[X] My Assistant

[PDP8E]

Here is a work in progress.
I was working on a another thread (processing the envelope challenge for PFK) and thought I could use the same technique to 'see' underneath Spirit's deck with the MI.
While I don't fix the focus, the technique does what amounts to a smart contrast...
If anyone would like to to do a mosaic, i would appreciate it (I haven't done them enough to pull them off like you guys)
I will post the whole underbelly later, but here are the test images:



Cheers and thanks!

[dvandorn]

Actually, PDP8E is operating under a misapprehension. I can tell his logical thought process was "If you get greater depth of field by reducing your aperture and thus cutting down on the light entering the camera, maybe you'll get greater depth of field merely by reducing the overall light level." And that's a fallacious logic chain.

You see, in the physics of photography, it's the actual size of the aperture, and not the amount of light reaching the photosensitive surface, that determines your depth of field (i.e., the range of distance from the camera in which objects are in focus). Focus has to do with the collimation (i.e., the parallel-ness) of the rays of light when they hit the film/CCDs. The smaller the aperture, the less "spread" you get from a beam of light entering, say, from the upper-right corner of the lens and then painted into the bottom-left corner of the film plane. The absolute greatest depth of field comes from a pinhole aperture, since there is almost no practical room for the light from any given area in the field of view to spread across the width of the aperture.

I have a degree in photojournalism -- some things you learn empirically, even if you're not a physicist...

-the other Doug

p.s. -- looking at PDP8E's other point, that reducing exposure time would increase depth of field, again that's not a truthful statement. The only thing that really increases depth of field is reducing aperture. If you increase the light on the subject, you can reduce aperture and thus increase depth of field, and perhaps at the same time you might need to reduce your exposure time in order to get a properly exposed image. That's the only way in which exposure time could work in with depth of field. But in general, photographers use exposure time to determine proper exposure (i.e., total amount of light) and aperture to determine proper depth of field. dvd