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GF1 IR

Jack

Sr. Administrator
Staff member
I hear you Vivek.

I had the 665 NM conversion done and think that perhaps I should have done a 720 or maybe even a 770 with this sensor. With the 665, I get an almost normal green channel in the histo, a pushed red as we'd suspect, and a virtually non-existent blue. And if I understand this correctly, green -- mostly plants full of chlorophyl which reflects IR like a mirror -- should be virtually non-existent and blue should be something low... Again, why does my TV remote show up as bright cyan in my LCD -- shouldn't it be white?
 

Cindy Flood

Super Moderator
Jack, I just adjusted the G1 IR raw file so that it was a little underexposed. I took it into CS4 and used the channel mixer. I had an IR preset (that I saved) which set the red channel to R0, G0, B+100, the green channel to R0, G+100, B0, and the blue channel to R+100, G0, B0. That gave the false color effect by swapping the blue and red channels. Then I used the Hue Saturation adjustment panel to finish the color tweaking. After that it was process to taste.

 
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johneaton

Member
Jack: For what it's worth, I had a G10 converted by Precision (at 720), but until I went out and shot a custom wb on my lawn on a sunny day I got mediocre results -- now with the custome wb it's what you would expect. Good luck! John.
 

Jack

Sr. Administrator
Staff member
Folks,

This is not the first IR camera I've owned. I have done all of the normal stuff: set WB on greenery, swap R and B channels via the Channel mixer, set levels, etc. I've even run the same images through dozens of WB settings during raw trying to get the greens to go translucent and bottom line is no matter what settings i use, I am still getting mostly GREEN GREEN's in my images! Which of course remain mostly GREEN after a R and B channel swap, since the green channel is left alone. (In point of fact, the original yellow greens swap to a cyan-greens after the R<>B swap, but regardless it is still too green.) I can make a high-contrast B&W, but it takes a lot of work and the greens don't go white, they stay mostly below 128 gray unless they're lit by direct sunlight like the trees in the foreground below.

Here is a typical example of what I'm getting. This is the in-camera jpeg straight out of the camera, just downsized in CS, after a greenery under sunlight WB. The image contains a variety of green trees, green grass, dirt, blue sky and white clouds. And of course the raw looks just like it under "as-shot" settings in the converter, though I can push it around significantly:
 

Howard

New member
Cindy,

I love the ir car. Do you have problems with infinity focus at the "wide end" like Jack has experienced?

Jack indicated earlier in this thread: "Focus: Precision adjusted the focus for the IR band. However, with the GF1 conversion, the sensor gets set back a bit so you lose crisp infinity focus at the wide end -- 25 Meters seems about it at the 14 setting, but you get to maybe 100 meters at the 45 setting. There is apparently a lens fix for this but then the 14-45 loses a bit of close focus ability when used on a normal camera, so I am still considering that one."

Howard
 

Cindy Flood

Super Moderator
Howard, I sold mine to another member a while back. Maybe he will read this and answer. He is very happy with my Precision converted G1 and 14-45 lens. He has experience with other IR converted cameras and I don't.
If I was doing it again, I would not do the false color 665nm (I'm not really a false color fan) and I would send my Pen 20 f/3.5 to be calibrated with the body. (Vivek says that not much calibration is possible with the G1.)
I never output a jpeg from my G1 IR, but I did not seem to have the problems with my G1 conversion that Jack is having. I would think that G1 and GF1 would behave the same.
BTW, I obtained the IR filter that was removed from mine and sent it to Vivek. He took a G1 apart, so I defer to him on the workings of the G1.
 

Howard

New member
Cindy,

I have been shooting IR for about 3 years, principally with a Canon G9 ir converted by Life Pixel. Not all lenses are suitable for IR as some produce hot spots. I would check with Precision before converting your Pen and having it calibrated to the 20 f3.5, to see if they can verify whether the 20mm lens is prone to hot spots.

Howard
 
V

Vivek

Guest
I hear you Vivek.

I had the 665 NM conversion done and think that perhaps I should have done a 720 or maybe even a 770 with this sensor. With the 665, I get an almost normal green channel in the histo, a pushed red as we'd suspect, and a virtually non-existent blue. And if I understand this correctly, green -- mostly plants full of chlorophyl which reflects IR like a mirror -- should be virtually non-existent and blue should be something low... Again, why does my TV remote show up as bright cyan in my LCD -- shouldn't it be white?

