p.6 #1 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
snapsy wrote:
Thanks Roger. Do you have any plans to take this copy apart? If your theory turns out to be true I wonder if this is strictly an assembly issue and/or if it's something which can develop over time as well (for copies which currently aren't affected).
I'm going to get the techs to retest this one on several camera bodies and see if it occurs on all of them. If it does, then yes, we'll probably open it up here. If, as some have said, it's only an A7rii issue and it's fine on other bodies, then it's probably electronic and there won't be anything we could do about it. In that case I'll send it in.
p.6 #2 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
RCicala wrote:
I'm going to get the techs to retest this one on several cameras and see if it occurs on all of them. If it does, then yes, we'll probably open it up here. If, as some have said, it's only an A7rii issue, then it's probably electronic and there won't be anything we could do about it. In that case I'll send it in.
Great, thanks. Btw it's not an A7rii-specific issue - I see it on the A7s, A7rII, A7rIII, and even the NEX-5N. The only difference in whether the causal user would notice it is whether or not their model focuses wide-open for AF-S; the A7rII and III do, whereas the A7s doesn't.
p.6 #5 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
RCicala wrote:
That's what I'm hoping. Then there's at least a chance it's mechanical. . .
Does the fact your measured shift starts being noticeable at ~70mm and peaks at 105mm dovetail with how the barrel extends and thus how those elements move with respect to a possible mechanical/spacing issue you theorized?
p.6 #6 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
snapsy wrote:
Does the fact your measured shift starts being noticeable at ~70mm and peaks at 105mm dovetail with how the barrel extends and thus how those elements move with respect to a possible mechanical/spacing issue you theorized?
...or did the factory install one of the elements backwards?
p.6 #7 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Roger,
Your data seems to closely match with what I've seen with my defective copy. I didn't notice any shift until approximately 50mm. At that point the issue was quite prominent. The degradation didn't seem linear but more of a step function once you hit some critical focal distance. My samples also show a severe degradation one stop down and additional, but less, degradation at f/8. Your measurements put precise numbers to what I've observed.
Based on what people have seen on this forum it almost seems as though Sony is trying a different approach to this lens design. When Fred first posted his test images he noticed a strange behavior where resolution actually degraded as the lens was stopped down one or two stops. It almost seems like that behavior is related to this issue. It could be possible that Sony has made some elements sensitive to both aperture and focal length. This issue might be the mechanism for this compensation being buggy.
RCicala wrote:
This has been a wonderful example of constructive forum input at it's best and in that spirit I'll ask a favor of any of you who have a misfocuser in your possession: would you check and see if the problem is there at 24mm? On this copy it wasn't, but was certainly apparent at 35mm.
p.6 #8 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
johnctharp wrote:
This has the opposite effect- for the same size display, more pixels means that pixels are smaller, and 1:1 viewing results in less ability to discern imperfections.
It would however allow for more of the frame to be viewed at 1:1, so an individual with very good vision might be able to still see the imperfections but also have more context for them with a higher resolution display.
I was going to say the same thing. High pixel density screens (retina etc) give the impression an image is sharper than it is. It's the reason I use a 27inch 2k screen for QC work. 4k/5k monitors need to be a lot larger than 27inch to lower the density sufficiently to enable accurate sharpness assessment.
p.6 #9 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Curious what the serial number is on the bad one. Mine seems fine but it’s in that batch of 181 that seems to be the area of issues. I’m actually 1812012 and I checked it again today. Seems okay
p.6 #10 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
GMPhotography wrote:
Curious what the serial number is on the bad one. Mine seems fine but it’s in that batch of 181 that seems to be the area of issues. I’m actually 1812012 and I checked it again today. Seems okay
I had several other 181xxxx that were OK, so it's certainly not all of them.
p.6 #14 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
If from what appears to be maybe the case and that is that there is some sort of mechanical issue with some of the lenses the surely Sony will have to recall them all (as an car manufacturer would have to with a car fault) to be checked and/or replaced. Personally I wouldn't be buying one until there is clarification form Sony on this. In the past where focussing issues were discovered after launch Sony solved the issue by updating the firmware which may not be possible in this case
p.6 #15 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Viramati wrote:
If from what appears to be maybe the case and that is that there is some sort of mechanical issue with some of the lenses the surely Sony will have to recall them all (as an car manufacturer would have to with a car fault) to be checked and/or replaced. Personally I wouldn't be buying one until there is clarification form Sony on this. In the past where focussing issues were discovered after launch Sony solved the issue by updating the firmware which may not be possible in this case
I would assume that it depends on whether the problem can be isolated to a specific batch (by serial numbers) which seems likely based on the evidence compiled so far. In that case they wouldn't recall all lenses but only those in the affected range.
p.6 #17 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Someone over at DP review posted that the last letter of the serial number on 2 lenses they tested were different. A good lens ended in A while a faulty lens ended in C. Both lenses were from the 181xxxx batch. This may be a clue.
My lens which is good (already reported in this thread) has a serial number 1814xxx ends in B. The production date is 01-2018 and it was purchased from B&H.
p.6 #18 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
col4bin wrote:
Someone over at DP review posted that the last letter of the serial number on 2 lenses they tested were different. A good lens ended in A while a faulty lens ended in C. Both lenses were from the 181xxxx batch. This may be a clue.
My lens which is good (already reported in this thread) has a serial number 1814xxx ends in B. The production date is 01-2018 and it was purchased from B&H.
My good copy (181xxxx batch) ends in M. Date code 01-2018, purchased through Greentoe.
p.6 #19 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
col4bin wrote:
Someone over at DP review posted that the last letter of the serial number on 2 lenses they tested were different. A good lens ended in A while a faulty lens ended in C. Both lenses were from the 181xxxx batch. This may be a clue.
My lens which is good (already reported in this thread) has a serial number 1814xxx ends in B. The production date is 01-2018 and it was purchased from B&H.
My copy ends in A and is affected. The full S/N on the box is S01-1811652-A.
