Hamiltionian

Lives in United States San Francisco, CA, United States
Has a website at https://thecentercolumn.com/
Joined on Jun 16, 2015

Hamiltionian's recent activity

  • Thanks, the effect you describe in the article is very similar to what I am experiencing with the 63mm and 45mm.  The 63mm is most obvious because the focusing physically shifts the entire front ...
  • Yes, I am talking about this effect.  The diaphragm is moving as well, but I am talking about the focus.  The slight amount of focus breathing can be seen on the live view image, but the smoking ...
  • Honestly, that's about what the 645z should be selling for these days.  The lenses that are included are all older lenses that go for a couple hundred bucks each.  The pentax medium format system ...
  • Created question thread GFX focus shift during manual focus
    While set in manual focus mode, after releasing the shutter button from down halfway, the lens changes focus a little bit out and then back to where I set it.  This is visible in both the view as ...
  • Agreed.  More quantitative (though still not incredibly precise) methods are showing that the tilt is on the order of 100 um across the mount.  This aligns with what I am seeing in images, with a ...
  • Check out the Oben CT-2331 and the Leofoto LS-224C. I would highly recommend the LS-224C over the Sirui. https://thecentercolumn.com/rankings/travel-tripod-rankings/
  • The photo is level, but the field isn't.  It is level enough near where I am standing for these purposes, but yes, perfectly flat subjects are much better.  I truly wish I was deceiving myself ...
  • I'm so sorry.  As someone who has gone through this before, I feel your pain. As you have figured out, you are going to need to get the sand out of all of the threading, which means removing as ...
  • Replied in Tilt Estimation
    Here is the rough method I am using to observe the amount of tilt.  TLDR;  I use focus select to look at the tilted focal plane and estimate the misalignment at 0.06 degrees or 75 um across the ...
  • Sadly no.  Craigslist.  But its ok, it came at a price that I was aware of the risks I was taking.  And the field tilt is so small that I would never have noticed it taking test images in a coffee ...
  • It very well could be the the lens mount being slightly tilted on the frame as opposed to the sensor tilted on the frame.  I think the effect on images would be the same.  I don't see any visible ...
  • Thanks again for the help.  The service center said that they would want to replace the entire front end of the camera to fix the tilt.  They claim that the camera has no capability for internally ...
  • So B mode requires the pictures to be in order so that it can create a depth map of the image.  Clearly this is ideal for the pepper with a relatively smooth surface.  It does mean that the ...
  • From the same shoot as last week, but later in the morning.  I am just beginning to experiment with focus stacking.  I have resisted focus stacking for a long while, but I am beginning to come around.
  • Thanks Chris.  Unfortunately the camera was acquired in a way that doesn't allow me to get refund, but fortunately it was acquired for a price that allows for some margin of error.  So I will be ...
  • Thanks Rick, this is exactly my fear when sending the camera in for service.  I learned the hard way with Canon that the service center doesn't seem to have the equipment, motivation, or knowledge ...
  • The math of the matter is derived on this wikipedia page: https://en.wikipedia.org/wiki/Scheimpflug_principle In short though, the angle psi (the greek letter) of the plane of focus is given by: wh ...
  • Created discussion thread GFX 50S Sensor Tilted
    So, I am putting my recently acquired Fuji GFX 50S through the paces and have determined that the sensor is slightly tilted  with respect to the lens focal plane from left to right.  The left side ...
  • I will throw in a vote for the Manfrotto Befree advanced.  The build quality is significantly better than the Mefoto tripods.
  • Negative cropping?  Is 30 shots what was necessary to cover that depth of field at f/11?  Also, are you shooting f/11 to reduce the number of shots required for the stack, or to reduce aliasing?
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