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Comparing 42MP vs 61MP: Real-World Resolution and Contrast

  
 
StephenLowell
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p.2 #1Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Fred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?
Sep 16, 2019 at 07:44 PM
DavidBM
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p.2 #2Comparing 42MP vs 61MP: Real-World Resolution and Contrast
StephenLowell wrote:
Fred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?


It's just because the higher the resolution, the higher the (absolute) increase in resolution when you increase the sensor resolution.
And central areas have higher resolutions to being with.


But all areas benefit, and all lenses benefit. A lot of rot is talked about lenses "not coping" with high MP. It's true that there will be very little improvement with a poor lens, but there will be improvement (of course you may be tempted to judge lenses by the pixel level, in which case you are looking at higher magnification when looking at a higher MP image: so flaws will be more visible, even if there is improvement. But if you compare at fixed magnification (of the sensor size, not pixel mag) you will mostly see improvement, perhaps in some poor lenses that improvement will be imperceptible.
Sep 16, 2019 at 07:50 PM
snapsy
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p.2 #3Comparing 42MP vs 61MP: Real-World Resolution and Contrast
StephenLowell wrote:
Fred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?


Lens resolving power gradually drops away from the center, which means the lens becomes the limiting factor. It's actually a significant issue with high MP sensors for landscapes - not because there's less improvement away from the center by itself but because it creates a more noticeable difference in sharpness between the center and edges.
Sep 16, 2019 at 07:52 PM
GabrielPhoto
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p.2 #4Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Fred Miranda wrote:
snapsy wroteFred, can you post a center crop comparison with both cameras upsampled to 120MP? That way both images will undergo resampling, which should provide a more equitable comparison methodology.
Both images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:


Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.
Sep 16, 2019 at 07:54 PM
nhsonyshooter
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p.2 #5Comparing 42MP vs 61MP: Real-World Resolution and Contrast
GMPhotography wrote:
Not to get OT but my Rokinon 85 is on fire with this body


They ever fix the AF on those?
Sep 16, 2019 at 07:59 PM
StephenLowell
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p.2 #6Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Thanks Snapsy,

It was something I'm aware of but for some reason thought there may be something more


snapsy wrote:
StephenLowell wroteFred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?
Lens resolving power gradually drops away from the center, which means the lens becomes the limiting factor. It's actually a significant issue with high MP sensors for landscapes - not because there's less improvement away from the center by itself but because it creates a more noticeable difference in sharpness between the center and edges.


Sep 16, 2019 at 08:03 PM
Fred Miranda
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p.2 #7Comparing 42MP vs 61MP: Real-World Resolution and Contrast
DavidBM wrote:
StephenLowell wroteFred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?
It's just because the higher the resolution, the higher the (absolute) increase in resolution when you increase the sensor resolution.
And central areas have higher resolutions to being with.

But all areas benefit, and all lenses benefit. A lot of rot is talked about lenses "not coping" with high MP. It's true that there will be very little improvement with a poor lens, but there will be improvement (of course you may be tempted to judge lenses by the pixel level, in which case you are looking at higher magnification when looking at a higher MP image: so flaws will be more
...Show more →

---------------------------------------------

snapsy wrote:
StephenLowell wroteFred, Maybe I'm missing something incredibly simple, but why is the resolution/contrast increase only expected or seen around the centre area of the image?
Lens resolving power gradually drops away from the center, which means the lens becomes the limiting factor. It's actually a significant issue with high MP sensors for landscapes - not because there's less improvement away from the center by itself but because it creates a more noticeable difference in sharpness between the center and edges.


Yes! and even at the very corners, resolution is higher with the R4...just not the same level as center.

here is a 2:1 crop showing the extreme edge (R3 vs R4):





2:1 magnification - Ignore the color difference. The R4 has a beta LR profile

Sep 16, 2019 at 09:39 PM
GMPhotography
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p.2 #8Comparing 42MP vs 61MP: Real-World Resolution and Contrast
1bwana1 wrote:
Yep, Ray Charles could see the difference side by side. The a7RIV is better.

Not sure how much I would notice viewed at different times, different viewing conditions, and if images were of different subjects.


