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06-02-2021, 11:53 AM - 11 Likes   #1
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Non modified Pentax 645Z infrared with DFA 25 lens.

Had a few hours to shoot this infrared image. Used a 40.5mm 720 IR drop in filter. The filter drops into the middle of the 645 DFA 25 lens. The internal filter seems to cut down on flare potential. This was taken at F8 and luckily the lens seems free of bothersome hotspots. Lots of lenses have IR hot spots. My Pentax APS-c 16-45 has a bad hotspot, while the cheap 18-55 kit lens doesn't. One never knows.

I shot some Kodak HIE IR film with a Leica M3 and 21mm R Super Angulon. This is the closest I've gotten with digital to that combo. I'm happy. My digital IR post processing needs practice. Digital IR Raw is so flat out of camera. Used Pentax DCU5, NIK Silver Efex Pro, and PSE to process this.

Thanks for looking,

barondla

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Last edited by barondla; 06-02-2021 at 06:48 PM.
06-02-2021, 12:41 PM - 1 Like   #2
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Very cool! What brand model 720 IR filter were you using?


Steve
06-02-2021, 12:56 PM - 1 Like   #3
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Great IR shot barondia! Really good tonality and balance. Interesting water reflections in IR.
06-02-2021, 06:38 PM - 1 Like   #4
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QuoteOriginally posted by stevebrot Quote
Very cool! What brand model 720 IR filter were you using?


Steve
Thank you. I ordered 3 no name IR filters on eBay years ago. Have a 665, 720, and 850. Only the 720 has any markings at all. Ordered them originally for the Pentax Q lenses. They were cheap (none over $15) and would allow me to experiment with the different ranges. Never imagined I'd be using them on digital medium format. More of that Pentax compatibility .

---------- Post added 06-02-21 at 08:44 PM ----------

QuoteOriginally posted by Bob 256 Quote
Great IR shot barondia! Really good tonality and balance. Interesting water reflections in IR.
Thank you. The Raw images are very flat. I tried for tonality and balance. Some IR shooters might think the processing looks too " normal B&W". Nothing I do looks like Kodak HIE film. So I'm still finding my way.

Thanks,
barondla

06-03-2021, 07:02 AM - 6 Likes   #5
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QuoteOriginally posted by barondla Quote

The Raw images are very flat. I tried for tonality and balance. Some IR shooters might think the processing looks too " normal B&W". Nothing I do looks like Kodak HIE film. So I'm still finding my way.

Thanks,
barondla
If you want more contrast picture in black/white, use 830 nm filter. But your exposures will go longer and you almost always will have pictures with foliage movement.
The best way is to shoot dedicated/converted IR camera. If you are in USA, Kolari Vision is the choice for conversion.
I converted 4 Pentax DSLRs to infrared at home. Not very difficult for me. I use 640 nm 2 mm thick filter on the sensor.
Main advantages for me are the possibility to use optical viewfinder, because Pentax is so good cameras that allow some submilimeter adjustment of sensor block inside the fixing cage and that is enough to get infinity even using 14 mm lens. Some fine focus adjustment is required for different lenses.
I use dfa 50 and 85 as well and they shine even at f1.4. Sharpness is incredible. It is even better compared to unconverted camera if it uses antialiasing filter (it is removed during conversion).
So using on-sensor IR filter allows to see what you shoot through the OVF.
640/665 nm filter allows more red light to reach the sensor and gives more possibilities to get false colors that can produce beautiful images. You always can add 720 nm or 830 nm filter on the lens and shoot using LiveView.
The flatness of RAW using 720 nm filter can be due to bad filter quality or shooting conditions. One my friend said to me that best contrast in image is achievable when the sun hits the object at 90 degree to you lens axis. And the sun is must for beautiful infrared image. Don't shoot in the overcast day, it is pointless. The image looks always flat and gray.






Last edited by Medex; 06-03-2021 at 07:15 AM.
06-03-2021, 07:51 AM   #6
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Magical images. The false color photos are fantastic. The B&W portrait looks very natural. I would not have expected that with IR.

