DIYPhotography.net

That's a great way to save money. I'm curious about the optical quality [Although the cokin filters I have are pretty crappy optically and nobody seems to care]

With a smaller point-and-shoot lens, you can use polarized sunglasses as a filter.

@Aron- thanks for the compliment. I love the cokin filter system. I agree about the optical attributes, but the system just rocks for ND sliding filters

@Matthew - Thanks for the tip. I guess that will work with old glasses that you're not afraid to break since you'll need two pieces of polarizing material

Whoo hoo!!
This is a nice surprise!

Im a photographic n00b and to be honest i dunno why the filtered image was taken at ISO 400 - it seemed like the correct thing to do at the time. What iso would you suggest?

If anybody is interested - the filter cost £2 from ebay abd was held onto the front of my lens with two elastic bands! [getto style!!!]

I love the grainy effect it gives

I think Matthew may be refering to using the sunglasses as a polarizing filter, not as an ND filter. I've taken off my ski goggles before and held them in front of my (p+s) camera to try to cut glare.

You are right that you could two layers of polarizing material to reduce light. If you're using a point and shoot you could probably do fine, but if you were using an SLR you'd probably need a circular polarizer after them.
There might be something to this - theoretically you could make a variable ND filter that goes from whatever a single polarizing filter is, down to no light. Hmmm. I need to get some polarizing film.

Is there a color cast when taking photos through the welding glass? If so, is there any way to remove it? It's hard to tell from the posted photo that is nearly black and white.

For a point and shoot, the sample set would give you all types of cool effects including an ND filter. They're also good as "graduated" filters to make a more dramatic sky for example. Again, optical quality isn't great, but they're cheap and don't take up much space in the bag.

Yes, you usually get a very strong green cast. Blue and (specially) red channels will be so severely underexposed that you may not be able to recover them, unless you want to add lots of noise.

This is the reason why most people that go the welding-glass route only do B&W. You can also experiment taking several photographs, exposing each one for a specific channel, and later merge them.

@Jim:
I've tried my welding glass as a filter and it seems to cast heavy yellow color cast. So the best solition I came up with is probably to shoot in RAW and then photoshop it.

I have a 15-stop welding glass (which I still have not had the opportunity to test properly, btw). It is so dark it is almost completely black, I can barely see even the sun when looking through it.

Now, when you put that in front of a camera, it will no longer be able to focus or measure: there is not enough light getting to the sensors for that.

Instead, I first take a test photograph without the filter, and adjust focus and exposition until I get the desired result. Then I put the filter (carefully, not to move the focus ring) and repeat the photograph, but multiplying the exposure time by 32768... that is correct, a 1/100s exposure without the filter becomes a 328 seconds exposure with the filter.

Singh-Ray makes a combination variable density, polariod filter which is the professional solution to this problem but it costs about $400 and would only work with a DSLR.

I think ISO 400 was used to keep the aperture somewhat closed and 30 sec is the longest a shutter is open.

I carry around two polarizing filters: One circular and one linear.  Stack them (circular, then linear) and you get a varying ND filter that will go all the way to black.

try with the plastic material when you getting medical X-ray pictures.. but you have to use the part where is no bones, its completely black. I use it also as a filter for my telescope to watch the sun

Hi guys,

I've done a little playing around with white balance correction, you can see the results here:

http://flic.kr/p/8ZCwdX

I also glued it onto a cheap £1 step up ring so I can screw it on and off:

http://flic.kr/p/8MkYc4

Hope this helps you guys