Hi! I have a E-PL1 with the 20mm panasonic. I want to be able to shoot wide open in sunlight. Can anyone recommend me what ND filter I probably will need for this? Right now I think I get to f/3,5 in sunlight.

Also, is there much difference in ND filter quality?

Thanks! Daan

It depends on what ISO and shutter speed you want to use but you would probably be looking at a minimum 5-stop ND or if you want to stick with the lower cost filters you could stack a 3-stop and 2-stop filters (i.e. ND8 and ND4 or 0.9 and 0.6 respectively) . If you want extended shutter speeds, you would need something like a 8-stop or greater filter. ND400 is around 8 to 9 stops.

As a starter, I would suggest you look into the Cokin P-series sized filters for MFT. You will need a stepping ring as well as an adapter for the 20mm lens. Start with a ND8 and ND4 and see how you go. If you want more than that, you will need to go to something like a HiTech brand filter. They do to 10 stop.

Note that when you get to more than 5 stops with most filters, you can get purple colour casts depending on the light. You can generally fix those with editing.

If you just want to have some fun, you can pick up welder's eye safety glass on eBay for around $10 or less. Most I have seen ship from the UK. They will generally give green colour cast.

I have a a few different brands of filters including HiTech. These are mid priced and are claimed not to be affected by colour casts. This is certainly untrue about my 8-stop filter.

Lee are one of the few brands that are reliably free of colour casts. These are hideously expensive and not available in the 85mm P-series with but only 100mm.

I expect others like B+W's 10-stop circular filters are OK too but these are screw in filters which means you need to buy a different one for each filter size (or use stepping rings).

The beauty of Cokin style filters is that you can get a quite modestly priced set of filters and then just by a different adapter plate for each lens. These cost around $4 on eBay for the P-series.

BTW, if you just want to experiment, the cheap Chinese filters from eBay are fine. Many UK and US sellers have these for not much more than the Asian suppliers if you are worried about buying on eBay.

Oh, Hoya also do screw in ND400 filers too. They are still more expensive than most of the square filters.

Hi Dean
Over the years B+W, Hoya and Cokin filters have all been good and I have never noticed any distortions in any of the final prints.
Hope that helps

Michael

Hi, thanks for the replys. Let's say that I want to keep shutter time and ISO the same, how many steps is it from 3,5 to 1,7? I'm a little confused on how to calculate this.

Thanks, Daan

There are always 2 stops when you halve or double the aperture.

This has to do with the Pi x R sqared formula. Each stop lets twice as much light it. 2 stops is 4 times the light. Your aperture is just the ratio of lens opening to focal lenght.