Digital IR

[peter brooks]

Interesting photos, Peter. How was you camera modified for IR?

See post #42, but briefly I did the open-heart surgery myself (that's what it felt like anyway) - replaced the 'IR cut filter' that was in front of the D200 sensor with a piece cut from Edmund Optics long pass filter material (750 nm).

So it 'sees' permanently in IR but the viewfinder view is normal. Luckily auto-focus is still spot on (as is the result of manual focus).

I was trying to remember how I did the false colour shots (it was around eight years ago), I think it involved swapping the blue and red channels in photoshop. I'll try to work it out again!

Great mine shots BTW.

[tuco]

.. a piece cut from Edmund Optics long pass filter material (750 nm). So it 'sees' permanently in IR ...

I see tutorials on how to remove the filters for my D810 to get full spectrum. It looks straight forward enough. And I see someone will sell you a 750nm filter to install over the sensor. Is there much different between the full-spectrum converted to BW vs one that has the 750nm filter installed?

[Ari]

I bit the bullet and bought an older Sony A-mount camera and lens and will have it converted professionally.
I'm going to get a full 830nm or 850nm B&W conversion done, as I don't want to mess with additional filters and slower shutter speeds.
From what I understand, the light loss is only 2-3 stops if the camera is converted, vs 5-6 (or more) stops if you use filters on the lens.

Tuco, the LifePixel website has lots of good information: https://www.lifepixel.com/photo-tuto...otoshop-videos

[Peter De Smidt]

If you have full spectrum, you'd need to use a filter on the lens for Vis, IR or UV. Since these focus light differently, this could lead to focus mismatches.

Ari, you might consider the super-color filter. If you use a BW adjustment layer, you can adjust the BW image quite extensively using the color controls. In particular, you'd be able to adjust the sky/folliage balance using the color controls instead of needing fancy masks.

[tuco]

Good info. Thanks you guys. My D810 hardly gets used. I think it's going to have a new, special purpose.

[Ari]

Ari, you might consider the super-color filter. If you use a BW adjustment layer, you can adjust the BW image quite extensively using the color controls. In particular, you'd be able to adjust the sky/folliage balance using the color controls instead of needing fancy masks.

Considered that, Peter. But I'd like to get images done in-camera as much as possible, and not spend more time on the computer.
Also I want to avoid using on-camera filters if possible, and I'll see if anyone can install a filter as strong as 900nm-950nm.
Definitely will be a one-trick pony, but I hope to concentrate on the image as much as possible, and less on the process.

[Peter De Smidt]

Sounds good, Ari.

Tuco, I look forward to hearing how it works out. I might get a D810 to convert.

[peter brooks]

Some less-than-bright-sunlight IR shots taken in April (2014) - barely spring in the north of England.


Churchyard by Peter Brooks
Looks oversharpened but there's just an incredible amount of detail in the foliage of these Yew trees.
I do find this venerable old MF 28mm f3.5 lens (42mm on the sensor size) to be very sharp.



Churchyard chair by Peter Brooks
Even when used in lower light levels IR seems to bring special qualities to images. (Same lens).

[Peter De Smidt]

Those have appealing tonality in the foliage.

[Peter De Smidt]