ND Filters

[Ian Chapman]

I use 'pro' camcorders with built in ND filters. Can someone explain how most small 'prosumer' handycams can seem to produce a good, watchable imagery without having ND filters built in?

Also, with DLSR type cameras when shooting video, is there truly a need for ND filters?

What I am referring to overall is the concept of 'correct' motion blur which we are meant to get via 1/50th (1/160th) constant shutter speeds achieved via ND filters. The 'old style' handy cams don't seem to produce anything unwatchable? Or am I wrong?

thanks

Ian

[Robert Young]

My take on it is that the ND filters on the pro cameras are used to give you flexibility with regard to depth of field.
If you need a shallow depth of field in a brightly lit scene you can do it by keeping the f stop low and adding ND.
The consumer cams don't have much capacity for shallow depth of field anyway, so it's not a big issue.
In bright light, they just default to high f stop, and fast shutter as needed.
Since they are most often recording in 60i or 60p, rendering of motion is excellent regardless of the other settings

[Ian Chapman]

Thanks for making these interesting and valid points, I guess you more or less answered a question which has been bugging me for ever r.e. handy cams.

[Dave Baker]

It depends on whether or not you want to stick to the 180 degree shutter "rule". If you shoot in full auto with a consumer camera, as Robert says the exposure will always be correct because they vary aperture, shutter and gain to do it, which often results in jerky motion in bright conditions because the shutter speed is too high. If you shoot in either Tv or full manual it will soon show up the weakness in the system.

I use a camera with automatic built-in ND filters, I can select only either on or off, which come it at f4.0, presumably to keep the lens at its sweet spot as much as possible, but that isn't always enough and in some circumstances even stopped fully down (shutter 1/50th, f8.0 with the 3-stop ND in) I still get an over exposure warning. Depending on the motion in the scene I can either increase shutter speed or add an external ND filter e. g. running water with increased shutter speed begins to look as if it is on a ratchet, while someone walking slowly wouldn't be affected too much. I prefer to keep an ND filter on all the time but no, not at night!

I also use a DSLR for video sometimes and that needs an ND filter for the same reason.

ND filters also do wonders for GoPro footage.

[Rainer Listing]

Just noting the consumer AX100 and AX700 have built in ND filters. Learn to adjust your shutter speed in accord with the motion in the scene and the result you want, don't just rigidly follow the 180 degree rule - it's a rule of thumb. Slow motion in dim light you can shoot 360 degrees, static or slow subject in bright light you can shoot 90 degrees, makes no difference. If you don't have an ND filter handy, staccato motion appearance is better than overexposure - you might be able to add motion blur in post if you really need it, you can't get back what you never had.