Here is another website that explains the difference between the photography
term ND2, ND4, ND8, ND16 and the
optical density term 2.0 OD ND filter, which is different than a ND2 filter.
As Ben pointed out correctly, a ND2 filter will cut the light in half. It also
has an optical density of 0.3. So to confuse things, a ND2 filter is the same
as a ND filter with OD of 0.3.
https://shuttermuse.com/neutral-density-filter-numbers-names/
[https://shuttermuse.com/wp-content/uploads/2016/01/nd-filter-names.jpg]<https://shuttermuse.com/neutral-density-filter-numbers-names/>
Understanding Neutral Density Filter Names and
Numbers<https://shuttermuse.com/neutral-density-filter-numbers-names/>
As a photographer who flunked out of engineering school, the main thing I want
to know is what ND filter do I need to achieve a certain f stop/shutter
speed/ISO combination and by your excellent table I see a neat way to turn
optical density numbers into f stop reduction numbers.
shuttermuse.com
So, if you have a ND filter, check if it is the photography filter factor or
the optical density.
Dirk-Uwe
________________________________
From: optimal-bounce@xxxxxxxxxxxxx <optimal-bounce@xxxxxxxxxxxxx> on behalf of
Ben Serar <serarphoto@xxxxxxxxx>
Sent: Thursday, June 24, 2021 3:01 PM
To: optimal@xxxxxxxxxxxxx <optimal@xxxxxxxxxxxxx>
Subject: [optimal] Re: Neutral density filter
Hi,
A regular 2 ND filter will cut the light in half.
Ben
On Thu, Jun 24, 2021 at 2:25 PM Bartsch, DIRK-UWE
<dbartsch@xxxxxxxxxxxxxxx<mailto:dbartsch@xxxxxxxxxxxxxxx>> wrote:
1% is the correct transmission for a 2.0 ND filter.
Here is a handy web reference from Edmund Optics
https://www.edmundoptics.com/knowledge-center/application-notes/optics/understanding-neutral-density-filters/<https://urldefense.com/v3/__https://www.edmundoptics.com/knowledge-center/application-notes/optics/understanding-neutral-density-filters/__;!!LLK065n_VXAQ!xEJUKUwYmzu_0aVltBEKFb1npZH5KZG2IP4JG84n_YYRaFUsh6uXEA9Rcq3OHmD0qg$>
[https://www.edmundoptics.com//globalassets/knowledge-center/app-notes/thumbnails/understanding-nuetral-density.jpg]<https://urldefense.com/v3/__https://www.edmundoptics.com/knowledge-center/application-notes/optics/understanding-neutral-density-filters/__;!!LLK065n_VXAQ!xEJUKUwYmzu_0aVltBEKFb1npZH5KZG2IP4JG84n_YYRaFUsh6uXEA9Rcq3OHmD0qg$>
Understanding Neutral Density Filters | Edmund
Optics<https://urldefense.com/v3/__https://www.edmundoptics.com/knowledge-center/application-notes/optics/understanding-neutral-density-filters/__;!!LLK065n_VXAQ!xEJUKUwYmzu_0aVltBEKFb1npZH5KZG2IP4JG84n_YYRaFUsh6uXEA9Rcq3OHmD0qg$>
Neutral Density (ND) filters are designed to reduce transmission evenly across
a portion of a specific spectrum. ND filters are typically defined by their
Optical Density (OD) which describes the amount of energy blocked by the
filter. A high optical density value indicates very low transmission, and low
optical density indicates high transmission (Equations 1 – 2).
www.edmundoptics.com<https://urldefense.com/v3/__http://www.edmundoptics.com__;!!LLK065n_VXAQ!xEJUKUwYmzu_0aVltBEKFb1npZH5KZG2IP4JG84n_YYRaFUsh6uXEA9Rcq2AlaPVkg$>
________________________________
From: optimal-bounce@xxxxxxxxxxxxx<mailto:optimal-bounce@xxxxxxxxxxxxx>
<optimal-bounce@xxxxxxxxxxxxx<mailto:optimal-bounce@xxxxxxxxxxxxx>> on behalf
of Laine <laine@xxxxxxxxxxxxxxxxxxxxx<mailto:laine@xxxxxxxxxxxxxxxxxxxxx>>
Sent: Thursday, June 24, 2021 2:16 PM
To: optimal@xxxxxxxxxxxxx<mailto:optimal@xxxxxxxxxxxxx>
<optimal@xxxxxxxxxxxxx<mailto:optimal@xxxxxxxxxxxxx>>
Subject: [optimal] Re: Neutral density filter
Are you asking what the transmission % is? 1%
On Jun 24, 2021 4:09 PM, Kirsten G Locke
<kglocke@xxxxxxxxxxxxxxxxxxxx<mailto:kglocke@xxxxxxxxxxxxxxxxxxxx>> wrote:
2.0 ND means that it cuts light by 10^2 (or 100) times.
Thanks,
Kirsten
Kirsten Locke, CRA. OCT-C. RN. FOPS
Clinical Trials Manager
Retina Foundation of the Southwest
9600 N. Central Expressway, Suite 200
Dallas, TX 75231
P: 214.363.3911, Press 0 and ask for me
F: 214.363.4538
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From: optimal-bounce@xxxxxxxxxxxxx<mailto:optimal-bounce@xxxxxxxxxxxxx>
[mailto:optimal-bounce@xxxxxxxxxxxxx<mailto:optimal-bounce@xxxxxxxxxxxxx>] On
Behalf Of Eric Kegley
Sent: Thursday, June 24, 2021 3:40 PM
To: optimal@xxxxxxxxxxxxx<mailto:optimal@xxxxxxxxxxxxx>
Subject: [optimal] Neutral density filter
Hello all,
This is the second time in a week that I am having to ask for help. What is
optical density of a 2.0 log unit neutral density filter?
Thank You,
Eric Kegley, CRA, OCT-C, FOPS, COT
Director of Imaging
Retina Consultants of Texas Research Centers
4460 Bissonnet St, Ste 200
Bellaire, TX 77401
O: 713.524.3434 ext. 4831
D: 713.394-7531
C: 281.236.0215
F: 713.795.4552
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