ND filters for SD1100 (point and shoot) cameras?

CanonBlue

« on: 27 / June / 2010, 10:40:59 »

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I hope its ok to put this thread here under general assistance. I'm trying to do lightning shots, and since most of the lightning here is occurring during the day, or with bright city lights reflected on the clouds, I haven't been able to get any long shutter shots to work -- they just come out completely white. It sounds like ND filters are the thing to try, but it doesn't seem like canon makes ND filters for this camera, which makes sense since it isn't designed to take different lenses. Does anyone know a way to make an ND filter for this kind of camera? I'm thinking that if I could just get a piece of plastic that was tinted properly I could probably sort of tape it on the front for storm photos, but I don't know what kind of tinted plastic to start with.

Also, in general to do long time exposure photos, is it better to use the exposure or shutter speed settings on the camera?

Thanks everyone!

Here you can see the one lightning shot I did get by luck, using the intervalometer and normal exposure. You can see that even in that short second, the sky is really bright, so a long exposure turns completely white very fast:

IMG_1684

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I use the chdk on my SX230 and SD1100 cameras, and I installed them using a Macbook, currently running 10.6.8.

reyalp

13386

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #1 on: 27 / June / 2010, 14:43:47 »

This is "CHDK Development > General Discussion and Assistance", meaning coding related discussion.

There is a built in ND filter in these cameras, which CHDK can force open or closed. They don't have any option for add on lens accessories (many older A series do, e.g. A5**, a6**, a7**)

You can buy filter gels if you want to go DIY http://en.wikipedia.org/wiki/Color_gel or get an ND filter intended for another camera and try to adapt it.

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Also, in general to do long time exposure photos, is it better to use the exposure or shutter speed settings on the camera?

You probably need to use CHDK overrides. You can force the ND filter in. The ISO should be set as low as possible (you can use the canon setting for this, if the firmware allows, CHDK overrides don't go any lower). If you zoom in, that will allow you longer exposures too, but may not be what you want with lightning.

I'd still suggest figuring out how to get MD to work instead, as this is known to work quite well in daylight (see my posts in your other thread)

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CanonBlue

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #2 on: 27 / June / 2010, 14:49:21 »

Thanks for the response. For lightning, I still don't see how the MD can possibly be fast enough, but I may keep trying it. However, now that I've been reading about ND filters I'm suddenly interested in other things, such as foggy shots of water, that seem to be done with long exposures. I have been fiddling around with the settings, and I've figured out how to use the CHDK to force the ND filter to be "in" or "out" and I can make the shutter time go up, but the photos are still way too overexposed for any sort of daytime shot.

Is it possible to take long exposure shots of things like waterfalls (daytime) using this camera and the chdk? Or is the only way to do that to get a physical ND filter?

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I use the chdk on my SX230 and SD1100 cameras, and I installed them using a Macbook, currently running 10.6.8.

reyalp

13386

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #3 on: 27 / June / 2010, 15:02:20 »

Quote from: CanonBlue on 27 / June / 2010, 14:49:21

Thanks for the response. For lightning, I still don't see how the MD can possibly be fast enough, but I may keep trying it.

These photos were done with MD in daylight.
http://picasaweb.google.com/reyalp/LightningJan192010#
http://picasaweb.google.com/reyalp/CHDK#5273218930144037074
MD (on some cameras at least) is obviously fast enough.

edit:
The sd1100 port appears to have the stuff necessary for fast MD implemented.

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Is it possible to take long exposure shots of things like waterfalls (daytime) using this camera and the chdk? Or is the only way to do that to get a physical ND filter?

You would need to add external filtering. Daylight is really bright, even with everything stopped all the way down you won't get a very long exposure.

« Last Edit: 27 / June / 2010, 15:04:41 by reyalp »

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CanonBlue

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #4 on: 27 / June / 2010, 15:21:54 »

MD (on some cameras at least) is obviously fast enough.

I guess I'm just questioning if its fast enough on the SD1100 specifically. I'm aware that a lot of other cameras have different/better features. On my camera specifically, it can't catch my arm waving in front of it, and I'd think lightning would be faster than that. But I'll try it some more -- we're supposed to have lots of thunderstorms in the next few weeks.

You would need to add external filtering. Daylight is really bright, even with everything stopped all the way down you won't get a very long exposure.

Ok, thanks, I was just looking for a straight answer on that. I think I'll look into buying a cheap ND filter and just propping it up in front of the camera or something. It would be fun to do things like long exposures of the ocean or river in daylight. (Or are those always done at dusk?)

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I use the chdk on my SX230 and SD1100 cameras, and I installed them using a Macbook, currently running 10.6.8.

reyalp

13386

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #5 on: 27 / June / 2010, 15:45:23 »

Quote from: CanonBlue on 27 / June / 2010, 15:21:54

MD (on some cameras at least) is obviously fast enough.

I guess I'm just questioning if its fast enough on the SD1100 specifically.

It should be, since it has the "fast" viewport addresses found. Of course, they could be wrong.

What script and settings are you using ?

Quote

It would be fun to do things like long exposures of the ocean or river in daylight. (Or are those always done at dusk?)

No, with other cameras they can be done in daylight.

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CanonBlue

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #6 on: 27 / June / 2010, 15:49:46 »

Let me just ask one more question about ND filters, and I'll get back to the lightning thread next time we have a storm. You're all probably right that if I try the MD script more, it will work for lightning, but I can't test it right now since its sunny outside.

My camera doesn't have a physical attachment for ND filters, but it looks like I can get one for around $16 on amazon, so I think its worth a try to just tape it on there with masking tape or something. But there seem to be different levels of ND filters-- any recommendations on one to start with? I'm thinking here of things like being able to take long exposure shots in daylight, of things like the ocean. (Actually, I'm not sure what else its good for, but there must be lots of things.)

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I use the chdk on my SX230 and SD1100 cameras, and I installed them using a Macbook, currently running 10.6.8.

reyalp

13386

Re: ND filters for SD1100 (point and shoot) cameras?

« Reply #7 on: 27 / June / 2010, 16:02:45 »

Quote from: CanonBlue on 27 / June / 2010, 15:49:46

My camera doesn't have a physical attachment for ND filters, but it looks like I can get one for around $16 on amazon, so I think its worth a try to just tape it on there with masking tape or something. But there seem to be different levels of ND filters-- any recommendations on one to start with? I'm thinking here of things like being able to take long exposure shots in daylight, of things like the ocean. (Actually, I'm not sure what else its good for, but there must be lots of things.)

See http://en.wikipedia.org/wiki/Neutral_density_filter which describes the grading system. Each step will double the exposure time. So if you can get a 1 second exposure now, and you want a 64 sec exposure, you'd want ND64

When attaching it to the camera, you should be careful to do as much as you can to avoid internal reflections. This means making sure light only comes in through the filter, and that anything it can hit other than the lens is flat black if possible. Black photo tape will be preferable to regular masking tape.

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