Jack, I know your IR experience with various formats and systems and sensors. That is why I was pointing out the difference here with the hardware.

I presume the Bayer filter in combination with the 665nm and lenses (which also cut the IR thus producing a very narrow bandpass filter in effect) are the culprits for the cyan instead of pure white.

If you still have your m4/3rds to m adapter, perhaps you would have tried your Leica m lenses...

FWIW, with my G1 (sans AA IR UV cut filter) I can see the foliage with IR effects when using old manual lenses and even without any IR filters on the lens (recall what you showed with your Mamiya back without its IR cut filter). Sadly, I can't record any images. My new conversion has been mighty slow and deliberate. Finding the glass of right thickness and dimensions being the major stumbling block.
 

pellicle

New member
Hi


As of right now, I am stymied... :confused: & :banghead:
if you wish to send me a RAW file I can have a fiddle with it here using DCRAW

or you can fiddle with dcraw yourself :)

you could send it by something such as mailbigfile and PM me for my email details
 

Cindy Flood

Super Moderator
Jack, I too was aware of your IR experience. I was just trying to show that I only used a simple workflow with the G1 IR. My foliage and grass was not green right out of the G1, it showed the IR effect.
 

Jack

Sr. Administrator
Staff member
I suspect the issue is as Vivek points out -- narrow bandpass effect -- which would explain the TV remote's IR beam looking cyan instead of white or hot pink. I am going to order some various strengths of IR filters and play around some more.

My whole reason for converting the GF1 was to have a small but relatively high-quality IR camera with a decent zoom that didn't hot spot and still offered AF! My "IMO" bottom line is that if 4/3rds lenses and or sensor systems cut this much IR, then the cameras do NOT make good candidates for conversion.
 

Terry

New member
Jack,
I have the Oly 14-42 zoom which you can try on the GF1 to see what happens with that lens.
 

Jack

Sr. Administrator
Staff member
Worth a try, but it sounds like it may be with all 4/3rds lenses... I do still have all my adapters, just don't have any old glass to mount to it except my Leica spotting scope ;)
 

scho

Well-known member
Worth a try, but it sounds like it may be with all 4/3rds lenses... I do still have all my adapters, just don't have any old glass to mount to it except my Leica spotting scope ;)
I wonder why there would be such a dramatic difference in performance between the G1 IR (see Cindy's images with the Precision IR converted G1 with kit lens) and GF1 IR with same lens.
 

Jack

Sr. Administrator
Staff member
It may be because they changed the bayer matrix in the GF1 so I have more visible light getting through mine than she did hers -- I don't really know. I ordered a couple longer band pass filters and will report back on my findings.
 

Terry

New member
Once you've done this conversion I know you can't go back but can they further modify to eliminate the color and go to the full iR?
 

Jack

Sr. Administrator
Staff member
Once you've done this conversion I know you can't go back but can they further modify to eliminate the color and go to the full iR?
Sure, they can replace with a stronger IR cut filter, or possibly even add a clear glass for a full-spectrum conversion. However since I did the most visible IR conversion, adding stronger over the lens pass filters will generate the same effect -- or in other words give me the widest possible range of IR options just by adding filters. Since this camera uses live view, unlike with SLR viewing I will still be able to compose via the LCD and focus adjustment should remain relatively close.
 

Diane B

New member
I'll be anxious to see what you end up with. If I was going to convert an m4/3rds in the future, it would likely be the GF1. I had it in mind when I bought it as my 10D is a bit long in the tooth with only 6 MP--and big/heavy (about the same as 5D).

I had tried the G1/14-45 with the Hoya R72--you know with long shutter time, but if I want IR, I know its certainly possible without conversion (though a pain LOL).


and same in false color



Diane
 
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Jack

Sr. Administrator
Staff member
That is more like it, especially the B&W, and more what I was looking for :thumbs:. But even with the R72 the grass below the bench still seems a bit green on false color, but the trees in the background are the more normal light cyan and pink, which is good ;). I get my filters on Wednesday, so hopefully will have some feedback later that day.
 
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