p.1 #1 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
I've just received the Sony A7R IV with its 61MP sensor, and while the ergonomic and software upgrades are impressive, I'm particularly interested in the extra detail provided by the 20% increase in linear resolution over the A7R III's 42MP sensor when using my best lenses at different apertures.
As expected, the resolution and contrast boost are most noticeable in the center of the image. Although the A7R IV's resolution advantage can still be seen off-center with our top lenses, the improvements are minimal.
For this comparison, I'll be using my best lenses, including the Voigtlander 65mm f/2 APO-Lanthar, Sony FE 135mm f/1.8 GM, Sony FE 50mm f/1.4 ZA, and several others. All of these lenses are optimal and perfectly centered.
This should give an idea of what to expect when upgrading from the A7R III to the A7R IV for landscape photography.
P.S. I used Lightroom's beta profile for this comparison, but note that colors may appear off with this profile. Distortion, chromatic aberration, and vignetting were not corrected, so please disregard color rendering in this analysis.
Voigtlander 65mm f/2 APO-Lanthar: A7R3 vs A7R4
thumbnail showing 1:1 areas at infinity distance
Center at f/2: Even wide open, I can see more fine detail on the A7R4 crop
Mid-zone at f/2: Wide open, the A7R4's resolution advantage is not very noticeable at mid-zone is not noticeable even with this superb prime lens
p.1 #10 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
It can certainly be incredibly good under ideal conditions. Working in a high end pro lab though I have printed extremely large (60 x 40 inch+) tests and the results were so close it was hard for people to pick. Sometimes it takes a reality check to recall why you loved that 42 meg sensor in the first place. With the best glass and ideal post processing that is.
The downsides I found were a greater proportion of handheld loses due to the denser sensor which therefore required a higher shutter speed/iso which lost some dynamic range and increased noise. Also diffraction is way more noticeable.
For me currently I would take the @40-45 meg with the build quality and the slightly better focus of the R4. It is the sweet spot for me and I lose nothing in real world. Lets see how close to that the A9II gets.
For those getting the R4 though Im sure you will love it regardless. Its what you do with it at the end of the day after all..
p.1 #11 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
GMPhotography wrote:
I'm noticing some good increases through all the images posted. I may repeat a BB with this body . Need to find which one CV 21 or CV 75
p.1 #13 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
RoamingScott wrote:
Looks like a nice boost in sharpness once downsampled!!
I don't believe any of the samples Fred has posted so far in the thread have been downsampled. The first sets are at native resolution and the last is with the A7rIII upsampled to the A7rIV resolution.
p.1 #14 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
Fred, 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.
p.1 #17 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
snapsy wrote:
Fred, 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:
p.1 #18 · Comparing 42MP vs 61MP: Real-World Resolution and Contrast
ftllens wrote:
I do see finer details for sure, but a lot less than I expected. What's more impressive is the CV 65's resolving power!
It should be 20% more detail for the center area using perfect technique and a high resolution lens. Off-axis, expect a much smaller improvement.
Any lens asymmetry (decentering, skew) will be more noticeable with the higher MP body.
Diffraction will rob some of that extra resolution (starting at f/5.6) so the A7R4's resolution advantage is more noticeable at optimum apertures. (focus stack may be needed to extract the extra fine detail)
All lenses will benefit from the extra resolution but only the best ones may see the ~ 20% resolution improvement at center.
