[thxbb12]

Don't get me started ;-)

[mst]

Sorry for the harsh words, but seriously: what a kindergarden, what a silly discussion! I understand that many of us are facing challenges by staying at home and needing to find a way to spend their time on something that seems to be useful or at least distracting. But watching this post from a Pentax lens announcement to a discussion about standard zoom ranges, turn it into a pro/contra ML debate and now a brand war... come on! Relax, please.

As Klaus put it: Pentax very likely know their customer base by now, what they expect and what part of the expectations they can fulfill without ruining the company. Photography in itself is such a wide field of options and opportunities to express yourself and your vision, with endless subjects to capture, offering so many niches... the same is true about both enjoying this passion as well as the manufacturers serving all the different needs. If a brand's survival would be depending on if they can offer a 24 to 120ish f/4 zoom or not... Leica would be long gone, for example.

Seriously, the last thing I personally need or want is someone else unrequestedly explaining my gear needs to me. Or to anyone else. If ML suits your personal needs, fine. If it doesn't, fine too. A brand doesn't offer what you need? Well, don't buy it. It's an additional option, not an obligation to buy. No one forces you to switch to a system that doesn't match your own needs but is perfectly fine for others.

P.S.: there is still a thumbs up button, David

[JJ_SO]

...And because the AF misses are due to different wavelengths focusing differently, and lenses do not have the same aberrations over the whole focus range and even less so over the whole zoom range, AFMA is even less helpful.

By listing more and more reasons for indirect DSLR AF failure, this does not mean that AFMA cannot help to mitigate the errors.

Wavelengths or not, look at a FoCal table like "reliability of AF" to recognize the general flaws and the general tendency of try and (often) error - in the same perfect conditions, constant lighting with enough brightness, no flicker, camera on tripod, AF-S and always the same direction of turning the focus ring away from the last position, there's no chance to come close to 100% reliability - not to mention difficult lighting conditions in terms of quality and quantity of the available light. If you want to ignore these facts, it's helpful for sure to use lenses starting at f/4 - with them you can stick longer to the idea of superior AF in DSLRs.

As to reliability of AF: how long did the designers and engineers had to work to come at least to a certain reliability in a narrow center area of focus points - and how long did it take Sony to come out with the α9, nearly fully covering the image area, nearly no blackout at 20 fps?

Yes it's boring to read always the same advantages of mirrorless, which is not a temporary hype like Lytro or Lomo or milky way pictures are or have been. It's a simple evolution, cutting away the disadvantages of looking in a mirror before taking a picture. And it's no more boring than to hear or read all the lame fairytales about DSLRs as better systems, meanwhile reducing the benefits to just OVF. Which, after all, melts down to not consume a lot of energy...

Current example: Yesterday I had troubles to AF in broad daylight with the D850 - using one of the upper outer focus points and a Tamron 100-400/4.5-6.3. Why? Because I used one of the focus-points which are no cross-types and which are limited to f/5.6! As soon as I zoom back from 400 to 250 mm (and the aperture just switches from f/6 to f/5.6) I can AF perfectly.

Do I need to mention that none of my Z bodies has the slightest problem to AF this lens in the outermost corners?

In my experience, AFMA is very helpful but not a medicine to the conceptional disadvantages of an indirect AF-sensor. And daves "80% of lenses need it" is also my experience, maybe even more, I only recall two lenses out of 20 with no need to AFMA.

[mst]

Current example: Yesterday I had troubles to AF in broad daylight with the D850 - using one of the upper outer focus points and a Tamron 100-400/4.5-6.3. Why? Because I used one of the focus-points which are no cross-types and which are limited to f/5.6! As soon as I zoom back from 400 to 250 mm (and the aperture just switches from f/6 to f/5.6) I can AF perfectly.

Great example, seriously. Personally, I find the Z viewfinders (any EVF, to be honest) extremely annoying in bright daylight or any high contrast scenario, since they give such a weird image. I would personally always rely on focus and recompose and an OVF, for sure. No issues at all with that approach, either, for decades now.

Now, does that prove one of us right or wrong? Certainly not. There is a system that fits your needs and wishes, and there is another one fitting mine. Why does it need an ongoing and never ending battle to prove the other side wrong or inferior?

[JJ_SO]

Great example, seriously. Personally, I find the Z viewfinders (any EVF, to be honest) extremely annoying in bright daylight or any high contrast scenario, since they give such a weird image. I would personally always rely on focus and recompose and an OVF, for sure. No issues at all with that approach, either, for decades now.

Now, does that prove one of us right or wrong? Certainly not. There is a system that fits your needs and wishes, and there is another one fitting mine. Why does it need an ongoing and never ending battle to prove the other side wrong or inferior?

I don't see the greatness of my example in your reasoning about OVF. But anyway, if you say so...

Yes, the brighter the light, the more difference between reality and EVF. But who knows, we might see adapting EVFs one day - if they can amplify their backlight and still stay close to colour rendition.

And your recomposing demands certain concepts of composition. You simply could not do that, if you have a wide angle lens, wide open and with certain amount of field curvature (which doesn't matter in the final result, but with your method I would miss focus and with my method I get the best sharpness in this specific example.

