Stephen Barrett

Stephen Barrett

Joined on Dec 2, 2011

Stephen Barrett's recent activity

  • SX50 at 600 mm EFL = 107.5 actual focal length -widest aperture is f/5.6 ==> D = 107.5 mm / 5.6 = 19.2 mm G3X at 600 mm EFL = 220 mm actual focal length -widest aperture is f/5.6 ==> D = 220 mm / ...
  • Created discussions Raynox Closeup Lenses on G3X?
    Several months ago, I decided not to wait for the Canon G3x and to upgrade from my SX30 to an SX50 instead. One reason was cost. I got a good deal on an SX50 demonstrator model for $220 Cdn, ...
  • Beautiful pictures, Ed. Thanks for the link.  I'll be spending some time looking at the rest of your portfolio.
  • Hello Jesus, Here is a link to my post about measured properties of the Raynox 150 and 250 and also the DOF formula: http://www.dpreview.com/forums/post/54177727 Properties of Closeup Lenses Aug 9/14
  • Yes, that's the one.  Amazing!
  • Hello Augustin, Really great picture of the girls!   I saw a P900 bird shot of yours somewhere with the most amazing feather detail that I have ever seen.  Now I can't find it and it doesn't seem ...
  • Hello Jesus, I have the Raynox 250 (8 diopter), Raynox 150 (4.8 diopter) and a 600 mm (1.67 diopter) homemade closeup lens and do a lot of focus stacking. I rarely use the Raynox 250 because the ...
  • Hello Wesley, I normally have my camera set to infinite focus when focus stacking with closeup lenses. Withe infinite focus, the distance of the closeup lens makes negligible difference in ...
  • Hello Vegetable Police, Here are a couple of my attempts to get more moon detail by stacking images: The first attempt is manual stacking of moon shots from different dates, using PhotoShop ...
  • Lion, tiger and bears, oh my! Wonderful shots, ANAYV. They don't look like zoo shots. They are all great, but I especially like the action in the bear shot.
  • Beautiful shots, Brian. I like them all, just as you posted them. Please keep posting.
  • Replied in SX50 EFL Tests
    Thanks Murry. After one of my technical posts, somebody said, "I just want to take pictures". That's what it's all about, but I can't help measuring things just for the fun of it: a little bit of ...
  • Created discussions SX50 EFL Tests
    Measurements of SX50 Equivalent Focal Length (EFL) Last year, imaging-resource.com reported that the EFL of the SX50 is 1146 mm, 4.5% less than Canon's specified 1200 mm. That inspired me to do ...
  • Hello Murry, You don't need to change gears. Your iris pictures are beautiful. If I understand what you said, you will be posting to the Retouching forum rather than the Canon Powershot Talk forum. ...
  • Hello Ed, Both shots look really good to me. Cropping the NX1 shot by about a factor of 4 (both width and height) didn't hurt anything. I downloaded the "original" shots, both 4000 x 2248, and ...
  • What a wonderful picture, Den! and thanks for the story to go with it.
  • Thanks Ed, We are both fine. I agree about how amazing it is - the way "everything works together in concert": System of nested Tubes System of nested Tubes There are 3 nested tubes, where the ...
  • Thanks Murry, Yes, it is very complex. It was difficult to disassemble the parts and I broke some of them in the process. I would say - forget about trying to do a repair of anything inside the ...
  • Thanks Ken, The story about the dissection is here: A Sad End http://www.dpreview.com/forums/post/55674598
  • Created discussions Some SX50 Parts
    Focusing Lens Focusing Lens The focusing lens is mounted on a copper-wire coil and they both ride on two smooth rails. The coil surrounds a magnetized strip without touching it. The coil is shown ...
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Total messages 645
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Last post 3 weeks ago
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Photos uploaded 316
Last upload Oct 23, 2012