p.3 #3 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
I have the same issue with the lens freshly bought last week. I am bringing it back to SonyCenter this afternoon.I will post the serial number later on.
p.3 #4 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
#1803448 - I do not have these issues - tested at 105mm on a fairly close subject at f/4, f/5.6 and f/8, and the subject just became sharper when stopping down. All shot with AF-S. Also tested with AF-A - no difference. All on A7R III with firmware 1.01 and lens version 01.
p.3 #7 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
As promised earlier today the serial number of my 24-105 that is NOT working correctly with A7R2 1814906 just left in the Sony Center that is going to send it to the lab.
p.3 #8 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
MikeEvangelist wrote: Results So Far
Thanks to everyone who shared their numbers so far. We've got over 50 lenses reported now, with not a single bad one with serial number below 10,000.
Over 10,000, about half of the lenses seem to exhibit the focus shift.
Keep 'em coming!
It's pretty fascinating to see the trend. I'd love to know what changed - it could be anything from assembly differences to sourcing a single part from a different vendor after running through their initial stock.
We could start a conspiracy theory that a CaNikon spy has sabotaged the process - I see a feature film in the making.
p.3 #9 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
I'm wondering what else is not quite right with the lenses in the 181 range... If they exhibit that great a difference, are there also other optical performance problems. I can't believe that some exhibit no focus shift and others exhibit what appears to be substantial focus shift without there being some other optical symptoms.
That is, unless this is really an electronics issue...
If there is a focus shift correction algorithm in the lens that is either not working correctly or is working but shouldn't be (as in, it has been designed to be used but this lens doesn't require it so it should be dormant, but it is going zombie), or possibly an interaction between the aperture encoder and the distance focus controller, the lens could be doing things a bit haywire on the electronic side.
I'm a bit worried that lenses in the 181 range that don't currently exhibit this problem could have it begin if it is tied to a slightly out of spec electronics part...
p.3 #12 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
FYI, Roger C. was able to get a hold of an affected copy today. If this mystery has any chance of being solved then Roger will get to the bottom of it. No pressure Roger
p.3 #13 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
FWIW my testing techs today started testing for this. They found ten of ten 180 SN lenses were fine. One of three 181 SN lenses exhibited the focussing abnormality you all are discussing. I can't give specific SNs I'm afraid.
I refuse to call it focus shift at this point. Focus shift is a pretty specific optical phenomenon caused by spherical aberrations. This is something else. For one thing, a quick test on the lens I have in hand shows even the slightest stop down from f/4 causes more change than I'd see on a Canon 50mm f1.2, and that is a poster child of focus shift in my experience.
I've finished my Sony testing, but I won't write it up until I get to spend a day or two with this particular lens. But even without the focus shift this lens is excellent wide open, but rather weird, and it's stop-down behavior is odd not even considering the focus shift.
p.3 #14 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Thanks Roger. It's comforting to hear "confirmation" of this issue from you. Perhaps you can bring this issue to the attention of your Sony contacts ?
RCicala wrote:
FWIW my testing techs today started testing for this. They found ten of ten 180 SN lenses were fine. One of three 181 SN lenses exhibited the focussing abnormality you all are discussing. I can't give specific SNs I'm afraid.
p.3 #15 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
JVJL wrote:
Thanks Roger. It's comforting to hear "confirmation" of this issue from you. Perhaps you can bring this issue to the attention of your Sony contacts ?
I have a couple of days ago, and repeated it referencing this thread. This is really good, factual stuff here. And I would not have been aware of the issue except for FM. We had tested a ton of them, but not for this.
p.3 #16 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
RCicala wrote:
FWIW my testing techs today started testing for this. They found ten of ten 180 SN lenses were fine. One of three 181 SN lenses exhibited the focussing abnormality you all are discussing. I can't give specific SNs I'm afraid.
