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09-25-2018, 06:17 PM | #1 |
Loyal Site Supporter | AstroTracer Article Suggestion
Afternoon, Just a suggestion for an additional article on a topic related to the AstroTracer capability (either built in or with the O-GPS1). A good overview of the star trailing (corners and edges) phenomena that appears when ultra wide and wide angle lenses are used in conjunction with the AstroTracer function. The best description of this type of distortion I have come across if from.... Quote: Astrotracer loses a little bit of its utility when shooting with very wide angle lenses. The rectilinear distortion of most wide angle lenses causes different parts of the image to appear move at different rates across the sensor, depending on its position, even if actually moving at the same rate in real life. Objects moving at a the edge of the frame appear to move faster than objects in the center. That means that even with the most accurate of Astrotracer shots, there will always be some star trailing in the corners of a wide angle rectilinear image. Less than a non-tracked image, but still some trailing. That said, Astrotracer still does an excellent job at tracking the center portions of a super wide angle shot and still allow for greatly extended exposures with reduced star trailing. Using the wide angle example shot from before, let’s compare the center and corners of the image:
Some additional discussion items to touch on that would be very helpful, would include:
I have not really found any discussion on this in the scientific/engineering literature - but I really do not know what it's called or referred to - other than rectilinear image distortion - of which I find precious little information on anything related to rate of movement within the frame of view. For me, this falls into the category of - Inquiring minds would like to know. That brings me to this suggestion, that I would like to submit for consideration. Pentax with the AstroTracer function tends to be tagged with this "problem", that appears to not be of Pentax's making - it just appears to be illustrated by the Pentax technology given the in-body tracking functionality is unique to Pentax. Having a somewhat technical based article by someone like a Forum member like bdery, would I believe be exceptionally useful - and quite possibly put a fatal nail to the issue with a well informed presentation. Thanks!! Last edited by interested_observer; 09-27-2018 at 11:50 PM. |
10-17-2018, 01:16 PM | #2 |
Afternoon, Just a suggestion for an additional article on a topic related to the AstroTracer capability (either built in or with the O-GPS1). A good overview of the star trailing (corners and edges) phenomena that appears when ultra wide and wide angle lenses are used in conjunction with the AstroTracer function. The best description of this type of distortion I have come across if from....Some suggested items/discussion points to cover....
Some additional discussion items to touch on that would be very helpful, would include:
I have not really found any discussion on this in the scientific/engineering literature - but I really do not know what it's called or referred to - other than rectilinear image distortion - of which I find precious little information on anything related to rate of movement within the frame of view. For me, this falls into the category of - Inquiring minds would like to know. That brings me to this suggestion, that I would like to submit for consideration. Pentax with the AstroTracer function tends to be tagged with this "problem", that appears to not be of Pentax's making - it just appears to be illustrated by the Pentax technology given the in-body tracking functionality is unique to Pentax. Having a somewhat technical based article by someone like a Forum member like bdery, would I believe be exceptionally useful - and quite possibly put a fatal nail to the issue with a well informed presentation. Thanks!! | |
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angle, article, astrotracer, distortion, exposures, frame, image, lenses, pentax, star |
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