p.1 #1 · Sony A7R IV Photographic Dynamic Range (PDR)
Bill Claff @bclaff_too, just published the Dynamic Range results (PDR) for the new Sony A7R4.
The Sony A7R4's dynamic range seems to be slightly lower than A7R3's at high ISO settings (ISO 640 and above).
However, from ISO 320-500, the A7R3 is capable of slightly higher DR.
p.1 #3 · Sony A7R IV Photographic Dynamic Range (PDR)
It's not a big surprise, is it?
Looks like mostly random variation around the central measure for a7r2 - 3 - 4. Which is all fine, they have been wonderful for several years now.
Below is the full a7r series at landscape ISOs up to ISO 600. blue=a7r4; black=a7r3; green=a7r2; and orange is the one obscured by them, it's the 2013 a7r.
p.1 #5 · Sony A7R IV Photographic Dynamic Range (PDR)
Fred Miranda wrote:
Thanks Tim!
I think the basic message of these graphs is
(a) probably the underlying overall DR of the r4 is fractionally less than the R3, but not noticeably so. Actually an impressive achievement given the extra photosites.
(b) the Aptina patent dual conversion crossover point is a little lower: at ISO 320 rather than 640; with the result that the performance above that and below 640 is a bit better on R4 than R3, and the reverse above 640.
That's actually a pity, in my book. I'd rather just use 100 and push in post before 640, and then use 640 and push in post. But that's a nerdy way of doing it (ISO-lessly) and this choice will be great for people who have auto ISO on and it's often around say 400.
Bottom line though: nothing here is really germane to whether to go with the r4 or r3
p.1 #6 · Sony A7R IV Photographic Dynamic Range (PDR)
DavidBM wrote:
Bottom line though: nothing here is really germane to whether to go with the r4 or r3
Yes and at least we know that the megapixel increase didn't affect DR in any significant way.
Their equal DR performance at base ISO is great news for landscape photographers taking advantage of more megapixels.
p.1 #9 · Sony A7R IV Photographic Dynamic Range (PDR)
Fred Miranda wrote:
Bill Claff @bclaff, just published the Dynamic Range results (PDR) for the new Sony A7R4.
The Sony A7R4's dynamic range seems to be slightly lower than A7R3's at high ISO settings (ISO 640 and above).
However, from ISO 320-500, the A7R3 is capable of slightly higher DR.
The performance of the A7R3 and A7R4 seem to be essentially identical except for the decision to change the sense node capacitance at ISO 320 rather than 640. If the change occurs at higher ISO (where there are fewer photoelectrons in the pixel) the capacitance change can be larger and the conversion gain consequently higher, which helps the high ISO performance more. The input referenced read noise is decreased a bit more for high ISO if the change occurs at higher ISO.
Making the shift at lower ISO seems to me to be a good decision for a camera that is aimed at applications that value the high resolution of the A7R4 (e.g. landscapes, portraits, etc). Those applications tend to use lower ISO settings. By changing the conversion gain at ISO 320 the A7R4 gets better performance at ISO 320-500. The cost is at ISO 640 and above, which is more oriented to action applications (e.g. sports, wildlife, etc). At higher ISO the A7R4 is slightly behind the A7R3, but the difference may be so small the it is not noticeable. Both cameras are approximately ISO-less at higher ISO.
It's hard to justify any complaints about cameras with this kind of superb performance.
p.1 #10 · Sony A7R IV Photographic Dynamic Range (PDR)
Daran wrote:
Only if your lens is soft.
With a high performance lens, I thought that higher sensor resolution = less moire.
With a soft lens, it should not matter as much as moire is masked just like when using a low pass filter.
p.1 #11 · Sony A7R IV Photographic Dynamic Range (PDR)
Correct. With a high performance lens, higher sensor resolution = less moire. Although it’s a bit more nuanced, generally moire results from a lens outresolving a sensor. A high performance lens will not outresolve a high resolution sensor as much as a lower resolution one.
p.1 #12 · Sony A7R IV Photographic Dynamic Range (PDR)
DavidBM wrote:
I think the basic message of these graphs is
(a) probably the underlying overall DR of the r4 is fractionally less than the R3, but not noticeably so. Actually an impressive achievement given the extra photosites.
