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New standard for digital Aerochrome? The Triple Bandpass TB550/660/850

Well, here it is, the fabled filter from Midwest Optical that seems to be great for Aerochrome-style photos: The Triple Bandpass TB550/660/850 (link). You can’t buy it from any store or online store, unfortunately, but only directly from Midwest Optical. Or, and this is how I did it, from a dealer on Ebay. That also comes out a lot cheaper.

Originally, I inquired with Midwest Optical. They only seem to sell to companies, colleges, and so on. And the prices are very high. Filter size 77mm costs around 1100 Swiss francs (is about the same in US dollars right now). Even filter size 37.5mm – which I have now – still costs around 600 Swiss francs new. Unbelievable. I paid around 50 francs/dollar for a 37.5mm at the Ebay dealer (including delivery costs).




Actually, I wanted to test today, but the Sahara dust, which is currently blown over all of Europe, leads to heavy cloud formation. The sun glitters only in between from behind the gray ceiling. Nevertheless, I took some pictures. Here is one of them, which shows very well the Aerochrome color change. The car is actually red, as is the hydrant.

Midwest Optical

Preliminary assessment: The TB550/660/850 filter seems to work very well, possibly with better results than with the green-orange combination. It is greenish-yellow (thus reminiscent of my combi), but reflects strangely. What does it do exactly? It lets only green, red and near infrared (NIR) pass. By simply switching color channels (NIR is imaged in the blue channel, so you make blue -> red, red -> green, and green -> blue), you get a false-color IR image that strongly resembles Aerochrome.

Because the process is so simple, I see great potential in it for video projects. The Orange-Green method is not very suitable for filming, because the processing is rather tedious and artifacts occur. I think and hope that this will be much easier with the TB550/660/850 filter. The blue vegetation (before the channel swap) is already there, the white balance also fits very well (with 2500 Kelvin).

Am curious how the results will look in sunshine. Stay tuned.

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