Photography industry changes...

[Apple fanboy]

It's always the photographer that makes the picture. Not the camera.

 

[Ledgem]

Focusing in mirrorless can be interesting.

Since AF in SLRs(or specifically passive TTL focusing-ultrasonic or IR active focus in P&S cameras was in use earlier) became practical in the mid to late 80s, phase detect focus has been the dominant method. In something like a Nikon F4 or any other camera of the area, you have a 3 or 5 pixel CCD sitting behind the reflex mirror-usually on the floor of the mirror box. There's a semi-silvered patch in the center of the reflex mirror that bounces light down onto the CCD. The AF module then works together with the motor to maximize the contrast between two adjacent pixels. That's also why you need an area of good contrast.

Over the past 30+ years, phase detect has been refined and improved tremendously where it's now lighting fast and precise. Modern high end cameras now have stupidly high numbers of AF points(I think the D850 has somewhere around 150). The low light capabilities have also been improved, as well as other things in in less-than-optimum conditions.

For years now, going back to P&S digitals, now cell phones, and high end interchangeable lens cameras we've the development of contrast detect AF technology. It essentially looks at the whole sensor, picks out what's important, and then maximizes the contrast in the area. It has the ability to be incredibly precise, but is also slow compared to phase detect. It's getting better, and does have the ability to focus over the entire imaging area(a big step up from the single center point in an F4). Still, the speed is a big turn-off.

A co-worker has the first generation A7R, and one of his two big complaints is how slow the AF is on it. Admittedly that's a fairly old camera as high end mirrorless goes. Incidentally, his other complaint is that it's as loud as a DSLR, something that's been addressed in newer cameras.

With that said, I admit to not having read up on it a HUGE amount, but as per that same co-worker the current high end Sony cameras actually use a separate phase detect system for course focus and then switch over to contrast to do the final "fine tune." That seems to me like the best of both worlds.

I don't know much about the first-generation A7R, but autofocus on mirrorless is no longer as slow as it used to be.

I use an E-M1 Mk2. It's mirrorless, but has special "phase detect" pixels interspersed throughout the sensor. While I'll grant that Olympus' 4/3 (mirrored) cameras were never the absolute fastest to autofocus in the camera world, my E-M1 Mk2 is faster than my old E-3 was, even when using 4/3 lenses. Switch over to the newer µ4/3 lenses, which have even more advanced autofocus motors, and the speed is insane. It's near-instant. A lens can rack through the entire focus range in less than a second.

Panasonic has also recently developed a new autofocus methodology called "depth from defocus." It's still a pure contrast-detect method, but they have an algorithm that analyzes the background blur to know which direction autofocus should go. It's a bit more complicated than that, but it compares very favorably with standard phase-detect systems. There was some website that ran a comparison between the Panasonic G9, Olympus E-M1 Mk2, and a Nikon D850, I believe it was. While the D850 won for speed and accuracy, it wasn't that far ahead of the two flagship µ4/3 cameras.

These days, the complaints about autofocus on µ4/3 that you'll hear about deal more with focus tracking than with autofocus speed. My guess is that focus tracking is probably still superior with Nikon and Canon, but it's developing at a rapid rate for Olympus and Panasonic, too. And unlike pure phase detect systems, mirrorless cameras can engage image recognition features; many portrait photographers enjoy Sony, Olympus, and Panasonic for the ability to recognize a human face, for example, and the options to specify autofocus on the left or right eye, even. Something like that simply isn't possible on your standard mirror-bearing DSLR, unless you flip the mirror up and have it operate in a mirrorless fashion.

 

[someoldguy]

It's always the photographer that makes the picture. Not the camera.

Oh yeah ...... blame the photographer ..... it's always the photographer's fault . .......

If I only had that Hasselblad .......

 

[bunnspecial]

If I only had that Hasselblad .......

My extended family was over yesterday afternoon for Easter dinner.

I had a roll of film that I needed to get out of my 220 back, so I put the Hasselblad through its paces. I have to tell you that chasing kids with a Hasselblad is not the easiest job in the world.

All of my lenses are chrome C lenses from the 1960s. They have notoriously stiff focus(even when serviced, which mine need to be) and 330º of focus throw. Even though I shoot a LOT of manual focus stuff, that's a big change considering that most MF Nikkors have 90-180º of throw and will move with one finger.

The Hasselblad is bad enough that I use a focusing handle on it.

To make my life easier, I stuck a gigantic Metz 60CT4 flash gun on the camera which let me shoot at f/11 all day. That has its issues, too, as the battery pack weighs several pounds-I mostly set it on the floor and just relied on the cable being long enough, but did sling it over my shoulder some.

The bigger issue, though, was with the sync cable. At least on 80mm C lenses, the PC socket is in front of the focus ring. I found that with the focusing handle attached in its most comfortable orientation(infinity sticking straight out to the right) it would foul on the PC cable at close distances. I COULD have moved the handle around, but stuck with unplugging and plugging back in the sync cord to get past it.

I settled on "zone focusing"-or just picking my focus point and waiting for someone to come into it rather than trying to focus for every shot. That is a time tested candid technique, and it makes things a lot easier.

So-the moral of the story-use the right tool for the job. A Hasselblad isn't always the right tool.