A provocative title – but a real consideration
Ok, it’s not really fair to call the A7r a “better crop camera” than an A77… but a comparison between the two is quite interesting. One really cool thing about the Sony A7r that has become more and more apparent is that it is an excellent APS-C camera. Follow me here… in the “crop mode” on the A7r, the camera captures a 1.5x cropped image (4200 x 3200 pixels or 15.3 MP if you’re counting) and you get the benefit of a cropped view in the EVF for framing.
In theory, a dedicated, higher megapixel camera body like the Sony A77 should provide more detailed images than using such a “workaround” feature. Actually, if you simply followed the stats, you’d expect the A77 to give you over 40% greater linear resolution (the A77 is a 24 megapixel camera, 6000 x 4000 image size).
In practice, this is really not the case. Actually, the A7r sensor has a number of advantages over the A77: 1) There is no translucent mirror in front of it 2) There’s no anti-aliasing filter to blur the image 3) The photosites are larger.
A quick test – is the A7r a better APS-C camera than the A-mount A77?
Certainly a camera is about more than simply a sensor and image quality. BUT – with the LA-E4 adapter for A-mount lenses, the A7r is actually quite responsive, and the AF is in the same ballpark as the A77. But how does the image quality compare?
Below are a few 100% crops at different ISOs to give you an idea. For this comparison, I used a very simple studio setup with bounce flash lighting. The only difference you’ll see is a slight shadow in the A7r images – because a radio trigger was used vs. the on-camera flash trigger in the A77. This does not impact image quality. These results are actually very representative if the images you could expect from either camera. More details are at bottom.
CLICK FOR FULL SIZE – Right click to download and pixel peep
Conclusions / Observations:
Shooting birds with a Sigma 180mm lens with both cameras, I was surprised at first by getting a little more detail and a little less noise from the A7r – even with a lower pixel count. That’s where this all came from. These comparison shots simply reflect the reality of the A77 and the quality of the A7r. These include:
- Megapixels get you very little on their own – the A77 24MP sensor can be easily matched by a better 15-16MP sensor
- The noise performance of the A77 is pretty poor, even at lower ISOs (200-400), even at web sizes. It’s really at the bottom of the pile, and there’s no way around it
- The AA filter does the A77 no favors, blurring fine detail… while the lack of AA filter on the A7r really helps with fine detail
- The 15MP images from the A7r match or nearly the 24MP A77 in terms of detail and overall quality at lower ISOs (up to 400) and surpass it at anything above 400
- The A77 handles better in “big lens” applications – so this isn’t a total hit-job. There’s room for a nice SLR-style body like this (and presumably the A77II)
All in all, it’s pretty amazing what a very good 15MP sensor can do. And for those who might have or want an A7r – and think they will get a significant Image Quality boost with a 24MP crop body (maybe as a second body, etc) – the “Crop mode” on the A7r is actually a very good solution. Instead of $700-800 on an A77, you might consider a new lens instead!
QUICK EDIT: John, below, was kind enough to share a comment about moire. If you view the flower photo at 200ISO, the A7r displays some moire in the petals (they are nylon). Thoughts on this are in the comments.
More details on the comparison / procedure
There are a number of ways that you can set up a comparison like this, but the results are always essentially the same. For this, a Sigma 35mm f/1.4 A-Mount lens was used on both the A7r and A77 – which were set up on a tripod and shot sequentially. An HVL 43M flash was set up off-camera and bounced off of a white ceiling from the same location for each camera. A radio trigger was used from the A7r and the on-camera flash was used to wirelessly trigger the flash from the A77. Images were taken into LR5.5, processed with no sharpening or noise reduction, Adobe Standard color profile for each. 5500K with zero tint correction was set for white balance on each image. Full size 80% sRGB JPGs were exported for the A7r images, and the A77 images were downsampled to the same dimensions and exported. (Downsampling typically yields a noise reduction benefit).