Kenko Pro Digital 1 ND4 or ND8

[One Click]

Hi,

I am looking at purchasing a Kenko Pro Digital 1 ND4 or ND8 in order to try and take some of those silky water shots I see people post.

I would like some advise please as which of these would be the best to purchase as far as versatility and also if anyone knows where I might get the best price would be great also.

Not wanting to move to something like the Lee filters yet due to my limited experience so please just some comments on the two I have listed or if there is another brand that is better.

Thanks.

[EdanTrevethickPhotography]

Really depends on what scene you are shooting and what shutter speed you are aiming to archive.

Also remember a CPL has ND side effects, so i would would get a CPL for waterfalls and then an ND 8 for sunrise/set.

[ameerat42]

....Looking them up...

- - - Updated - - -

Found them here: http://www.kenkoglobal.com/photo/fil...d4,_8,_16.html

So, ND 4, 8, 16 reduce the exposure by 2, 3 and 4 stops respectively.

I reckon for silky water I'd get the ND 16, which I know you didn't mention.

You could stack them, but that might reduce image quality.

[arthurking83]

The main point we need to know and understand to answer the question properly is, under what conditions do you want/need the ND filter.

That is, do you predominantly shoot in the middle of the day? ... do you shoot later in the afternoon? .. do you shoot at night?

The ambient light you're shooting in will determine which filter is best for your situation.

eg. if you shoot in the middle of the day, and lets say the normal exposure for a scene is ISO100, f/8 and 1/100s .. obviously what you want to do is to get the shutter speed down to say 10s or something like that.
Longer is better, but lets just keep it simple for now.

With f/8 used in that situation, you could change that to f/16 which then slows exposure time down to 1/25s.
to get to 10s now, you need 6 more stops of attenuation.
So as Am described, going with that number style for ND rating .. 6stops = an ND64.

So for a worst case situation, you probably want an ND64, or stronger .. ND128, ND10,000 .. or whatever.

One of those 3 ratings will cover you no matter what.

Problem is:

Lets say you're shooting water falls later in the afternoon, near or just after sunset,(which is the same as early in the day at or before sunrise) .. and it's in a deep gully where not much light gets through.
At that time of day in those conditions, your normal exposure may be in the order of ISO100, f/8 and 1s without the use of an ND filter.

if you now try to use that same ND filter(eg. the 6 stop ND64) .. your 1s exposure will now change to 2 minutes as a minimum.
if you open up the aperture for a reasonable exposure time of say 30sec, you need to open up to f/4. DOF may be compromised in some way for the scene.

This can be a problem because longer exposures can cause noise on digital sensors. So you gain one advantage, only to introduce a possible new problem.

Try to work out what is a normal light situation that you will shoot under and use that as your guide.

Many people spend the extra money on variable ND filters just for those reasons.
That is, they may need an ND8 for some situations, but then an ND10000 for other situations .. paying $100 for two specific and inflexible filters may not be as practical, or efficient in the long term as say paying $200 for a vari-ND filter that you can adjust to suit to your need.

What is your price range or maximum?

... and on a side note, what camera (brand/model).

[One Click]

Thanks for the info.

With reference to your more detailed explanation Arthur I start to get a little lost when you start talking numbers.

I would say I would aim to use during the day. Camera Nikon D750 and price range $150-$200 max.

[arthurking83]

Ah!

the numbers are the really easy part.
Understanding how the photographic community came to the conclusion that this is the system we should be using is a head spinning experience!

to make the numbers easier to understand, try to think of only one exposure variable to begin with:

That is, forget about ISO, and forget about aperture values to start with. Concentrate solely on shutter speed to begin with.
Each doubling(approx) and halving(approx) of shutter speed is one stop.

So 1/50s is half of 1/100s and so the difference between each shutter speed = 1 stop.
1/50s = 1stop brighter(+1Ev) and 1/100s = 1stop darker(-1Ev).

Same with your ND filters.

If you add a 1stop(ND2) filter to your lens, and the original shutter speed(keeping ISO and aperture constant) was 1/100s because you have darkened the light through the lens by 1 stop, you now need 1stop brighter exposure(ie. longer shutter speed) .. hence shutter will now be 1/50s.
In trying to understand the exposure system, concentrate on the one variable to begin with(in this case shutter speed) and learn it well.
The reason you want to concentrate on shutter speed, is that this is the important variable for you. Shutter speed determines the movements within a scene, which is what you're after.

[One Click]

Okay so I've gone ahead and ordered a Kenko Pro ND1000 from Amazon. I'm not going to have a clue as to what to do with it but could prove fun

[ameerat42]

Well, let's see what a 10-stop fllter does...

1000, 500, 250, 125, 60, 30, 15, 8, 4, 2, 1...

So, if you started off needing 1/1000 sec, you will need a full 1 sec

Did you order a complementary set of FLOODlights?