Stacking ND filter with contrast filter with B&W film

Paulw617 · Feb 3, 2018

I have successfully stacked multiple ND filters with color film and have just added the filter factors together (for example, a 1.8 ND filter with a 3.0 ND filter for 6 + 10 = 16 stop compensation). Now I would like to stack an ND filter with a yellow Y48 contrast filter using B&W film. Do I still just add the filter factors together (for example, 6 + 2 = 8 stop compensation) or do I multiply the filter factors together (for example 6 x 2 = 12 stop compensation)? Of course I also add time for reciprocity.

Ansel Adams in his wonderful book The Negative, says that when you stack an ND filter with a contrast filter you multiply the filter factors. He gives an example of using a polarizer (2.5x) with a red #25 filter (8x) and says the total exposure adjustment would be 20 stops (2.5 x 8 = 20).

trendland · Feb 3, 2018

Paulw617 said:
I have successfully stacked multiple ND filters with color film and have just added the filter factors together (for example, a 1.8 ND filter with a 3.0 ND filter for 6 + 10 = 16 stop compensation). Now I would like to stack an ND filter with a yellow Y48 contrast filter using B&W film. Do I still just add the filter factors together (for example, 6 + 2 = 8 stop compensation) or do I multiply the filter factors together (for example 6 x 2 = 12 stop compensation)? Of course I also add time for reciprocity.

Ansel Adams in his wonderful book The Negative, says that when you stack an ND filter with a contrast filter you multiply the filter factors. He gives an example of using a polarizer (2.5x) with a red #25 filter (8x) and says the total exposure adjustment would be 20 stops (2.5 x 8 = 20).

That is not a real easy mathematics isn't it ?
One simple rule you should have in remind will help :
If you have ND 1000 you have to correct your exposure. The factor is given then.
What will hapen with 2 ND 1000 ?
The light passes through the first ND.
It is strongly reduced then.
This reduced light have to pass the second ND 1000.
What will hapen : ND 1000 + ND 1000
is ND 2000 ?? ?
IT IS ND 1.000.0000 then ....
Trink about

with regard

trendland · Feb 3, 2018

Sorry I just notice tipping failure.
One "O" was to much
ND 1.000.000 = 1 million

and don't be afraid from this.

with regards

trendland · Feb 3, 2018

To all wich may be confused now :
ND 1000 is a modern type of classification.
ND 3 does the same work. (10 stops)
But to compensate 10 stops via exposure
correction you will have a factor of x 1000 (light strenght).
......

with regards

ic-racer · Feb 3, 2018

Both are correct. Read carefully. An advantage of log is that you can add to multiply.

Paulw617 said:
I have successfully stacked multiple ND filters with color film and have just added the filter factors together (for example, a 1.8 ND filter with a 3.0 ND filter for 6 + 10 = 16 stop compensation). Now I would like to stack an ND filter with a yellow Y48 contrast filter using B&W film. Do I still just add the filter factors together (for example, 6 + 2 = 8 stop compensation) or do I multiply the filter factors together (for example 6 x 2 = 12 stop compensation)? Of course I also add time for reciprocity.

Ansel Adams in his wonderful book The Negative, says that when you stack an ND filter with a contrast filter you multiply the filter factors. He gives an example of using a polarizer (2.5x) with a red #25 filter (8x) and says the total exposure adjustment would be 20 stops (2.5 x 8 = 20).

pentaxuser · Feb 3, 2018

Paulw617 said:
Ansel Adams in his wonderful book The Negative, says that when you stack an ND filter with a contrast filter you multiply the filter factors. He gives an example of using a polarizer (2.5x) with a red #25 filter (8x) and says the total exposure adjustment would be 20 stops (2.5 x 8 = 20).

Something sounds wrong here. There are filter factors and stops so a Polariser has a factor of 2.5(1 and a third stops) and a red filter has a factor of 8(3 stops) so you add the stops,4 and a third or multiply the factors to give 20 which is about 4 and one third stops . So stops are added and factors are multiplied.

