John Sheehy

Lives in NY, USA
Works as a Retired Communications Technician
Joined on Jul 9, 2003

John Sheehy's recent activity

  • If there really is extra optical blur with the 60MP sensor, then you should see it with all similar lenses. "Resolution" as reported is not just spatial, but is based on contrast, too. So, while ...
  • We're hearing about cherry-picked lenses here. I wonder what the overall results would be with a wider range of fast short lenses. If the net effect is that lenses differ and go both ways in the ...
  • Replied in Just curious:
    The farther apart they are, the more the 5 images should separate as 5 ghosts. They'd have to be very close to appear as one blurrier image, and I don't think you could make the holes yourself, ...
  • Yeah, sun paper is slow enough already without a pinhole; I forgot how long that would take. The webcam would have to be run through code that stacked a lot of frames with light that low, and any ...
  • The R5's burst speed is limited by other factors. The sensor can be read out 60 fps. The R7 has less margin; it bursts at 30fps but reads out the sensor at 34 fps.
  • That's not how it works. The longer the exposure, the larger the percentage of total exposure time that is happening at the same time in the entire sensor. On the R5, the period where exposure is ...
  • ... and EFCS is just as shock-free as full-electronic. EFCS only causes shutter shock at the end of exposure, and only challenges stability with very fast bursts, where the shock at the end of the ...
  • For non-flash photography, there is no technical reason for such limitations; it seems to be a marketing decision. The fact of the matter is that all shutter modes use electronic shutter under the ...
  • There was one on Amazon for the EF mount that had a variable hole size (not sure what the shape would be, though), but it has been out of stock for months.
  • I have a couple packs of "sun paper" here somewhere, but I have only tried it with objects of various transparencies on top of the paper; I should make a pinhole camera out of a box and try the ...
  • Yes, I've done that, but it is not the same as a perfectly round hole done in a precise factory, in a very thin material. The factory product gives just classic diffraction; the hole in a plastic ...
  • The sharpness vs hole size trend has two modes; the smaller the hole, as you say, the more tightly a point in the field will render on the recording medium, AOTBE, but the smaller the hole, the ...
  • Why is it that when I offer options, someone always seems to reply to them as if they were a mandate? I am not here to tell people that you must or should do things a certain way; I just offer ...
  • Yes, you can always put extension tubes on the pinhole and do that, and then each dark dirt artifact will be smaller in the final image. I don't think that you will decrease diffraction, though, ...
  • The trick is in recomposing smoothly and not overly fast, because fast, jerky recomposition is more likely to make the AF lose track of the subject, especially if it is against a cluttered background.
  • You don't need to, but I prefer recompose because then the AF point is consistently in the center and I don't get any lost shots because the small AF zone was not in the center when the next ...
  • Yes, they can lock onto an object that it focused on and maintain focus as it moves through the frame, with no camera idea on what that object is. On the R5, you use full tracking mode and set the ...
  • Being that the heavy diffraction destroys the contrast of the finest details anyway, why not use a very low exposure with a faster shutter speed? Especially if you have a camera where the read ...
  • The difference is much smaller than with the other cameras, but more than "a hair", I think. Just 50% faster could result in a lot less visible motion distortion in some cases. Has anyone ...
  • Replied in Confused ...
    Do you expect problems with visible read noise? If not, then this is moot, as photon noise is exactly what you would expect with absolute exposure. A person shooting in even light with a decent ...
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