(b) the Aptina patent dual conversion crossover point is a little lower: at ISO 320 rather than 640; with the result that the performance above that and below 640 is a bit better on R4 than R3, and the reverse above 640.
That's actually a pity, in my book. I'd rather just use 100 and push in post before 640, and then use 640 and push in post. But that's a nerdy way of doing it (ISO-lessly) and this choice will be great for people who have auto ISO on and it's often around say 400.
Bottom line though: nothing here is really germane to whether to go with the r4 or r3
cheers
d
...Show more →
The reason is the change in gain. Dual gain sets in around iso 640 for the A7r3, whereas Sony intended to change gain earlier for the A7riv, at around half that value.
p.1 #13 · Sony A7R IV Photographic Dynamic Range (PDR)
Holger wrote:
The reason is the change in gain. Dual gain sets in around iso 640 for the A7r3, whereas Sony intended to change gain earlier for the A7riv, at around half that value.
p.1 #14 · Sony A7R IV Photographic Dynamic Range (PDR)
DavidBM wrote:
That's what I said!
The Aptina patent is the dual gain patent.
Sorry, maybe I overlooked that in haste.
Aug 30, 2019 at 03:14 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.1 #15 · Sony A7R IV Photographic Dynamic Range (PDR)
Interesting. Very similar performance but the decision to put the Aptina gain at ISO 320 vs. 640 will give this camera better ISO 400 at the expense of better performance above ISO 800. You lose almost a quarter of a stop high ISO performance vs. the A7r III and a little over a third of a stop vs. the A9. It makes the camera a little more of a low ISO specialist and a little less of a jack of all trades. Probably a sensible decision given Sony's FF camera line up.
Used as an APS-C camera it has slightly higher DR than any of the currently available Sony APS-C cameras and it's high ISO performance is right in the middle of the pack among these cameras. It should double very well as an APS-C camera. It has slightly higher resolution, slightly higher low ISO DR, and still quite decent high ISO performance for an APS-C camera. DR and high ISO performance are each about a stop less performance than using the full sensor, but that was to be expected.
p.1 #16 · Sony A7R IV Photographic Dynamic Range (PDR)
Steve Spencer wrote:
Interesting. Very similar performance but the decision to put the Aptina gain at ISO 320 vs. 640 will give this camera better ISO 400 at the expense of better performance above ISO 800. You lose almost a quarter of a stop high ISO performance vs. the A7r III and a little over a third of a stop vs. the A9. It makes the camera a little more of a low ISO specialist and a little less of a jack of all trades. Probably a sensible decision given Sony's FF camera line up.
Used as an APS-C camera it has slightly higher DR than any of the currently available Sony APS-C cameras and it's high ISO performance is right in the middle of the pack among these cameras. It should double very well as an APS-C camera. It has slightly higher resolution, slightly higher low ISO DR, and still quite decent high ISO performance for an APS-C camera. DR and high ISO performance are each about a stop less performance than using the full sensor, but that was to be expected. ...Show more →
Nice summary of the differences and comparisons to alternatives.
I have trouble visualizing what a quarter or a third of a stop of dynamic range actually would look like in an image. Would one be able to see it? In what way would it matter?
p.1 #17 · Sony A7R IV Photographic Dynamic Range (PDR)
dclark wrote:
I am not sure what you mean by "normalized", but I believe that these curves have been normalized in the sense that Claff uses the term (i.e. normalized for print size and threshold SNR).
