Using a 9 stop ND

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Short question: how to use a 9 stop ND in low light?

Longer question:

I've just received my LCW 9 stop filter and had a play around with it.

So far what I have done is:

Switch to aperture priority (my usual shooting mode).

Focus and check shutter speed.

Calculate shutter speed for 9 stops more.

Attach ND filter.

Switch to manual and dial in aperture and new shutter speed.

Press shutter / use bulb mode and take it from there.

That seems to work.


But:

What happens when it is too dark to focus through the ND 9 stop? Do I have to manually focus?

Can anyone point me to a helpful guide please? I've been searching but to no avail.
 
As you said above you set it all up before hand, when focused either focus lock or switch to manual so it can't change and carefully attach the filter. Providing you dont move the focus when attaching the filter it should still be in focus. To double check, before attaching the filter, focus and then make a note of where the lens is on the focus window if it has one.
 
Thanks Tom, I'll try switching to manual when I have a focus point and see how it goes.

Failing that, I'll give focus locking a go.

Cheers.
 
There are a few good threads on how to use extreme NDs, including the long welding glass one.

You seem to have the basic technique sorted. Be sure to cover the viewfinder during exposure. If you get sunlight going in there, or any light really, it will cause havoc. The way I sometimes do the exposure calc is to count the clicks on the shutter speed dial, ie when set in third-stop increments, nine stops is 27 clicks down from your starting exposure (you may find the LCW ND500 is nearer 8.5 stops).

Also (on Canons at least) when you're on B for really long times, the frame counter counts the seconds.
 
HoppyUK said:
There are a few good threads on how to use extreme NDs, including the long welding glass one.

You seem to have the basic technique sorted. Be sure to cover the viewfinder during exposure. If you get sunlight going in there, or any light really, it will cause havoc. The way I sometimes do the exposure calc is to count the clicks on the shutter speed dial, ie when set in third-stop increments, nine stops is 27 clicks down from your starting exposure (you may find the LCW ND500 is nearer 8.5 stops).

Also (on Canons at least) when you're on B for really long times, the frame counter counts the seconds.
Click to expand...

Could you please explain this a little more for me. I am about to the hit the purchase button for an ND500, but do not understand how to use it, i.e. 'clicks on the shutter speed dial'. So if I have set my Aperture to F16, and it automatically comes up at 1/100, then I go to manual and change this to 5". Is this correct? :thinking:

How do I know if I am set up in third-stop increments?
 
I have found this thread really interesting, so I hope you don't mind me posing another question...

If the ND500 only goes to 8.5, would it be more worthwhile me purchasing the Fader ND Mark II as it goes from 2-8 stops, so I guess it would be more versatile?
 
weebleswobble said:
Could you please explain this a little more for me. I am about to the hit the purchase button for an ND500, but do not understand how to use it, i.e. 'clicks on the shutter speed dial'. So if I have set my Aperture to F16, and it automatically comes up at 1/100, then I go to manual and change this to 5". Is this correct? :thinking:

How do I know if I am set up in third-stop increments?
Click to expand...

If you can set 1/100sec, then that is a third-stop increment so it must already be set. I think it's the default on a 450D (see handbook).

Counting the number of clicks on the shutter speed dial is just an easy way of making the exposure adjustment, without having to do any mental arithmetic - it will always be the same.

Many people also write down a table of all the permutaions, but I don't bother. I count the clicks and take a test shot. That gets things close but It usually needs a little tweaking anyway, so take it from there.

When you get your filter, check what the actual exposure factor is with a few test shots, they all vary a bit. My ND500 is actually 8.3 stops (not 9) so 25 clicks for me.
 
Thanks so much, I can't wait to receive the filter and try it out! I have ordered it direct from the Hong Kong site as is cheaper, so it could be a case of anxiously looking for the postman for a while.
 
Another question... I tried playing again with the exposure in manual (before I receive the filter!), but now that it is a little darker, when I tried doing the 26 clicks, it took me to bulb. So when this happens, how do I figure this out manually to know I have got 8.3 stops?
 
weebleswobble said:
Another question... I tried playing again with the exposure in manual (before I receive the filter!), but now that it is a little darker, when I tried doing the 26 clicks, it took me to bulb. So when this happens, how do I figure this out manually to know I have got 8.3 stops?
Click to expand...

Haha! You can only use that trick up to the shutter's longest speed, which is 30 seconds. Then you go into bulb and have to time it manually. (Tip - watch the frame counter during the Bulb exposure, and it will count the seconds for you - saves you using a watch.)

But the problem is that you have a pretty long (dark) exposure to start with, though you're unlikely to be in that situation in daylight. Basically if your normal exposure is faster than 1/15sec, you can use the clicks trick with a 9-stops filter, below it you could run into the 30 secs limit so have to work it out manually.
 
Really sorry for the ignorance, but how do I work it out manually?
 
weebleswobble said:
Really sorry for the ignorance, but how do I work it out manually?
Click to expand...

You know what a stop is? In exposure terms, it is any halving or doubling of the light.

Shutter speeds are easy. 1/500sec is half 1/250sec - that's one stop difference - which is half 1/125sec, which is half 1/60sec (rounded) etc, so just run that sequence down until you reach eight or nine stops or whatever.

Lens apertures are confusing - f/4 is twice the light passing area of f/5.6, which is double f/8 etc. That is the tricky one, as halving/doubling is represented by multiplying/dividing by 1.4 (square root of 2) and lower numbers mean more light. You just have to lean the sequence, which runs f/1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22.

ISO is easy too - 800 is twice as sensitive as 400, which is twice ISO200 etc.

All three of these controls also have intermediate settings for fractions of a whole stop.

These are the corners of the 'exposure triangle' and all they are all used together to control exposure, to adjust it to the light and to obtain a variety of creative effects - depth of field, movement blur etc. Adjust one, and you must compensate by adjusting one or both of the others. For example, 1/125sec at f/8 with ISO100 is the same exposure as 1/250 sec at f/11 with ISO400.
 
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