Justwalking is completely correct that the DOF formula ignores diffraction. What the DOF formula shows is only that you need to scale the effective aperture exactly in proportion to the sensor size, to get the same DOF.You probably did not understand that Dof formula with magnification just ignore the diffraction effect at all.
Then it is the diffraction formulas that take over, to add the very important information that scaling effective aperture in this way also automatically causes diffraction effects to match in the captured images.
On the surface, this seems quite a remarkable coincidence. I can easily understand how people miss it when reading most literature. What I do not understand is why Justwalking still misses the concept, after multiple explanations.
Justwalking has once again scrambled something in his concepts. We're talking about f/8.5 on sensor size 4.3 mm, versus f/47 on sensor size 24 mm. In both cases, about 380 Airy disk diameters fit across the frame. So with respect to the final image as seen by the human, these combinations in fact are exactly the same.but F'=8.5 is not the same as F'=47 for
It's annoying that no derivation or source for these numbers is given.System with your small sensor become diffraction limited at f/5.6 and FF with f/14.6.
Based on the ratio of the numbers, I think that what Justwalking has done is to compare a 7 megapixel 1/2.5" sensor versus a 36 megapixel FF sensor.
If that's the case, then what he's saying is that it's more challenging to fill 36 megapixels with pixel-sharp detail than it is to fill 7 megapixels with pixel-sharp detail. I would have no disagreement with that statement in isolation, but it's not relevant to the current discussion.
It seems you've missed another key concept.It's not idea. It's a math.
All math is just an idea, until it has been shown to describe reality.
Your math, unfortunately, does not survive that test. So yeah, what you're doing is just an idea.
Indeed, the images are not identical to what I posted in the other thread.Also i can't trust to your last picture with safety match. They do not looks like your previous in parallel thread, sorry.
That's because I looked at comments in the other thread, considered what I could do to further reduce irrelevant distractions, adjusted the test setup accordingly, and shot new pictures. In the current setup, I have taken more care to match the focus point, I have removed a previously unnoticed tilt of one camera to better match the alignment of foreground and background, and I have adjusted the processing of both images to remove some distracting chromatic aberration. None of those things have any effect on the topic of discussion, of course.
By the way, Justwalking -- and now I am talking directly to you -- please take note that accusing another member of dishonesty would be considered very bad form. I'm happy to see that you did not quite do that. I suggest staying safely back of that line in the future.