Welding glass Long exposure.

shannensdaddy

shannensdaddy

Suspended / Banned
Messages
470
Name
Darren
Edit My Images
No
Hi Folks
I recently saw a few mono images taken using a piece of welders glass as a filter for long exposure and they looked really good.
Has anybody tried this, quick question how do you work out the exposure time ..

Thanks.
 
Tired it years ago. Take a normal, proper exposed shot without the glass, attach the glass and adjust by 10 stops or so and take the same shot again. Compare the 2 histograms looking in terms of lights and dark start positions. Keep adjusting the exposure and taking a shot with the glass, until the histogram gets close. once you are close work out the difference in stops.
 
Last edited:
There's a very long thread on this topic already, but it hasn't surfaced in a while - Search should find it.

Basically you need to calculate the ND strength of your welding glass (they vary, you'll find guide values in the other thread), take an exposure with and without and determine the difference in stops.
 
This is a good way to determine the actual strength of the 'stoppper' range of filters too.
 
Welding glass is a cheap way of getting into long exposures. Think we've all been there sometime.
If you Google enough you'll find suppliers who will give approximate f stop numbers but these are only a guideline.

The worst thing is that you get a terrible colour cast with most welding glass. That's why the majority are in mono. Green, blue, purple etc depending on the glass used.

You'll have to cobble together some way of holding the glass to the front of your lens. It must be totally light proof, and don't forget the light entering the camera through your viewfinder. That will want blocking off.

It's a good, cheap, fun way of starting out on the long exposure method but if you are in earnest about this then you'd be better off going for a dedicated filter sooner rather than later.
 
Yes as above welding glass comes in different strengths, the higher the number, the darker the glass.
To save the search through the old thread which could take a while, (well worth a read though) here's a quick resume:

#8 = 10 stops
#9 = 11.4 stops
#10 = 12.8 stops
#11 = 14.2 stops
#12 = 15.7 stops
#13 = 17.1 stops
#14 = 18.5 stops

They do go further, but have never tried anything higher than #14 and cant really think of a situation where it would be needed.
Hope this helps.
 
mickledore said:
You'll have to cobble together some way of holding the glass to the front of your lens. It must be totally light proof, and don't forget the light entering the camera through your viewfinder. That will want blocking off.

It's a good, cheap, fun way of starting out on the long exposure method but if you are in earnest about this then you'd be better off going for a dedicated filter sooner rather than later.
Click to expand...

Here's a simple way to fit it, combined with a 3 stop graduated filter here:

[url=https://flic.kr/p/somawY]Welding Glass fitment by Steve Bennett, on Flickr[/URL]

Though I have a selection of 10 stop filters, I still enjoy using welding glass and use it quite often still. I might be a bit mad though, or stuck in my ways, I first used it back in the 1970's :)
 
Thanks for taking the time to respond..I have order a piece of glass and hopefully it will fit into a cockin P series holder and if not I could always give Stevie B method a go.
 
Even if it fits in a Cokin holder that is unlikely to do the job properly. You must, absolutely must prevent any light at all from reaching the sensor other than through the glass. The welding glass must be fastened without any gaps at all between it and the lens. The filter holder you mentioned sits too far foward. Don't block out the light and you are wasting your time.
Similarly with light coming in through the viewfinder. That will also hit your sensor and spoil the shot.

It isn't as simple as just holding a piece of glass somewhere in front of your lens.
 
I am looking to give it a go and see how I get on. I could make up some sort of gasket for the filter housing , and have a Nikon DK5 that you place over the viewfinder on the D7200 to stop stray light from entering.
Trying this to see how I get on. I have seen images created with the glass and they were good not perfect but different .
 
I've tried this before. At the time there weren't that many 10 stop filters around and you were looking at £100+ to get one. Nowadays with loads of cheap options out there (Haida stuff is good) for about £25-40 I don't think I'd bother.

Welding glass is fun but requires a bit of faffing to get it right. I glued and taped mine to a step up ring. Not pretty but it worked. B&w only though of course.
 
shannensdaddy said:
I am looking to give it a go and see how I get on. I could make up some sort of gasket for the filter housing , and have a Nikon DK5 that you place over the viewfinder on the D7200 to stop stray light from entering.
Trying this to see how I get on. I have seen images created with the glass and they were good not perfect but different .
Click to expand...

Dont bother trying to use the Cokin type holder, it's more trouble than it's worth.
You will need to remove the glass for composition and focusing as you won't be able to see through it except in the very brightest of conditions, it's the same with a 10 stop filter too. It soon becomes a pain with a filter holder, the same can be said of gluing the glass to a step-up ring having to screw it on and off all the time.

Unfortunately with you using Nikon, colour shots are not easy, the custom white balance system that Nikon cameras use struggles with the colour cast of the glass.
For B&W though you should be fine, it's not bad optically, in fact better than a lot of the cheaper 10 stoppers and pretty resistant to flare aswell.

The shots in this album on Flickr were all taken with welding glass, I do very little post processing, a slight tweak to contrast and saturation is usually about it.

https://www.flickr.com/photos/steveblackdog/albums/72157633164648722
 
When I first tried this I attached it to the lens with a sheet of balsa wood that had a hoel cut in it that was the same size as the outside diameter of my lens end, Nowadays foam board may be easier.
 
You must log in or register to reply here.
Back
Top