screw-in IR Band Pass / Hot Filter vs. non-converted camera?

[sirhawkeye64]

Not sure if this is the right forum, as it's more of a generic question, not really specific to any genre or about technique...

So long story short, I had a Nikon Z5 converted to a full-spectrum camera for IR photography and in the process, also purchased a Band Pass filter so the camera could be used for normal photography as well (the conversion and filter came from LifePixel).

Has anyone tested this filter (or a band pass filter in general) and compared it to a non-converted camera? I'm curious to see if there are any differences between the two as I plan to use the Z5 as both an IR camera and possibly a backup camera (if the band-pass filter works as I expect without any serious or noticeable loss of IQ) versus carrying 3 cameras (my Z7, Z6 and Z5) on my travels. I always bring a backup camera with me just in case, but am seeing if I can get away with my Z7 (primary camera) and the Z5 (IR/dual purpose camera or if I should still bring the Z6 as well).

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NOTE: If I don't reply to a direct comment in the forums, it's likely I unsubscribed from the thread/article..

 

[petrochemist]

You don't say which band pass filter you are getting. I think there are at least 20 types.

I have used several different types with my FS converted cameras, but have never done direct correlations. Of those I've tried there are certainly minor differences, but all seen to give usable images. I was told where ordering my clip in filter that the model I'd chosen would give a slightly cooler image than the original I never found this a big issue as it's something easily corrected by white balance.

 

[sirhawkeye64]

You don't say which band pass filter you are getting. I think there are at least 20 types.

I have used several different types with my FS converted cameras, but have never done direct correlations. Of those I've tried there are certainly minor differences, but all seen to give usable images. I was told where ordering my clip in filter that the model I'd chosen would give a slightly cooler image than the original I never found this a big issue as it's something easily corrected by white balance.

I'm getting a visual light band pass filter. This one specifically:

External Mounted Visible Bandpass Filters

From the world leaders in camera conversions come the highest quality filters money can buy! We only use high quality materials and glass. Our visible bandpass filter pairs perfectly with a full spectrum converted camera allowing you to shoot normal visible light images. We selected filter...

www.lifepixel.com

Supposedly LP says it lets you shoot "normal" visible light photos, same as you would get with a non-converted camera. I was just curious if there was any visible differences (in terms of possible band leaks where some wavelengths of light -- beyond the visible spectrum -- might get through).

 

[petrochemist]

You don't say which band pass filter you are getting. I think there are at least 20 types.

I have used several different types with my FS converted cameras, but have never done direct correlations. Of those I've tried there are certainly minor differences, but all seen to give usable images. I was told where ordering my clip in filter that the model I'd chosen would give a slightly cooler image than the original I never found this a big issue as it's something easily corrected by white balance.

I'm getting a visual light band pass filter. This one specifically:

https://www.lifepixel.com/shop/filt...ers/external-mounted-visible-bandpass-filters

Supposedly LP says it lets you shoot "normal" visible light photos, same as you would get with a non-converted camera. I was just curious if there was any visible differences (in terms of possible band leaks where some wavelengths of light -- beyond the visible spectrum -- might get through).

The at least 20 types I referred to are all visual light pass models it's just the transitions vary in rapidity & exact location. The clip in models I had an example of had IR cut offs varying by about 10nm IIRC. I've no experience of the lifepixel model in particular.

The actual transition between visual & IR is somewhat vague, with our eyes dropping off in sensitivity as the wavelength increases. No hot mirror I've ever come across shows a noticeable increase in transmission between 650nm (definitely visible) and 1100nm the top wavelength visible to silicon sensors. So there wont be a leak just a variable transition based on the actual filter. It won't be difficult to get a normal looking result using such a filter but it might not be exactly the same as the unmodified camera.

 

[sirhawkeye64]

You don't say which band pass filter you are getting. I think there are at least 20 types.

I have used several different types with my FS converted cameras, but have never done direct correlations. Of those I've tried there are certainly minor differences, but all seen to give usable images. I was told where ordering my clip in filter that the model I'd chosen would give a slightly cooler image than the original I never found this a big issue as it's something easily corrected by white balance.

