50 Lux Black Chrome - Focus shift?

[DwF]

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If Quarantine saves are asses, we'll all be crazier for the time in activities we should never have pursued!   Really, this is a good thread, and I also appreciate that 2-d aspect Farnz mentioned because we forget what we mainly point our cameras at is 3 dimensional.

David

PS she's not too tough to look at DKMoore, keep them coming!

[dkmoore]

39 minutes ago, a5m said:

Can you elaborate on this?

I'm glad you're figuring out what's going on with the lens. Looks like everything is copacetic.

I should be more careful what I say because the majority of my interactions have been fantastic. I did send an M246 there three times and once with a 28 Lux and 50 Lux. The 28 Lux was NEVER corrected and was replaced. I don't think they were able to shim it or something. They didn't mess with the 50 because they thought it was "within tolerance." The M246 was never corrected and was returned to Leica for a full refund. All were bought new. It was a very weird situation. My guess was that they were trying to mate the 28 Lux to the M246 and it just jacked the equation. I have since only had them adjust equipment separately and I don't have them adjust to a given camera since I rotate lenses and cameras.

I'm not sure what happened but it wasn't fun. They did respond incredibly quickly and tried to to make it right. And ultimately I didn't get stuck holding a flaming bag of crap. I have nothing but good feelings toward them as they have gone above and beyond many times for me. 

[dkmoore]

38 minutes ago, DwF said:

If Quarantine saves are asses, we'll all be crazier for the time in activities we should never have pursued!   Really, this is a good thread, and I also appreciate that 2-d aspect Farnz mentioned because we forget what we mainly point our cameras at is 3 dimensional.

David

PS she's not too tough to look at DKMoore, keep them coming!

I certainly proved that quarantining did make me CRAZIER, ha ha. 😷🤯🙃

And I do count myself lucky on the wife front.

[a5m]

1 hour ago, dkmoore said:

I should be more careful what I say because the majority of my interactions have been fantastic. I did send an M246 there three times and once with a 28 Lux and 50 Lux. The 28 Lux was NEVER corrected and was replaced. I don't think they were able to shim it or something. They didn't mess with the 50 because they thought it was "within tolerance." The M246 was never corrected and was returned to Leica for a full refund. All were bought new. It was a very weird situation. My guess was that they were trying to mate the 28 Lux to the M246 and it just jacked the equation. I have since only had them adjust equipment separately and I don't have them adjust to a given camera since I rotate lenses and cameras.

I'm not sure what happened but it wasn't fun. They did respond incredibly quickly and tried to to make it right. And ultimately I didn't get stuck holding a flaming bag of crap. I have nothing but good feelings toward them as they have gone above and beyond many times for me. 

Haha no worries, I do that too. I think the wait and turnaround times don't help.

I agree, weird they weren't able to fix it. But in my experience too I felt they value customer service. Like entirely replacing your lens, or fixing the aperture of a Noctilux 50/0.95 I had at no cost outside of warranty.

Also good tip to adjust individually. Better to learn the quirks of your gear and maintain all-around compatibility.

[GiorgioNuvolari]

Thank you all for a great and very educational discussion! This was superb for a newbie. Best, GN

[dkmoore]

18 hours ago, farnz said:

I'm simply pointing out that depth of focus is a three dimensional effect but using the (linear) text on the book to judge what's in or out of focus is only really considering the focus depth in two dimensions (the horizontal X-plane and the 'depth' z-plane).  The Y-plane is the vertical plane.  

Mentally drawing corner to corner lines indicates that they would cross above the text so it's not at the centre point of where the lens is pointed.  This is likely to mean that the word "remain" is straddling the south-west and south east quadrants of the 'focus cylinder' instead of crossing its centre point where it's dropping in and out of focus might be different and your interpretation of the focus area extending more towards you than away from you might not be correct. 

Additionally the book is tllted at an angle to the camera, which might accentuate in and out of focus areas.  This could mean that what you're interpreting as 'receding focus' might actually be a result of the angle of the book at any point. 

All of the above *could* be leading you to the conclusion that there's more in focus in front than behind where you believe the point of actual focus to be, which might not be the case in reality.  Testing requires the elimination of as many variables as practicable to try to get to the point where the only variables left are the ones that the tester adjusts during the test and repeatable results are achieved from which meaningful conclusions can be drawn.  (My apologies if this sounds like lecturing, it's not intended to be, I couldn't think of a way to put it any more clearly.)

Pete.

My apologies that I keep quoting you. But I have another question that may be of interest to many readers and certainly me. 

My assumption after these tests is that the angled ruler method (Straight on) is also flawed because the ruler is slanted up and the camera slanted down. Yet I see this method used very very frequently by reputable folks.

Is that method just as inaccurate as well? 
 

 

[IkarusJohn]

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6 hours ago, dkmoore said:

My apologies that I keep quoting you. But I have another question that may be of interest to many readers and certainly me. 

My assumption after these tests is that the angled ruler method (Straight on) is also flawed because the ruler is slanted up and the camera slanted down. Yet I see this method used very very frequently by reputable folks.

Is that method just as inaccurate as well? 
 

Not so much, as you’re managing only 2 dimensions, provided your camera  is set up exactly square to the ruler.

Think of it this way - hung vertically, you’d have no sense of the depth of field. Set horizontally, you would have no idea what was in focus.  At 45°, you get an elongated egg representing the plane of best focus. So, even though you can measure that plane, you have to recognise that you are looking at a diagonal slice.  I find that test good for assessing consistency of my lenses (best plane of focus) and focus shift.  With the M10-D, I’ve found all my lenses of varying ages (primarily 75 Summilux to 50 APO Summicron black chrome) to be excellent.

I hope that helps.
 

[dkmoore]

2 hours ago, IkarusJohn said:

Not so much, as you’re managing only 2 dimensions, provided your camera  is set up exactly square to the ruler.

Think of it this way - hung vertically, you’d have no sense of the depth of field. Set horizontally, you would have no idea what was in focus.  At 45°, you get an elongated egg representing the plane of best focus. So, even though you can measure that plane, you have to recognise that you are looking at a diagonal slice.  I find that test good for assessing consistency of my lenses (best plane of focus) and focus shift.  With the M10-D, I’ve found all my lenses of varying ages (primarily 75 Summilux to 50 APO Summicron black chrome) to be excellent.

I hope that helps.
 

Yes, it was helpful. Thank you!