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05-13-2011, 03:28 PM   #1
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IR problems with my K-5

Sitting on an outdoor bar a week ago, takings snaps on a colleage with my K-5 I ran into trouble, I found out later when I looked through the snaps - all pictures were bathed in red colour. There were no red lights there, that night, but IR heaters, and the K-5 sensor saw that IR radiation as red light. So the photos were awash with red light! Some could be saved by turning then into B&W, but some were lost, for ever!

What's the cure, you might ask! Only one company makes an suitable infared filter, and that's Heliopan, a German company! Costs about as much as a non-Ltd lens, but seems to do the job, and does the job as both UV and infrared filter!

Hopefully, these filters will make photographing red objects much simpler, and red flowers will be red flowers, not oversaturated, formless things!

More to come!

Cheers,

Tord

05-13-2011, 03:47 PM   #2
Ole
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Thanks for the tip about the heaters!
I don't see how your new filter would impact your red flowers in normal light, though!
05-13-2011, 03:53 PM   #3
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From what little details in your post, it does sound like you have no idea what IR photography is all about. There is nothing wrong with your K-5.
If you didn't know all un-modified digital cameras with an infrared filter attached will give a red image straight from the camera.
That's normal, and occurs whether you're using B+W, Heliopan, Hoya, Cokin or generic made in China IR filters.
05-13-2011, 05:17 PM   #4
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QuoteOriginally posted by creampuff Quote
If you didn't know all un-modified digital cameras with an infrared filter attached will give a red image straight from the camera.
That's normal, and occurs whether you're using B+W, Heliopan, Hoya, Cokin or generic made in China IR filters.
And if you also didn't know, unless your camera has been modified (internal filter removed or swapped) then it doesn't matter if you are using an infra-red filter, you still will not get true infra-red.

Now, piecing together your post, I don't think you are referring to actual infra-red photography as that is a totally different beast.

05-13-2011, 07:31 PM   #5
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what this guy is complaining about seems to be unwanted IR contamination from a very strong heat source. Which is difficult but not impossible,because anyone who has tried IR photography with a Pentax DSLR knows that pentax doesn't skimp on their hot mirror - they use very strong ones, but some IR can get through if the source is strong enough.

Hot mirror filters are very expensive, most dichroic filters are. But I wouldn't worry about needing to buy one, pentax DSLRs do fine with red subject matter.
05-15-2011, 10:13 AM   #6
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QuoteOriginally posted by Tord Quote
Sitting on an outdoor bar a week ago, takings snaps on a colleage with my K-5 I ran into trouble, I found out later when I looked through the snaps - all pictures were bathed in red colour. There were no red lights there, that night, but IR heaters, and the K-5 sensor saw that IR radiation as red light. So the photos were awash with red light! Some could be saved by turning then into B&W, but some were lost, for ever!

What's the cure, you might ask! Only one company makes an suitable infared filter, and that's Heliopan, a German company! Costs about as much as a non-Ltd lens, but seems to do the job, and does the job as both UV and infrared filter!

Hopefully, these filters will make photographing red objects much simpler, and red flowers will be red flowers, not oversaturated, formless things!

More to come!

Cheers,

Tord
I have been taking pictures of a person with a 2000 W IR heater behind her, and I could see no interference at all from the heater. The ambient light was such that I got a correctly exposed picture with the exposure values 1/8 s, F/4.0 and ISO 1600/32. About half of the heater was shielded by the person in front of it. Distance to person: about 1.5 m, distance to heater: about 3.5 m. In the picture, the heating elements of the heater had the red channel overexposed.

If you had less ambient light, and therefore relatively more IR compared to visible light, that could be a reason why you got problems from the IR heaters when I did not. I used the 18 - 135 WR on my K-5, and I have a 62 mm Hoya HD UV filter attached to it.

/Jonas
07-08-2013, 10:54 PM   #7
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Long time ago, but some of you might be interested in an update?! As I wrote, my shots were awash in red light, when I looked on them afterwards. Heliopan did help a bit, but not all the way! These filters are indeed very expensive, thrice the price of say Hoya, but helps a bit. I now use Nikon, and it is not nearly as sensitive.
08-11-2013, 08:03 PM   #8
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QuoteOriginally posted by Tord Quote
Long time ago, but some of you might be interested in an update?! As I wrote, my shots were awash in red light, when I looked on them afterwards. Heliopan did help a bit, but not all the way! These filters are indeed very expensive, thrice the price of say Hoya, but helps a bit. I now use Nikon, and it is not nearly as sensitive.
As a physicist I can only tell you that thermal IR and reflected IR are two different beasts. Thermal IR is an unpolarized EM wave and there are special thermal imaging cameras that will detect , grade and image it's intensity. Reflected IR/NIR is polarized and has quite different optical properties. Term "IR contamination" is related to emission (unpolarized) IR and that's what you are dealing with. IR photography on the other hand operates in reflected IR/NIR environments. From my experience K-5 sensor is quite susceptible to polarized NIR, especially if you filter out visible part of spectrum quite well. Apparently IR cutoff filter used in this camera is quite "NIR forgiving" as compared with other brands/models. Now, IR cutoff filters mounted in front of photo sensors can only "kill" polarized(reflected) IR. They cannot do anything about unpolarized type. All cameras will give you red ghosting and tinting if you take pictures in proximity of IR sources.


Last edited by atarget; 08-12-2013 at 07:33 AM.
08-12-2013, 06:17 AM   #9
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QuoteOriginally posted by atarget Quote
As a physicist I can only tell you that thermal IR and reflected IR are two different beasts. Thermal IR is an unpolarized EM wave and there are special thermal imaging cameras that will detect , grade and image it's intensity. Reflected IR/NIR is polarized and has quite different optical properties. Term "IR contamination" is related to emission (unpolarized) IR and that's what you are dealing with. IR photography on the other hand operates in reflected IR/NIR environments. From my experience K-5 sensor is quite susceptible to polarized NIR, especially if you filter out visible part of spectrum quite well. Apparently IR cutoff filter used in this camera is quite "NIR forgiving" as compared with other brands/models. Now, IR cutoff filters mounted in front of photo sensors can only "kill" polarized(reflected) IR. They cannot do anything about unpolarized type. All cameras will give you red ghosting and tinting if you take pictures proximity of IR sources.
Had no idea! Well, thank you for enlightening me! I solved it partially by changing brand to Nikon which seems a bit less sensible ;-)!
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