I'm getting a visual light band pass filter. This one specifically:

https://www.lifepixel.com/shop/filt...ers/external-mounted-visible-bandpass-filters

Supposedly LP says it lets you shoot "normal" visible light photos, same as you would get with a non-converted camera. I was just curious if there was any visible differences (in terms of possible band leaks where some wavelengths of light -- beyond the visible spectrum -- might get through).

The at least 20 types I referred to are all visual light pass models it's just the transitions vary in rapidity & exact location. The clip in models I had an example of had IR cut offs varying by about 10nm IIRC. I've no experience of the lifepixel model in particular.

The actual transition between visual & IR is somewhat vague, with our eyes dropping off in sensitivity as the wavelength increases. No hot mirror I've ever come across shows a noticeable increase in transmission between 650nm (definitely visible) and 1100nm the top wavelength visible to silicon sensors. So there wont be a leak just a variable transition based on the actual filter. It won't be difficult to get a normal looking result using such a filter but it might not be exactly the same as the unmodified camera.

OK I'm not sure exactly what wavelengths the filters blocks out or how much variance they may be (although I would think they are relatively "accurate" as I would imagine people would start calling them out if the filters had serious problems). I guess in the end, I could do some test shots between the converted Z5 with the filter and my Z6.

 

[petrochemist]

You don't say which band pass filter you are getting. I think there are at least 20 types.

I have used several different types with my FS converted cameras, but have never done direct correlations. Of those I've tried there are certainly minor differences, but all seen to give usable images. I was told where ordering my clip in filter that the model I'd chosen would give a slightly cooler image than the original I never found this a big issue as it's something easily corrected by white balance.

I'm getting a visual light band pass filter. This one specifically:

https://www.lifepixel.com/shop/filt...ers/external-mounted-visible-bandpass-filters

Supposedly LP says it lets you shoot "normal" visible light photos, same as you would get with a non-converted camera. I was just curious if there was any visible differences (in terms of possible band leaks where some wavelengths of light -- beyond the visible spectrum -- might get through).

The at least 20 types I referred to are all visual light pass models it's just the transitions vary in rapidity & exact location. The clip in models I had an example of had IR cut offs varying by about 10nm IIRC. I've no experience of the lifepixel model in particular.

The actual transition between visual & IR is somewhat vague, with our eyes dropping off in sensitivity as the wavelength increases. No hot mirror I've ever come across shows a noticeable increase in transmission between 650nm (definitely visible) and 1100nm the top wavelength visible to silicon sensors. So there wont be a leak just a variable transition based on the actual filter. It won't be difficult to get a normal looking result using such a filter but it might not be exactly the same as the unmodified camera.

OK I'm not sure exactly what wavelengths the filters blocks out or how much variance they may be (although I would think they are relatively "accurate" as I would imagine people would start calling them out if the filters had serious problems). I guess in the end, I could do some test shots between the converted Z5 with the filter and my Z6.

My point was there is no such thing as 'accurate' in this matter.

A wide range of different hot mirrors have been used internally by camera manufacturers, such that some are significantly more IR sensitive than others. Despite this all give realistic colours ifd shot with a modicum of skill.

 

[rumple]

Has anyone tested this filter (or a band pass filter in general) and compared it to a non-converted camera? I'm curious to see if there are any differences between the two as I plan to use the Z5 as both an IR camera and possibly a backup camera

I'm starting to use a full-spectrum camera as backup.

In your case, you can do the test as you have all the equipment and must test it anyway. I suggest a colorchecker passport in sunlight and in tungsten to create a Dual-Illuminant DNG Profile.

In my case, in tungsten lighting I could not get the image to the correct white balance (far too warm), so I added an 80A filter to the stack to cool it, and now things are fine.

But you'll know when you try it.

 

[sirhawkeye64]

Has anyone tested this filter (or a band pass filter in general) and compared it to a non-converted camera? I'm curious to see if there are any differences between the two as I plan to use the Z5 as both an IR camera and possibly a backup camera

I'm starting to use a full-spectrum camera as backup.

In your case, you can do the test as you have all the equipment and must test it anyway. I suggest a colorchecker passport in sunlight and in tungsten to create a Dual-Illuminant DNG Profile.

In my case, in tungsten lighting I could not get the image to the correct white balance (far too warm), so I added an 80A filter to the stack to cool it, and now things are fine.

But you'll know when you try it.

OK I'll have to try that then. Luckily I have a passport color checker somewhere....