Just a few minutes ago I finished developing the test photos and uploading them to Flickr, and now I am extremely happy that I am not working as an editor at DPReview or another review site. 😉 If I had to do these tests every day, I am sure the work would make me lose my mind in no time. Unless you’ve actually tried it yourself, you cannot even begin to imagine how much patience is needed to compare the sharpness of two fast lenses at a short distance to the subject (~1,8m). I spent at least half an hour arranging the SD1M / 50mm f/1.4 Art combo on the back rest of the sofa, which, in the end, I didn’t manage to do perfectly anyway. Because of the very shallow depth of field due to the short distance, the right side is slightly more out of focus than the left one. In addition, the back of the sofa is not a 100% level, which is easily visible if one looks at the upper corners of the 100% view. And to round things off, a small error snuck in as well: it appears that, after having taken the f/1.4 photo with the SD1M/ 50mm f/1.4 combination, I must have accidently moved the tripod a tiny bit, because the rest of the photos of the aperture series shows a slightly shifted framing.
Even though not everything worked out perfectly, I think the pictures still sufficiently illustrate what they are supposed to. Below I have only included the 100% crops of the lower left corner of various shots with different apertures. On Flickr you can download each of the 11 test photos in full resolution and get granular on the other corners as well. Since both lenses produce very high sharpness in the middle of the picture at wide open aperture, it is not really necessary to look at that part of the image.
Let us now proceed to the interesting part, the comparison. (Please click on the crops to open them in a new browser window at full size; since the crops are too big for a blog entry, the blog software scales them down and reduces them to pixel-mush.)
Left: SD1M + 50/1.4 Art @ f/1.4; Right: DP3M @ f/2.8
Left: SD1M + 50/1.4 Art @ f/2.8; Right: DP3M @ f/2.8
Left: SD1M + 50/1.4 Art @ f/4; Right: DP3M @ f/4
Left: SD1M + 50/1.4 Art @ f/5.6; Right: DP3M @ f/5.6
Left: SD1M + 50/1.4 Art @ f/8; Right: DP3M @ f/8
Left: SD1M + 50/1.4 Art @ f/11; Right: DP3M @ f/11
I believe the pictures speak a very clear language, and the comparison can therefore be summarized like this: the 50 mm f/1.4 Art on the SD1 Merrill is sharper than the DP3 Merrill at the respective wide open apertures (f/1.4 vs f/2.8) as well as when stopped down. In some cases the difference is rather extreme.