[MarkJerling]

Hmmm..... I think we are talking about two differ definitions of "slowest it will go." Your's looks like "the slowest it will ever go" and ours is the "slowest it will go before increasing the ISO above the baseline."

If you take the camera from full sun into progressively dimmer scenes, the AE system first picks slower and slower shutter speeds whilst keeping ISO at the baseline value (e.g., 100 or 200 if you have highlight protection). At some "speed limit" shutter speed, the AE system switches to holding shutter speed constant and raising ISO until ISO hits its max value.

OK, I'll test that. But, you must agree, what's been put forth in this post of yours is a very different idea from what was posited originally.

[MarkJerling]

Thus a series of AE settings in progressively dimmer scenes might look like this:

t=1/500, ISO=100
t=1/250, ISO=100
t=1/125, ISO=100
t=1/60, ISO=100 <-"speed limit" where the camera switches from slower shutter to higher ISO
t=1/60, ISO=200 -- speed stops changing, ISO increases
t=1/60, ISO=400
t=1/60, ISO=800
t=1/60, ISO=1600
t=1/60, ISO=3200 <-Max ISO limit where camera switches back to slower shutter
t=1/30, ISO=3200 -- ISO stops changing, shutter time increases
t=1/15, ISO= 3200
t=1/8, ISO= 3200
t=1/4, ISO= 3200
t=1/2, ISO=3200
t=1, ISO=3200
BLINKING t=1, ISO=3200 -- the AE system has reached its sensitivity limit

In my K-1 the "speed limit" is a function of F and the chosen program mode.

I've just quickly tested with one lens as I don't have time to do more this morning. What you're describing here does work, but, still not with the focal length / shutter speed relationship originally put forth.
But, the progression you describe is certainly there. For the 28-80mm lens (which is the only one I have time to test this morning) the slowest it will go before it changes the ISO value up is 1/125 at the 80mm zoomed end and 1/90 at the 28mm zoomed end. I'll report back when I have more time to show what happens with other zooms and primes, bot manual and auto.

[biz-engineer]

I'll report back when I have more time to show what happens with other zooms and primes, bot manual and auto.

Don't worry. You could just trust us and agree , and so you'd save the time of trying it out

1/125 at the 80mm zoomed end and 1/90 at the 28mm zoomed end.

You may not get the same shutter speed values, because the earth magnetic field in New Zealand is not the same as the intensity of magnitic field in Europe and NA.

[MarkJerling]

Don't worry. You could just trust us and agree , and so you'd save the time of trying it out

I don't have to trust you and agree, especially as the shutter speed to zoom range relationship is not as you say it is. Test and verify is the scientific method.

[biz-engineer]

Test and verify is the scientific method.

It's not a surprise that a photographer don't believe something until he can see it, it's called something like visual dominance of the senses of something like that.

[MarkJerling]

It's not a surprise that a photographer don't believe something until he can see it, it's called something like visual dominance of the senses of something like that.

Test and measure....

A 'no-brainer Nobel Prize': Hungarian scientists may have found a fifth force of nature - CNN

[stevebrot]

Ok I’ve thought about it, the problem with auto modes is they stop you from thinking, this is usually where mistakes happen

...and auto-ISO (the core dependency here) is almost painfully unpredictable in that it is not a form of programmed exposure, but instead appears to be a set of use-cases paired to specific behaviors. Plug in the right lens, light, and auto-ISO range and one gets an apparent accommodation to a focal length rule that may or may not result in 1/FL shutter speed when paired with an actual programmed exposure mode.

I have said before on this site the "Auto-ISO is Evil", with my meaning being not that using will endanger one's immortal soul, but that it may result in unexpected exposure settings (LV100) or "illegal" combinations with no particular reason to expect such.


Steve

(...Auto-ISO is Evil...)

[stevebrot]

Test and measure....

A 'no-brainer Nobel Prize': Hungarian scientists may have found a fifth force of nature - CNN

I watched a Star Trek Discovery episode a few days ago that also suggested a means to address dark matter, only using fungal spores set in an alternate dimension. Heady stuff, that Star Trek. Prescient.


Steve