Jerome Marot
Well-known member
I have been experimenting with IR last week-end. I use a modified digital camera, of which I removed the IR block filter and an Heliopan RG 780 IR filter. That particular filter has a maximum at 780 nm and cuts all the visible under 700 nm.
With this setting, I can take typical B&W IR pictures after some post-processing:
The filter is mounted in an adapter which ends in an open cylinder and I had the curiosity to look through the filter with my naked eyes. It takes some effort to make sure the cylinder is well fitted and that you do not get light leaks. Then, at first it is dark until my eyes get accustomed. After a few seconds, I see this:
(It is the same image with different post processing, to make it appear red. I see everything red through the filter, obviously.)
I was surprised but I checked the relevant literature. Apparently, it is not uncommon that the human eye has some residual sensitivity to IR light which normally goes unnoticed because of the much higher sensitivity to visible light.
Try it, you may also be surprised!
A word of caution: do not directly look at the sun through the filter, for blindingly obvious reasons.
With this setting, I can take typical B&W IR pictures after some post-processing:
The filter is mounted in an adapter which ends in an open cylinder and I had the curiosity to look through the filter with my naked eyes. It takes some effort to make sure the cylinder is well fitted and that you do not get light leaks. Then, at first it is dark until my eyes get accustomed. After a few seconds, I see this:
(It is the same image with different post processing, to make it appear red. I see everything red through the filter, obviously.)
I was surprised but I checked the relevant literature. Apparently, it is not uncommon that the human eye has some residual sensitivity to IR light which normally goes unnoticed because of the much higher sensitivity to visible light.
Try it, you may also be surprised!
A word of caution: do not directly look at the sun through the filter, for blindingly obvious reasons.