DoF may not exist...

Started 2 months ago | Discussions thread
DMillier Forum Pro • Posts: 22,788
Re: You asked. Here's the answer.
2

Greg7579 wrote:

JimKasson wrote:

Greg7579 wrote:

Evidence. LOL.

Go have some fun and shoot.

There is nothing extraordinary about anything I have said about GFX DOF.

I see the evidence every day when I shoot.

Go shoot some GFX and you will see.

But no worries. Carry on Sir.

Hey ... here is some GFX DOF. I took this a short time ago on a hike by our hotel.

Check out that beautiful glacier. Svinafellsjokul. The aiming point was on the close ice face, that was very far away. I took another one with the aiming point on the back mountains. Guess what happened?

They were both sharp. If they weren't, one was misfocused. You didn't use AF, did you? That's not reliable, for a single shot, although if you shoot enough shots with AF, you'll get one that's critically sharp.

And what do you think the tables say?

Let's say the near face is 400 meters away.

Diffraction will be a far, far greater source of blur than DOF.

OK Jim. I'm at dinner with a tablet drinking Icelandic beer and I need to check if both shots were the same with the focos point radically shitfted. But is all far away. It all should be good. I need to intensely peep. Of course no one else does. Teresa took the shot with her iphone and it looks great .... on the phone.

We are finally ll lucky. It has been overcast here for two weeks amnd we got here today to this glorious scene. And I got it. I had the monopod and the incrediblec45-100. I swear James .... I'm gonna sell all my GF lenses and use only the 45-100. 🤓

Erik .... No worries.

Here's how I see this ongoing situation:

- there are reasonably well understood optical and physical laws that have well proven models that produce well attested predictions across a range of formats

- you would expect them to work exactly the same with GFX when fed the correct parameters (why wouldn't they, it's just a sensor like any other)

- there's you continually making claims about how GFX defies those predictions (this is making "extraordinary claims")

- extraordinary claims require extraordinary evidence, as Erik noted. To not look at the evidence is a kind of intellectual negligence

- there are some people trying to get to the bottom of this, partly motivated by a desire to help you understand exactly how your camera works and put your practical experience on an empirical basis to help you get it right more often

- there's you constantly promising to engage with some simple tests then just as constantly backing away again when the chips are down

- then soon enough you are repeating your extraordinary claims

I'm very puzzled by your inconstancy. If you are not going to work with Jim, why do you keep repeating your claims when you know that is going to provoke another round of offers to work with you on testing?  You know this is going to happen. If you really aren't prepared to do any testing yourself, why not just say so and never repeat your untested claims again?

As an individual we are entitled to believe anything we want privately, sane or crazy. The flip side is as soon as we start making public claims and try to persuade others to our view, we are then obliged to justify our words. Your MO of making a big claim and demanding that everyone just believe you is asking a lot, IMO. When we share advice, we should concentrate on general rules that apply to everyone, not just something that works for one. Jim has provided a relatively straight forward method of doing exactly that and offered to hand-hold you through the process. I think it would be valuable to you and everyone else to engage.

From a personal perspective I've learned a lot from the debate, so I'm very happy to have had he chance to watch from the sidelines. It's been very useful to understand that my own 40+ years of practical experience with depth of field (largely ignoring calculators and tables) and going with instinct have clearly led me up the garden path: all those years just added up to me habitually making the same errors and focusing too far away. The information was in the tables all the while, I just paid no attention to it.  I'm going to pay much more attention to tables from now on, and a lot less to instinct and experience.

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