Infrared with the M system

Thanks 'barbara j' and 'petrochemist' for appreciating the amount of effort involved in putting together those filter comparison posts. Most folks in the M forum don't shoot IR so this thread is probably of little interest to them.

I did it because I wanted a comparison to see what filters get what kinds of results with various types of processing, especially fine-tuning hues to see if similar results can be gotten with various filters. They can --- the yellow/orange/red filters behave similarily, and the Hoya R72, 850 nm , and 950 nm also to a degree for B&W IR.

I also did it because I could find no other reference that's as complete. Both Kolari Vision and LifePixel have matrices of results but they don't go into this much depth, and they are targeted towards selling you their very good but somewhat expensive filters. Such a comprehensive comparison is kind of a 'holy grail' if you're trying to decide what type of conversion to get, or to understand what kind of budget filter options are available.

After doing all this work, I think I need to bring only three filters in my camera bag to cover most types of infrared shooting I'd do with my full-spectrum camera:

1. Tiffen Blue #47 - I like the results of this filter the most and it requires little to no post processing (but only works with a full-spectrum conversion)

2. 590 nm - Similar results in some ways to the Tiffen Blue #47, but it requires post-processing. Results have less chromatic aberration than the #47, and only requires a straight red/blue channel swap or 180 degree hue shift for nice golden foliage. I can see why this conversion is so popular as it also allows you to shoot the deeper IR filters like 720, 850, etc.

3. 850 nm - Seems like this has the most contrast and greatest effect for B&W IR style photos. 720 is nice but lets in some visible red light, and 950 has less contrast and needs exposures that are much longer.

On a very tight budget you could do a similar set with a BG3 Blue/IR filter from China, a used Hoya 25A for Super IR Color, and an 850 nm filter for B&W IR all from eBay for $60 - $70, which is about the cost of a single filter from one of the conversion companies.