And you also can't do that with erratically moving objects. It's a rather static method with more sources for inaccuracy than the indirect AF already has.

Sure, one can go on and take pictures like we're used to during the last century, why not, nothing wrong with that - but I enjoy the possibilities I gained and sometimes my main object is not centered in the "safe area". Isn't photography not also a sometimes surprising idea? But maybe it's a good thing that the users of old, traditional methods (which once were simple workaround to get at least a chance of a sharp picture) stick to it and stay on to their turf.

[mst]

Well done, JoJu, very well done actually, perfectly proved my point... q.e.d.

[davidmanze]

Sorry for the harsh words, but seriously: what a kindergarden, what a silly discussion! I understand that many of us are facing challenges by staying at home and needing to find a way to spend their time on something that seems to be useful or at least distracting. But watching this post from a Pentax lens announcement to a discussion about standard zoom ranges, turn it into a pro/contra ML debate and now a brand war... come on! Relax, please.

As Klaus put it: Pentax very likely know their customer base by now, what they expect and what part of the expectations they can fulfill without ruining the company. Photography in itself is such a wide field of options and opportunities to express yourself and your vision, with endless subjects to capture, offering so many niches... the same is true about both enjoying this passion as well as the manufacturers serving all the different needs. If a brand's survival would be depending on if they can offer a 24 to 120ish f/4 zoom or not... Leica would be long gone, for example.

Seriously, the last thing I personally need or want is someone else unrequestedly explaining my gear needs to me. Or to anyone else. If ML suits your personal needs, fine. If it doesn't, fine too. A brand doesn't offer what you need? Well, don't buy it. It's an additional option, not an obligation to buy. No one forces you to switch to a system that doesn't match your own needs but is perfectly fine for others.

P.S.: there is still a thumbs up button, David

Oh I see, you're prompting me

  OK, done it !!

[Brightcolours]

PS. Over the years I've heard many togs say that using AF fine tune causes more issues than it solves and as a consequence never tune their lenses ...... were these people getting the best from their lenses ?? .........80% of mine needed tuning!

AF fine tuning as in AF micro adjustment? That is not the same as lens calibration.
AFMA is really only a band-aid to be able to overcome an AF issue in the field. 

AF on DSLRs can be "miss" due to different wave lengths not focusing on the same plane. It depends on what the AF sensor is sensitive to. "Recently (last few years)", I have seen many complaints regarding Nikon cameras and different AF results in daylight and in artificial light. I bet that is due to a certain band of "invisible" light (IR/UV) that the AF sensor sees in focus before it would see visible light in focus.
You can't AFMA that away.

And because the AF misses are due to different wavelengths focusing differently, and lenses do not have the same aberrations over the whole focus range and even less so over the whole zoom range, AFMA is even less helpful.

Morning BC !!
 A là Pentax K5 ....  which below a certain artificial light level would front focus ...... rectified in the K5II ...... by adding an IR filter to the AF array
  Nonetheless that wasn't my point ...... I am talking about general fine tuning in normal light ....

My point was that general fine tuning in normal light is also problematic (different AF distances may give different levels of aberrations), hence the preference to get a lens "calibrated" instead of AFMA, the issue you pointed to. DSLRs can perform well for portraits, you do not need eye AF live view stuff for that.

[davidmanze]

...And because the AF misses are due to different wavelengths focusing differently, and lenses do not have the same aberrations over the whole focus range and even less so over the whole zoom range, AFMA is even less helpful.

    I'm not sure what world I live in ..... and I don't have any super optical technical knowledge ........ but you always come up with theories, (which could be technically right no doubt)  ..... that I struggle to align with my own experiences. 
Nikon has not a flawed system..... and as JoJu says ..... most of his lenses needed AFFT and the result is fine ...... so all I can conclude is these theories just don't apply themselves in any meaningful way to my shooting.
  If DSLRs didn't have AFFT I would have dumped them years ago!!
  --
 JoJu, the Tamron has trouble at 600mm@ F6.3 to achieve focus on the outer corner points (D500) .... this is normal ....... not great, but normal.

[JJ_SO]

Well done, JoJu, very well done actually, perfectly proved my point... q.e.d.

BS. My intention is not to prove anything right or wrong, but there are certain gaps in your reasoning which don't work out well in reality. And btw., if it's not about right or wrong, then why are you trying to demonstrate one of the most problematic ways to gain precise focus? Yes, maybe in 5-8 MP times. Yes, with optics available at 5-8 MP times this works precisely enough.

But either one remains in the era 5-8 MP (these pictures were not bad by any means) and uses gear from that era, or one wakes up and adjusts some focus techniques which no longer lead to maximum sharpness. Your recomposing will work in a landscape picture at f/8, as most other focusing methods will work as well, including using a DoF scale on a lens. But after that scenario it gets quickly more complicated.

Which proves my point how hard and stubborn the DSLR-fans stick to old techniques. What has worked yesterday, can't be wrong tomorrow - no matter how much easier life got in the meantime...