Neutral Density filters - the flavour of the moment!
"Verticals" © Richard Evans Photography
I'm going to round of the "Fun with filters" posts by devoting an entry to Neutral Density (solid ND) filters. If there's a single single photographic accessory that's capturing the imagination at the moment - it's the ND filter! Whether you love the dream-like slowed down feel of the images, or are sick to death of yet another milky sea - long exposure imagery is currently filling the pages of the photographic press and seem to be the most consistently highest voted images on 500px.
Essentially, an ND filter is a square of either black resin or glass, that sits in front of your lens and drops the amount of light that is able to enter it and get to the sensor. This opens up all sorts of daylight possibilities that were only available in very low light and will allow you to run really long exposure times during daylight hours, to produce stunning and unusual artistic effects.
As for the ND grad filters - solid ND filters are either measures in light stops (one stop - 10 stop) or with a number equivalent (ND2 - ND 1024), but unlike the grads, these filters are uniformly tinted to one strength. They are also slightly smaller as they don't need the up and down adjustability of the grads. The longer exposure times available then allow you to keep static items in pin sharp focus, while moving items like the sky or moving water, will be blurred. As the tints are neutral, the filter should (in theory) add no colour cast to your image.
In order to get the kind of smokey etherial effects that are so fashionable at the moment, the majority of long exposure fans are polarized around one single product - the Lee's filters "Big Stopper". There are plenty of other products out there, good and bad - but the big stopper does seem to be rightly popular due to it's combination of high image quality and the ability to offer really long 10 stop exposure times. They are however - extremely expensive! The filter is just over £100 and you will need a Lees holder that will run you about the same again when you add the adaptor ring - so it's really not an impulse buy!
I've shopped about and found that you can get Hitech filters that will fit a Cokin P holder, up to an equivalent density and at the moment I'm on the fence debating whether to spend £100 on one of these or bite the bullet and go with the guarantee of quality. It's a tough call! At present, I have a couple of ND8 filters and by stacking two of these up with an ND grad, I achieved the image above. The lake was fairly choppy, but the long exposure rendered it like polished concrete and gave an interesting effect. Obviously - using a single darker filter will offer better quality than stacking in 3, but it allowed me to experiment!
Pointing this kind of setup at the sea will or a fast moving waterfall, will offer you the best opportunity to capture a dramatic blur. Also, architecture images look fantastic with a blurred out sky filled with drama. These images catch the eye and captivate the imagination - it's no wonder everyone seems to be doing it! If you're into these kind of images, why not give it a go? You can get cheap Ebay versions to allow you to experiment, but these typically aren't available above ND8 and this really isn't dark enough to allow for the desired effect - you'll need to stack a couple up together. The cheapest decent quality 8, 9 or 10 stop filters I've seen are from Hitech and they go from around the £100 mark to fit a Cokin P holder - the larger sizes are more expensive.
Using the filters, requires you to work in a certain way – as they're so dark, looking through the viewfinder to focus is near impossible - so here are a couple of tips to make things easier:
Set up your gear and compose your image as usual - tripod shooting is the only option with exposures this long! Focus your image with only the filter holder attached, so you get everything pin sharp. Then switch to manual focus to lock it down.
Add your filter and start shooting - referencing the histogram of your images so you can adjust if needed. With an exposure over 30 seconds you'll need to switch to manual and select "bulb mode" to get the correct exposure time.
Make sure that "noise reduction" is switched on if you have it, as a long exposure can get pretty noisy without this.
Practice will improve results, so start experimenting!
Budget ND idea…
I did recently read a great budget article showing how you can use the glass lens from a welding mask, to replicate the 10 stop effect - the great thing about this is welding lenses are REALLY cheap! I searched Ebay quickly and found that you can get a box of 10 for £3.50, so 35p each. They're an odd size, so they won't fit any filter holders, and the glass is green to protect the welders eyes from the flare, but you can get around both these issues:
The green cast from the glass will give your images a strange colour cast, but this can be corrected if you shoot in raw. Better still - as this is a cheap experimental gig - why not shoot your images with the intention of converting them into greyscale monos? The green cast makes no difference whatsoever when you convert to mono, so you can get creative fine art landscapes images for under £20 - maybe under £15.
Now I've written it down - I'm definitely going to give this a go! If it works out ok - I'll post up a "how to" so you can see how to make up your own.
To finish, I found this really comprehensive guide to all things ND, so if you want to get a more expansive overview, click through and give it a go:
http://www.redbubble.com/people/peterh111/journal/4421304-the-ultimate-guide-to-neutral-density-filters
As usual - if you're enjoying these posts, do let me know with a comment - I'd love to hear from you! Keep shooting!
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