The performance of the A7R3 and A7R4 seem to be essentially identical except for the decision to change the sense node capacitance at ISO 320 rather than 640. If the change occurs at higher ISO (where there are fewer photoelectrons in the pixel) the capacitance change can be larger and the conversion gain consequently higher, which helps the high ISO performance more. The input referenced read noise is decreased a bit more for high ISO if the change occurs at higher ISO.
Making the shift at lower ISO seems to me to be a good decision for a camera that is aimed at applications that value the high resolution of the A7R4 (e.g. landscapes, portraits, etc). Those applications tend to use lower ISO settings. By changing the conversion gain at ISO 320 the A7R4 gets better performance at ISO 320-500. The cost is at ISO 640 and above, which is more oriented to action applications (e.g. sports, wildlife, etc). At higher ISO the A7R4 is slightly behind the A7R3, but the difference may be so small the it is not noticeable. Both cameras are approximately ISO-less at higher ISO.
It's hard to justify any complaints about cameras with this kind of superb performance.
Agree I think I’m still going to be in good shape at ISO 1600 anything more than that I’ll pull out my lights.
Starting to get excited for it. Just wish I had it for my trip starting Sunday. I should have called Sony Pro.
Aug 30, 2019 at 08:22 AM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.1 #18 · Sony A7R IV Photographic Dynamic Range (PDR)
chiron wrote:
Nice summary of the differences and comparisons to alternatives.
I have trouble visualizing what a quarter or a third of a stop of dynamic range actually would look like in an image. Would one be able to see it? In what way would it matter?
A third of a stop DR will matter a lot more in some images than others. In those images in which you are clipping highlights and you would still like to pull up shadows a bit more, being able to pull up those shadows a third of a stop more without more noise is something you may well notice. You could just live with more noise in the shadows, but that will limit how big you can present the image. It isn't a huge difference, and even a whole stop difference isn't a night and day difference, but if you work with enough files over a range of high DR situations you can recognize the difference and what it means for your shooting.
p.1 #19 · Sony A7R IV Photographic Dynamic Range (PDR)
Steve Spencer wrote:
Interesting. Very similar performance but the decision to put the Aptina gain at ISO 320 vs. 640 will give this camera better ISO 400 at the expense of better performance above ISO 800. You lose almost a quarter of a stop high ISO performance vs. the A7r III and a little over a third of a stop vs. the A9. It makes the camera a little more of a low ISO specialist and a little less of a jack of all trades. Probably a sensible decision given Sony's FF camera line up.
Used as an APS-C camera it has slightly higher DR than any of the currently available Sony APS-C cameras and it's high ISO performance is right in the middle of the pack among these cameras. It should double very well as an APS-C camera. It has slightly higher resolution, slightly higher low ISO DR, and still quite decent high ISO performance for an APS-C camera. DR and high ISO performance are each about a stop less performance than using the full sensor, but that was to be expected. ...Show more →
p.1 #20 · Sony A7R IV Photographic Dynamic Range (PDR)
dclark wrote:
Making the shift at lower ISO seems to me to be a good decision for a camera that is aimed at applications that value the high resolution of the A7R4 (e.g. landscapes, portraits, etc). Those applications tend to use lower ISO settings. By changing the conversion gain at ISO 320 the A7R4 gets better performance at ISO 320-500.
Steve Spencer wrote:
Very similar performance but the decision to put the Aptina gain at ISO 320 vs. 640 will give this camera better ISO 400 at the expense of better performance above ISO 800. You lose almost a quarter of a stop high ISO performance vs. the A7r III and a little over a third of a stop vs. the A9. It makes the camera a little more of a low ISO specialist and a little less of a jack of all trades. Probably a sensible decision given Sony's FF camera line up.
The A7RIV's conversion gain change vs the A7rIII may not be an intentional decision made by Sony to rebalance/target low ISO performance but instead just the natural consequence of the A7rIV's smaller pixels, which means a lower FWC-per-pixel, which translates to a naturally lower LCG/HCG switching point, with consideration for potential differences in per-pixel read noise of the new sensor's design as well.
