First of all, I'm an absolute beginner, so I'd appreciate replies in that manner. Recently I have been watching videos on YouTube about how to take photos with long exposures. Yesterday, I watched video with Scott Kelby where he was giving a short tutorial on shooting photos of the seaside. After emphasizing the importance of using a tripod and remote cable, he put a "natural density filter with 9 stops" on his lens which he said would reduce the amount of daylight (they were shooting at around 2 p.m.) and I was wondering if it is possible to shoot similar photos without any filters. I only have the kit lens and do not want to invest in any filters before getting to know my first DSLR a little better.

If Kelby had shot the picture without that filter, would the sea not be as calm as it looked? If not, does this mean one can never shoot waterfalls during daylight without using any filters under any circumstances?

Essentially, it's all dependent on the light. How 'bright' the daylight is will determine if it's at all possible to slow the shutter speed down enough to give that 'smooth' water look - which usually means for a waterfall shutter speeds should be in the 1/15 or less range, and for ocean or lake smoothing, usually into the multiples of seconds.

Waterfalls can sometimes be done without an ND filter - if the waterfall is located in a forested area, where it's partially in shadow, or early morning/late day, when the sun is behind the cliff or blocked by trees. Oceans would require being fairly early or late in the day, as even overcast afternoons are usually far too bright for the camera to slow the shutter down.

Your key controls for reducing the light to the sensor are: 1. Aperture, which is the most important, and 2. ISO, which is the sensitivity gain of the sensor. Always set ISO manually to the lowest number your camera allows. Then, set the aperture to the smallest setting you think you can get away with for your lens (smaller apertures are denoted by LARGER F numbers...so F22 is much smaller than F10)...the caveat is that once the apertures get too small, the lens starts to lose details and sharpness due to diffraction - the hole is too small and the details can be less discernable. Sometimes achieving the slow shutter is more important overall, so you can stand to use a very small aperture and sacrifice some detail to diffraction - that's up to you.

However, in bright afternoon, even with the ISO set manually down to 50 or 100, and the aperture of the lens all the way down to F22 or so, you STILL may find the shutter speeds are 1/100 or faster...which simply isn't enough to get any of that ribbony effect or smoothing effect in moving water. And that's where the ND filters come in - by knocking 2, 3, 5, or 9 stops of light from getting into the lens, you are able ot bring that shutter speed down the same number of stops. A 1/100 shutter becomes something like a 2 or 3 SECOND shutter when paired with a 9 stop filter at the same settings.

You don't have to invest heavily in ND filters -9 and 10 stop filters can be expensive, but you can also look around for cheaper 2 or 3 stop filters, and buy 2 or 3 of them to stack at the end of the lens. If you're just experimenting to see if you like them, don't worry if the image quality isn't the best in the world - try it out, and if you like it, save up for the better brands and optics, or for the stronger 9 or 10 stop filters.

The key is reducing the light as much as possible - make the camera think it's dark out, so it has to lengthen the shutter to compensate - whether you do that by shooting in the shade, early or late in the day, blocking the sun behind the landscapes or buildings, lowering the ISO and using a smaller aperture, or using neutral density filters.

This is a very helpful post, especially for a novice like me. I have some more questions if you don't mind. Since I have a kit lens (18-55mm), I suppose I won't be able to use the filter if I decide to upgrade to a better one in the future? Would a 3-stop ND filter help me do the job? I'd like to shoot during daylight and get the silky smooth feel or would I have to should at or after sunset? I guess no ND is needed for night shots?

I have watched many videos on YouTube about long exposure and really enjoyed their work. It's a shame few of them mentione they were using filters.

One final question, can I mount two 3-stop filters on top of each other and still get good quality pictures?

Thank you on that shot - that actually IS a long exposure shot, however it was taken at night, so didn't require any filters. I do a lot of night shooting, and mounting the camera on a tripod and using long exposure times is usually the best way to get nice crisp details.

