help needed: process IR-bandpassfilter image

Based on some posts here on CR which suggest that IR photography is possible with an unmodified 5D3, I decided to give it a try and I ordered two clip-in filters for my 5D III:

1) 642 bandpass filter which includes a tiny bit of the visible spectrum in its transmitted light. It blocks again long IR, but is transparant for short-wave IR.

2) a classical 742 nm IR-filter.

My 5D is unmodified and I have no intention to modify it. If it doesn't work, I can still return the filters. Since I am complete unskilled in processing IR-images, I would greatly appreciate if some skilled person could take a look at a single raw file from each of the two filters. The questions that I have are:

1) Do the files look like normal IR-images compared to what you would get out of a modified 5D? Especially with the BP filter, I can imagine that if the lowpass filter blocks all IR-light you will end up with only red photos on your sensor and this is not good.

2) Could someone please load them into photoshop and spend a few minutes to see if it is any good or not with these two filters? If you drop me a PM, I can send you the CR2 files (two files, one for each filter + a no-filter photo of a gray card).

Thanx!
Niels
 
Yes, you can do IR with a filter + unmodified 5D3. This is how I started IR before I eventually modified a 6D. I used a Tiffen 720nm filter, which IMHO is really the only way to go about it.

- Go much lower than 720nm (I tried with 620nm) and the visible light overpowers the IR. The problem is an unmodified camera is much more sensitive to the visible spectrum than to IR. What you will see is your images are completely red. You can try converting them to B&W, but they won't be IR images.
- Go too much higher and the exposure time becomes ridiculous. As it is you lose about 13 stops with a 720nm filter.

Note that the first step in processing an IR image is to manage color balance. What most do is to 'switch' the red and blue channels. Go to both red and blue and where red is 100, set it to 0. Where red is 0 set it to 100, and do the same for blue. That being said, most of my images consist of just moving the sliders until I like the result.

The images do have a different look than those from a modified camera, but they are still nice. There are two factors.
- Your shutter speed is much less do to the mentioned loss in stops. Therefore clouds and other things will of course look different.
- The camera is much more sensitive to visible light, so it will look different.

Here's one shot with an unmodified 5D3 + 720nm filter. You can clearly see the effects of the long exposure.
Passing Time by Joseph Calev, on Flickr

Here's another one from an unmodified 5D3.
Lost Days by Joseph Calev, on Flickr

Here's nearly the same placed with a modified 6D (590nm) for comparison.
Path of Dreams by Joseph Calev, on Flickr
 
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Oct 16, 2010
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To get started with processing, try converting the files to black and white as one of your first steps. With the 742nm filter, if you find that leaves are light in colour and blue skies are darker in colour, then it is probably working. Unfortunately, I'm not familiar with a 642nm filter to say how it should look.

If you find that you like IR photography, before spending a lot of money on filters, I strongly suggest picking up a cheap second hand camera and getting an IR conversion. I had mine done by this guy - http://www.isaacszabo.com/irorder.html. Depending on the camera, it is only $150-$200 and it takes away a lot of the frustration with the slow shutter speeds.
 
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Thanx for the replies :)

I know it sounds silly, but I also have a modified 600D which I have occasionally used for IR. Lack of time and IR-knowledge has caused a bunch of IR raw files to end up on my harddrive without ever being processed. I love the typical IR-look and I'm confident that I will learn how to process in the near future, as well as use the technique more often.

I also like UWA lenses and I own both the 15 and 21mm from Zeiss. I'd like to use them with IR on a FF, so that's why I ordered these filters in the first place. They are clip-in and only work on FF. There's also a version for crop.

Nevertheless: comparing the IR raw's from my modified 600D and my 5D3 with the same 742nm filter shows deep red images from the 600D and incredibly blue photos from my 5D3. I find that a bit weird :eek: Anyone who can explain the blue color?

On a side note: I don't mind the *long* exposure times: I use a tripod and it is a welcome addition to blur out water and clouds. However, I'd really like to use the 642nm bandpass filter and I am considering to get a secondhand 6D and have it modified.
 
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nhz

Jan 9, 2016
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niels123 said:
Nevertheless: comparing the IR raw's from my modified 600D and my 5D3 with the same 742nm filter shows deep red images from the 600D and incredibly blue photos from my 5D3. I find that a bit weird :eek: Anyone who can explain the blue color?

