Infrared with the M system

antmanik wrote:

Great thread, thanks for sharing.
I'm interested in how the conversion works, what changes are actually made to the camera?
Is 'color' of non-visible light filtered to pixel sensors with a new color filter array?
What is the range of wavelengths captured in "full-spectrum"?

I look forward to seeing more of these photos, thanks again.

Thanks. The conversion to full spectrum for the M200 that was done was just to remove both 'internal' factory filters from the sensor (the UV-IR 'cut' filter and the secondary near-IR 'cut' filter. To do this the technician takes the camera apart all the way to the sensor, removes the filters, then puts the camera back together, in a clean-room environment. This leaves the 'raw' sensor (which still has a glass cover on it so it's not really raw'). The sensor is also recalibrated so the focus distance is still correct for the EF-M lenses. Mine was perfect as all the lenses still work after my conversion.

The camera should now be sensitive to a 'full range' of wavelengths, from ultraviolet in the 250-300nm range, all the way to infrared, around the 1000 nm range. To take photographs now a lens filter must be used to cut all but the desired portion. I have filters for the ranges shown in the first post.

When you use a 'color infrared' filter --- it will cut off wavelengths shorter than about 590 nm, and mostly the red channel will record the data, but the other color channels will still record a little data. Using a deep infrared filter like an R72 which only passes around 720 nm and longer, will use almost entirely just the red channel.

With a 'hot mirror' filter or Visible + H-alpha (IR) filter all the channels get used, more like in normal photography. With any IR filter you generally use a custom white balance, with the 'visible-range' filters you get an image which would be similar to the unmodified sensor, with the 'non-visible-range' filters you get an image which looks more 'appealing' instead of being mostly red or pinkish.

The full-spectrum conversion removes the sensor's anti-aliasing filter, which softens the image slightly to avoid moire. I do notice that the modified sensor is sharper at the pixel level and shows moire, DxO PhotoLab 5 has a moire reduction feature that helps with this for images that show moire.

For cameras which have an ultrasonic 'sensor cleaning' feature a full-spectrum conversion removes the piezoelectric 'cleaner' but the M200 does not have this feature to begin with so there is no loss there.

Here are a couple more images I shot this morning

Originally 'green' pine tree on the Gulf of Mexico; Tarpon Springs FL. Full-spectrum Canon M200, Hoya 55mm Red 25A filter (around 600 nm cutoff for 'color IR'), EF-M 11-22mm, 11mm, f4, 1/250s, ISO 100, red/blue channels swapped in Adobe Lightroom after initial processing with DxO PL5

Anclote Key light from Howard Park beach 2 miles away; Tarpon Springs FL, Full-spectrum Canon M200 , 67mm Hoya R72 filter (deeper IR 720 nm cutoff), EF-S 55-250 IS STM with Kenko 1.5x SHQ teleconverter, 375mm, f8, 1/400s, ISO 1000, processed only with DxO Photolab 5 with aggressive Deep Prime de-noise, white-balanced so that trees were 'gray' and contrast greatly enhanced. (The lighthouse is just a 'dot' on the horizon in the first image)

Brackish Cove at Howard Park, Tarpon Springs. Full-spectrum Canon M200, Hoya 25A filter, Canon EF-M 15-45mm IS STM, 15mm, f4, 1/320s ISO 100, red/blue channels swapped in Lightroom, also DxO PL5

Brackish Cove at Howard Park, Tarpon Springs. Full-spectrum Canon M200, Hoya 25A filter, Canon EF-M 15-45mm IS STM, 15mm, f4, 1/320s ISO 100, red/blue channels NOT swapped, processed with DxO PL5

Post-sunset dusk sky over Klosterman Bayou, Palm Harbor FL, at low tide. Full-spectrum Canon M200, Hoya 25A filter, Canon EF-M 15-45 IS STM, 28mm, f4.5, 1/80s, ISO 100, red/blue channels swapped in post.  Hard to tell this is an IR image!