Taking Pics with ND filters

[jonnypb]

Right, just got my ND8 for my 10-20 and my ND110 is on it's way as well.

I'm new to long exposures using ND filters so would love some advice of how best to setup the shots. If I have the ND110 there will be very little light so I'd compose the shot without it on 1st but then can you just stick it in AV mode and dial down to F32 and let the camera do all the rest or is it best to shoot in manual mode? I've heard of a few people taking an exposure reading without the filter on then working out what it would be with the ND110 filter on

Any tips/advice most welcome

Thanks

 

[oldgit]

Patience young grasshopper.

As usual in these things there is no right answer, plenty of wrong answers, but no right answer.

If you are doing 20 second shots, what happens when the sun goes in?
If a bird flies past do you catch its shaddow?

Experimentation is the usual answer

No problem with Av mode usually

 

[milou]

Hello

I use the B+W 10 stop ND filter for the very long exposures.

My method is to tend to stop down to f/16 (or f/8 is quite successful if you want to avoid massive exposures), use ISO50 or 100 and engage mirror lock-up. After focusing, I click to lock the mirror up, whack on the filter and open the shutter with a shutter release cable. Alternatively use auto-focus and then switch to manual focus before putting on the filter. You can't see anything through the lens with it on.

I use a Canon timed remote which enables me to dial in how many seconds I want the shutter to open. It's best to experiment but after a while, you get a feel for how long the shutter needs to be open, and always use the histogram as a guide. If you use f/16 and the 10 stop around dusk, be prepared for exposures of 400 seconds. Obviously the resulting noise has to be dealt with in post-processing.

I find that the use of the filter has to bring something extra to the image, e.g. I took a shot of a waterfall with and without the 10 stop - both images (at 4 and 270 seconds) looked the same.

I also use Lee filters to help balance exposure and to blur the sea but never in conjunction with the 10 stop.

If I don't want the excessive 10 stop shutter speeds, I use a Lee 0.9 ND sometimes with an inverted 0.9 ND grad. I really like 0.8 to 1.6 secs for catching a wave sweep on a beach.

Hope this helps, but have fun and experiment!

[Edit for tartage -some long exposures: http://www.flickr.com/photos/milouvision/sets/72157600209276621/]

David

 

[DollyBuster]

With (very) long exposures – in fact it is measurable in any shutter speed over 1 second – you get Red Shift, a.k.a. reciprocity failure, increasingly affecting the image's color gamma.

Wikipedia says

The true characteristic of most photographic emulsions is not actually linear, (see sensitometry) but it is close enough over the exposure range of about one second to 1/1000th of a second. Outside of this range, it becomes necessary to increase the exposure from the calculated value to account for this characteristic of the emulsion. This characteristic is known as reciprocity failure. The film manufacturer's data sheets should be consulted to arrive at the correction required as different emulsions have different characteristics.

Digital camera image sensors can also be subject to a form of reciprocity failure.