With the 5D3 and external filter you are using almost exclusively red light and a little bit of near-IR close to 700nm or so, due to the very strong internal IR blocking filter (don't know the one from 5D3, but most of them have very low transmission above 680nm). How the curves for the external IR-pass filter and internal IR-blocking filter cross, difference in the Bayer filters on the sensor in this wavelength band and RAW processing will determine the color of your files. Difficult to predict without seeing the actual transmission curves of the filter.

My experience from an unmodified Sony digicam was similar to your 5D3 i.e. with external Hoya R72 images were strongly red, and when using longer IR wavelength like 87C or RM90 the color shift to purple/blue.

Of course color also depends on other factors like preset white balance: without that most IR shots will look red. With my IR-modified 450D (720nm) with white balance set on e.g. grass/foliage, the RAW images look perfectly neutral in e.g. Windows photo viewer or Faststone Image viewer but Photoshop will show a red/brown image. With a 'normal' white balance (e.g. 'sunny') the images would look strongly red out of camera. With longer IR wavelength (e.g. 830nm front mounted filter) the color shifts to purple/blue.
 
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If I modify a 6D, it'd be nice if I can also use it for normal photography and still use the viewfinder.

Astronomik has an "original white balance" clip-in filter. The mirror is locked-up and the filter is put in place: http://www.astronomik.com/en/clip-filter-fur-canon-vollformat.html
Major drawback for any "action" (e.g. weddings, parties, events): the viewfinder is always blocked with the filter in place and liveview is too combersome on these types of photography.

Solution: such a filter as a screw filter in front of the lens.
Problem: this company only has the clip-in OWB filter.
Where to get an OWB screw-in filter in 77mm or 82mm? I think 77mm would be sufficient.
 
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nhz

Jan 9, 2016
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niels123 said:
If I modify a 6D, it'd be nice if I can also use it for normal photography and still use the viewfinder.

Astronomik has an "original white balance" clip-in filter. The mirror is locked-up and the filter is put in place: http://www.astronomik.com/en/clip-filter-fur-canon-vollformat.html
Major drawback for any "action" (e.g. weddings, parties, events): the viewfinder is always blocked with the filter in place and liveview is too combersome on these types of photography.

Solution: such a filter as a screw filter in front of the lens.
Problem: this company only has the clip-in OWB filter.
Where to get an OWB screw-in filter in 77mm or 82mm? I think 77mm would be sufficient.
My experience is that external filters that correct for removal of the original IR-blocking filters always have a downside. They are an option only if you primarily do astrophotography or IR and using the camera for normal light isn't critical. But despite the limitations there is significant cost involved.

IMHO the only really effective IR blockers are those with interference coating (e.g. B&W 486 MRC, if I remember correctly). But those are expensive, they attract attention (extreme purple glow when viewed from an angle) and don't work for WA work: strong hue shift in the corners for focal length below about 35mm, but for critical work e.g. snow scenes even 50mm can be a problem.

The IR absorption filters (e.g. B+W 489, but there are better ones) can work when there isn't too much IR light present, but it will be difficult to get correct colors, especially for subjects like nature (green foliage etc.) because they don't block all the IR and have a different transmission curve in visible light than the internal blocking filter.

Internal IR blockers usually are a combo of absorption and interference, but because of their place in the optical path the IR reflectance and hue changes in the corner are not a problem there. Buying an additional APS-C body could be cheaper than a 77mm interference filter and has less problems, depending on your lens range it might be a better solution.
 
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nhz said:
niels123 said:
If I modify a 6D, it'd be nice if I can also use it for normal photography and still use the viewfinder.

Astronomik has an "original white balance" clip-in filter. The mirror is locked-up and the filter is put in place: http://www.astronomik.com/en/clip-filter-fur-canon-vollformat.html
Major drawback for any "action" (e.g. weddings, parties, events): the viewfinder is always blocked with the filter in place and liveview is too combersome on these types of photography.

Solution: such a filter as a screw filter in front of the lens.
Problem: this company only has the clip-in OWB filter.
Where to get an OWB screw-in filter in 77mm or 82mm? I think 77mm would be sufficient.
My experience is that external filters that correct for removal of the original IR-blocking filters always have a downside. They are an option only if you primarily do astrophotography or IR and using the camera for normal light isn't critical. But despite the limitations there is significant cost involved.

IMHO the only really effective IR blockers are those with interference coating (e.g. B&W 486 MRC, if I remember correctly). But those are expensive, they attract attention (extreme purple glow when viewed from an angle) and don't work for WA work: strong hue shift in the corners for focal length below about 35mm, but for critical work e.g. snow scenes even 50mm can be a problem.

