Filters

[KEV145]

Hi all,

Quite a while since I posted so apologies for that.

My query is that I have 2 filters, a 5 stopper and a 10 stopper, these are both the screw on type so they will also screw together.

I was discussing this at my local camera club and said I would then get 15 stops.

One of my colleagues disputed this saying as they are 2 individual filters it would be more than that.

Any thoughts or answers would be greatly appreciated.

 

[Box Brownie]

According to this guide https://www.bhphotovideo.com/explora/photography/hands-on-review/a-guide-to-neutral-density-filters

It is indeed only (?) a matter of adding the numbers up! However, note the caveat about diffraction 'issues' common to any stacking of filters!

 

[Canon Bob]

You've specified the values in 'stops' and so simple addition of their 'stop' values will apply.

 

[hunnymonster]

1 stop = halving the light.

5 stops = halving it 5 times - n in the front = n/32 at the back

10 stops = halving it 10 times - n in the front = n/1024 at the back

n/32 in the front = n/(1024*32) = n/32768 (or halving it 15 times)

 

[KEV145]

Many thanks for your replies, appreciate it.