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ND Filter Dilemma


rjsphd

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I am off to Iceland in a short while and expect to need a ND filter for water shots.  I have 3 lenses: a 21mm and 35mm taking E46 and a 75MM taking E60.  I like the idea of variable filters, but they may be overkill and are pricey, so I want to get it right.  My gut tells me I will use the filters mostly on the wide angles, so go with the smaller diameter rather than an E60 with step-up/down ring for the E46.  Or maybe a 6-stop filter is enough for most situations.

 

I welcome your thoughts and advice.

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For many applications like water shots you may be better off without an ND filter.  You could instead shoot 10 images for example at 1/20 sec and combine them in PS.

 

Rick

 

Interesting idea. Can you explain more of "better off" part? Just less gear? I'm curious. I never thought of trying that.

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Let's say you would like a 5sec timed exposure.  Instead of using an ND filter you could, for example:

 

10 shots X 1/2 sec exposure = 5 sec equivalent exposure

 

The best part is that you do not have to use an ND filter (could degrade image with reflections and theoretically an extra piece of glass).

Also you would have a shot with basically no noise because, at 200 iso your effective iso becomes 20.  200 iso / 10 shots = 20 iso (effective).

And, you don't have to worry about tripod shake over 5 seconds.  

 

Next, open PS.  Import.  Open as layers. In layers select all of the layers and select edit menu and then auto align layers.  From layers menu choose create smart object.  Then from the layers menu choose smart objects, stack images, mean.  You can now view the time lapsed image and you may have to crop a tiny bit if they didn't quite line up.

 

Now you have a sharp image of a 5 second exposure, with an effective iso of 20 without the problems caused by an ND filter.

 

Hope this helps,

 

Rick

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I use a Lee system now for my landscape filters but when I used screw in I usually took a 6 stop ND and a polariser in each size. Polariser can't be truly replicated in post processing and it makes a decent 2 stop ND when *wound down*.

 

Personally I always prefer to do it in camera if possible. This kind of blending is no fun for me.

 

Gordon

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I use a Lee system now for my landscape filters but when I used screw in I usually took a 6 stop ND and a polariser in each size. Polariser can't be truly replicated in post processing and it makes a decent 2 stop ND when *wound down*.

 

Personally I always prefer to do it in camera if possible. This kind of blending is no fun for me.

 

Gordon

 

 

Me too.  Unless, I didn't bring an ND filter.

 

Rick

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You have to remember not to shoot in phase with the waves or the water smoothing just won't occur.

 

I use an app that calculates the periodicity of the waves and suggests the correct shutter speed.   B)

 

Rick

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I use an app that calculates the periodicity of the waves and suggests the correct shutter speed.   B)

 

Rick

 

 

My app is called Cabernet .....I like your technique Rick I'm going to give it a try...Thank You for shairing

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