I previously compared a Canon G9 to an Olympus E-500 DSLR, and the Canon G9 had much greater resolution than the Olympus E-500.
Now that I have a new Olympus E-620 DSLR incorporating Olympus’ latest technology, I was eager to see if Olympus finally made a DSLR that could produce a higher quality image than a Canon G9 point and shoot camera.
The Olympus image was shot at 54mm focal length using the 14-54mm f/2.8-3.5 lens, ISO 200, f/7.1, 1/400 second, and saved in RAW format. The RAW was converted to a DNG file using the Adobe DNG converter, and then opened in Adobe Camera Raw 4.6. I used an unsharp mask to make the image a little sharper.
The Canon image was shot at 22mm focal length, ISO 100, f/5.6, 1/1000 second, and just saved as a JPEG. No unsharp mask is needed because the G9 applies sharpening to the JPEG before saving it—too much sharpening in my opinion.
Canon G9
Olympus E-620
When you compare the images from the two cameras, the E-620 image seems to be exposed an extra 1/3 EV compared to the G9 image. However, based on the camera settings, in which the E-620 has 2/3 higher f/stop, 1 EV higher ISO, and 1 1/3 EV of slower shutter speed, one would expect the E-620 image to be exposed by an extra 1 2/3 EV. There is a 1 1/3 EV discrepancy. In other words, the E-620 is shamefully overrating its ISO compared to the G9. ISO 200 on the E-620 is equivalent to ISO 80 on the G9. Can this really be true?
According to the good folks at DxOMark, the G9’s true measured ISO at ISO 100 is 139. DxOMark hasn’t profiled the E-620, but the E-620 is just the consumer version of the E-30 which DxOMark did test, and DxOMark says that at ISO 200, the true measured ISO of the E-30 is 128. Thus DxOMark does agree with me that the similar E-30 camera is less sensitive at ISO 200 than the G9 at ISO 100. My real world test confirms the DxOMark testing. [HOWEVER, when I did a test at ISO 400, both cameras had the same sensitivity at ISO 400.]
Now let’s compare some 100% crops:
Canon G9
Olympus E-620
Canon G9
Olympus E-620
From looking at the full images you can see that there was slightly more zoom used on the E-620 shot, so on that basis you would expect the E-620 to show slightly more detail. But if you compare the first set of crops, which is from an area near the center of the image, it’s really hard to say if one camera has resolved more detail than the other.
When you compare the second set of crops from an area near the edge of the image, the E-620 beats the G9. The G9 image shows a little bit of chromatic aberration and is slightly softer. But before you proclaim the E-620 the clear winner at the edges, I should point out that on my E-500 camera, this lens showed no CA at the zoom end used to take the above image, but there was quite a bit of CA at the wider end of the lens.
In both sets of crops, the image from the E-620 has more contrast. It’s impossible to determine if that’s the result of bigger pixels, a better lens, the tone curve applied by Adobe Camera Raw, or the fact that the lens on the E-620 had a lens hood.
From a resolution perspective, I call this test even. The 12 MP DSLR resolves the same amount of detail as the 12MP point and shoot camera with a much smaller sensor. The bigger pixels don’t provide a noticeable advantage when it comes to resolution. If there is slightly better image quality from the E-620 (and you need to do some determined pixel peeping to see it), it's probably because the Zuiko 14-54mm lens is slightly better than the lens which comes with the G9.
DYNAMIC RANGE
Because of the bigger pixels, the DSLR is supposed to have greater dynamic range than a point and shoot camera like the G9. Is this the case? Unfortunately, I can’t really see it in the image. You will notice that there are some very dark shadow areas in the lower left side of the image. We can try to bring this up using the Photoshop Shadow/Highlights adjustment for the G9 JPEG, and the Adobe Camera Raw “Fill Light” slider for the E-620 RAW file.
Canon G9
Olympus E-620
It seems to me that the G9 JPEG captured more detail in the shadows compared to the E-620 RAW file which is supposed to have much greater dynamic range. Once again, the bigger pixels of the E-620 were unable to demonstrate an advantage over the smaller pixels of the G9.
My finding of no DR difference is also consistent with the test results at DxOMark. According to DxOMark, at ISO 100 the G9 has a DR of 9.4 EV, and at ISO 200 the Olympus E-30 (which has the same sensor as the E-620) has a DR of 10.07 EV. That’s not a very big difference, and I did expose the E-620 shot by about 1/3 EV higher than the G9 shot. If DxOMark is correct about the Olympus DSLRs having an extra 2/3 EV of DR at these ISO settings, then the extra DR is to be found in the highlights, because I don’t see any extra DR in the shadows.
CONCLUSION
With the E-620, Olympus has finally achieved parity with the Canon G9 point and shoot camera with respect to resolution and overall low-ISO image quality. But there is still no reason to use the E-620 for typical landscape or travel photos taken during daylight hours. The Canon G9 is a lot more convenient to carry around and it has better exposure metering.
Want a second opinion? Read the Canon G10 vs. Hasselblad H2 comparison at Luminous Landscape:
In every case no one could reliably tell the difference between 13X19" prints shot with the $40,000 Hasselblad and Phase One 39 Megapixel back, and the new $500 Canon G10. In the end no one got more than 60% right, and overall the split was about 50 / 50, with no clear differentiator. In other words, no better than chance.
UPDATE
Although I discovered here that the E-620 overrates its ISO, relative to the G9, when the E-620 is at ISO 200 and the G9 at ISO 100, I later experimented with ISO 400 and was surprised to discover that both cameras behave nearly the same at ISO 400 (with respect to creating images with the same apparent exposure). Very strange.
