ISO Performance at low ISOs (ISO 200-800)
Let’s take a look at how the Olympus OM-D E-M1 performs at low ISOs. Here are some 100% crops at ISO 100, 200, 400 and 800:
As expected, both ISO 100 (boost) and 200 are very clean.
ISO 400 adds a tiny bit of noise, but the image is still very clean. Pushing to ISO 800 we now see some more noise, but there is still no loss of details in the image, including in the shadows.
High ISO Performance (ISO 1600-25600)
Let’s see what happens when ISO is boosted to much higher levels:
ISO 1600 increases the amount of noise and the grain size now looks bigger and more noticeable, especially in the shadows. Increasing ISO to 3200 nearly doubles noise and now we are starting to see some artifacts in the shadows. There is a little bit of color loss in the shadow areas. Both ISO levels are very usable though and a single pass of noise reduction software will deal with it pretty well, since most details are preserved.
Further increasing ISO to 6400 adds a lot more noise and now we are at a point, where we are starting to lose details in the shadow area. And by ISO 12800, the image looks pretty much unusable to me, although down-sampling the image might produce acceptable results for the web. The last available ISO level is 25600, which is way beyond my comfort level:
I would never use such high ISO level on the OM-D E-M1, because there is a heavy loss of detail and color throughout the image.
Let’s see how it fares against other cameras. Select the next page below.