There is a conversion table on Wikipedia

pentaxuser

Paulw617 · Feb 4, 2018

Yes of course - stops are added and factors are multiplied. Thanks much.

trendland · Feb 4, 2018

Paulw617 said:
Yes of course - stops are added and factors are multiplied. Thanks much.

Well - thats fine .....often high class
maths are "kindergarden maths" at the moment when we understand the procedure.

with regards

pentaxuser · Feb 4, 2018

There is something very strange going on here. Paulw617 opens the thread with #1 ic-racer appears to have made the second post but it is #5. I reply next #6 which as ic-racer immediately was the reply before mine is correct as his was #5. Then the OP replies #7 then there is another reply listed which says Ignored member but I cannot see it. I think this is telling me that someone I have placed on my ignore list replied which makes sense but why does the thread as it appears to me go from # 1 to ic-racer's #5 with nothing in between.

Surely my ignored member did not furnish #2,3 and 4 in succession or did he and that is the explanation? I have never in my 12 years here used the Ignore button before so I am not familiar with its operation but presumably I get to see that he has replied only while his is the last reply?

Have I got this right?

Thanks

pentaxuser

trendland · Feb 4, 2018

pentaxuser said:
There is something very strange going on here. Paulw617 opens the thread with #1 ic-racer appears to have made the second post but it is #5. I reply next #6 which as ic-racer immediately was the reply before mine is correct as his was #5. Then the OP replies #7 then there is another reply listed which says Ignored member but I cannot see it. I think this is telling me that someone I have placed on my ignore list replied which makes sense but why does the thread as it appears to me go from # 1 to ic-racer's #5 with nothing in between.

Surely my ignored member did not furnish #2,3 and 4 in succession or did he and that is the explanation? I have never in my 12 years here used the Ignore button before so I am not familiar with its operation but presumably I get to see that he has replied only while his is the last reply?

Have I got this right?

Thanks

pentaxuser

That's realy confusing? But may be it is the result to ignore me Pentaxuser ?

with regards....

trendland · Feb 4, 2018

I can't use the ignore function - because
it isn't real smart.....

with regards

MattKing · Feb 4, 2018

pentaxuser said:
I have never in my 12 years here used the Ignore button before so I am not familiar with its operation but presumably I get to see that he has replied only while his is the last reply?

Have I got this right?

Yep. Although it's probably an unintended consequence that you can see an indication that the last is his/her reply.
Ironically, the thread still makes more sense than if you read the ignored posts .
If you want to read the ignored posts, look for the light grey "Show Ignored Content" - at your peril!

pentaxuser · Feb 4, 2018

Thanks, Matt. I thought that what you have told me would be the case. It was just that while I had frequently seen two replies in succession from the ignored person in many a thread in the past I don't think I have even seen 3 in such quick succession that there were no intervening posts from anyone else.

What had also thrown me was that since I placed the person on "Ignore" I had seen neither hide not hair of him in the form of any "ignored member" nomenclature so seeing this had puzzled me. it was maybe just as well that I had seen "ignored member" and asked for an explanation or I might have assumed that I had a computer glitch that had permanently wiped out 3 useful replies

pentaxuser

trendland · Feb 4, 2018

pentaxuser said:
Thanks, Matt. I thought that what you have told me would be the case. It was just that while I had frequently seen two replies in succession from the ignored person in many a thread in the past I don't think I have even seen 3 in such quick succession that there were no intervening posts from anyone else.

What had also thrown me was that since I placed the person on "Ignore" I had seen neither hide not hair of him in the form of any "ignored member" nomenclature so seeing this had puzzled me. it was maybe just as well that I had seen "ignored member" and asked for an explanation or I might have assumed that I had a computer glitch that had permanently wiped out 3 useful replies

pentaxuser

....ahh now I see then it was just a computer failure... !

with regards

PS : Machines sometimes in the future take over the command on mankind

hacked - sepiareverb · Feb 4, 2018

This is why I carry a camera with a TTL meter at all times. Too dumb for that kind of math.