Hmmm it’s hard to miss on screen at full resolution. The detail is popping really nice. Certainly beats the A7rIII and I love that cam. So far I’m glad I went for it
Sep 16, 2019 at 09:52 PM
samosh
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p.2 #9Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Fred, any chance you can do similar test with "good" but not the best lens like G or Batis?
Sep 16, 2019 at 10:05 PM
alundeb
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p.2 #10Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Thanks for the tests, Fred.

At native resolution, it seems that the 4 is showing a tiny bit more actuance than the 3, if there is any difference. Normally, as we get higher resolution sensors and compare images at native resolution using the same lens at the same aperture, we should observe lower actuance with the higher resolution camera, because we are looking at a higher magnification and see more lp/mm, where the lens MTF is lower.

I am going to postulate that the A7r4 is using smaller microlenses, with lower fill factor than the A7r 3. The reports on increased ISO noise, even normalized, points in the same direction.

If this is the case, it is going to be good for:
- Less need for sharpening
- Possibly less corner smearing with certain lenses

And it is going to be less good for certain things as well:
- Lower light sensitivity
- More aliasing, compared to the same sensor resolution with gapless microlenses. However, increased resolution always means less aliasing, so it will still probably be better than the A7r III sensor in that regard.

If there is more data coming in that supports this, I am going to suggest to Jim Kasson to look into it. He found that the GFX 100 sensor is doing the opposite, abandoning the smaller microlenses used in the GFX50 sensors.
Sep 17, 2019 at 01:35 AM
 


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GMPhotography
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p.2 #11Comparing 42MP vs 61MP: Real-World Resolution and Contrast
In C1 I can’t use the base sharpening I did for the A7rIII. I have dropped it pretty good.
Sep 17, 2019 at 03:20 AM
LBJ2
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p.2 #12Comparing 42MP vs 61MP: Real-World Resolution and Contrast
alundeb wrote:
Thanks for the tests, Fred.

At native resolution, it seems that the 4 is showing a tiny bit more actuance than the 3, if there is any difference. Normally, as we get higher resolution sensors and compare images at native resolution using the same lens at the same aperture, we should observe lower actuance with the higher resolution camera, because we are looking at a higher magnification and see more lp/mm, where the lens MTF is lower.

I am going to postulate that the A7r4 is using smaller microlenses, with lower fill factor than the A7r 3. The reports on increased ISO
...Show more →

Interesting. "tiny bit more [acutance]" You might be on to something. Like everyone else, I've been starring at /pixel peeping these and other test images on the iMac 5K...with a few questions yet to be answered. Early days of course and Sony has been known to make a few tweaks here and there after new product releases. Also, interesting and something I didn't know "the GFX 100 sensor is doing the opposite, abandoning the smaller microlenses used in the GFX50 sensors." Shooting Leica M10 for over a year now, I've seen the significance/results first hand of properly adjusted micro lenses.

https://www.cambridgeincolour.com/tutorials/sharpness.htm
Sep 17, 2019 at 07:36 AM
vdo1
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p.2 #13Comparing 42MP vs 61MP: Real-World Resolution and Contrast
GabrielPhoto wrote:
Fred Miranda wrote
snapsy wroteFred, can you post a center crop comparison with both cameras upsampled to 120MP? That way both images will undergo resampling, which should provide a more equitable comparison methodology.
Both images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:
Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.


At $99 that thing looks like the most effective upgrade to the R3, you don't even need new L brackets and stuff....
Sep 17, 2019 at 07:55 AM
snapsy
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p.2 #14Comparing 42MP vs 61MP: Real-World Resolution and Contrast
alundeb wrote:
Thanks for the tests, Fred.

At native resolution, it seems that the 4 is showing a tiny bit more actuance than the 3, if there is any difference. Normally, as we get higher resolution sensors and compare images at native resolution using the same lens at the same aperture, we should observe lower actuance with the higher resolution camera, because we are looking at a higher magnification and see more lp/mm, where the lens MTF is lower.

