ND filter questions

[Sami Sanpakkila]

Hi,

I am looking for ND filters to put in front of my LEX and canonFD prime lenses. The EX1 states it uses ND filters 1=1/8 and 2=1/64.

1) To get the same amount of light loss am I looking for ND filters marked ND8 and ND64? Or how do the numbers translate?

2) Am I good with some cheaper ND filters from ebay like Hoya or Marumi? I really dont want to spend more than about 100 euros to get 1 or 2 good ND filters for both my 72mm and 52mm thread Canon FD lenses.

Would really appreaciate some advice, thank you!

Sami

[Eric Pascarelli]

ND filters are generally designated by their optical density, where

.3 = 1 stop
.6 = 2 stops
.9 = 3 stops,
1.2 = 4 stops

etc. (though there isn't much "etc" after that).

They are usually referred to as N3, N6, N9 etc. as shorthand.

The ND filters on the EX1 are labeled by their light transmission - so 1/8 = 3 stops and 1/64 = 6 stops. (2^3 and 2^6, respectively)

Hence, to get the equivalent of the 1/8 filter you would need to buy an ND .9 and to get the equivalent of the 1/64 filter you would need an ND 1.8.

[Sami Sanpakkila]

Thanks Eric,

Most places Im looking at the ND filters they are named ND4, ND8 or NDx8 NDx64. Maybe thats more common for the screw on filters? All the 4x4 filters I see are named just the way you said.

Do you think if I would get an ND64 with a thread size of 58mm I could use them on my 52mm lenses with a step up adapter. The distance from the lens shouldnt make a difference? Those mattebox filter holders place them away from the lens as well right?

Sami

[Eric Pascarelli]

No - distance shouldn't matter except that the farther they are away, the more likely that dust etc. on the filter will be in focus and visible in your shot.

Matte boxes certainly hold the filters a bit farther away than screw ons.

Why wouldn't you just use the internal filters on the EX1?

[Steven Thomas]

Quite often I'm striving for those tighter DOF shots. Granted it's a bit easier than 1/3" cams for a given stop, but having a matte box with extra filters will allow you to stay close to f1.9 under bright outdoor light.

I was shooting with ND2 yesterday and needed more ND to get closer to f1.9. I believe I was at f5.6 and cluld not open anymore without over exposing my shot. I thought about going to the shutter, but I'd rather not.

I'm looking to buy a reasonable matte box with rails and hardware.

[Michael H. Stevens]

To really open up in bright light I find I need BOTH the internal ND filters and the matte box. A good quality but cheap filter is the Format or CA does a generic version which is what I have. While ordering you might want to get some graduated ones as well

[Sami Sanpakkila]

Originally Posted by Eric Pascarelli

Why wouldn't you just use the internal filters on the EX1?

I need to cut down the light before it hits the adapters ground glass or grain will show up in the footage. If too much light gets there using the cameras aperture or ND filters wont help.

Thanks for all your advice!

Sami

[Michael H. Stevens]

Originally Posted by Sami Sanpakkila

I need to cut down the light before it hits the adapters ground glass or grain will show up in the footage. If too much light gets there using the cameras aperture or ND filters wont help.

Thanks for all your advice!

Sami

In that case a matte box that swings away or screw on filters. There will be a slection of very cheap used filters for CLA going up on www.lenses35.com by mid week.

[Sami Sanpakkila]

Sounds very interesting! What is CLA?


Sami

[Michael H. Stevens]

Originally Posted by Sami Sanpakkila

Sounds very interesting! What is CLA?


Sami

Cinema Lens Adapter, same as DOF adapter. Sorry for using non-standard abbreviations.