I have a 9-stop ND filter which I do occasionally use when I want to do daytime long exposures - not just for making smooth water, but also for getting cool motion blur effects with people, and if you make the exposure long enough, you can even 'erase' people from a shot if they stay in motion and walk all the way through the frame before the exposure is over. Here are a few daytime long exposures I took using the 9-stop ND filter:

batmura wrote:

This is a very helpful post, especially for a novice like me. I have some more questions if you don't mind. Since I have a kit lens (18-55mm), I suppose I won't be able to use the filter if I decide to upgrade to a better one in the future?

Actually, you can - you buy the filter with the filter threads that match the lens typically, so if your kit lens has a 49mm thread, that same filter can attach to any lens with a 49mm thread. But a better method I usually recommend is to buy a filter in a much larger thread diameter - such as a 66mm or 72mm. It will be a little more expensive, however because of the much larger threading, that filter could be used on many more lenses - any lens with a filter size all the way up to that number. All you do is buy some cheap 'step up rings' - which allow you to put a larger filter on a smaller lens. If you buy a filter in a large size like 66mm, you could buy the cheap step up ring and use it now on your kit lens...and then if you buy another lens later with a larger thread diameter, the filter can still be used with it - you just get another step ring to that size. Step up rings are cheap - $5 - 10 or so, so getting one expensive filter and a bunch of cheap step rings is much cheaper than having to buy multiple expensive filters.

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Would a 3-stop ND filter help me do the job? I'd like to shoot during daylight and get the silky smooth feel or would I have to should at or after sunset?

Well a 3 stop ND filter would certainly help in lower light - say, dusk or early dawn, or in a deep forest, etc. In bright daylight though, it probably wouldn't be enough much of the time. 'Stops' are measured in the shutter speeds by doubles or halves...so to know how much shutter speed you can gain or lose with a '3 stop filter', go outside and set your aperture as small as you can, then snap a shot. What shutter speed did your camera choose? If it was 1/200 for example, then you can cut the number in half for each 'stop' the ND gives you - 1 stop would be 1/100, 2 stops would be 1/50, and 3 stops would be 1/25. 1/25th of a second wouldn't be very long, so it probably still wouldn't stop flowing water or give you much motion blur. You can always test it by taking test shots in the conditions you expect to be shooting in, and seeing how many stops you need to lose to get the shutter speed into the seconds.

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I guess no ND is needed for night shots?

Right - in fact often at night the light is so low that you need to even open up the aperture, set the camera on a tripod, and expose for many seconds, even 20, 30 seconds, to get a well exposed shot.

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One final question, can I mount two 3-stop filters on top of each other and still get good quality pictures?

Yes - the quality may be slightly reduced, but so small that likely you wouldn't notice in most cases. As long as the filters are of a decent quality to begin with - some el-cheapo third-world filters you buy off eBay for $3 may not be very good and could be more damaging to your quality.

One final question, can I mount two 3-stop filters on top of each other and still get good quality pictures?

Everything in zackiedawg's replies is completely valid.

One thing I would add is about stacking lenses.

This depends really on your focal length, the lens and the amount of filters you are stacking.

For example I can stack 3 filters on my 24-70mm but it will vignette heavily from 24-28mm.

You may find a 3 stop and 2 stop ND filter more useful than one darker ND filter, as it will give you more flexibility. However, with each piece of glass you're putting in front of your lens, you are adding an extra element that light has to travel through which may affect your image quality.

Also worth remembering is that a circular polariser, when used to maximum effect, is also a 1 - 2 stop ND, depending on the brand used. If you use a circular polariser with a 2 or 3 stop that can also help.

What I did was looked at my various lenses and picked a filter size that would be suitable for all. I then bought step up rings to allow fitting of my ND filters on smaller lenses.

Good point Phil - I didn't really think of that as my DSLR has a little shutter that closes off the viewfinder when I switch to live view mode, and I almost always shoot in live view mode when using the ND400 filter (it can gain up and allow focusing and composing right through the filter, even when the optical viewfinder view is virtually black). But I have seen light bleed through the viewfinder in the past, and it's something to remember on long daytime exposures!

I assume you used filters, and because it was a long exposure, I assume you were using a tripod as well.Now, let me give you an advice: when you are going to use ND filters for a long exposure, try focusing before you put on the filter/s, it's a lot easier to see and for the camera to focus.