DREW WILEY · Feb 4, 2018

Funny. Most red filters require a 3 EV (3 stops) of compensation on pan film. If a particular polarizer or whatever (like a .60 ND filter) requires two more EV, that equals five stops. You can count that with fingers! A 20X compensation is about 4-1/3 stops. Otherwise, stacking filters is a recipe for some sharpness loss, esp if they're cheap filters.

trendland · Feb 5, 2018

sepiareverb said:
This is why I carry a camera with a TTL meter at all times. Too dumb for that kind of math.

...too dumb...

with 2 x ND 1000 you would allways need some math - because your TTL meter may indecate something : "low light" but your camera computer is the silly guy who will be "too dump" next.

with regards

PS : TTL is a nice feature but better you tell your camera : "Come on - exposure time next will be 7' hours 45" min. - so hurry up....

DREW WILEY · Feb 5, 2018

Hope your camera also comes with a GPS, cause it will be dark in the woods by then. I once ran into a pro photographer in the Wind River Mtns who was packing six lenses and about twenty filters. By the time he sorted through all that gear and made a specific choice, it was already dark, and he had to repack it using a flashlight.

wyofilm · Feb 5, 2018

DREW WILEY said:
Hope your camera also comes with a GPS, cause it will be dark in the woods by then. I once ran into a pro photographer in the Wind River Mtns who was packing six lenses and about twenty filters. By the time he sorted through all that gear and made a specific choice, it was already dark, and he had to repack it using a flashlight.

Wait around too much longer in the Winds and a grizzly will eat you. They love camera gear. Helps their digestion.

DREW WILEY · Feb 6, 2018

I did darn near get my 4X5 trampled by a moose up there last time, but no bears anywhere. Due to a shortage of whitebark pine nuts, the young male grizzlies leaving the Jellystone area have stuck pretty much to the lowlands seeking food. My hiking companion was worried, however, and carried a canister of bear spray on his hip. We'd been out nearly two weeks when he put his pack back on after crossing a stream. Somehow his pack strap pulled that canister up behind his pack and his back, pulled the pin, and discharged pepper spray all over his back as well as pack fabric! It was like a really bad sunburn. He dumped everything out of the pack, stripped off his clothes, and jumped into a lake with the empty pack. But he still had to wear it on his burnt back another day and a half before reaching the truck at the trailhead. If there was a bear anywhere around, he would have laughed his head off.

wyofilm · Feb 6, 2018

DREW WILEY said:
I did darn near get my 4X5 trampled by a moose up there last time, but no bears anywhere. Due to a shortage of whitebark pine nuts, the young male grizzlies leaving the Jellystone area have stuck pretty much to the lowlands seeking food. My hiking companion was worried, however, and carried a canister of bear spray on his hip. We'd been out nearly two weeks when he put his pack back on after crossing a stream. Somehow his pack strap pulled that canister up behind his pack and his back, pulled the pin, and discharged pepper spray all over his back as well as pack fabric! It was like a really bad sunburn. He dumped everything out of the pack, stripped off his clothes, and jumped into a lake with the empty pack. But he still had to wear it on his burnt back another day and a half before reaching the truck at the trailhead. If there was a bear anywhere around, he would have laughed his head off.

What a terrible story for your friend. Sounds awful.

For those that don't know (clearly you do) don't mess with moose. They usually trot off ... but not always. They can be very aggressive.

pentaxuser · Feb 6, 2018

wyofilm said:
For those that don't know (clearly you do) don't mess with moose. .

Certainly on his first visit to Canada a Scotsman got quite a shock at seeing this massive creature. He asked his Canadian guide what it was and the reply was: "That, Jock, was a Moose"

When the Scotsman had recovered he said: "All I can say is that in that case I hope we don't meet one of your cats" "

pentaxuser

hacked - sepiareverb · Feb 6, 2018

I like that one! We have a lot of moose here in VT. I hit one of the interstate in my Mini Cooper about five years ago. Not fun for anyone involved.

wyofilm · Feb 6, 2018

sepiareverb said:
Mini Cooper

Yikes! I can't imagine.

Stacking ND filter with contrast filter with B&W film

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