[Daedbird]

I think I would have preferred a 24mp FF sensor

[osv]

hmmm....

full-frame noise comparison: 24mp sony a7 vs. 36mp sony a7r

"At 3200 ISO there's another noticeable decrease in quality with the A7r exhibiting more noise than the A7, but arguably retaining more detail in the vase. At 6400 ISO up to the maximum 25600 ISO both cameras go steadily downhill with more noise and less detail. You could argue the A7 crops may contain fractionally sharper details, but we're in the realms of serious pixel peeping here and I don't think there's a great deal in it, especially if you down-sample the A7r or output them at the same size.

In my view I'd say the A7r is the winner here, capturing finer details at the lower sensitivities and only barely falling behind at higher ISOs - an advantage which is effectively eroded if you down-sample the A7r images or print them the same size. I hoped the A7 might fight back with decisively lower noise at high ISOs, but it's not obvious in my tests below. So if the highest quality is your priority, the A7r should be your top choice, but for the best results, shoot below 400 ISO."
Sony A7 vs A7r noise | Cameralabs

[ElJamoquio]

At the very least, that's not an objective measurement... and the 3200 iso comment is very likely irrelevant/wrong.

[osv]

it is kinda sketchy... the a7 at 3200 looks slighty better to me, but comparing jpegs at that level is kinda pointless, the compression artifacting is more noticeable than the noise.

[dtmateojr]

Don't try to be coy, the axis are aperture & resolution, you can see that. (Ask Roger Cicala if you want the data in tabular form.)




You can take their particular sharpening technique up with them, if you want, but the're saying something that shouldn't be a shock to anyone who's really shot landscape - the effects of diffraction are not something to be scared of, and a lot of blur that introduces can be mitigated by simple sharpening to gain acutance back. If you shoot with lower resolution in the first place, you have less raw data to even have that option. Here, check this out, it also contains the graphs that confused you because the obvious axis values were not labeled..




I still don't think you're getting it. You're losing resolution with every lens on every sensor once it's past it's MTF peak and starting to lose resolution to diffraction. When you start with more pixels, though, the absolute resolution will always be greater, up to some arbitrary lens-dependent point, maybe around f/16. You are not 'wasting' anything unless you're shooting pretty bad lenses at very small apertures all the time.

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Ok I think his graph shows lpcm (still no axis labels there so who knows). Which means a good lens should hit 1680 at f5.6. He did not even get to 1000 which is consistent with the results of the sharpening jokers. His second graph went a bit past 1000 but still not good enough. And that's why you do not see a "sharp" drop in resolution going from f5.6 to f8 to f11 because the lens is already incapable of fully utilizing the sensor even at f5.6. Imagine if at f5.6 the resolution was at 1500

Back to the table, how the heck does MTF50 get 80% of MTF10?!!! Stop believing those clowns man.

[ElJamoquio]

Ok I think his graph shows lpcm (still no axis labels there so who knows). Which means a good lens should hit 1680 at f5.6. He did not even get to 1000 which is consistent with the results of the sharpening jokers. His second graph went a bit past 1000 but still not good enough. And that's why you do not see a "sharp" drop in resolution going from f5.6 to f8 to f11 because the lens is already incapable of fully utilizing the sensor even at f5.6. Imagine if at f5.6 the resolution was at 1500

Back to the table, how the heck does MTF50 get 80% of MTF10?!!! Stop believing those clowns man.

To whom are you referring as 'clowns?'

[dtmateojr]

To whom are you referring as 'clowns?'

Whoever was trying to defy physics with photoshop lol!

[ElJamoquio]

Whoever was trying to defy physics with photoshop lol!

That's really nobody, then, though.

Do you feel a bit of trepidation when smaller pixels have resulted in better resolving power in repeated tests?

[dtmateojr]

That's really nobody, then, though.

Do you feel a bit of trepidation when smaller pixels have resulted in better resolving power in repeated tests?

Wait, let's make this really easy for everyone shall we.

105 lpmm for MTF10 is barely 10Mp. So they claim to magically produce data that isn't there at f22 but could NOT go past 10Mp on a 36Mp camera in ANY OTHER aperture? Surely you would have wondered about that, no? Nah, you just swallowed it whole without even blinking.

[oxidized]

I really dont this argument in "defense" of more pixels. Okay, as diffraction kicks in you just get less and less detail. I.E. for lack of an extreme example, lets call it a "smudge". Who cares of this smudge covers 1 pixel 2 pixels, 4 or 8 pixels. Its still just a smudge. Being a able to crop 8 pixels into 2 isnt going to get you anything. Neither is sharpening this "smudge". All you are left with is a ton of pixels eating up your computing power and taking up space on your hard disk. Yes, 36MP may be great, for when you shoot at a len's sweet spot (and this is assuming its not a KIT lens), however if you are wide open (and assuming you are not shooting something like an OTUS or Leica) or at F9+ the improvement in IQ from the whatever extra mega pixels this sensor is giving you is marginal (if even).