Thanks for the tips and info. I have considered sending an old body off for IR conversion.

Thanks for sharing,
barondla
06-03-2021, 11:50 AM   #7
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QuoteOriginally posted by barondla Quote
Had a few hours to shoot this infrared image. Used a 40.5mm 720 IR drop in filter. The filter drops into the middle of the 645 DFA 25 lens. The internal filter seems to cut down on flare potential. This was taken at F8 and luckily the lens seems free of bothersome hotspots. Lots of lenses have IR hot spots. My Pentax APS-c 16-45 has a bad hotspot, while the cheap 18-55 kit lens doesn't. One never knows.

I shot some Kodak HIE IR film with a Leica M3 and 21mm R Super Angulon. This is the closest I've gotten with digital to that combo. I'm happy. My digital IR post processing needs practice. Digital IR Raw is so flat out of camera. Used Pentax DCU5, NIK Silver Efex Pro, and PSE to process this.

Thanks for looking,

barondla
NICE! Gonna have to try this trick with mine. Where'd ya gitcher filter? Just off Ebay you say, but do you remember the vendor?

06-03-2021, 11:52 AM   #8
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QuoteOriginally posted by Medex Quote
If you want more contrast picture in black/white, use 830 nm filter. But your exposures will go longer and you almost always will have pictures with foliage movement.
The best way is to shoot dedicated/converted IR camera. If you are in USA, Kolari Vision is the choice for conversion.
I converted 4 Pentax DSLRs to infrared at home. Not very difficult for me. I use 640 nm 2 mm thick filter on the sensor.
Main advantages for me are the possibility to use optical viewfinder, because Pentax is so good cameras that allow some submilimeter adjustment of sensor block inside the fixing cage and that is enough to get infinity even using 14 mm lens. Some fine focus adjustment is required for different lenses.
I use dfa 50 and 85 as well and they shine even at f1.4. Sharpness is incredible. It is even better compared to unconverted camera if it uses antialiasing filter (it is removed during conversion).
So using on-sensor IR filter allows to see what you shoot through the OVF.
640/665 nm filter allows more red light to reach the sensor and gives more possibilities to get false colors that can produce beautiful images. You always can add 720 nm or 830 nm filter on the lens and shoot using LiveView.
The flatness of RAW using 720 nm filter can be due to bad filter quality or shooting conditions. One my friend said to me that best contrast in image is achievable when the sun hits the object at 90 degree to you lens axis. And the sun is must for beautiful infrared image. Don't shoot in the overcast day, it is pointless. The image looks always flat and gray.





These are super cool....but I'm not converting my cameras for this....
06-03-2021, 01:20 PM - 1 Like   #9
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QuoteOriginally posted by barondla Quote
Magical images. The false color photos are fantastic. The B&W portrait looks very natural. I would not have expected that with IR.

Thanks for the tips and info. I have considered sending an old body off for IR conversion.

Thanks for sharing,
barondla
I recommend K-30/50 with replaced solenoid (or newer cameras), because these cameras support all lenses formats (including KAF4; K-30 can be cracked-FW upgraded) and have good enought/fast LiveView focus and 16 Mpix sensor. Older cameras are really bohring for infrared.
06-06-2021, 10:03 AM   #10
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QuoteOriginally posted by texandrews Quote
NICE! Gonna have to try this trick with mine. Where'd ya gitcher filter? Just off Ebay you say, but do you remember the vendor?
Looked it up. Renee_Studiosupply (16082). According to my eBay history the filter I haven't used is a 590 instead of 665. I'll mark the filter accordingly.

Thanks,
barondla

---------- Post added 06-06-21 at 12:48 PM ----------

QuoteOriginally posted by Medex Quote
I recommend K-30/50 with replaced solenoid (or newer cameras), because these cameras support all lenses formats (including KAF4; K-30 can be cracked-FW upgraded) and have good enought/fast LiveView focus and 16 Mpix sensor. Older cameras are really bohring for infrared.
Had considered converting the K-01. I thought optical viewfinder was fairly useless for IR, since we don't see IR?

