[Nico]

Hi, I am looking at various sites for IR photography. There are few sites that shows images taken with unmodified Pentax slrs and IR filter. Of course exposure times are longer with hot spot but still capable.
If all SLRs are fitted with IR block filters, how can this be possible? Since I did not see other images from other slrs with similar setup, Iam wondering if the IR block filters inside Pentax slrs are somehow different. Thanks.

[Buddha Jones]

Not sure what an IR Block Filter is but if you put a Hoya R72 filter on any of your lenses, it will work.

[flyer]

Almost all digital cameras have an IR filter, otherwise the sensor would be to sensitive to IR light vs visible light. But the IR block filter still lets some IR light go through. So, if you put a filter that block most of the visible light spectrum, the sensor will only record whatever little IR light that reaches it. This is why it is possible to take IR pictures without modifying the camera, but since the amount of IR light that reaches the sensor is limited, the exposure times are on the very long side. You can have the IR block filter removed from your camera, but it will become an IR camera only.

[Stacey]

Hi! I'm new to the forum but I am wondering about this also! I went to my local camera store today and the salesman told me that an IR filter would not work on my camera (Pentax K100D) & that the only way I'd be able to acheive the IR look would be to digitally manipulate it. He also stated what the OP said, that if I wanted to take IR pictures I'd have to get my Pentax modified to an IR camera and then and only then would I be able to take IR photos with the IR filter...but then the camera would be totally unable to take normal color pictures.....

Do I really need to have a converted camera to use an IR filter? Or can I just use the Hoya R72 (I've heard alot about that one!)...and then would there be any thing I would need to do differently to achieve the IR look?

Thanks for the help!

[flyer]

Hi! I'm new to the forum but I am wondering about this also! I went to my local camera store today and the salesman told me that an IR filter would not work on my camera (Pentax K100D) & that the only way I'd be able to acheive the IR look would be to digitally manipulate it. He also stated what the OP said, that if I wanted to take IR pictures I'd have to get my Pentax modified to an IR camera and then and only then would I be able to take IR photos with the IR filter...but then the camera would be totally unable to take normal color pictures.....

Do I really need to have a converted camera to use an IR filter? Or can I just use the Hoya R72 (I've heard alot about that one!)...and then would there be any thing I would need to do differently to achieve the IR look?

Thanks for the help!

No. You can use a Hoya R72 (or similar) filter to take IR pictures. The downside to an unmodified camera is the long exposure time since the IR filter is almost black.

[christinelandon]

However, the IR block filter on the sensor of K100D series cameras lets substantially more IR pass than the sensor filters on K10D/K20D/K200D series. Thus, exposure times with a K100D and a good on-lens filter such as the Hoya R72 (there are some other good ones out there) will be longer than with an IR-modified camera, but still workable. Plus, you take off the R72 and you've got your wonderful color DSLR, something not possible with an IR-modded camera.

[creampuff]

Hi! I'm new to the forum but I am wondering about this also! I went to my local camera store today and the salesman told me that an IR filter would not work on my camera (Pentax K100D) & that the only way I'd be able to achieve the IR look would be to digitally manipulate it. He also stated what the OP said, that if I wanted to take IR pictures I'd have to get my Pentax modified to an IR camera and then and only then would I be able to take IR photos with the IR filter...but then the camera would be totally unable to take normal color pictures.....

Do I really need to have a converted camera to use an IR filter? Or can I just use the Hoya R72 (I've heard alot about that one!)...and then would there be any thing I would need to do differently to achieve the IR look?

Thanks for the help!

Stacey, the info the salesman gave you is unfortunately incorrect. Your K100D is definitely capable of IR photography with the use of an IR filter like the Hoya R72 or similar. There are however a few steps that you would need to carry out when digitally post processing your IR images.

In fact if you do not wish to modify your camera as a dedicated IR only camera, the K100D series of cameras are very IR friendly. Typical exposures in bright sun usually take about 1 sec or so whereas for the K10D and equivalent cameras, exposures can be as long as 30 seconds.

Some of my IR images here.

[pentkon52]

I kept my istD to do IR work along with a Hoya R72 filter.

My exposures at ISO 200 are a bit long, but not a s long as my K10D and D200.

istD i can do 1/4 second or there about, with fstops around F5.6.

With the K10D and D200, same settings, my exposures are 25-30 seconds.

They have a stronger filter in front of the sensor.

I know of no place that will convert a Pentax camera to dedicated IR, but that does not mean there now one will.