[ElJamoquio]

Wait, let's make this really easy for everyone shall we.

105 lpmm for MTF10 is barely 10Mp. So they claim to magically produce data that isn't there at f22 but could NOT go past 10Mp on a 36Mp camera in ANY OTHER aperture? Surely you would have wondered about that, no? Nah, you just swallowed it whole without even blinking.

I'm sorry, but responding to aggressive posts in the past has always gotten me banned instead of the aggressive poster.

[dtmateojr]

I'm sorry, but responding to aggressive posts in the past has always gotten me banned instead of the aggressive poster.

So you can't respond in a civilized manner after I have shown you the fault in your argument?

[ElJamoquio]

I have done nothing but respond in a patient and civil manner to your aggressive posts. You have shown no flaws in my argument, FWIW. I've explained to you that using airy disks throws information away, which is some/a lot of the reason where your analysis does not reflect reality, and you've been shown several measurements that indicate that you are missing *something*, so I would hope you'd at least reconsider some of your conclusions.

I will respond no further to you.

[dtmateojr]

Of course airy discs throw away info. That is basically the effect of diffraction. Claiming that you can resolve past hard limits of diffraction is the fault of your argument. The obviously unscientific "findings" that were posted (borderline magic) are funny at best. I can't believe that you believe them.

[jsherman999]

Ok I think his graph shows lpcm (still no axis labels there so who knows). Which means a good lens should hit 1680 at f5.6. He did not even get to 1000 which is consistent with the results of the sharpening jokers. His second graph went a bit past 1000 but still not good enough. And that's why you do not see a "sharp" drop in resolution going from f5.6 to f8 to f11 because the lens is already incapable of fully utilizing the sensor even at f5.6. Imagine if at f5.6 the resolution was at 1500

I'm not quite sure how to take this comment - are you saying that Roger's bench testing is incorrect, or that the lens is so 'bad' so it's not showing the effect you expected to see? The 50mm in question is a pretty standard lens, ie it resolves quite well stopped down and isn't going to be an outlier in any way. Roger's team tests hundreds of lenses per year as part of their business, so he's going to know if something is giving 'bad' results right away. That link also has a few other lenses tested, all showing the same thing - 36MP giving more resolution than the lower-MP sensors at the same apertures, and past your f/11 point.

Here's a statement by Joseph James : "A common myth is that smaller pixels suffer more from diffraction than larger pixels. On the contrary, for a given sensor size and lens, smaller pixels always result in more detail. That said, as we stop down and the DOF deepens, we reach a point where we begin to lose detail due to diffraction softening. As a consequence, photos made with more pixels will begin to lose their detail advantage earlier and quicker than images made with fewer pixels, but they will always retain more detail. Eventually, the additional detail afforded by the extra pixels becomes trivial (most certainly by f/32 on FF)."

The bolded sentence describes what you see when you plot the resolution as Roger Cicala did and DXOmark did in the earlier plot I posted - the slope of the curve gets a little steeper with the higher-MP sensor past the MTF peak (meaning it loses resolution slightly faster,) but it never intersects the lower-MP curve until very low apertures, and not at f/11 with any of those tested lenses. Meaning, as Joseph says - it always resolves more. Past about f/16 with most lenses, the difference is going to be pretty small, and there's probably no difference between any sensor + lens at f/32, as Joseph says.

If you want to imagine perfect lenses only** and concentrate on just the Airy disk diameter vs. pixel size, you still are not seeing anything bad at f/11 at even large prints (16'' on long side in example below) and pretty close viewing distances (25cm)


(from here)

** and by the way, how are you defining 'perfect lens'? A perfect lens has traditionally been described as one that is sharpest wide-open, that does not suffer from any aberrations at all wide open and thus is 'diffraction limited' at maximum aperture. You mention a 'perfect lens' being diffraction limited at some other aperture, and that breaks the definition of 'perfect lens'. Just an aside.


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---------- Post added 02-24-14 at 06:23 PM ----------

Of course airy discs throw away info. That is basically the effect of diffraction. Claiming that you can resolve past hard limits of diffraction is the fault of your argument. The obviously unscientific "findings" that were posted (borderline magic) are funny at best. I can't believe that you believe them.

I don't see anywhere where anyone said details completely lost to diffraction were somehow recoverable, if that's what you were implying, I saw where someone said MTF can be affected by sharpening. (You don't disagree with that, do you? )

By the way, that person's methods and data is available if you want to contact them on that link.