We now move to a smaller aperture – f/8 – to see how performance changes as the lens is stopped down. This is where one generally expects lens characteristics to become less distinct and a greater uniformity in the images to emerge. Shutter was at 1/30 for this series. The point of focus was the trunk of the tree on the right side of the frame, roughly 7m away. The sun was to the left at almost a right angle to the camera, with the light-colored leaves of the tree in the foreground brightly lit by direct sunlight, while the spruces in the background are dark and backlit. Again, apologies for the fogging on the upper right edge.
The FED shows moderate contrast and reasonably good detail in across the frame, though as before the corners do show some softening (look at the plants in the lower right).
The brighter I-26 seems to have similar sharpness but shows some improvement over the FED lens in the corners, producing a more uniformly-resolved image.
The I-50/fake Elmar develops very low contrast and tons of glow when stopped down, presumably due to the light being forced through the worst part of the damaged front element. Surprisingly, however, the resolution is otherwise acceptable. In specific circumstances, this softness and glow could be used to good effect.
Once again, the Jupiter-8 produces a solid image. It is not pin-sharp – it seems more or less on par with the I-26 – but it has a bit more contrast than wither the I-26 or the FED, and it seems to offer a bit more detail in the heavily backlit branches in the background.
The next post will show what happens when the lenses are put to one of the more difficult tests: shooting into the sun.