how one would calculate a visual angles for a spatial shifts? For example: I have normal image at 0 shift, 5 degrees and 8 degrees shift of the same image. participants suppose to look only at the centre of the image where the blinking cross is displayed. Screen is 800 x 600 pixels, or 30degrees width and 23 degrees height. What visual angle will be at 5 and 8 degrees shift at the lower 1/4 of the visual field?

Question

phi · Answer

is this what you mean? http://answers.yahoo.com/question/index?qid=20080707020013AAjoMJ2

anonymous · Answer

Thank you for looking at the question. I am afraid it is not the correct answer in this case.

anonymous · Answer

Phi - It is my fault - I think my question has not been asked clearly.

phi · Answer

It looks like I cut and pasted to the wrong post, and it is definitely not relevant to your question.  
But unfortunately I don't understand your question well enough to answer it.