Phocus distortion correction.

[jerome_m]

Some doubts have been expressed in this thread that Phocus could correct distortion when no all subjects were at the same distance from the camera. I had some time to specifically test that today, using the HCD 28mm lens and the HTS tilt-shift adapter. In place of the traditional brick wall, I tried to choose something a bit more interesting.

First, the HCD 28 alone, with and without automatic correction, straight on the building.

[jerome_m]

Then, from the same position, I used the HTS with 10mm shift up. We can see that Phocus still corrects automatically, using the amount of shift saved in the exifs. Everything is still at the same distance.

[jerome_m]

Now, the same building (another wall, actually) taken at an angle with the HCD28 alone. This is f/4, so we also have noticeable vignetting. The camera was also tilted a bit up, I would normally correct the perspective in photoshop but I leave everything as is for the sake of the test.

[jerome_m]

Last, the same with the HTS on. There is 2° of tilt, so that everything is sharp front to back and 1mm of shift to bring the subject back into its position.

[jerome_m]

My conclusion is that Phocus succeeds in correcting the quite noticeable distortion of the HCD28 in all cases. The straight elements on the building (actually square ceramic rods fit on a metal grid) appear straight after correction.

I wanted to post this test because of the discussion initiated in the thread cited in the first message, which I felt deserved a more complete answer. This message will however terminate my participation in this forum as my understanding is that technical tests of the sort are neither wanted nor really needed. Thank you for your attention.