 5 seconds in lightroom and ingressing the files using USB ain't fast.

I will need to reserve final judgement until i get back to my office and view these files on 30" screens.

For those of you who can focus the S2 manually and consistently with tele's on low contrast targets at f f2.5-3.4 - I take my hat off to you. I literally have to press my entire eye to the eyecup and seriously concentrate. So much for spontaneity.

I think the focussing screen needs work. Its fantastically bright - for sure - but I believe the split image/microprism focusing screen (if it's as good as Dfarkas reports) - should be standard.

Not having confidence on one's equipment is a very unwelcome distraction.

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I have used three S2 cameras and have no focus issues.

 

If you have a focus issue, please try this simple demonstration so we can see the problem.

 

Simply take a shot of your keyboard at your widest f stop aimed at the "Y" key. Any problem? Show us. BTW this test works shooting the lower contrast edge of the key, but is not as visible in a jpeg as a demonstration. I shot this picture handheld at a high ISO for adequate shutter speed, rather than a tripod. I can also see how challenging it is to keep aim at a small target hand held. You need steady hands. I have the camera set on manual focus, and then hit and release the AF button to set focus in this test. Continuous AF might be inconsistent as camera movement off the Y key might fool the system. I am also shooting sitting in a chair to minimize moving the camera closer or farther as I focus.

 

Remember, one of the reasons we buy the S2 with fast lenses is so we can achieve thin depth of focus. Frankly, I can to it much faster with an S than I can with an M. I salute any who can get their M to better an S in this test. Remember, a rangefinder is best for focusing wide angle lenses versus tele.

 

The shot is a demonstration of just how thin the DOF is for those of you who haven't seen it for yourselves. The second photo is just a crop of the first shot. Aim wrong and there is no room for error. Easy to duplicate this test with your camera system. Of course you can also use Tim Jackson's chart downloadable here:

Nikon D70 Focus Chart

But the keyboard challenge is easier to compare on this forum.

 

Cheers,

Jack

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Well, I'll add to this by telling you that my S2 is on its way back to Leica to fix focus issues. I received one of the first production run cameras and have had to send it back for focus calibration twice before.

 

All four of my lenses and the body are on their way back to Leica for adjustment. I still love this system as the results (when all is well) are fantastic.

 

BTW, my body has a consistent front focusing problem not back focus, FWIW.

 

Derek

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Something is certainly wrong in these described cases. I only got to play with the S2 and that lens over lunch. I shot about 50 frames wide open (just across the table while chatting) and every time I used the AF correctly it worked. Certainly is no margin for error in close wide open.

100% crop.

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Edited by hoppyman
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Evidently, according to Lloyd, the back focusing manifests itself at medium to far distances. His controlled test results are pretty dramatic.

 

There is speculation that the AF area is so large that unless the intended critical focus point fills the center circle, the sensor can grab something else. This speculation is not Lloyd's, but that of others trying to understand the issue and then alter their way of shooting.

 

I'm puzzled about it all.

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Evidently, according to Lloyd, the back focusing manifests itself at medium to far distances. His controlled test results are pretty dramatic.

 

There is speculation that the AF area is so large that unless the intended critical focus point fills the center circle, the sensor can grab something else. This speculation is not Lloyd's, but that of others trying to understand the issue and then alter their way of shooting.

 

I'm puzzled about it all.

 

OK - so a pattern seems to be emerging - the above would help explain my erratic results.

 

To be clear, I love the S2 when its on the money. Early adopters of these systems should be in no doubt that we are all effectively beta testers.

 

BTW - I am using the new firmware.

 

Jack: I will post some keyboard shots - its a smart target - i was using magazine articles on a slope

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I am curious if there is a correlation to the percentage of S2 users who have focus issues that use the shutter button for AF trigger versus the rear button for AF trigger. I am not suggesting there isn't a problem with AF on some S2s. I just wonder if the chosen method to trigger AF is a contributor.

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I am curious if there is a correlation to the percentage of S2 users who have focus issues that use the shutter button for AF trigger versus the rear button for AF trigger. I am not suggesting there isn't a problem with AF on some S2s. I just wonder if the chosen method to trigger AF is a contributor.

 

I use the rear button for AF trigger. As an aside - I tend to press this to wake the camera from sleep (set to 5mins) - often whilst holding the main focus button if in a hurry (typical grab and shoot old habit). This of course sets the camera into bios upgrade mode - so then needs to be switched off for a few seconds and back on again - er - shot missed....:mad:

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Evidently, according to Lloyd, the back focusing manifests itself at medium to far distances. His controlled test results are pretty dramatic.

 

There is speculation that the AF area is so large that unless the intended critical focus point fills the center circle, the sensor can grab something else. This speculation is not Lloyd's, but that of others trying to understand the issue and then alter their way of shooting.

 

I'm puzzled about it all.

 

This is it . I tested it today with a friends S2 . The focusing is very accurate if the subject fills the center circle. This is easy to test with almost any large sign.

 

We used both the 35 (as a test of a wide FOV) and the 180 (narrow FOV) . The 180 was much more consistent ...but if the circle catches any sharp,high contrast edge it will focus on it. Front or back .

 

The 35 was all over the place (the circle taking in a large FOV) .

 

I need to do more testing tomorrow but it appears that the S2 does not focus track ..rather it focus locks ..so if you are used to Nikon/Canon and the rear AF button .(.which you lock and hold to follow focus). So I accept that operator error (locking focus on the wrong point and assuming its changing with my composition ) could be part of the problem.

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I am curious if there is a correlation to the percentage of S2 users who have focus issues that use the shutter button for AF trigger versus the rear button for AF trigger. I am not suggesting there isn't a problem with AF on some S2s. I just wonder if the chosen method to trigger AF is a contributor.

 

Mark

 

I think this is a factor. I was using the AF button on the back (the way I learned to use my Nikon s ) . I believe the AF button focuses and locks focus. You have to tap it again to refocus . I couldn t focus on a person walking by putting the + on their chest and just shooting.

 

But I also had misses where I may have locked the focus too soon .

 

This also happened with stationary targets .

 

I am going to Dale tomorrow and sort this out.

 

I am sure technique is a part of it but I also can demonstrate that the full image circle is being used to select the focus point.

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The rear button on the S2 can be customized a number of different ways. Our preferred setting is for Single AF activation for static subjects...but it can be also set to Continuous Auto Focus to track a subject. The latest firmware update significantly increased the functionality of the rear button.

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Hmm. i changed the function of the rear button at the same time as the update. I did the keyboard test with all four lenses and i get near identical results from MF and AFs modes.

 

Looking back at results I was worried about, they all seem to fall int othe wide circle range. Small target in cross hair but sharp well-defined edges or contrast within the outer circle.

 

The same shots MF were OK

 

I think this might be nailing it.

 

Ed

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