What filters for long shutter speed in daylight

[miniman]

Going away for a few days next week and hoping to get some camera time in. One of the things I want to have a go at is long exposure shots during the day (e.g. of running water so that the water is blurred, you know the kind of thing). Anyway, I have the following selection of lenses to play with:

Canon 50mm f/1.8
Canon 70-200mm f/2.8 IS
Sigma 24-70mm f/2.8
Sigma 10-20mm f/4-5.6

I think I need at least a ND filter to reduce the light and allow a longer exposure. Is there something suitable that will fit one of more of these lenses (quite keen on fitting the 10-20mm and 50mm but that seems like quite a challenge as one is 77mm filter thread and one is 52mm

Thanks in advance for any advice!

[MartinP]

I use Cokin filters. The filter fits in a holder to which you attach the appropriate sized adaptor ring for the lens that you are using. I have P series Cokin filters which allow up to an 82mm adaptor ring, and I think they do an even bigger filter series. The disadvantage of this type of system is that you can't use them with a lens hood, but you only need one set of filters for all of your lenses. Similar systems are available from other filter manufacturers.

As well as the ND filter, you could think of using a polariser. That will reduce the light by 2 to 3 stops and also give you control over reflections (very useful around water!).

Hope that helps.

[fastfreddy]

You can also use 2 linear polarising filters together and rotate one of them in relation to the other to increase/decrease light getting through to the lens.

[Simpo Two]

fastfreddy said:

You can also use 2 linear polarising filters together and rotate one of them in relation to the other to increase/decrease light getting through to the lens.

They say that linear polarisers can mess up AF. However if you're using a tripod then you can probably use manual focus anyway so yep, it seems like a good idea. You need a LOT of ND to get long shutter speeds in sunlight - ND4 + CP was nowhere near enough when I tried it in NZ - only got down to 1/5th at f25.

Edited by Simpo Two on Sunday 24th February 19:15

[Jenx]

Simpo Two said:

[ You need a LOT of ND to get long shutter speeds in sunlight - ND4 + CP was nowhere near enough when I tried it in NZ - only got down to 1/5th at f25.

If you had a Canon you could get ISO 50

Martin.

[Simpo Two]

[RobDickinson]

I use Cokin - even on my 10-20 at 10mm.

Cokin 'P' with CPL, and currently an ND2 and ND4. This is NOT enough, even with f22+/ISO100 to give sufficient length of shutter for more than 2 seconds in sunlight(if your lucky).

Its fine for shady conditions for 30+ seconds.

For longer shutters you'll need a couple of ND8's or even an ND1000 ( 10 stop).

Also at those apertures (and filters) it shows up every spec of dirt...

[miniman]

Thanks all, have just ordered a Cokin P system, some adapter rings, 2/4/8 Grad, 2/4/8 Grey and a remote shutter release. Will post results!