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Live view and ND filters

Discussion in 'Canon Conflab' started by Geoff_s, Jan 3, 2019.

  1. Geoff_s

    Geoff_s Member

    Hopefully I can make sense!

    I have started experimenting with a 10 stop ND filter. Now a while back someone showed me a technique on a Canon 1DX Mark II whilst using Live View.

    Essentially, while holding the shutter open on bulb (I think), the image would gradually appear on the LCD, and you would release the shutter when happy with the image displayed. Not very professional, I know, but good fun!

    The thing is that I have forgotten how to do this, or I must be getting something wrong, or maybe I misunderstood what I was seeing, or dreamt it.

    I have checked the manual and it specifically says that the exposure simulation will not work with bulb. OK, so what was I looking at? I distinctly remember seeing the image gradually appear on the LCD.

    Can it be done or have I lost some marbles?
     
  2. Chester AP

    Chester AP Well-Known Member

    I can't answer your question, but if you need to take some shots soon I can advise the easiest way to take the shot manually whilst you wait for the answer. Just needs a simple bit of mental arithmetic (works for me).

    Put the camera and lens on your tripod with attached cable release or working remote control, set the lens aperture and ISO you want to use, frame the shot and find the shutter speed for the correct exposure without the filter. You will then need to multiply this shutter speed by 1,024, or 1,000 which is close enough. Finally, attach the filter.

    If you use a low ISO so that the 'normal' shutter speed is 1/30 or 1/60 of a second, the exposure with the filter can be timed sufficiently accurately with a watch. But always use the cable release or remote control, make sure that the mirror 'lock up' facility is set on, and turn off any image stabilisation.

    So if the 'normal' shutter speed is 1/30 of a second, you will need 1000/30 seconds which is 33 seconds.
    Or if 1/60 second, with the filter you will need 1000/60 which is (close enough to) 17 seconds.

    Last time I took some shots with my ND1000 (10 stop) filter, the biggest problem was some curious ducks who landed in shot, causing blurred darker areas in the foreground.
     
  3. PeteRob

    PeteRob Well-Known Member

    Interesting question. I don't know what the effective exposure time is for liveview. It is intended to let you view the scene "live" and so normally must refresh at some tens of Hz to avoid semblance of flicker. The ability to visualise scenes with a ND filter must relate to the camera ISO range. Certainly the ELV image on mirrorless cameras (I've never used liveview on a DSLR) get less realistic as the light level goes down and appears as if the ISO is shifted to high values. The 1Dx has good lowlight performance so I'd think it would do better than most in low-light. I guess they might also integrate the signal over longer times making it jerky and unreactive to changes and this could accord with your memory of seeing an age appear in time.
     

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