Light Trails Discussion

[cerebrus]

One question:

If I want to take a longer exposure for light trails, but do not want the street lights to get blown out, can I use a ND filter?

[Francis247]

Originally Posted by cerebrus One question: If I want to take a longer exposure for light trails, but do not want the street lights to get blown out, can I use a ND filter?

Hi cerebrus,

This is an interesting point for discussion. I think I will move it to a new thread to get more Point Of View if you don't mind. Cheerz.

[Francis247]

For the ND filter, unless you are getting those grad-ND filter. If not, a normal ND filter will cut the light out evenly throughout the frame so those spots that are not so bright may get underexpose.

Other techniques to overcome street lights getting blown out is to use a black card to cut the amount of light for those bright areas. Eg. If your exposure is around 15 secs, to prevent those bright spots getting blown out, use a black card to block off those bright spots area for around 5~8 secs then remove the black card.

[cerebrus]

Originally Posted by Francis247 For the ND filter, unless you are getting those grad-ND filter. If not, a normal ND filter will cut the light out evenly throughout the frame so those spots that are not so bright may get underexpose. Other techniques to overcome street lights getting blown out is to use a black card to cut the amount of light for those bright areas. Eg. If your exposure is around 15 secs, to prevent those bright spots getting blown out, use a black card to block off those bright spots area for around 5~8 secs then remove the black card.

Thanks! I was just thinking that I want more trails to appear, so need longer exposure. Also, with the ND filter, I wanted to reduce the slightly lit portions and make the image darker at those parts. Will try the black card thingy, most of my shots have been from two to three seconds.

[PnS]

Learnt from a fellow CSer that you can cut a small piece of black card with a handle, and you actually move it around the bright areas rather than keep it stationary so you dont get a distinct bright/dark edge

[Francis247]

Originally Posted by PnS Learnt from a fellow CSer that you can cut a small piece of black card with a handle, and you actually move it around the bright areas rather than keep it stationary so you dont get a distinct bright/dark edge

Yap, that is an idea too that can work to prevent overexposure at certain spot. But it is a bit hard unless you know where to the piece of black card.

[cerebrus]

Originally Posted by Francis247 Yap, that is an idea too that can work to prevent overexposure at certain spot. But it is a bit hard unless you know where to the piece of black card.

Think this is one advantage of a P&S, I can test it out with live view before taking the shot.

[pingo]

cerebrus. I love your avatar. Are there any kinds of spiders that glow in the dark?

[cerebrus]

Originally Posted by pingo cerebrus. I love your avatar. Are there any kinds of spiders that glow in the dark?

Errrr none that I know of. Have come across glowing fungus before though. Hmmm.... that would be an interesting subject to shoot....

Avatar is a macro of a baby Heavy Jumping spider. Glad to know you like it.

[kevinsph]

Originally Posted by Francis247 For the ND filter, unless you are getting those grad-ND filter. If not, a normal ND filter will cut the light out evenly throughout the frame so those spots that are not so bright may get underexpose. Other techniques to overcome street lights getting blown out is to use a black card to cut the amount of light for those bright areas. Eg. If your exposure is around 15 secs, to prevent those bright spots getting blown out, use a black card to block off those bright spots area for around 5~8 secs then remove the black card.

mmm~~~ interesting~~~ will try that out thanx for sharing~

[denniskee]

this may be abit off the subject.

using black card with long exposure (using bulb mode), you can do a multiple exposure (most digital compact and dslr lack this feature).

i tried both ball head and pan head, while ball head is faster, it lacks the precise adjustment.

ok, this is how it goes,

1) mount camera on the pan head.

2) determine the position of both scence (double exposure) you want to capture, ie note down the marking on the pan head.

3) note the focal length (if using zoom lens) for the composition you want.

4) if the bright spot (eg. buildings) in both image does not overlap, use correct exposure. but if they overlaps, minus about 1 stop.

5) shoot the 1st scence, cover lens with black card after the pre-determine exposure time.

6) adjust pan head to 2nd scence, adjust focal length, remove the black card and expose for the 2nd scence (can play with zooming in or zooming out effect also).

have fun!!

but you can also take 2 seperate photo, and merge them using software.