I am going to postulate that the A7r4 is using smaller microlenses, with lower fill factor than the A7r 3. The reports on increased ISO
...Show more →

The increase in High ISO noise is attributable to lower high ISO DR, which is attributable to no advancement in read noise with the new sensor in combination with more pixels, which increases aggregate read noise at high ISO. It's also due from the earlier ISO dual gain switch. I doubt the fill factor is any less - sensors with geometries much smaller than this still achieve near 100% fill factors (smartphone sensors).
Sep 17, 2019 at 08:18 AM
GabrielPhoto
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p.2 #15Comparing 42MP vs 61MP: Real-World Resolution and Contrast
vdo1 wrote:
GabrielPhoto wrote
Fred Miranda wrote
snapsy wroteFred, can you post a center crop comparison with both cameras upsampled to 120MP? That way both images will undergo resampling, which should provide a more equitable comparison methodology.
Both images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:
Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.
At $99 that thing looks like the most effective upgrade to the R3, you don't even need new L brackets and stuff....


Indeed I am very curious to see how different plugins results will compare to the real thing.
Sep 17, 2019 at 08:28 AM
vdo1
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p.2 #16Comparing 42MP vs 61MP: Real-World Resolution and Contrast
GabrielPhoto wrote:
vdo1 wrote
GabrielPhoto wrote
Fred Miranda wrote
snapsy wroteFred, can you post a center crop comparison with both cameras upsampled to 120MP? That way both images will undergo resampling, which should provide a more equitable comparison methodology.
Both images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:
Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.
At $99 that thing looks like the most effective upgrade to the R3, you don't even need new L brackets and stuff....
Indeed I am very curious to see how different plugins results will compare to the real thing.


You know, I just went through some reviews and sample shots and I believe that asking an 120% scale from it is not a big ask at all. What was obvious from one review was that bicubic is terrible when compared with Topaz. There was no contest.

Maybe if Fred could share one of the RAWs you could do a run at it, just to show the difference vs bicubic on one of the images used here.

Sep 17, 2019 at 08:33 AM
Fred Miranda
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p.2 #17Comparing 42MP vs 61MP: Real-World Resolution and Contrast
vdo1 wrote:
GabrielPhoto wrote
vdo1 wrote
GabrielPhoto wrote
Fred Miranda wrote
snapsy wroteFred, can you post a center crop comparison with both cameras upsampled to 120MP? That way both images will undergo resampling, which should provide a more equitable comparison methodology.
Both images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:
Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.
At $99 that thing looks like the most effective upgrade to the R3, you don't even need new L brackets and stuff....
Indeed I am very curious to see how different plugins results will compare to the real thing.
You know, I just went through some reviews and sample shots and I believe that asking an 120% scale from it is not a big ask at all. What was obvious from one review was that bicubic is terrible when compared with Topaz. There was no contest.



I will try topaz gigapixel instead of PS bicubic when comparing both cameras.
Sep 17, 2019 at 08:36 AM
vdo1
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p.2 #18Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Fred Miranda wrote:
vdo1 wrote
GabrielPhoto wrote
vdo1 wrote
GabrielPhoto wrote
Fred Miranda wroteBoth images interpolated to 121MP using PS bicubic:

Center area at f/4 for both:
Hey Fred I got Topaz Gigapixel if you want, I can use it to match the A7R3 file to the A7R4 size to see how close it can get to it.
At $99 that thing looks like the most effective upgrade to the R3, you don't even need new L brackets and stuff....
Indeed I am very curious to see how different plugins results will compare to the real thing.
You know, I just went through some reviews and sample shots and I believe that asking an 120% scale from it is not a big ask at all. What was obvious from one review was that bicubic is terrible when compared with Topaz. There was no contest.
I will try topaz gigapixel instead of PS bicubic when comparing both cameras.


Thank you Sir!!! This was the review featuring bicubic that I was talking about:

http://www.northlight-images.co.uk/topaz-ai-gigapixel-review/



Sep 17, 2019 at 08:38 AM
httivals
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p.2 #19Comparing 42MP vs 61MP: Real-World Resolution and Contrast
In his blog, Jim Kason recently tested various software for uprezzing and as I recall he ended up thinking gigapixel was currently the best.
Sep 17, 2019 at 08:49 AM
GMPhotography
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p.2 #20Comparing 42MP vs 61MP: Real-World Resolution and Contrast
OT I'm out shooting just did s few Pixel Shift to look at

One other point in manual focus I could almost shoot without focus peaking its now in low instead of medium

So big improvement on EVF

Having little issue seeing LCD in daylight
Sep 17, 2019 at 09:07 AM


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