The other day I had both the Sony A7r and the Olympus OM-D E-M10 with me, so I decided to took a few shots just to stack the cameras one against the other.
The Sony was fitted with the excellent Contax Zeiss 50mm f/1.7 Planar, one of the “film era” lenses that still – like most of the Contax Zeiss lineup – shines on digital.
On the Olympus I had the latest offering of Panasonic, that just recently hit the shelves: the Lumix G 25mm f/1.7, that given the 2x crop factor of micro 4/3 sensors it is equivalent to a 50mm.
First the entire scene at f/1.7. You’ll notice that the Panasonic has much more depth of field. This because the 2x of the crop factor it applies also to the aperture, not in terms of light gathering ability (so the exposure will be the one needed for a f/1.7 lens), but in terms of depth of field. So the Panasonic, while gathering light like any f/1.7 lens, has the depth of field of a f/3.5 lens on full frame.*
*Basic explanation: even if thanks to the crop factor the lens is equivalent to a 50mm lens, you’re using anyway a 25mm focal length, and the depth of field is focal length dependent.
Contax Zeiss 50mm f/1.7 Planar @ f/1.7
Panasonic Lumix G 25mm f/1.7 @ f/1.7
Now the 100% crops at f/1.7:
Contax Zeiss 50mm f/1.7 Planar @ f/1.7
Panasonic Lumix G 25mm f/1.7 @ f/1.7
The full scene shot at f/8:
Contax Zeiss 50mm f/1.7 Planar @ f/8
Panasonic Lumix G 25mm f/1.7 @ f/8
And now the 100% crops at f/8:
Contax Zeiss 50mm f/1.7 Planar @ f/8
Panasonic Lumix G 25mm f/1.7 @ f/8
Here instead I resized both f/8 images for a 1m x 75cm print, and sharpened each to its best for print (that’s why they may look slightly over-sharpened). So you’re actually seeing two crops from a “virtual” 1m x 75cm print:
Contax Zeiss 50mm f/1.7 Planar @ f/8
Panasonic Lumix G 25mm f/1.7 @ f/8
As you can see, the Sony A7r, with 36Mp vs only 16Mp for the Olympus, it delivers a bit more detail. The point is: would you miss the added detail without doing a side by side comparison like this?
Honestly? I don’t think so, unless you were to print larger than 1m.
And now consider this: I shot the A7r on a tripod, with a 2s self timer, to avoid inducing any vibration. Instead, I shot the Olympus handheld*, and thanks to IBIS I would have been able to do so even at considerably lower light levels. I guess the question becomes: for a bit more sharpness are you prepared to carry around much bigger and heavier lenses and a tripod?**
*I did not have with me a spare tripod plate, nor the hex key needed to swap the one on the Sony on the Olympus
**The argument about bigger and heavier lenses applies even if you have a Sony body with IBIS like the A7II or A7r II. Consider this: an entire Olympus kit from 18mm to 200mm with 2 zooms and 2 fast primes (E-M10 + 9-18 + 35-100 + 15/1.7 + 45/1.8) weights less than 920 grams! And you can go as low as 385 grams (Panasonic GM-5 + 12-32 + 35-100), stuffing all in a pocket. And every lens is stabilized, either in camera or with OIS.
For serious landscape work I am, but for travels, street and any other application where absolute sharpness is not paramount I will rather grab the Olympus.
