dsjtecserv

dsjtecserv

Lives in United States Northern, VA, United States
Works as a Technical Director
Joined on Jan 21, 2005

dsjtecserv's recent activity

  • I belive Leonard would have been referring to the section entitled Malus' Law and Other Properties . I tried to paste the pertinent text, but DPreview gave an "unexpected server error". At any ...
  • I appreciate the good-natured response. Take care, Dave! Dave
  • I'm at a loss as to how you can reach this conclusion. As Leonard's diagram shows, at the moment of sunset, as viewed from any spot on the surface of the earth (disregarding elevation ...
  • Please explain why the sun setting further north goes through less atmosphere than when it sets further to the south, relative to the observer. In either case the view of the sun is tangent to the ...
  • If you use the 50 mm lens at the same distance from the subject that you would have used the longer lens (if you had one), and then crop the image to give the same framing that you would have ...
  • A rainbow exists only in the perception of the viewer, and must always be located at an angle of view 42 degrees from the center of a point projected from a straight line from the sun through the ...
  • Polarizers are just as effective, and arguably more useful, in non-sunny situations and for scenes that don't involve the sky. They tend to be oversold for their effect on enhancing blue skies, ...
  • Just the sensor. That's the only place where the dust could be focused enough to cast a discernible shadow. With a very wide angle lens and small aperture, droplets on a filter in front of the ...
  • You said: "The below set shows that - the exaggerated perspective is achieved with wider focal lengths." The below set does not show that. the exaggerated perspective is not achieved with wider ...
  • It is only achieved with a wider focal length and moving into the position at which the perspective relationships are what you want. Without the movement, that perspective would not be achieved, ...
  • If someone asked me what aperture I shot at, I'd answer f/8. If someone asked what depth of field I shot at, I'd tell them the shooting parameters and then launch into a boring explanation about ...
  • Yes, as gollywop has said, this isn't new; it was always the whole idea behind depth of field, and it applied just as much back when we were using film. What has changed is that the mechanisms for ...
  • The whole point of that series is that perspective doesn't change with focal length . It only changes with a change in location of the camera. I'd suggest you read over the introductory paragraph ...
  • Sorry, wish I could be more fun. Maybe if I tried to square a circle of confusion...? Dave
  • The key point is what I have bolded below, in my original response. Only the objects that fall exactly on the plane of optimum focus (which has not depth) are as sharp as they can be (which does ...
  • OK. I bolded the same word before you italicized them, because I believe they represented a misconception or miscalculation on the part of the OP, since he says the viewer "has to" move back. To ...
  • Here's the crux, I think. The only thing that exists due to the lens alone is a range of blur circles in sizes that correlate to the distance of the object from the plane of best focus. These ...
  • Where do you get that? If the image has been cropped to a smaller size and then enlarged so that the print is the same size as the uncropped print, then the viewing distance would be presumed to ...
  • I'd agree, although the combination of 8 x 10(~12) and about 12 inch viewing distance, or its equivalent with other print sizes (e.g. 16 x 20 at about 26 inches, etc) is "special" in that it ...
  • If an APS-C sized image is enlarged by a factor of 13.5, the resulting print will be about 8x 12, the same size that is assumed for the full frame print. Since the prints are the same size, the ...
Activity older than 12 months is not displayed.
Total messages 2696
Threads started 37
Last post 2 days ago
Total comments 4
Total likes 20
Last post 5 months ago
Total reviews 0
Entries 0
Votes cast 4
Photos uploaded 0