Dave

[Entropy]

Hi, I am looking at various sites for IR photography. There are few sites that shows images taken with unmodified Pentax slrs and IR filter. Of course exposure times are longer with hot spot but still capable.
If all SLRs are fitted with IR block filters, how can this be possible? Since I did not see other images from other slrs with similar setup, Iam wondering if the IR block filters inside Pentax slrs are somehow different. Thanks.

All digital cameras have IR block filters, you are correct.

As others have said, the quality of these IR block filters varies. Older digital cameras tend to be FAR better suited to IR work without modification than newer ones - newer ones tend to have better IR filters (which are worse if you actually want IR).

Higher end cameras also tend to have better IR filters (worse for IR work).

[LeoTaylor]

I agree with all that has been posted except that pesky salesman.

My K100D with a Hoya R72 will take good photos on sunny days in the 0.2-1 second range (tripod needed). As mentioned, you see only black through the view finder thus I either frame with the filter off or just take some trial shots since the LCD works fine with the filter.

Of course, my filterless K110D can take the same sunny shot in less than 1/1000 second.

There are many IR threads on this forum, unfortunately you can't search on two letters (IR) and few people spell out InfraRed. A few good threads to look at are, "IR photography K10D/K100D", " IR photography with the K10D", and "Infrared With The *ist D." The latter has my comparison of IR exposures with my normal K100D, my wife's istD. and my modified K110D.

[LeoTaylor]

All digital cameras have IR block filters, you are correct.

As others have said, the quality of these IR block filters varies. Older digital cameras tend to be FAR better suited to IR work without modification than newer ones - newer ones tend to have better IR filters (which are worse if you actually want IR).

Higher end cameras also tend to have better IR filters (worse for IR work).

----

Wandering off topic a tad....

I'll add that from an astrophotography viewpoint none of the cameras have "good" IR filters. An important wavelength to photograph nebulas is 656 nanometers which is VISIBLE RED yet built in filters always attenuate well into the visible spectrum. It is possible to make a filter that blocks IR longer than 690 nm and passes 656 nm, I have a couple. Unfortunately such good filters are too expensive for commercial cameras.

Canon once made an astrophotography DSLR with a "good filter" but it was not a big enough market for them.

[alohadave]

----

Wandering off topic a tad....

I'll add that from an astrophotography viewpoint none of the cameras have "good" IR filters. An important wavelength to photograph nebulas is 656 nanometers which is VISIBLE RED yet built in filters always attenuate well into the visible spectrum. It is possible to make a filter that blocks IR longer than 690 nm and passes 656 nm, I have a couple. Unfortunately such good filters are too expensive for commercial cameras.

Canon once made an astrophotography DSLR with a "good filter" but it was not a big enough market for them.

Fuji also makes a version of the S5 (Based on Nikon's D200) that is designed for IR/UV work. It's marketed to scientific/police for forensics.

[TysonG]

As others have said, the *istD/DS/DL/etc and K100D series have weaker hotmirrors (IR cut filters) over the sensor. This is a boon for those into IR--just grab a Hoya R72 and go.

The reason the K10D and up have stronger hotmirrors is that this affects IQ. One of Leica's run of their M8 had a very weak hotmirror and suffered from IR contamination (google M8 IR contamination).

Shooting the other day with my istD I saw similar IR contamination in shots of reddish clothing, manifesting as purplish smudges.

The solution seems to be:
* when you want IR, use a Hoya R72.
* when you want just visible light, use a B+W 486 UV/IR cut filter.

That way you get the best of both worlds: IR when you want it, better IQ when you don't want IR.

I've got a B+W 486 on order and will post before/after photos when it arrives.

[alohadave]

I have some example shots from my K100D Super and a Hoya R72 filter.

https://www.pentaxforums.com/forums/post-your-photos/29898-infrared.html

This camera is well capable of IR as has been stated before. One thing that I've heard is that certain lenses have IR hotspots, but the 18-55 kit lens works great (it's the only lens that I've tried out so far).

When you are shooting IR, you must do PP, unless you like very red pictures. The first set, I just set the white balance and used levels and curves to get where I wanted. The second set is using false color, where the red and blue channels have been swapped along with other processing.

Also, you'll want to dial in a positive EV adjustment. +1 is a good place to start with, otherwise most shot will come out very underexposed. The AE system seems to work fine with the filter on (besides underexposing), and the AF seems to be accurate, but I haven't done any close work, just landscapes.

[Phaser]

foud this
Digital ImageMaker - Pentax K20D Digital Camera Infrared Tests