The IR absorption filters (e.g. B+W 489, but there are better ones) can work when there isn't too much IR light present, but it will be difficult to get correct colors, especially for subjects like nature (green foliage etc.) because they don't block all the IR and have a different transmission curve in visible light than the internal blocking filter.

Internal IR blockers usually are a combo of absorption and interference, but because of their place in the optical path the IR reflectance and hue changes in the corner are not a problem there. Buying an additional APS-C body could be cheaper than a 77mm interference filter and has less problems, depending on your lens range it might be a better solution.

I currently use a 5D3 + 7D2 (both unmodified) on events, assignments etc. I don't do a lot of paid 'stuff' and for close-up I chose the 7D2 because of the greater DOF in macro work. Having two FF's over FF + crop is an advantage when shooting indoors, low light, etc. That's why I thought: if I get myself a 6D for IR, then why not as well see if I can relatively easy use it for 'normal' photography as well. I currently have 600D for IR and I have an "original white balance" filter which clips in the body behind the lens and in front of the mirror. It works very well and there is no noticable difference compared to an unmodified body.

Drawback of the FF clip-in's: you only have live view left because the mirror is locked up. Not good on a wedding ;)
 
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Valvebounce

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Hi Neils.
I'm sorry, but I don't quite get your logic, you have 2 perfectly good cameras for a wedding, and you want to add in to the mix a camera that one might say is an oddball, not only are the controls allegedly quite different, (I don't own one but I've seen it mentioned often enough) plus would it be fair to say you have (or will have) deliberately compromised it to make it do IR, not something many want for wedding shots then you want to reverse the compromise with another compromise that could lead to missed shots of someone's wedding?
I don't think that is the way to go.
I'd get the 6D convert it for IR and enjoy it, use the well matched pair you have for your weddings or if you don't like the 7DII as a wedding camera replace it or add an unmodified 6D to the fleet.
Just my thoughts on the problem, hopefully they will help you towards a solution.

Cheers, Graham.
 
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Personally I only use my modified 6D for IR. I'm not sure I'd trust a clip in because when you convert the camera they change the filter in front of the sensor to collect only IR, but if that works for you...

If you really can't dedicate a camera to IR, you may want to consider a full spectrum camera. Then you only need to add IR+UV cut filters in front of your lenses to go back to visible light. The main drawback, of course, is that you can only use lenses that take filters.

In my case I converted a camera to infrared specifically because I wanted to use lenses that don't take filters - like my TS-E 17, 11-24, and 8-15 fisheye. Also, most of my IR is wide angle, so I only wanted a FF camera.

Also, if you're looking to convert a camera I wouldn't use anyone but these guys - http://www.lifepixel.com/. They're a bit slow but they do a great job.
 
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nhz

Jan 9, 2016
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niels123 said:
That's why I thought: if I get myself a 6D for IR, then why not as well see if I can relatively easy use it for 'normal' photography as well. I currently have 600D for IR and I have an "original white balance" filter which clips in the body behind the lens and in front of the mirror. It works very well and there is no noticable difference compared to an unmodified body.

Drawback of the FF clip-in's: you only have live view left because the mirror is locked up. Not good on a wedding ;)

Yes, that's my point: I have no experience with the clip-in type of filters, but I assume they work just as well in an APS-C body as the original IR-blocking filter (maybe just a bit more vulnerable to dust / alignment issues etc...). But IR-blocking filters that go in front of the lens have optically different properties because of the ray angles there.

Using the 6D with the mirror locked up for normal photography would be inconvenient indeed (slow live view, high battery use etc.). Plus in this case you may also have extra cost for external IR filters, compared to using an internal IR-pass filter instead of a 'clear' filter.
 
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nhz

Jan 9, 2016
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kirispupis said:
If you really can't dedicate a camera to IR, you may want to consider a full spectrum camera. Then you only need to add IR+UV cut filters in front of your lenses to go back to visible light. The main drawback, of course, is that you can only use lenses that take filters.
The main drawback IMHO as mentioned previously is several problems that arise with external IR+UV cut filters, you either get incomplete IR blocking (with absorption filters - resulting in less than great color and strange effects on fine fabric, metal etc.; often also slightly lower sharpness and more CA) or optical problems (with interference filters - resulting in hue shifts in the corners with WA lenses, more flare/reflections and a purple glare from the filter that draws all attention to your camera).
 
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