This site is supported by the advertisements on it, please disable your AdBlocker so we can continue to provide you with the quality content you expect.

Horizontal banding- adapted lens

Discussion in 'X-T3, X-T2, X-T1, X-T20, X-T10, X-T100' started by Leonardo Kibanoff, Jul 11, 2018.

  1. Leonardo Kibanoff

    Leonardo Kibanoff Member

    Joined:
    Apr 11, 2017
    Messages:
    65
    Likes Received:
    6
    Location:
    Parlin NJ

    -Return to Top-

    Hey All-
    Just an observation and really just a curiosity since it only happens under this one condition
    Noticed some horizontal banding that moves vertically when using an adapted lens
    that happens only when pointing to my chandelier that has LED candelabra bulbs- and only at these bulbs,
    My hats in the house are also LED and the symptom doesn't show up or even pointing to my PC screen
    again not complaining about it, just curious why it does it? anyone know?
    Thanks
     
  2. Goldingd

    Goldingd Premium Member

    Joined:
    Jan 20, 2014
    Messages:
    1,055
    Likes Received:
    414
    Location:
    Anaheim CA

    -Return to Top-

    Electronic shutter selected?
     
  3. Richard_R

    Richard_R Eclectic eccentric Staff Member

    Joined:
    Dec 10, 2011
    Messages:
    8,468
    Likes Received:
    9,363
    Location:
    Melbourne, Australia

    -Return to Top-

    and/or a shutter speed that synchronises with the 60hz refresh rate of US AC power.
     
  4. Jackpinoh

    Jackpinoh Member

    Joined:
    Aug 27, 2017
    Messages:
    35
    Likes Received:
    11

    -Return to Top-

    The camera processor does not read the entire image sensor at the same time. Artificial lighting powered at 50 hz or 60 hz is actually flickering at those frequencies. Cameras with electronic shutters can capture different levels of light during sensor readout unless the shutter speed is an exact multiple of the lighting power frequency. This results in banding in the image.
     
  5. Leonardo Kibanoff

    Leonardo Kibanoff Member

    Joined:
    Apr 11, 2017
    Messages:
    65
    Likes Received:
    6
    Location:
    Parlin NJ

    -Return to Top-

    Electronic shutter is off, So, why just the chandelier? And no other LED's in the house?
    Just to be clear- I'm not actually taking photos, just pointing at the chandelier, the banding is active and travels from bottom to top of rear displace (evf also) like an old black and white tube tv
     
  6. magmouse

    magmouse Premium Member

    Joined:
    Jul 19, 2015
    Messages:
    855
    Likes Received:
    1,426
    Location:
    London, UK

    -Return to Top-

    A lot of LED fittings have switch-mode supplies that run at much higher frequencies than the mains supply. Depending on this frequency, they might create a strobing effect with the refresh rate of the sensor/rear screen. Other LED types might have different frequencies, so I am not surprised it is just one type that exhibits the effect.
     
    Leonardo Kibanoff likes this.
  7. Jackpinoh

    Jackpinoh Member

    Joined:
    Aug 27, 2017
    Messages:
    35
    Likes Received:
    11

    -Return to Top-

    Any bulbs (LED, incandescent, or florescent) plugged into household current will produce the effect--voltage or each is switching continuously at 50/60 cycles per second and going through zero twice for each cycle (AC current is a sine wave), although the light from the source element doesn't decay as fast and never is completely off, it does dim significantly twice each cycle. What you see on your screen or in the EVF is being transmitted from the sensor which is being read out sequentially while the light is changing.
     
  8. lawsofphysics

    lawsofphysics Premium Member

    Joined:
    Apr 17, 2013
    Messages:
    2,647
    Likes Received:
    1,050
    Location:
    usa

    -Return to Top-

    If the mechanical shutter is used, it is impossible to see banding from modulated light sources – such as LEDs.

    I can not think how an adapted lens could cause banding when the mechanical shutter is used.

    It would help to see an example.

    I will speculate what you see is not banding but has something to do with lens ghosting. Lens coatings and lens internal design can make ghosting artifacts more likely. FUJIFILM lenses are designed to minimize ghosting because the design team uses simulations taking the sensor location and camera internal surfaces into account. Some adapted lenses may have low ghosting levels while others may have very high levels. If the ghosting levels are low it's just good luck.
     
  9. Leonardo Kibanoff

    Leonardo Kibanoff Member

    Joined:
    Apr 11, 2017
    Messages:
    65
    Likes Received:
    6
    Location:
    Parlin NJ

    -Return to Top-

    Mechanical shutter is used, never had the need to go electronic
    I'm pretty sure it's not ghosting.

    I'll try and get a quick clip or at least a still and post when I get home tonight
     
  10. magmouse

    magmouse Premium Member

    Joined:
    Jul 19, 2015
    Messages:
    855
    Likes Received:
    1,426
    Location:
    London, UK

    -Return to Top-

    The OP is referring to banding on the EVF and rear screen, not in images, so it will be down to the particular light source strobing at a frequency that interferes with the screen refresh rate. Not sure why this would appear with adapted lenses specifically, though.
     
  11. Leonardo Kibanoff

    Leonardo Kibanoff Member

    Joined:
    Apr 11, 2017
    Messages:
    65
    Likes Received:
    6
    Location:
    Parlin NJ

    -Return to Top-



    This is what I'm seeing
    Adapted Minolta 50mm macro
    Mechanical shutter only
    just pointing cam to chandelier


     
  12. DanGleabols

    DanGleabols Premium Member

    Joined:
    Feb 28, 2014
    Messages:
    244
    Likes Received:
    108
    Location:
    Halifax, UK

    -Return to Top-

    Banding is due to electronic shutter + shutter speed + flickering light.

    You have the camera set to mechanical shutter so banding will not be present in final photos (although some inconsistency of exposure over a series of photos may be seen)

    The EVF and LCD work by effectively producing a video from the sensor using the electronic shutter (even though you are using mechanical shutter only for the Actual picture) this makes sense as using the mechanical shutter to produce the preview video would 1) wear out the shutter very very quickly 2) be noisy as hell.

    Normally you can mitigate the banding with evf by syncing the shutter speed with the frequency of the electrics, but as you can't control this for the preview so your stuck with it.

    As to why one light is worse than others; I'm no electronics expert but you can apply electronics to smooth out the flickering and I guess some have better design than others.
     
    lawsofphysics likes this.
  13. lawsofphysics

    lawsofphysics Premium Member

    Joined:
    Apr 17, 2013
    Messages:
    2,647
    Likes Received:
    1,050
    Location:
    usa

    -Return to Top-

    Thanks. I guess I missed that.

    I agree the banding must only be a function of the EVF scan rate since the banding is cause by aliasing between the scan rate and the light modulation frequency.

    I can not think of how the lens alone could make any difference.

    So,
    • if the camera was on a tripod
    • when the effective angle of view (I.e. composition) is identical for both lenses
    • when the light reaching the sensor (exposure) is identical
    it's a total mystery how the banding could be different.
     
    magmouse likes this.
  14. Leonardo Kibanoff

    Leonardo Kibanoff Member

    Joined:
    Apr 11, 2017
    Messages:
    65
    Likes Received:
    6
    Location:
    Parlin NJ

    -Return to Top-

    Not sure if I mentioned- this does not happen with native lenses
     

Share This Page

  1. fujix-forum.com uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice