DIY filters for daytime long exp ?

Mountainsandh

Saw the thread on the filter for Cokin system... just wondering, have any of you guys made your own welding glass or other (saw on Google car windows film ? ) filter for daytime long exposures ? How do you hold it on, elastic bands ?
I'd love to try that sometime, but photo budget is fairly depleted after Xmas, so not really looking at proper shop bought filters.
Ignoramus question too : I'd like to try daytime long exp with my fisheye lens, but the hood is sort of petal shaped (you know the way) so the welding glass wouldn't be ideal, am I right ? or is it worth my while trying to fill the gaps with cloth or something ?


Don't know when I'll have the chance to try, but am just itching to...

pixbyjohn

Kevin Longshanks used welding glass as a filter, its been a while so I can't easily find the thread.
For the fisheye lens just roll a piece of cardboard the diameter you need and fix your dark glass/filter to one end

FoxT

If you have 2 polarising filters of the same diameter, that might work. If you rotate 1 relative to the other so they are cross polarised you should get at least 5 - 8 stops of ND filtering. (ie much greater light-blocking power than just 1 filter on its own.)

Try it on a non-fisheye first.

If they are 'circular polarisers' You will have to put the outside one on backwards, otherwise it wont work. So fiddly..

If they are 'linear' polarisers you can stack them by screwing them together - but you will probably have to focus manually....


-FoxT

Mountainsandh

Thanks Fox T, I should have said, I've no filters.

Mountainsandh

PixbyJohn great idea, I'm going to check if I can get glass this week.

At the moment I'm thinking of doing street/urban photography with the people in motion, but not too much in motion, I want them pretty well defined, so not a super long exposure, so even a lighter glass would probably do.

.Longshanks.

pixbyjohn wrote: »

Kevin Longshanks used welding glass as a filter, its been a while so I can't easily find the thread.
For the fisheye lens just roll a piece of cardboard the diameter you need and fix your dark glass/filter to one end

Yep and was picked up by diyphotography.net as well
http://diyphotography.net/quickie-use-a-welding-glass-as-a-14-stops-nd-filter

Although they exposed my n00b error at the time by forgetting to adjust the ISO in-between two shots

Kbeg3

I bought some welding glass last year cost me about 80 cent each. Haven't used them a whole lot. Here is one from the summer

Mountainsandh

Cool... is it really awkward to use it, Kbeg, what do you think ? should I just wait and buy proper filters ?

.Longshanks.

Mountainsandh wrote: »

Cool... is it really awkward to use it, Kbeg, what do you think ? should I just wait and buy proper filters ?

Attached like this

To give this

Kbeg3

Mountainsandh wrote: »

Cool... is it really awkward to use it, Kbeg, what do you think ? should I just wait and buy proper filters ?

Not that awkward to use. I have used blue tack on mine and stuck it to the thread adapter of my Cokin P filter holder, so now it just screws on.
For a few Euro you can't really go wrong. Although if I see a proper 10 stop ND filter at Focus on Imaging in March I might be tempted!

Promac

Try getting a step-up ring (10 euro) and glue the welding glass onto the front of it. Should still come in under 20 euro for the lot.

Mountainsandh

Thanks everyone ! If and when I get any results I'll be sure to post something.

Look at this, this is really cool, if a bit messy
http://www.pdnphotooftheday.com/2009/09/2039

edit : but how the hell can you have a F32 aperture ?

Cakes.

My 18 - 55mm kit lens goes up to F36 when used at 55mm

Mountainsandh

oh ! Gotta try out with whatever different lenses I have so... the smallest I have ever noticed I get is F22... but I don't remember ever setting out to try and get the smallest aperture, so maybe I can achieve that too.

.Longshanks.

At f36 you mightn't need any filters, just a tripod!

JayEnnis

You'll probably have a hell of a lot of diffraction at f/36 though. Best off trying to stay around f/16

Link

And a sample of my own which shows this.

Mountainsandh

Thanks JayEnnis, didn't know anything about this, great I learned something new today !

Mountainsandh

Got welding glass today, for 5 euros in a hardware shop in town ! Have no idea which grading it is other than it's number 11, as the man in the shop admitted he didn't know himself what it stood for. For a fiver I'm willing to try anything .

Am a bit daunted though, because I saw other people online who said their glass was coloured but fixed colours from raw file after. Thing is, I can shoot raw but have no idea or software to fix afterwards, I might download the lightroom trial again, had done that before.

.Longshanks.

Mountainsandh wrote: »

Got welding glass today, for 5 euros in a hardware shop in town ! Have no idea which grading it is other than it's number 11, as the man in the shop admitted he didn't know himself what it stood for. For a fiver I'm willing to try anything .

Am a bit daunted though, because I saw other people online who said their glass was coloured but fixed colours from raw file after. Thing is, I can shoot raw but have no idea or software to fix afterwards, I might download the lightroom trial again, had done that before.

It will come out totally green unless you can;
(a) fix it in LR / PS / similar by shooting RAW, or
(b) you use your first totally green shot to create a custom white balance before taking your next pic.

Cakes.

I got some today too. There 11 and 13. The man in the shop looked dead confused as to why someone in secondary school would need welding glass ( I was in my uniform ):pac:

Mountainsandh

Thanks Kev, was just reading about that on a Flickr group. Not sure I'm knowledgeable enough to fix the WB to be honest (haven't read my manual yet :o), but I'll try Lightroom. From what I gather online, an 11 would be a 14 stops, although I'm simply not able to do mad calculations for exposure, so I'm thinking relentless trial and error for me all the way .

Mountainsandh

Cakesofrice wrote: »

I got some today too. There 11 and 13. The man in the shop looked dead confused as to why someone in secondary school would need welding glass ( I was in my uniform ):pac:

So we'll both be experimenting Cakesofrice, be sure to show us your results if/when you get some
I have Mr Mountainsandh booked to do some diy job on the glass this evening to come up with a mounting plan. If he doesn't come up with something, I might try and get a filter/thread adapter sort of thing in the best stocked chemist tomorrow, unfortunately where I am, I'm not sure they'll even have that. I've seen a lot of people online seem to buy the ring and superglue the glass to it to avoid light leaks.
Like this : http://photography-matters.blogspot.com/2011/01/frankenfilter.html

I've also read that you may have to darken the viewfinder to avoid light leaks too.

Cakes.

I was just planning on using elastic bands :pac:

On the canon strap that came with my camera there is a little rubber piece that slides over the viewfinder when the eyepiece is off it blocks light leaks.

Mountainsandh

That's cool... don't have anything like that with my Pentax, but I'm sure I'll come up with something (or Mr M will ).

Cakes.

The man on that link you posted looks to have gotten some pretty good results using welding glass with number 12 on it.

Hopefully 13 or 11 will be ok.

If you convert the photo to black and white or even take it in black and white will the green make a difference ?

okmqaz42

Great thread, you just inspired an impulse purchase from Ebay. A couple of euros!

Now to destroy one of my filters and get some super glue!

swingking

Cakesofrice wrote: »

The man on that link you posted looks to have gotten some pretty good results using welding glass with number 12 on it.

Hopefully 13 or 11 will be ok.

If you convert the photo to black and white or even take it in black and white will the green make a difference ?

It actually will make a difference. You will basically have a black and white comprising of nothing but the green channel.

This will leave you with a flat looking image with no contrast or shape.

Mountainsandh

Well I was thinking I'd probably convert to B&W after allright. Although I think depending on what colours/tones you're starting with, your B&W will come out different. That is, a conversion to B&W from green tint will be different from a conversion from red tint...
Anyway, I'll see if I can get anything at all to start with, that in itself would be an achievement for me. It's exciting, but I've things in my head I would like to do and no idea if I'll ever get near it.

Mountainsandh

swingking wrote: »

It actually will make a difference. You will basically have a black and white comprising of nothing but the green channel.

This will leave you with a flat looking image with no contrast or shape.

don't know if I can find it again, but there was a guy who showed how he used the sliders in Lightroom to Magenta, and his pic came out really well in the end (well, I liked the results anyway).

found it ! http://kimcphoto.com/2010/03/welding-glass-as-nd-filter/

Kbeg3

I must get mine out again this weekend and try some more shots.

Kbeg3

Took a couple of shots today

Here is the scene without a welding glass filter


With the filter straight from the camera


Final image processed in Lightroom and Photoshop

Mountainsandh

Am abroad for a bit, and didn't have space to take tripod, so mine'll have to wait, thks all, all experience and shots will help ! gave up on the fisheye idea for now, too tricky, will use regular lens instead for ease of mounting.

Cakes.

I went out to take some photos yesterday and the glass fell off the string mount I made and broke. I got two 11 and two 13 so I'll try again during the week