05-23-2012, 02:13 PM
I agree with the f/11 statement. I wish I tried the same shot with f/2.8 focusing at the same area... But when it comes to the hypothesis regarding the reflections from sensor to rear element and then back to the sensor surface, I have doubts. The STF's rear element seems to justify the hypothesis. But the Canon 50mm f/1.2 for instance shows PF (see the PZ APS-C review) although the rear element is curved:
![[Image: 463px-DoubleGauss4text.svg.png]](https://upload.wikimedia.org/wikipedia/commons/thumb/9/92/DoubleGauss4text.svg/463px-DoubleGauss4text.svg.png)
Maybe we should consider from where was the crop taken. Would a center crop justify it?... I'm not sure, because it's all over the in focus area. What do you think?
And the CZJ 135mm f/3.5 I used (which could be a usual suspect because of lacking modern coatings)... Not exactly a flat rear element to redirect the light at the same spot on the sensor:
![[Image: czjson3.5_135.gif]](http://www.praktica-users.com/img/diagrms/m42/czjson3.5_135.gif)
Maybe we should consider from where was the crop taken. Would a center crop justify it?... I'm not sure, because it's all over the in focus area. What do you think?
And the CZJ 135mm f/3.5 I used (which could be a usual suspect because of lacking modern coatings)... Not exactly a flat rear element to redirect the light at the same spot on the sensor: