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Author Topic: IR conversion consideration  (Read 4103 times)

stevegoldenberg

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IR conversion consideration
« on: December 14, 2006, 10:53:10 am »

Hello!

I have a 20D that I would like to convert to IR. I saw Michael's post on MaxMax.com and I checked out their options. I was at first thinking of just doing an IR-only conversion for the autofocus and exposure benefits. However, I realized that an IR+visible conversion might allow me to take some interesting photos which capture both the visible spectrum and the IR spectrum - similar to what Michael suggested in the Leica M8 silver lining article: B&W exposures would capture light in the lower end of the spectrum with an IR+visible capture.

Am I correct in thinking this?  Do any of you have an IR+visible camera and, if so, would you be willing to email me an image (preferably a RAW image but any would be great).  

Also, is the IR glass that is removed from the camera also the Anti Alias filter? Does this improve the sharpness of the photos taken after conversion?

Best regards,

-Steve Goldenberg
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marcmccalmont

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IR conversion consideration
« Reply #1 on: December 15, 2006, 06:45:43 am »

I’ve had the same thoughts but I think we are treading on new grounds not much experience out there. The company does not have loaners or much of an opinion on the subject or  samples of pictures taken with a visible light conversion. They did say it would be sharper but were vague about any interactions with raw converters.
Marc
« Last Edit: December 15, 2006, 06:51:01 am by marcmccalmont »
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Marc McCalmont

:Ollivr

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IR conversion consideration
« Reply #2 on: December 15, 2006, 03:16:15 pm »

Some things I read and learned on this subject:

-its unlikely they remove the AA filter on a bayer sensor. Picture quality would suffer from that (color sensing errors -->moiré). One exception would be the b/w sensor in the Kodak 760m (since no color is read at all).
-I am getting into IR aswell at the moment but for some reason I wont be able to submit any pictures before the 24th.. ... I use a Sigma which has a removable IR filter (it is included in the sensor dust protector). This has some advantages out of which I would suggest you get the IR+visible option:
---You can still use your DSLR for normal shooting
---You can do colour IR (not painting an IR image but creating composites of e.g. one IR channnel plus two normal ones from different exposures - one with IR block and one with IR pass filter)

For composition and focusing, you can either do that first and then put on the IR pass or use a weaker IR filter. I got myself the darkest, but through e.g. a Hoya IR 72 you can still focus and compose. I even read its possible to focus with the B&W 093 but have not tried it yet.

O.
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stevegoldenberg

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IR conversion consideration
« Reply #3 on: December 19, 2006, 05:07:11 pm »

All, I received some great feedback from the MaxMax company:

--------------------
You probably would not want to take a picture with an IR+Visible camera and no filter.  The problem is that visible light and IR light have different focal points.  If you take a picture of both, you won't get a sharp picture.

The IR Cut Filter (ICF) is also cemented to the Anti-Aliasing (AA) filter.  When we remove the ICF and AA gets removed too.  Sharpness is improved but on an IR-Only camera, the IR light is mostly coming through on the red pixels, so net sharpness doesn't change much.  However, on an IR+Visible camera, taking a normal picture using our IR cut filter, XNiteCC1, will show better sharpness.  In fact, because of user requests, I am getting some custom glass made to convert the Canon 5D and Nikon D80 and D200 to Visible-Only cameras with an ICF but no AA.
-------------------------------

Also

------------------
On an IR+Visible, the AF works normally with a CC1.  You don't need to compensate for focus.  The camera sees through the lens and treats it like you have a UV sunlight filter.  Sometimes, you need to force a white balance, but that is about it.  On the IR+Visible using an IR filter, you need to set everything manually.
--------------------------
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Steve Goldenberg
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howiesmith

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IR conversion consideration
« Reply #4 on: December 19, 2006, 05:33:53 pm »

Quote
All, I received some great feedback from the MaxMax company:

--------------------
You probably would not want to take a picture with an IR+Visible camera and no filter.  The problem is that visible light and IR light have different focal points.  If you take a picture of both, you won't get a sharp picture.

The IR Cut Filter (ICF) is also cemented to the Anti-Aliasing (AA) filter.  When we remove the ICF and AA gets removed too.  Sharpness is improved but on an IR-Only camera, the IR light is mostly coming through on the red pixels, so net sharpness doesn't change much.  However, on an IR+Visible camera, taking a normal picture using our IR cut filter, XNiteCC1, will show better sharpness.  In fact, because of user requests, I am getting some custom glass made to convert the Canon 5D and Nikon D80 and D200 to Visible-Only cameras with an ICF but no AA.
-------------------------------

Also

------------------
On an IR+Visible, the AF works normally with a CC1.  You don't need to compensate for focus.  The camera sees through the lens and treats it like you have a UV sunlight filter.  Sometimes, you need to force a white balance, but that is about it.  On the IR+Visible using an IR filter, you need to set everything manually.
--------------------------
[a href=\"index.php?act=findpost&pid=91461\"][{POST_SNAPBACK}][/a]

With some very good lenses (apo), there is no IR focus correction, so an IR+visible would focus OK.  apo lenses are designed to focus all wave length to the same point.  Other lenses could be a problem.

Look at the lens.  Usually, if an IR focus change is required, there is a small red dot on the focus collar.  No red dot, possibly no IR correction.

I had a Canon 500 f/4L that required no IR focus correction.
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marcmccalmont

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IR conversion consideration
« Reply #5 on: January 27, 2007, 10:07:32 pm »

I just got my 5d back From MaxMax with a visible light conversion done. They call it a HR conversion when the AA & bandpass filter are removed and replaced with their CC1 visible light filter. I am quite pleased. The images appear sharper, better reds and more real (3 dimensional)
A lot was lost in the conversion to srgb (reds) and 8 bit jpeg but here is a quick color and B&W image. Available light, 70-200 2.8 IS, on the dining room table.
Marc

[attachment=1674:attachment][attachment=1676:attachment]
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thomas mcconville

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IR conversion consideration
« Reply #6 on: January 27, 2007, 11:06:14 pm »

Quote
Hello!

I have a 20D that I would like to convert to IR. I saw Michael's post on MaxMax.com and I checked out their options. I was at first thinking of just doing an IR-only conversion for the autofocus and exposure benefits. However, I realized that an IR+visible conversion might allow me to take some interesting photos which capture both the visible spectrum and the IR spectrum - similar to what Michael suggested in the Leica M8 silver lining article: B&W exposures would capture light in the lower end of the spectrum with an IR+visible capture.

Am I correct in thinking this?  Do any of you have an IR+visible camera and, if so, would you be willing to email me an image (preferably a RAW image but any would be great). 

Also, is the IR glass that is removed from the camera also the Anti Alias filter? Does this improve the sharpness of the photos taken after conversion?

Best regards,

-Steve Goldenberg
[{POST_SNAPBACK}][/a]
check out this site...they may have a little more info for you  [a href=\"http://www.lifepixel.com/]http://www.lifepixel.com/[/url]
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