Stephen Barrett

Stephen Barrett

Joined on Dec 2, 2011

Stephen Barrett's recent activity

  • Hello Ken, I agree with Mario. I have both the 250 and the 150 and use the 150 much more. With my SX30 at full optical zoom, the DOF of the 250 is less than 0.1 mm. With your SX50 at full zoom, the ...
  • Created discussions Properties of Closeup Lenses
    This post is divided into 4 main sections: A) Focal Lengths and Principal Planes of the Raynox-250 and Raynox-150 B) Closeup-Lens Magnification Formula with Infinite Focus of the Camera (1) B1) The Formula
  • All very nice shots, Evan. You are making good use of the full optical zoom of the SX50.
  • Hello Don, You are right. I haven't been very clear about the point of it all. Originally, the intention was to estimate how large a subject was in shots taken with a closeup lens. But then I got ...
  • Thanks for your comments, Dale. It's good to get the opinion of somebody with experience.
  • Thanks for your comments, Brian. The description of your camera innards makes me wonder whether or not you could control the focal length and focus of a PowerShot lens once you remove it from the ...
  • Hello Mario, When you say optical correction, do you mean that the original RAW image is distorted? I realize that there is a lot of distortion at the wide-angle end of the zoom, but thought that ...
  • Ah, Mario, another challenge! Here is my answer to the challenge: Telephoto shots display 5% more field of view than what should be able to fit on a normal 1/2.3" sensor (6.17 mm x 4.55 mm). ...
  • Thank you for your thoughtful comments, Don. In my original post, I mentioned the possibility of cropping, which would make the frame size smaller than the maximum that would fit on a sensor. You ...
  • sueanne wrote: "I just want to take the picture……." Good point, sueanne Brian wrote: "… but did you say in what way it matters." I guess it doesn't matter photographically but, to me, it's a matter ...
  • Hello again, Ed, I didn't realize that you took that shot at full optical zoom. Then I wondered how you got enough depth of field. You must have backed off quite far, which I never thought of ...
  • Very nice, Ed. I like how continuous it is horizontally.  They are holding hands.
  • Created discussions The 5% Solution
    The Problem I am having a recurring problem with discrepancies of approximately 5%. Most often, I notice the problem when I take a shot with a closeup lens and want to know the size of something in ...
  • Replied in Geranium
  • What a wonderful variety of wildlife you have there, Evan. Thanks for posting your excellent shots, Stephen
  • Hello Dick, I guess you solved the mystery then.  That's a lot of humidity.
  • Hello Dick, I think that the variations have nothing to do with your camera settings, but that the "ghost effect" is just reflections from your window.  A slight change of angle or position or ...
  • Replied in SX50 - Rainbow
    Very nice, Augustin.  You can even see the fainter outer rainbow a little bit - the "double rainbow".
  • You have done a very impressive job of capturing these insects, Augustin. They are nicely in focus and show lots of detail and are interesting.  You must be very patient.
  • Thanks for the comments coody, GuardianFlash and Biff Exploder. Coody, you said a lot with one word. You are right that there is blur, but I have excuses: 1) The bugs were low on the wall, so I had ...
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Total messages 462
Threads started 84
Last post 3 weeks ago
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Photos uploaded 231
Last upload Oct 23, 2012