Bokehddicted wrote:
I posted the theory below one year ago.
I am still certainly it is a Sony E-mount protocol tolerance problem:
The aperture value is not a discrete value: 1.4, 2.0, 2.8 but rather either an analog signal or digital continuous value in the spec of the protocol.
In either case the focus assist zoom mode needs to make a decision when at what delta a change of aperture is making it snap out of focus assist.
At some point in the chain, the analog signal of the position of the aperture ring needs to be transformed into a digital value. Either in the lens (if E-mount protocol for aperture is digital) or in the camera (if analog).
The camera needs to have a ‚threshold‘ at what delta a ‚change‘ happened.
The problem is likely that there is slight jitter (mechanical and/or electric) in the signal before digitalization.
A threshold window too narrow will make any form of random high jitter be interpreted as ‚change‘ and it will snap out of magnification.
Up to a certain camera generation, Sony cameras had a signal path and or jitter tolerance that did not break this function.
Starting with A1, A7s3, A7r5 (maybe others) this changed so that seem to have changed so that now manual lenses like Loxia or Voigtlander ‚slip through‘ in terms of their level of tolerance in regard to the aperture signal value stream.
Some lenses are within tolerance to still work, but might slip later. Others will stay in tolerance forever.
The theory explains everything anyone ever posted on the issue.
And it could be easily changed.
BY SONY.
They could change the tolerance value for aperture value triggering for the magnifaction feature so that it quite a bit more tolerant. To the point that it would work again for everyone like it did with older bodies.
BY FIRMWARE UPDATE
Neither Zeiss nor Voigtlander should need to change anything. Tolerance and jitter slip has to be accommodated for in the Sony E-mount spec and Sony firmware.
IMHO obviously. I dont have insight knowledge but lots of experience in related fields.
Anyone supporting this? Would change who to put pressure on.
Bokehddicted wrote:
For me the problem is rather obvious.
The zoom function is designed to stay zoomed while you focus. And to get out of zoom when anything (or some defined things) change. For buttons it is easy. If you press some, it snaps out of it.
For things that have a more ‚analogue‘ readout, like the aperture on the Loxia. Even if the aperture is not in declicked mode, there seems to be a rather broad range of non-discrete values being communicates from the lens to the body.
The function that needs to make a call whether something ‚changed‘ needs to make ‚threshold‘ check, rather than a binary button check.
In my theory, they might have changed that threshold for those more non-discrete things, or only for the aprerture in particular.
That would explain many things. You might have a body or a firmware with wider or more narrow threshold.
And your particular lens, old or young, might be within the tolerance to trigger.
Anyone see some sense here?
The one thing I am not certain on, is whether Sony actually really changed their protocol and tolerance in the way of a deliberate change in firmware code.
I am sceptical that Sony would actually change such a tolerance value, leading up to numerous complaints from people using the focus ring magnified view feature for manual lenses. It does not make sense, and there is no real conceivable reason for de facto breaking a working protocol.
I wonder if the faster processors, most noticeably the A1 having a 10x faster processor, have not exposed a lingering and potential issue, that would not have appeared if it weren't for the vastly upgraded responsiveness of the later Sony cameras.
This would make coming to a solution complicated: Sony can lay the issue with Zeiss, seeing their lenses as being out of spec. Zeiss will not need to point elsewhere, as they have downgraded their support for the Loxia lenses to virtually non existent.
Aug 23, 2023 at 03:47 PM
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