I will not waste more time into pointless equivalence discussions. I remain convinced it's only working fine in theory. In practice, it's not working and only kind of a crutch to roughly translate one giben FL on one sensor to another one. One cannot scale up or down apertures and FLs without scaling up or down tolerances of the used machinery and output.
That's very clear visible in wide-angle and ultra wide-angles - the closer FL goes towards 0, the more the lenses on smaller sensors struggle and show flaws everywhere. Be it corners, centers, CA, flares: For wide angle the sensor can't be too big. Opposite situation in Tele: The flaws are no longer in the lens or too big tolerances, but in it's user (shaking and needing high ISO to get shorter shutter speeds), the atmospheric conditions (wind, dust or mist).
The equivalencing game is working in theory - not so much in reality. Telling else is ignoring the limits of manufacturing and shooting conditions - no one is shooting in deep space, as no one gets close to absolute 0° K
I only explained that your notion on diffraction was wrong, JoJu. That you imagine all kinds of other things about equivalence is a separate matter.
Equivalence is just a sound and simple theory, and there is nothing about it that does "not work in practice".
Believe in what you like.
:lol:
Science is not a "believe" or faith. It is knowledge
I promised not to waste more time on this subject.
This post is exactly the kind of crap stuff that drives me nuts and that we see everywhere from MFT zealots (mind you, I shoot MFT):
https://www.43rumors.com/panasonic-200mm...e-quality/
How is a 200mm f2.8 MFT lens equivalent to a 400mm f2.8 FF lens? Let's convert the focal length, but omit the aperture. How convenient...
If you find a valve and a strong enough bicycle pump you can blow it up... With some luck and a really strong pump the black will turn into white.
It's because you get with both lenses the same shutter speeds at f/2.8 or any other aperture. That's what you equivalence preachers ignore in big style  DoF is only one thing in a picture.
I like Nasim's ideas to that subject: "Everyone's right, Everyone's wrong". And I requite his quote of a reader (who plays sort of same role as some of us here, me included":
Quote:And I loved this quote by our reader Betty, who summed up a lot of what I have said in this article: “As soon as you start using different cameras (!), with different processing engines (!), different sensors (!) and different pixel densities (!), and then start zooming a lens (!) to achieve or compensate for different crops, all bets are off. Your ‘results’ are meaninglessâ€. What a great way to describe what a lot of us are sadly doing.
It all comes down to the fact that even if one has different cameras with different sensor sizes, we will not carry them and their lenses around but take the picture with what's at hand. With a bit of luck and (even non-scientific) knowledge, the tool will be decent enough.
Btw. the Earth was a disc for quite a while according to scientists, bumblebees can't fly and homeopathy can't help. Using science to explain non-scientific, incomparable things because the differences do matter, leads to wrong assumptions. Which doesn't matter more than ignoring them and use "da wide" and "da long" lens.
11-16-2017, 06:42 AM
(This post was last modified: 11-16-2017, 06:44 AM by Brightcolours.)
Quote:If you find a valve and a strong enough bicycle pump you can blow it up... With some luck and a really strong pump the black will turn into white.
It's because you get with both lenses the same shutter speeds at f/2.8 or any other aperture. That's what you equivalence preachers ignore in big style DoF is only one thing in a picture.
No, you don't get the same shutter speed.
If you shoot an Olympus 200mm f2.8 on an Olympus OM-D EM10 at f2.8, ISO 800, and an Olympus 200mm f2.8 on an Olympus OM-D EM10 at f2.8, ISO 100, and let the camera figure out the exposure with the same metering method, do you get the same exposure time? Of course not.
Guess why.
And yes, homeopathy can't help, indeed.
And that the earth was considered a flat disk by scientists is a myth.
Quote:​Lets say you have a 20mp MFT sensor, and a 20mp FF sensor. Lets say you will make prints the same size, or look at 100% pixel size on a screen. Lets assume lenses of equal quality.
Lets assume you would see diffraction softening kick in at f8 for the 20mp FF sensor. You then WILL see diffraction softening kick in at f4 for the 20mp MFT sensor.
You scale up two things and the third and fourth you leave equal, You don't define equal quality, simply because there is no - machinery will not polish a µ 4/3 2 times more precise or mount it 2 times more precise.
Great. So much for your "scientific" experiments. Of this flock of assumptions, you will not see two or three coming together in reality fulfilling the condition of "exactly scaled". So, fantasizing about theoretically perfectly scaled conditions doesn't lead to any single better picture. Therefore posts like this have no value in reality. With your many assumptions you don't do science a big favour. In fact meeting a badly tempered scientists who read your posts could end up painful.
Not for the scientist.
11-16-2017, 07:33 AM
(This post was last modified: 11-16-2017, 07:33 AM by Brightcolours.)
There is no reason what so ever to mount a lens "precise".
And you wanting to not accept "equivalence" and therefore introducing "equal quality", that is just funny. In your world, one can't compare a Nikkor AF-S 50mm f1.4 mounted on a Nikon D750 and a Sigma 50mm f1.4 Art mounted on a Nikon D750, because... the lenses are not of equal quality, don't do everything the same.
In your wold, we can't call that Nikkor 50mm f1.4 mounted on FF equivalent to that Sigma 50mm f1.4, because "they don't render the same", "they don't have the same sharpness".
Funny how equivalency, which touches on the two fundamental aspects of lenses (FOV and DOF) in your world starts to be about everything except what it is about.
And equivalency certainly is not about "better images". Another straw man from you.
And yes, diffraction softening really is the same with similar sensor resolutions and equivalent f-stop values. With above mentioned caveat.
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