Neutral density filter question.

Shadow 2

A
Shadow 2

  • 0
  • 0
  • 27
Shadow 1

A
Shadow 1

  • 2
  • 0
  • 25
Darkroom c1972

A
Darkroom c1972

  • 1
  • 2
  • 43
Tōrō

H
Tōrō

  • 4
  • 0
  • 43

Recent Classifieds

Forum statistics

Threads
198,826
Messages
2,781,507
Members
99,718
Latest member
nesunoio
Recent bookmarks
0

pbromaghin

Subscriber
Joined
Sep 30, 2010
Messages
3,807
Location
Castle Rock, CO
Format
Multi Format
I have an odd-ball neutral density filter. It's a Kodak Series VI and it says it is a 2.5. Looking around I see info on 2.4 and 2.6, but no 2.5.

Does that number mean it is a number 2.5 and so about 8 stop, or is it a factor of 2.5 and so a little more than 1 stop?
 

Dan Fromm

Member
Joined
Mar 23, 2005
Messages
6,823
Format
Multi Format
I have an odd-ball neutral density filter. It's a Kodak Series VI and it says it is a 2.5. Looking around I see info on 2.4 and 2.6, but no 2.5.

Does that number mean it is a number 2.5 and so about 8 stop, or is it a factor of 2.5 and so a little more than 1 stop?

You have it. Why don't you look through it? -1 stop doesn't look at all like -8 stops.
 
OP
OP

pbromaghin

Subscriber
Joined
Sep 30, 2010
Messages
3,807
Location
Castle Rock, CO
Format
Multi Format
You have it. Why don't you look through it? -1 stop doesn't look at all like -8 stops.

Hmm. Good question. It's the only neutral density filter I have. I've never dealt with them before and so have no basis from which to judge.

I plan to be using iso 400 film in an old folder with a fastest shutter of 1/250. In the past a red filter has worked with B&W to get the exposure down to what the shutter can handle. I found this in the drawer and thought it would work for color film.
 
OP
OP

pbromaghin

Subscriber
Joined
Sep 30, 2010
Messages
3,807
Location
Castle Rock, CO
Format
Multi Format
Or just meter through it.

Another good suggestion. It's a Series VI which is quite a bit smaller diameter than any lens I have for a metered camera.
 

Bill Burk

Subscriber
Joined
Feb 9, 2010
Messages
9,310
Format
4x5 Format
Hmm won't fit a camera with a meter...

How about shining a light on a table with a beam that you can cover with the filter... Meter the light before and after.
 

Ian C

Member
Joined
Feb 8, 2009
Messages
1,251
Format
Large Format
Depending on the filter maker’s policy, ND filters can be marked in:

1. Density units

2. Stops of light absorbed

3. Time multiplication factor

I have examples of each type in my possession.

For example, 0.40 ND = 1.5 stop = 2.5X time factor. Each value describes the same filter expressed in different units.

I suspect that your “2.5” filter is time factor 2.5X.
 
OP
OP

pbromaghin

Subscriber
Joined
Sep 30, 2010
Messages
3,807
Location
Castle Rock, CO
Format
Multi Format
OP
OP

pbromaghin

Subscriber
Joined
Sep 30, 2010
Messages
3,807
Location
Castle Rock, CO
Format
Multi Format
Now that I have seen the filter in good light, I feel really stupid for even starting this thread. It says very clearly on the edge of the filter - 2.5x multiplication factor - meaning a little over 1 stop. Thanks to all of you for your help.
 
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links.
To read our full affiliate disclosure statement please click Here.

PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Ilford ADOX Freestyle Photographic Stearman Press Weldon Color Lab Blue Moon Camera & Machine
Top Bottom