Marianne Oelund

Marianne Oelund

Lives in United States Seattle region, WA, United States
Works as a Electronics Engineer
Has a website at actionphotosbymarianne.com
Joined on Jan 22, 2004

Marianne Oelund's recent activity

  • Replied in Astro in Texas
    Does "southest" mean southwest, or southeast? I'd like to learn which areas of Texas are, or are not, desirable for astrophotography. My friend has family in the Houston area, and we will likely ...
  • Replied in Relative coma
    I am not sure what you mean by "wider" - are you referring to the lens barrel diameter? The 14-24/2.8 does very nicely at or near 24mm (yes, for astrophotography, the situation is reversed with ...
  • Show us that you understand PDAF processing algorithms. Given two arrays containing the sensel values read from the two detection lines of a single AF sensor: unsigned int Leftline[LINESIZE], ...
  • Lack of "common sense" is actually needed here, as some aspects of PDAF are counter-intuitive. You may possess "common sense" in spades, but it will not help you here.  My approach is to use ...
  • Replied in Amazing
    Your inability to think, combined with your incorrigible stubbornness, pride and arrogance certainly is making a spectacle of yourself here. It seems you're unaware that you are posting on a public ...
  • No, AF fine tune will not affect operation of the green dot focus confirmation for non-CPU lenses. Your Samyang lens is equipped with a CPU, but the AIS 28mm f/2.8 is not. The only approach that ...
  • Whether or not there seems to you, to be a "secondary aperture," there certainly is one.  It has been conclusively proven: http://www.dpreview.com/forums/post/50073569 It is an invalid assumption ...
  • Replied in Know your camera
    First, you must understand that "shooting at a higher ISO" actually is underexposing your sensor, and both incur a similar penalty in noise .  (One advantage that is sometimes important when ...
  • Excellent and meaningful results, Michael! If you have time, it would be interesting to see how the Siemens star performs as an AF target.  Mr. Shepherd has repeatedly condemned it for such use.
  • They marry and have children, some of whom grow up to despise "aura" and "placebo" so much, that they imagine seeing them where they do not truly exist.
  • Yes, that works nicely, although the diaphragm may need to be stopped down some in order to see its location exactly (press the lens-release button on the camera and slightly rotate the lens away ...
  • That would be the wrong direction.  At 200mm, the combo needs to go quite far forward, perhaps even to the point where the camera body is in front of the tripod center.
  • First rule of teleconverters:  Results depend on the quality of the base lens, more than the TC.  You will probably not be impressed with the result of adding a TC to your Tamron (none of the ...
  • The SWM on mine failed abruptly.  It had been working fine, but one day I pulled it out of my bag, and there was no AF at all. It was repaired by Nikon (SWM replacement) and has been working ...
  • Here's my method for finding the NPP (non-parallax point - which, by the way, is not the same as the front nodal point).  It's fast enough that you can use it to document a large number of points ...
  • Replied in Better than free
    Considering all the money you've saved by not buying a (1) D70 (2) D90 (3) D300 (4) D7000 (5) D700 (6) D800 (7) etc. You'll be far ahead of most of us! I admire your patience ...
  • Uncompressed NEF uses a regular array for the image data, making it possible for software utilities to directly access pixel values without performing decompression first.  Greatly simplifies ...
  • Replied in Relative coma
    I took a few astrophotos last night with my Sigma 50 Art, at f/1.4 for comparison purposes. The 100% crop that Todd provided (see his link above) has a 4th-magnitude star as the brightest one.* The ...
  • Prior to Live View, focusing for astro subjects was a time-consuming trial-and-error process. Today, it can be done quickly with Live View, however it's not uncommon for the screen to be facing ...
  • Sante's description is perfectly correct - for conventional hard, uniform-thickness coatings.  It just doesn't apply to nanocrystal coating. RB Fresno gave a couple of references in his post above, ...
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Total messages 4300
Threads started 70
Last post 8 hours ago
Total comments 6
Total likes 7
Last post 7 months ago
Total reviews 1
Last review Jan 23, 2004
Entries 1
Votes cast 0
Last entry Oct 17, 2012
Photos uploaded 9
Last upload 6 months ago