[X] My Assistant

[Tman]

If there already was a discussion about, then I would gladly ask: where is it? Otherwise does someone know something about the object size in the pics, getting from Pancam and Navcam, in comparison with "seen by human eyes"? For example, probably the object sizes getting from Navcam are smaller as we would see it with our own eyes at the same position, but how much approximately? And how about Pancam?

Primarily I would like to know the "real" size of sun by the sunset seen from Spirit on sol 489 (Pancam): http://www.unmannedspaceflight.com/index.p...indpost&p=10917

[Tman]

Thank you for your explanations - again something learned for educational background.

Due to my primary concern (Doug (the other) has it discussed): By the stiching software PTGui is both to set in "Lens Settings" -> "horizon field of view" and "focal lenght". Exactly, when I set one of the two, then there is automatically the other setting provided from the software itself.
Now for a Pancam panorama I only always apply the "horizon field of view" with 16,6 degrees and the software provide 123.386 mm "focal lenght" (for a Navcam pan 45 degrees and get 43.4558 mm).

Has someone the knowledge what that means in "plus" and/or "minus" magnification when we look at the Pancam and Navcam raw pictures from Mars - as per description "for human eyes at the same position like the camera".

Or, How about the real focal lenghts for both cameras, Pancam and Navcam by the MERs?

[dilo]

...
Now for a Pancam panorama I only always apply the "horizon field of view" with 16,6 degrees and the software provide 123.386 mm "focal lenght" (for a Navcam pan 45 degrees and get 43.4558 mm).

Has someone the knowledge what that means in "plus" and/or "minus" magnification when we look at the Pancam and Navcam raw pictures from Mars - as per description "for human eyes at the same position like the camera".

Or, How about the real focal lenghts for both cameras, Pancam and Navcam by the MERs?

Hi Tman, I do not fully understand your first question, but on the last one you can find lot of informations; try:
http://athena.cornell.edu/the_mission/ins_pancam.html

About focal lenght, real value is 14.67mm on NavCam and 5.58mm with PanCam; these numbers are almost 9 times smaller than those mentioned by Doug because sensor size (the CCD) is smaller than classic picture film; this is exactly the same issue you encounter when reading specification of a digital camera lens, where "equivalent" focal lenght is larger than real focal lenght written on the lens!
I hope is more clear now...

[Tman]

About focal lenght, real value is 14.67mm on NavCam and 5.58mm with PanCam; these numbers are almost 9 times smaller than those mentioned by Doug because sensor size (the CCD) is smaller than classic picture film; this is exactly the same issue you encounter when reading specification of a digital camera lens,  where "equivalent" focal lenght is larger than real focal lenght written on the lens!
I hope is more clear now... 

Yes, thanks, it's clearer, though, are you sure about these (focal lenght) values for Navcam and Pancam? Isn't it inverted?

Have you a guess about the proportion between Pancam and human eye for object sizes on Mars? What do you think about this sunset from sol 489? Would sun be smaller if we would be there at the same position and look with one's own eyes westward this sunset - how many times?

[dilo]

Yes, thanks, it's clearer, though, are you sure about these (focal lenght) values for Navcam and Pancam? Isn't it inverted?

Have you a guess about the proportion between Pancam and human eye for object sizes on Mars? What do you think about this sunset from sol 489? Would sun be smaller if we would be there at the same position and look with one's own eyes westward this sunset - how many times?

Oops, you're almost right Tman... in fact, NavCanm value is correct while PanCam focal lenght is 43mm!!! (the smaller number was referred to hazcam ). Very sorry!
Anyway, if you have a 15inch monitor and use a 1024x768 resolution, you should stay about 1m away in order to have the correct view of the sunset image; in fact, consider that scale is 0.28mrad/pixel for PanCam, so distance from monitor must be about 3500 times the pixel size!