You should have a t-shirt that says, "I am a photographer, and I know things." A good deal of what you list is knowledge of what you cannot do--the limits of your equipment--such as what their best aperture is (which is to say, which apertures are not their best), or that digital-age lenses are hard to focus manually.

I only just got a mirrorless camera, and have no experience with it yet (except to take a few shots to verify that it works). But you are right that I will have to rely on experience about depth of field and other things in order to benefit from it. I am pretty comfortable with the Canon 650D which I have used for the last dozen years or so, but there are many things in my R5 I will have to learn. I suspect that people today who buy a first camera will never have a clue about what it can do (or what it does do)--as indeed we never use all the possibilities in our computers.

In 20 years selling cameras, I found that too many people bought cameras that soon remained hidden in some closet because they did not learn how to use the features it offered. I did my best to prevent that, and I had to ask more questions than I answered. They said, "I want the best camera you have--that does everything for you." What they really wanted was a simple camera without many settings to worry about, like a Yashica Electro 35 rangefinder. My theory was that a first camera should make a very fine back-up or second camera later on, as one progresses in needs and desires.

Your remark that mirrorless cameras are easier to focus manually with manual film camera lenses is encouraging. I have some nice Takumar prime lenses I can try with adapter if I suspect the digital zooms are not the best in some cases. (I can't afford all the new primes I would l would like.) But of course I will have to master the new equipment--which was all developed to improve the performance of old techniques and experience.

My doctorate is in philosophy, which indicates that I favor ponderous book-study, which I love in itself, so practical craft is more an adventure than a profession for me. I am sure this shows in my posts, as the first thing I did to learn photography was to study books on it, and this need not be considered a flaw unless you want something else from me.

When you say there are never any unexpected results, you characterize the professional exactly. Predictability is a major selling point, but surprising other people can be a great gift. Ticking every box and following every standard is probably a goal in professional work that amateurs are less likely to achieve, partly because they can't, but sometimes because they have the time to waste on surprises in the hope of something different. It is more like a Sunday drive without specific speed requirements or even destinations. This is different from the taxi driver or race car driver.

As what is good includes knowing limits (seeing what does not work well), being good must include making all the mistakes--in your case, by systematic tests, if not by never making an error.

But since there was no better equipment for the job, the assumption is probably that photojournalism (like written journalism) does not or cannot require the best work. Reporters must write whether they have anything to say or not; and photojournalists must produce pictures whether they are good or not. But Twain, Dickens, and Hemingway wrote for papers, and Eisenstadt, Capa, and others took pictures for them. Similarly, Galileo's telescope was really bad.

When I shot outdoor scenes in large format, I found acceptable DOF from a chart or wheel, and then stopped down another stop for better focus. (In large format, small apertures have much less diffraction.) If I could gain a bit of height in the camera, the foreground was farther away and more likely to fall into DOF--that is why Adams had a shooting platform on top of his vehicle. The foreground could start at 15 or 20 feet away, or more, so focusing around 30 feet would cover distant scenes at f22 or f32.

In those days people wanted sharpness overall except for special cases, but now it is fashionable to make everything as blurry as possible except the subject--or it seems sometimes that the bokeh is itself the subject. People stand around admiring and complimenting the exquisite fuzziness captured. It is no accident that this arises with the small formats we use now. They begin to fall apart with small apertures. Stacking focus for near and far is a protest against this, but it seldom looks natural (to me)...

No, apparently it does not have IS. But I would not use such low speeds without a tripod anyway--I would resort to ISO rather than shutter speeds that slow. Even with high shutter speeds, I prefer a tripod for that bit of extra edge. I guess it is a habit from the old days.

Oh, wait--you mean IBIS in the camera? I had not thought about that (not a feature of my Rebel series 650D). Yes, it is made for the mirrorless cameras. Does it assist automatically or do you have to do something in the camera for IBIS? Mine is just the R model, their first mirrorless, so it may not have it.

They did not eliminate the focus ring--just the switch to manual (the override from autofocus). Instead of the lens switch, the switch is in the camera. Naturally we like a focus ring that responds to manual without any switch, but I still believe that I will almost never manually focus it unless it is on a tripod for carefully composed shots, in which case the change to manual is a piece of cake.

One feature it has that is good for video is STM focus, which is quieter. (Yes, it is cheaper, and I don't mind that they made the lens a lot cheaper by skipping the rarely used features while still being super-sharp. Even IS is for me unnecessary for a lens so wide that hand-holding is easy even at 1/20 second).

When lenses had hyperfocal guides on the focus ring, I used them mainly for outdoor scenes... Using large format, I used a chart or wheel for the data. It is not always easy to see the focus when stopped way down, so I compose and focus wide open, or partly stopped down...

Sadly, who wants upside down photos?

Hey--excellent cameras could be made cheaply with no adjustments at all. Each camera would work just for one situation, such as sunny beaches or snow scenes, birthday cakes with flash, night skies, etc. Just use the one with the right aperture, shutter speed, focus distance, etc. Nothing to set.

Ah, now I understand you.

The lens in question can be manually focused, but you select it in the camera menu, not a switch on the lens.
For most photographers, I assume focus is hardly critical in a 17mm full frame camera, as most planes will be quite sharp, even if approximate. That is a great advantage of the lens for a start, for everyday use.

I accept what you say about video--not my thing--but I assume when you are shooting video it is no problem to set that in the camera controls? If you are frequently switching back and forth, I can see how a switch on the lens is better. If I ever try video, I can set it in the camera--but surely when everything looks sharp in the frame, it is hard to focus manually with any degree of precision? (I can set the view screen to 10x magnification, if that helps.)

On the other hand, if there is a switch that can be set wrong, I am prone to have it set wrong. That is a reason not to have it if you can leave it out. My one and only wedding was my brother's, and no one else took pictures, and I had the camera set on the wrong shutter speed for flash synchronization with that model (not my usual camera)--no pictures. (It was a surprise wedding--we thought it was a birthday party--so I was trying out a different camera and only had Kodachrome 25 in dim evening light outside.) I had no desire to go into that field, but as it happened nobody ever asked me to.

I have some great Canon L lenses with a close-up switch for macro, so that is something else to go wrong, even if in theory it is a great feature.

Yes, I read that when I used a Speed Graphic (amateur) 50 years ago--they were antiques then. I still have one though, and like it. I play with it using Canon as a back, but never got the Hasselblad to work that way--too complicated and expensive.

Note that a 4x5 inch negative is not so much enlarged for prints, so the critical sharpness required for tiny digital sensors (even full frame, and even medium format) was far less. A photo in a newspaper was rarely bigger than 4x5 itself (often smaller), and even so, coarsely printed.

If all we made were 4x6 prints for the album, millions of sins would never be found out. For ages, the old Brownies were medium format negatives that were just contact printed. Simple lenses were just fine. Holding the camera still was the biggest challenge, except under full sun or flashbulbs.

I am not a pro--and never tried video--but surely professional videographers have video cameras? OK, maybe wedding photographers use regular cameras, but I don't do those either.

But what do you mean?

(Sorry--this was reply to:

"Makes the lens useless for professional video work")

The proposal was for autofocus based on the aperture set, for hyperfocal distance when set for that... It would save calculating this at the time and setting it manually.

(a comparison on automation)

Oh, I like autofocus now.
But many people today seem to prefer manual exposure, yes?

Well, if I am presetting it, I can be as accurate as I like. I would err on the side of more focus range.