DSLR lightning grabs and those annoying bars???

[Hank Schyma]

Hey guys,
I'm shooting video w/ a nikon DSLR... When it captures lightning and I want to grab the stills from the video, often there are bars blocking out half the image. Has anybody found a shutter speed that works best with lightning? Again, I Had a very close strike last week with BARS!!!! Any suggestions would be immensely appreciated!
Happy hunting
-h

 

[Skip Talbot]

That's the problem with a rolling shutter. You can try to minimize the problem by lengthening your shutter speed. I'm not sure how low you can go on a Nikon. A Canon with the Magic Lantern mod can shoot 5 second exposures in video mode. It's still possible to get frame tearing with that long of an exposure, but it's going to be a lot less likely than with a 1/30" or 1/24" exposure, which is as long of an exposure as you can get with 30 or 24 fps. You'll also need a neutral density filter to shoot slower than those frame rates during the day.

 

[Dan Robinson]

Yep, this is the dreaded rolling shutter effect from CMOS sensors. As far as I'm aware, there is no way to eliminate rolling shutter from a CMOS camera shooting video at standard framerates (30p/60i). In some cases, you can edit the footage frame-by-frame, removing individual frames one-by-one that exhibit the split-screen effect and replacing them with the preceding or following frame (or just a totally white frame). This is the way that some wedding videographers deal with the problem from camera flashes. It's not ideal, obviously, and it's a labor-intensive workaround. In the end, though, lightning is unfortunately a subject that all current and near-future CMOS-based cameras will never be able to capture natively without the rolling shutter effect being a problem.

 

[Hank Schyma]

Well, that wraps up this thread. Thanks guys, I really appreciate it! See you Tuesday.

 

[STexan]

To re-use and old thread that talks a bit about Magic Lantern ...
I know a few guys here use ML and I have recently applied it to a Canon 5D Mark II. I posted a few this question on the ML forum but it generated no replies so maybe one of you could help me.

My primary use for ML will be using it's HDR bracketing (stills) feature to shoot interiors but my question should be realized by those using ML HDR outdoors, as well .. assuming letting ML auto-determine the number of exposures and using 1.5 stops separation ...

For example, if I were shooting a tall, sunlit anvil a little before sunset against a green field say
1: where should you begin with the exposure initially? Let the camera decide and begin at 0 compensation?
2: what metering mode works best in wide shots? Avg, center weighted, spot?
2: I normally shoot in aperture priority and a set ISO of 100-200 if on tripod. Does ML HDR work as well in Aperture Priority mode, or should Manual mode be used always as they seem to suggest?

I ask these question because, I've seen significant blown out highlights throughout the entire bracketing sequence (bulbs, brigther scenes through a window, etc) if I don't begin with significant exposure compensation. I assumed ML would take the initial exposure, look at it, and compute the remaining exposures better then it seems to do (beginning at 0 compensation and auto metering) where perhaps 10+ stops of dynamic range exist.

Thanks

 

[James Langford]

I'm really moving away from HDR in my photography and more towards using masks to blend multiple exposures. I got pretty tired of the amount of noise generated by the HDR processing. To answer your questions:

1) The best results I have had are exposing your middle or "0" exposure with the best balance in the scene. In the example of a big sunlit anvil I would likely expose at a meter of +1 or so because the scene will be so bright overall. You will have blown out highlights and dark shadows but that is what the bracketing will help you with. Also, in the event of really extreme light variations you may need to bracket 5 or more images.

2) I generally use the standard default metering, which I think is Average. I usually snap a few shots off and adjust my exposure accordingly until the histogram is mostly centered in the middle and then I turn on the bracketing feature.

3) You will have an easier time controlling and adjusting your exposure in Manual mode. In Aperture priority you will have to adjust the exposure compensation value which is not as accurate as changing the shutter speed directly. Generally I will pick an aperture, say F8 or F10 for daylight shooting and then adjust the shutter till the metering reads where I want it.

For example, if I were shooting a tall, sunlit anvil a little before sunset against a green field say
1: where should you begin with the exposure initially? Let the camera decide and begin at 0 compensation?
2: what metering mode works best in wide shots? Avg, center weighted, spot?
2: I normally shoot in aperture priority and a set ISO of 100-200 if on tripod. Does ML HDR work as well in Aperture Priority mode, or should Manual mode be used always as they seem to suggest?

I ask these question because, I've seen significant blown out highlights throughout the entire bracketing sequence (bulbs, brigther scenes through a window, etc) if I don't begin with significant exposure compensation. I assumed ML would take the initial exposure, look at it, and compute the remaining exposures better then it seems to do (beginning at 0 compensation and auto metering) where perhaps 10+ stops of dynamic range exist.

Thanks

 

[Paul Knightley]

I found that it has been much more of a problem with HD video than I used to get with SD. Admittedly I'm using a video camera rather than DSLR, but I guess you're shooting in HD on your DSLR. I've just upgraded my video camera to one which shoots 1080p at 50fps - I'm looking forward to what I get, although lightning always looks best from a single shot on an exposure, rather than a video grab.

 

[STexan]

I agree. I prefer to shoot stills whether I'm photographing a twister or lightning ... but the 50 fps ... is that a European thing? Seems all the reasonable final outputs here in the USA will "downgrade" to 24 or 30 fps, regardless. Let us know if the 50 fps has any real discernible difference in final production runs.