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09-27-2013, 06:59 AM   #1
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Help - IR image

Thought I'd try my hand at producing a false colour IR image so after a little research I bought an IR 720nm filter and went out today to try it out. From reading various sites it seemed that 720nm is a good starting point for this type of image but I'm finding it impossible to get any good results from PP. I'm pretty sure I've followed all the instructions in the below guide but my results after switching Red and Blue channels are not good. The resulting image has a very blue tint and the green foliage is not white which is what I expected. Has anyone had similar results with K5 when trying to process IR images or could advise where I'm going wrong?

An In-Depth Guide to Infrared Photography: Processing

Thanks for any replies :-)

09-27-2013, 07:12 AM   #2
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You must use a camera without IR blocking filter. The K-5, as what I've heard, is not good for that...

Edit: A long time a go I tried it with tulips :


Last edited by fs999; 09-27-2013 at 07:19 AM.
09-27-2013, 07:40 AM   #3
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thanks FS999, but I've read that K5 is mean to work ok with IR filter. Also seem to find lots of picture online (unless they all have IR filter removed from body).

https://www.pentaxforums.com/forums/pentax-k-5/124121-k-5-infrared.html
09-27-2013, 08:05 AM   #4
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QuoteOriginally posted by mde1970 Quote
thanks FS999, but I've read that K5 is mean to work ok with IR filter. Also seem to find lots of picture online (unless they all have IR filter removed from body).

https://www.pentaxforums.com/forums/pentax-k-5/124121-k-5-infrared.html
A couple of things - first it would be nice to see a sample so we can see what you're talking about with the results. Also, you mentioned a 720nm filter, but not a hoya r72 filter. Any other brands can be hit or miss, they are often just a deep red filter and not truly an IR filter - you can get cheap $20 filters that claim to be IR, but they are cheap for a reason! Unless you've seen results online from the specific filter you purchased and know what to expect from it, this could be one of the reasons your images aren't turning out as you'd hoped.

You're right in that pretty much any camera can do IR, its just that the strength of the IR cut filter is always different and can result in very long, multiple second exposures to be properly exposed. The K-5 is alright for IR, though exposure at low ISO will be in the multiple second range (if you really want to give IR a try, pick up an old 6mp dslr pentax body, the cut filter on that sensor was very weak and you can do IR handheld without any modifications - a k100d is ideal because it also has SR, the only 6mp body with that feature).

09-27-2013, 09:57 AM   #5
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firstly thanks for the reply. I've attached one test image unaltered (just raw to jpg conversion). The filter is not a hoya but it is a cheap £15 filter so this could be the issue. Is there any way of checking a filter to see if its try IR filter of just a red filter as I'm tempted to return the item if I can be certain its not as advertised?

One step I missed out was the WB setting when I took these shots. Does this have much affect on the end result?
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PENTAX K-5  Photo 
09-27-2013, 01:17 PM   #6
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This is not an IR filter, it's a red or even deep orange filter.
Leaves should be white and the sky black !
09-27-2013, 01:26 PM   #7
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QuoteOriginally posted by fs999 Quote
This is not an IR filter, it's a red or even deep orange filter.
Leaves should be white and the sky black !
Yeah obviously a deep red filter, straight out of the camera for IR there will be a red tint to the shot, but the foliage will be some form of white from the start.
09-27-2013, 01:33 PM   #8
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I do have a UV filter attached to my lens and wonder if somehow this is blocking some of the IR light and messing the picture up? I'll remove the UV filter and try again to see if this has any effect. If not I'll return this and get a hoya filter. Checking the add on ebay they claim this is 100% IR filter and have a 30 day return policy so should not be a problem.

cheers for the help guys!

09-27-2013, 02:23 PM   #9
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QuoteOriginally posted by mde1970 Quote
I do have a UV filter attached to my lens and wonder if somehow this is blocking some of the IR light and messing the picture up? I'll remove the UV filter and try again to see if this has any effect. If not I'll return this and get a hoya filter. Checking the add on ebay they claim this is 100% IR filter and have a 30 day return policy so should not be a problem.

cheers for the help guys!
Just for reference.
Here is a SOOC ( i did re-size it of course) jpeg with Hoya R-72 filter. K-5 DA 55-300.

Last edited by Ex Finn.; 11-11-2014 at 05:45 PM.
09-27-2013, 02:27 PM   #10
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QuoteOriginally posted by mde1970 Quote
I do have a UV filter attached to my lens and wonder if somehow this is blocking some of the IR light and messing the picture up? I'll remove the UV filter and try again to see if this has any effect. If not I'll return this and get a hoya filter. Checking the add on ebay they claim this is 100% IR filter and have a 30 day return policy so should not be a problem.

cheers for the help guys!
UV is from the opposite end of the septrum, should have no affect on your image. I do not remember if I have always taken the UV filter off my lenses when shooting IR film but I bet I have not and the only reason would be to have one less layer of glass between the subject and the film.
09-28-2013, 03:41 PM   #11
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QuoteQuote:
One step I missed out was the WB setting when I took these shots. Does this have much affect on the end result?
White balance helps. Use the grass or green foliage for a WB source in costume WB.

The image will look something like this (taken with a Q, 01 standard prime with B+W IR 092 deep red):
Attached Images
View Picture EXIF
PENTAX Q  Photo 
View Picture EXIF
PENTAX Q  Photo 
View Picture EXIF
PENTAX Q  Photo 

Last edited by sundr; 09-29-2013 at 11:03 AM.
09-30-2013, 02:41 AM   #12
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Cheers All. So called 'IR Filter' has been returned and the Ebay sell did provide a speedy refund.

Lesson learnt and will be ordering a Hoya IR filter in next few weeks.
07-18-2014, 09:42 AM   #13
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I'm experiencing same issue with cheap ir filter from eBay. But! I tried do some picture with my smartphone and...it works perfectly! mde1970: how's images with r72 filter mounted, is it how it used to be? Thanks!

Last edited by wil3m; 07-21-2014 at 11:58 AM.
08-01-2014, 07:17 PM   #14
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QuoteOriginally posted by wil3m Quote
I'm experiencing same issue with cheap ir filter from eBay. But! I tried do some picture with my smartphone and...it works perfectly! mde1970: how's images with r72 filter mounted, is it how it used to be? Thanks!
The K-5, like almost all other digital cameras, has an IR blocking filter in front of the sensor. Thus, even if you place a 720nm filter in front of the lens to block most visible light, there will still be little infrared light hitting the sensor. The best (and possibly the only) way to do proper digital infrared photography, at least with a DSLR, is to have your camera modified by an experienced professional, who will remove the built-in IR blocking filter and insert a visible light blocking filter. 720nm is the one most commonly used, but there are other choices. I had my K-01 modified by Isaac Szabo of szabophotography. You can find him on eBay.

Rob
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