Q: Q 1: What is the difference between field curvature and spherical aberration? We have been looking over them and the pwp diagrams and still are confused/dont understand. Q 2: What is axial chromatic and does it have to look like a circle with either red fringe and yellow inside or purple with blue and yellow centre? If not then we are now both a bit lost again :-s Also, another question I have is about my over all marks, I dont know if I will pass over all or not and was wondering if you think I need to do the make up longer test on Wednesday or not? A: Have you had a look at lecture capture, so you can get the explanations that go along with the pwp diagrams? Also check out other sources of info, such as text books etc 1. Spherical Aberration is due to rays passing through the lens on-axis (centre of the lens) forming a different point of focus compared to off-axis rays (rays from the edge of the lens), resulting in no clear point of focus, i.e. nothing is pin sharp. Field Curvature is where focussed rays form a curved field of focus, rather a flat plane, so the focus will vary between the centre and edges of the frame. 2. Axial chromatic is due to coloured wavelengths focussing at different points due to dispersion - it may appear as a blue haze around focussed areas, or as indicated in out of focus highlights in the lecture diagrams. The exact colour of the fringe may vary depending on the degree of correction within your lens, and the location behind the lens where the film/sensor intercepts the rays. If you are uncertain whether you will pass, you may choose to sit the makeup test on Wednesday to be on the safe side - the results from this makeup test will only be counted if you are below the pass limit upon completing the final two projects.
Posted on: Sun, 20 Oct 2013 05:17:54 +0000
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