Are infrared filters stack-able?

Capture Lights · 04-07-2015, 01:03 PM

I was just wondering, say if i stack two 720nm infrared filter on top of each other, what will be the result? anybody tried this?

will it be an 1440nm infrared? or still 720nm, but just darker? or what's your experience with stacking infrared filters?

**TER-OR** · 04-07-2015, 01:23 PM

Should just make it darker, since both filters do the same thing - only allow the 720nm wavelength light. Perhaps the stack will be neutral but I'd bet they will add some light blocking (I could be wrong if the filter is good enough).

Think about stacking multiple layers of colored glass, for instance. Still the same color of light shining through, but unless that transmittance is very high you will get some loss.

Capture Lights · 04-07-2015, 01:37 PM

hum, if that's the case, then there's no point of owning two sets of 720nm infrared filters =) thanks terry

anybody tried this out?

redrockcoulee · 04-07-2015, 01:42 PM

Originally posted by Capture Lights

I was just wondering, say if i stack two 720nm infrared filter on top of each other, what will be the result? anybody tried this?

will it be an 1440nm infrared? or still 720nm, but just darker? or what's your experience with stacking infrared filters?

Each filter was designed to omit light below 720nm, there is no way that stacking them would stop the ability of light at or above 720nm to pass through s othe answer is no, only less light hence longer exposure

Capture Lights · 04-07-2015, 02:02 PM

sounds convincing, i was thinking getting another one of those filters that a friend was giving away, it seems it would be more useful for someone else since i got one already.

narual · 04-07-2015, 03:03 PM

No one needs to try it out. It's basic physics. colors are a shorthand description for wavelengths.

This is like asking if putting 2 green filters on a lens will make it let orange light through.

AquaDome · 04-07-2015, 03:10 PM

You can stack them. The result is less light, thus a longer exposure. Many of the less expensive IR filters only give you two stops, so I bought two of each to get four stops of density.

I wouldn't attempt to stack more than two filters - you would likely begin to see vignetting in your photo.

Capture Lights · 04-07-2015, 03:28 PM

Originally posted by narual

No one needs to try it out. It's basic physics. colors are a shorthand description for wavelengths.

This is like asking if putting 2 green filters on a lens will make it let orange light through.

Originally posted by AquaDome

You can stack them. The result is less light, thus a longer exposure. Many of the less expensive IR filters only give you two stops, so I bought two of each to get four stops of density.

I wouldn't attempt to stack more than two filters - you would likely begin to see vignetting in your photo.

thanks, i've plenty of nd filters, so ill just use those to cut down more light if needed.

AquaDome · 04-07-2015, 04:34 PM

ND filters are not all equal when it comes to blocking IR. I use ProStop IRND filters.

04-07-2015, 01:03 PM	#1
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113	Are infrared filters stack-able? I was just wondering, say if i stack two 720nm infrared filter on top of each other, what will be the result? anybody tried this? will it be an 1440nm infrared? or still 720nm, but just darker? or what's your experience with stacking infrared filters?

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04-07-2015, 01:23 PM	#2
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	Should just make it darker, since both filters do the same thing - only allow the 720nm wavelength light. Perhaps the stack will be neutral but I'd bet they will add some light blocking (I could be wrong if the filter is good enough). Think about stacking multiple layers of colored glass, for instance. Still the same color of light shining through, but unless that transmittance is very high you will get some loss.

04-07-2015, 01:37 PM	#3
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	hum, if that's the case, then there's no point of owning two sets of 720nm infrared filters =) thanks terry anybody tried this out?

04-07-2015, 01:42 PM	#4
redrockcoulee Pentaxian Join Date: Nov 2009 Location: Medicine Hat Posts: 2,306	Originally posted by Capture Lights I was just wondering, say if i stack two 720nm infrared filter on top of each other, what will be the result? anybody tried this? will it be an 1440nm infrared? or still 720nm, but just darker? or what's your experience with stacking infrared filters? Each filter was designed to omit light below 720nm, there is no way that stacking them would stop the ability of light at or above 720nm to pass through s othe answer is no, only less light hence longer exposure

04-07-2015, 02:02 PM	#5
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	sounds convincing, i was thinking getting another one of those filters that a friend was giving away, it seems it would be more useful for someone else since i got one already.

04-07-2015, 03:03 PM	#6
narual Veteran Member Join Date: Jun 2013 Location: South Bend (Notre Dame), Indiana Photos: Gallery \| Albums Posts: 1,988	No one needs to try it out. It's basic physics. colors are a shorthand description for wavelengths. This is like asking if putting 2 green filters on a lens will make it let orange light through.

04-07-2015, 03:10 PM	#7
AquaDome Veteran Member Join Date: Jan 2014 Location: New Carlisle, IN Photos: Gallery \| Albums Posts: 1,475	You can stack them. The result is less light, thus a longer exposure. Many of the less expensive IR filters only give you two stops, so I bought two of each to get four stops of density. I wouldn't attempt to stack more than two filters - you would likely begin to see vignetting in your photo.

04-07-2015, 03:28 PM	#8
Capture Lights Senior Member Join Date: Mar 2014 Posts: 113 Original Poster	Originally posted by narual No one needs to try it out. It's basic physics. colors are a shorthand description for wavelengths. This is like asking if putting 2 green filters on a lens will make it let orange light through. Originally posted by AquaDome You can stack them. The result is less light, thus a longer exposure. Many of the less expensive IR filters only give you two stops, so I bought two of each to get four stops of density. I wouldn't attempt to stack more than two filters - you would likely begin to see vignetting in your photo. thanks, i've plenty of nd filters, so ill just use those to cut down more light if needed.

04-07-2015, 04:34 PM	#9
AquaDome Veteran Member Join Date: Jan 2014 Location: New Carlisle, IN Photos: Gallery \| Albums Posts: 1,475	ND filters are not all equal when it comes to blocking IR. I use ProStop IRND filters.