I got my hands on the Sony/Zeiss 24 mm f/1.8 (Official name: Sony Carl Zeiss E 24mm F1.8 ZA). It is a measure of how freaked out I am about the purple corners on the NEX-7 that the first thing I did was test for the effect. The results are good:
| Avg error | WC error | |
| f/1.8 | 1.3 | 2.0 |
| f/2.8 | 1.4 | 2.6 |
| f/4 | 1.6 | 3.2 |
| f/5.6 | 2.1 | 2.8 |
| f/8 | 2.2 | 2.8 |
| f/11 | 2.2 | 2.8 |
| f/16 | 1.4 | 2.2 |
As before, the errors are for chromaticity only (luminance errors are ignored) measured in CIELab Delta-E.
The fact that the errors don’t get worse as the diaphragm opens tells me that Sony is performing correction in the camera firmware, and what we’re looking at are the residual errors. The color shifts are not consistant. If you want to correct them, you’ll need a profile for each f-stop.
Here are the errors wide open:
| UR | LR | LL | UL | |
| L* | -13 | -12 | -10 | -13 |
| a* | 0 | 0 | 0 | 0 |
| b* | 1 | -2 | -1 | 1 |
At f/4:
| UR | LR | LL | UL | |
| L* | -10 | -7 | -5 | -8 |
| a* | 1 | 1 | 0 | 0 |
| b* | -1 | -3 | -2 | 0 |
At f/8
| UR | LR | LL | UL | |
| L* | -9 | -7 | -6 | -8 |
| a* | 2 | 2 | 1 | 1 |
| b* | -1 | -2 | -2 | -1 |
At f/16
| UR | LR | LL | UL | |
| L* | -10 | -9 | -8 | -9 |
| a* | 1 | 1 | 0 | 0 |
| b* | -1 | -2 | 0 | -2 |
Well, that’s out of the way. How good is the lens for actually taking pictures? Stay tuned.
Leave a Reply