Thanks philber, a very simple answer, I've prepare the ISO setting to 1600 before I have entered into the church. The 18mm Distagon was use with f=5,6. I love this lens!

Excellent shot, especially composition-wise. But I cannot understand the EXIF. Why use ISO 1600 and such a fast shutter speed? Also, the shot seems to have a great DOF for such a wide aperture. Could the EXIF simply be wrong?