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01-28-2013, 08:57 AM   #1
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How many stops ND filter should I get?

I recently got a DA 15mm Limited and bought it specifically for landscapes and other creative shooting. I've seen some very cool work using an ND filter by a few people in the "15mm controls my mind" thread and want to experiment with that myself. Thing is, I don't know how many stops I should get. I want to be able to get some seascape shots where the water looks fuzzy (long exposure) while maintaining good exposure with sunset/sunrise (and possibly looking into the sun).

Here is one example by Twitch:




and another of a sunset (found on google)


I was looking at a Hoya 49mm HMC 9-stop ND400, but it's ~$45 and that seems a little bit excessive to me for a filter.

01-28-2013, 09:04 AM   #2
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QuoteOriginally posted by NitroDC Quote
I was looking at a Hoya 49mm HMC 9-stop ND400, but it's ~$45 and that seems a little bit excessive to me for a filter.
And that's the cheap one, compared to the B+W and some Cokin-mount filters. It does its job, though.





01-28-2013, 09:31 AM   #3
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QuoteOriginally posted by NitroDC Quote
I was looking at a Hoya 49mm HMC 9-stop ND400, but it's ~$45 and that seems a little bit excessive to me for a filter.
I use that filter for some work (77mm one) - $45 is really cheap for this particular filter, it consistently rates as one of the best on the market....
01-28-2013, 09:41 AM   #4
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If you want to shoot in daylight, then think of the sunny 16 rule -- ISO 100, 1/100 f/16

Lets close that off with an ND:

1 stop: ISO 100, 1/50, f/16
5 stops: ISO 100, 1/3, f/16
10 stops: ISO 100, 10 sec, f/16

So, with a 10 stop filter, you can get into the 10+ second range. In less than ideal light, you could easily hit 30 seconds.

You might also want to consider getting a remote shutter release as the shutter cannot go beyond 30 seconds by itself. Bulb mode is the only way to do it and you don't want to be holding down the shutter button by hand.

01-28-2013, 09:57 AM   #5
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You can get a super cheap variable ND. Its quality won't be good, but it will give you a good idea what you want. Just don't get scared if a cheapo variable ND filter draws an X across the frame or reduces sharpness.
01-28-2013, 10:35 AM   #6
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QuoteOriginally posted by kcobain1992 Quote
And that's the cheap one, compared to the B+W and some Cokin-mount filters. It does its job, though.





Very nice shots. Is that the same 9-stop one?

QuoteOriginally posted by enoeske Quote
If you want to shoot in daylight, then think of the sunny 16 rule -- ISO 100, 1/100 f/16

Lets close that off with an ND:

1 stop: ISO 100, 1/50, f/16
5 stops: ISO 100, 1/3, f/16
10 stops: ISO 100, 10 sec, f/16

So, with a 10 stop filter, you can get into the 10+ second range. In less than ideal light, you could easily hit 30 seconds.

You might also want to consider getting a remote shutter release as the shutter cannot go beyond 30 seconds by itself. Bulb mode is the only way to do it and you don't want to be holding down the shutter button by hand.
Luckily I have a remote shutter (both wireless and wired -- wired can set time, etc). Also thank you for the explanation & rule. Haven't read about that one yet.


QuoteOriginally posted by Na Horuk Quote
You can get a super cheap variable ND. Its quality won't be good, but it will give you a good idea what you want. Just don't get scared if a cheapo variable ND filter draws an X across the frame or reduces sharpness.
Yeah, I have heard that those are just two linear polarizers stacked on one another. I've seen the X effect -- not good.
01-28-2013, 11:09 AM   #7
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Yes, that is the 49mm Hoya. Has caused me no problems so far (although I haven't used it as much as I'd wished).
01-28-2013, 05:50 PM   #8
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Had the same dilemma a few months ago, went with the ND400, I thought it was expensive for a filter too, but bit the bullet. Here are a couple of mine with the ND400. I've heard you can use these filters to take pictures of things that aren't boats, but I wouldn't know about that (yet)








01-29-2013, 01:53 PM   #9
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QuoteOriginally posted by Kozlok Quote
Had the same dilemma a few months ago, went with the ND400, I thought it was expensive for a filter too, but bit the bullet. Here are a couple of mine with the ND400. I've heard you can use these filters to take pictures of things that aren't boats, but I wouldn't know about that (yet)
Great that you have such still waters. When I tried long(ish) exposures of boats over here at the Adriatic, they get blurred from the waves. Even docked, in a marina.
01-29-2013, 02:12 PM   #10
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I know it is basic, and also not variable in the same way, but have you tried a bit of welders glass and some bluetack?
Don't laugh, I went on a day with some other togs and one guy got some absolutely amazing results using this method
01-29-2013, 03:11 PM   #11
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Not to be confusing but bear in mind if we believe Hoya's NDX400 ND filter does indeed have a filter factor of 400 as it implies and is accurate then a filter factor of 400 computes to
Filter factor = 2^x
Where the exponent x = number of stops. Solving for x yields.
x ≈ 8.64 stops.
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