Thanks,
barondla
06-06-2021, 07:38 PM - 1 Like   #11
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QuoteOriginally posted by barondla Quote
Had considered converting the K-01. I thought optical viewfinder was fairly useless for IR, since we don't see IR?
The human eye can see close to 700 nm under appropriate conditions. These filters are not perfectly sharp establishing a spectral passband edge, and some visible will be passed, particularly when the target scene is lit by sunlight and one somehow keeps stray daylight out of the eye-OVF interface. I think night operation would be pretty difficult, unless one were using a 690-ish laser to illuminate.

Of course, if the camera can record a decent image, then the tiltable monitor/display can display it. I would think this would be the preferred method of aiming and particularly focusing. Could autofocus work? Do I correctly recall that the flash units use IR for illumination to aid focus? If so, then the lenses would have to be focus equalized between IR and visible. And this suggests that focus could be manually established in the visible, then the IR filter inserted replacing the glass blank, and let the camera decide how long the exposure should be for the set ISO value.

Awaiting further enlightenment
06-28-2021, 06:57 PM - 1 Like   #12
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ok. I tried this with my 645z & 25mm. Only filter in 40.5mm I could find was an 830mm. Very disappointed in the results as they were very grainy. Couldn't get a white balance so had to do it in post. Couldn't get any kind of image under 30 sec, F/4, 3200 ISO. Nothing really useable below 3200. I guess 830 is too high for it, though I would have expected it to. Guess I will stick to full spectrum converted cameras (waiting on a K-01 to come back from conversion, replacing an Oly micro 4/3 camera.) I'm not giving up, just ordered a 3 pack 650, 685, 720nm pack from ebay. Just need to wait three weeks for it to arrive.

Last edited by cdd29; 06-28-2021 at 07:59 PM.
06-28-2021, 08:46 PM   #13
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QuoteOriginally posted by cdd29 Quote
ok. I tried this with my 645z & 25mm. Only filter in 40.5mm I could find was an 830mm. Very disappointed in the results as they were very grainy. Couldn't get a white balance so had to do it in post. Couldn't get any kind of image under 30 sec, F/4, 3200 ISO. Nothing really useable below 3200. I guess 830 is too high for it, though I would have expected it to. Guess I will stick to full spectrum converted cameras (waiting on a K-01 to come back from conversion, replacing an Oly micro 4/3 camera.) I'm not giving up, just ordered a 3 pack 650, 685, 720nm pack from ebay. Just need to wait three weeks for it to arrive.
Interesting. Wouldn't expect ISO 3200 to be "very grainy", unless they were underexposed. In bright sun, with 720 IR filter, the correct exposure is 4.5 - 5 stops over the meter reading. The 850 probably requires at least 2 extra stops of exposure ( need to shoot this more to be sure). My picture above was shot at ISO 800 F8 at 15 seconds.

I have #1 custom white balance set for the 720 IR filter. Used sunlit green grass to set. Custom white balance #2 is set for the 850 filter. Couldn't get it to set using grass - not enough illumination. I happened on a white metal plate, flat on the ground and in full sun. It allowed easy setting. Shooting Raw means white balance could be set later, but it is nice to review shots, on the camera screen without the red cast.

Thanks,
barondla

Thanks,
barondla

Last edited by barondla; 06-28-2021 at 11:07 PM.
06-29-2021, 05:54 AM - 1 Like   #14
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Even at Facebook resolutions you can see how grainy it is (these are FB screen grabs so no EXIF info, but 30 sec, F/4, ISO3200). Focus is soft also, which is surprising as my shots were prefocused before I dropped in the filter. I'll grab some 720 screw on and try it again with my 55mm.
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06-29-2021, 06:00 AM - 1 Like   #15
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Also please note that as the active sensor region is thinned for various purposes pertinent to giant arrays providing charge storage, the IR response is reduced. A thick silicon detector can generate charge from photons out past 1100 nm, but a thin detector's response may fade at much shorter wavelengths in the near IR.
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