70D - bright lights cuasing artifacts when shooting video

Question

I'm getting lots of artifacts created by bright light sources when shooting video. It seems to be the intensity of the light and not the type of light that is the problem. They show up in the picture as a kind of mirror reflection, often in green, on a different part of the image. Any ideas how to avoid this?
Canon 70D, 50mm 1.8, NTSC, 30fps, 1/60 shutter, no filters
video shows the problem http://youtu.be/iCAiGoJCGSM
The bottom of this pic shows the green reflections from the lights at the top

Answer 1

metice wrote:
Thanks Tim, the lens is the Canon 50mm 1.8.
I'm using a UV filter - is it worth taking this off?
I'm quite disappointed because it's very noticeable on many night shots which have the light source in the frame. Anything else that can be done to lessen the glare, apart from changing the lens?
Hi,
Yes, those are definitely optically related flare effects.
And, yes, definitely try again without the UV filter, especially if it's an inexpensive, single-coated or uncoated filter. Any filter will increase flare effects when shooting in tough lighting situations like these, a high quality multi-coated might minimize it but still is likely  to show some add'l flare. Cheaper filters can do horrid things to your images, potentially blurring them and causing focus errors, in addition to increasing flare effects.
Try using a lens hood, too. That physically protects the lens, but also can minimize veiling and other types of flare from bright light sources just outside the image area by preventing oblique light from striking the lens. The 50/1.8 has fairly well recessed front element, but a hood might help even more. Since you are using the lens on a crop sensor camera, instead of the OEM hood (which is designed for full frame), you might look for a 52mm screw-in hood designed for a short telephoto.
Unfortunately, you will still see some flare effects... The 50/1.8 isn't the best lens dealing with flare. The EF 50/1.4 and Sigma 50/1.4 both are better, but of course they cost more. Also, the 5-bladed aperture of the 50/1.8 contributes to the appearance of those flare effects... The 8-bladed aperture of the EF 50/1.4 or the 9-bladed aperture of the Sigma 50/1.4 give somewhat nicer background blur results (the eight curved blades or the premium EF 50/1.2L can be even better, but that's a rather pricey lens).
You also might experiment with stopping the lens down a little... both the Canon EF 50/1.8 and 50/1.4 are sharper at f2.0 or f2.2 than they are wide open. You might find they control flare better at a bit smaller aperture, too. I'd experiment with f4, f5.6 and f8, too.
A zoom lens likely would be worse than using a prime such as you are doing. But some zooms deal with flare pretty effectively.
Also watch the viewfinder and try slightly changing your position. Even just a little change can make a huge difference.
Compare these two images I made with my 24-70/2.8L.... I could see the flare occurring in the viewfinder and all I did to dodge a lot of it was change my position slightly.  
I nearly always use a lens hood. Here's an example of the difference a lens hood can make. The EF-S 10-22mm lens has a huge lens hood that's a bit of a pain to pack. (Most Canon hoods reverse neatly on the lens for storage in minimal space. The 10-22mm's hood is just too large diameter to do that comfortably in any of my camera bags.) I thought about using the lens without any hood, since it's very shallow and doesn't seem it would be very effective anyway, so I did the following test shots...
As you can see, the first shot without the hood showed a very strong ghost flare. The second shot, after simply adding the hood, shows no flare at all. Note: it was a breezy day, so the clouds moved a bit while I was installing the lens hood. But, obviously the hood is effective. So I carry and use the hood, even if it is a bit of a pain.
Finally, there are times when flare effects can work for you, might actually add to the image. For example, I think that's the case here...
Above is a bit abstact... it's the sun reflecting off the corner of a building and was shot with an EF 100/2.8 USM macro lens. I think it would be pretty boring without the flare effects.
Regarding filters... I have various that I use, too. Including UV  for "protection" (plus C-Pol and othersfor different purposes). They are all stored in my camera bag until actually needed. I never leave a filter on a lens all the time. IMO it's sort of silly to expect much real "protection" from a thin piece of glass (I've actually seen lenses gouged and damaged by broken filters). And there are just too many situations such as yours, where a filter can do more harm than good in the images. Another imporant factor... I use mostly B+W MRC and Hoya HMC or SHMC filters, which are high quality, multi-coated. There are other high quality brands... in fact most manufacturers offer different qrades at different price ranges.
Plus, when using a filter, it's even more important to use a lens hood as well, to keep oblilque light off the filter.
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
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