I refuse to call it focus shift at this point. Focus shift is a pretty specific optical phenomenon caused by spherical aberrations. This is something else. For one thing, a quick test on the lens I have in hand shows even the slightest stop down from f/4 causes more change than I'd see on a Canon 50mm f1.2, and that is a poster child of focus shift in my experience.
I've finished my Sony testing, but I won't write it up until I get to spend a day or two with this particular lens. But even without the focus shift this lens is excellent wide open, but rather weird, and it's stop-down behavior is odd not even considering the focus shift. ...Show more →
Thanks for that early peek Roger. Very interesting. It's clear from the behavior of the lens mounted on a camera that sharpest focal plane is moving when the lens stops down beyond f/4. If this shift is not the result of SA, which would caused by the mixed convergence/refraction of rays between the periphery of the lens and inner areas and which would also cause softness @ f/4 that you don't see on the bench results, does this then suggest the convergence across the entire surface area of the lens is well aligned at both f/4 and stopped down and thus the rays are shifting in unison/maintaining alignment? If so, what optical/lens phenomena might be behind that? Sorry if I'm not using the correct terminology here - my grasp is a bit tenuous on optics.
p.3 #17 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
Thanks Roger. It will be very interesting to see how Sony reacts to this issue. I would be highly disappointed if they force AF-S mode to focus stopped down in the next firmware release. This would be a tempting and easy "fix" to minimize PR damage as well as warranty costs. I'm not trying to pick on Sony as Apple has a long history of hiding issues by masking them in iOS / MacOS releases.
p.3 #18 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
snapsy wrote:
Thanks for that early peek Roger. Very interesting. It's clear from the behavior of the lens mounted on a camera that sharpest focal plane is moving when the lens stops down beyond f/4. If this shift is not the result of SA, which would caused by the mixed convergence/refraction of rays between the periphery of the lens and inner areas and which would also cause softness @ f/4 that you don't see on the bench results, does this then suggest the convergence across the entire surface area of the lens is well aligned at both f/4 and stopped down and thus the rays are shifting in unison/maintaining alignment? If so, what optical/lens phenomena might be behind that? Sorry if I'm not using the correct terminology here - my grasp is a bit tenuous on optics....Show more →
I honestly don't know, this lens has some odd behaviors. It doesn't have a great deal of spherical aberration (although there is some spherochromatism) and the behavior is so odd -- dramatic change in focus distance with very minor changes in aperture; apparently present in one group but not the other. That I really think there's another explanation going on.
But I have a large optically tested group that don't have this behavior. So first thing is to test it thoroughly optically and see if it has something the others don't. If it has more spherical aberration that will be immediately apparent. If there's a change in field curvature, lateral and longitudinal chroma, etc. we should find it. If it looks like the others optically, then we need to look at the aperture behavior and focusing behavior and other stuff.
Not saying I'll figure everything out. But I bet we can eliminate some possibilities.
p.3 #19 · 24-105mm FOCUS SHIFT survey - FINAL RESULTS
RCicala wrote:
I honestly don't know, this lens has some odd behaviors. It doesn't have a great deal of spherical aberration and the behavior is so odd -- dramatic change in focus distance with very minor changes in aperture; apparently present in one group but not the other. That I really think there's another explanation going on.
But I have a large optically tested group that don't have this behavior. So first thing is to test it thoroughly optically and see if it has something the others don't. If it has more spherical aberration that will be immediately apparent. If there's a change in field curvature, lateral and longitudinal chroma, etc. we should find it. If it looks like the others optically, then we need to look at the aperture behavior and focusing behavior and other stuff.
Not saying I'll figure everything out. But I bet we can eliminate some possibilities. ...Show more →
Thanks again. Are there any clues in the fact that the focus shift direction moves toward the camera when stopped down (negative shift) vs the more common away (positive shift)? Here's a graphic for others to use as a reference, which depicts SA for the wide-open aperture. The 24-105 is acting like case 'c', where the peripheral rays are converging too far behind the sensor plane (not refracting enough)...which then shifts backwards to the correct plane when stopped down:
