IR Modded DSLR

[Spad]

I have an IR modded DSLR with a 720nm filter.

Is this any good for doing astrophotography??

Thanks!

[pipnina]

I think planetary imagers often use IR to get higher contrast in some situations, but for deep sky there is limited use.

You can use it to capture stars through dust clouds, as well as more distant galaxies that would otherwise be invisible at optical lengths, but your sensitivity is going to be much lower and most of the "interesting" stuff is going to be gone with the optical information!

[Steve Ward]

Works for James Webb ... 😉

[Elp]

Do you have more information? From what I understand, most first stage mods involve removal of the IR cut filter or adjusting the colour correction opening out a cameras sensitivity in the red so can pick up more hydrogen alpha. I haven't heard of a DSLR camera mod specifically for IR imaging unless you're referring to the sensors filters being completely removed (full spectrum mod) so are able to image in IR during the day, if so it can be used with an appropriate UV/IR cut or luminence filter.

Edited May 19, 2023 by Elp

[Spad]

Screw on or Cokin type IR filters on DSLR's require long exposures. So the mod on mine allows you to shot like a normal colour camera, but it's in IR.

I believe they do remove the IR Cut Filter on the sensor. Some are full spectrum, mine is a 720nm.

Here is an image of the sensor.

It needs cleaning too!!!

Spose the easiest thing to do, is slap it on a telescope and do some shooting!

 

Edited May 19, 2023 by Spad

[Elp]

Its a bit confusing, I thought they removed the front IR filter as an initial mod but on astronomiser it states an IR filter remains on which doesn't make sense. There's also usually an anti aliasing filter which remains on. You can test it on an emission nebula, but likely you will need a UV/IR cut filter or a luminence filter in the image train otherwise you'll get bloat especially around stars.

Edited May 19, 2023 by Elp

[michael8554]

5 hours ago, Elp said:

Its a bit confusing,

You're not the only one.

1) An "IR mod" only allows IR to be captured.

For amateur use that's a specialised "daylight snaps" type of mod which gives an interesting and unusual look to the images.

The visual band that includes Ha is completely filtered out, and adding a filter won't bring it back.

2) An "Ha mod" retains the IR cut filter, and dispenses with the bandpass filter that restricts the Ha response.

3) A "Full Spectrum" mod removes all filters, so captures UV, visual, and IR.

For refractors requires at least an IR cut filter to prevent stars bloated by IR.

Best for where Pollution, Moon, Ha, O111 etc Filters are always added.

So Spad:

"I have an IR modded DSLR with a 720nm filter."

Which type do you think that is ?

Michael

 

[Spad]

Number 1

So pretty much useless for astrophotography then!

Also... daylight snaps is quite a narrow view. It far more capable than that generalisation. When yiu start fannying with the on camera white balance, in Photoshop, and shooting at night (not astro). You can get some quite startling and ethereal images.

[pipnina]

14 hours ago, Elp said:

Its a bit confusing, I thought they removed the front IR filter as an initial mod but on astronomiser it states an IR filter remains on which doesn't make sense. There's also usually an anti aliasing filter which remains on. You can test it on an emission nebula, but likely you will need a UV/IR cut filter or a luminence filter in the image train otherwise you'll get bloat especially around stars.

Some cameras have multiple filters, some only have one. Dichroic coatings can be used to make a single glass surface allow 400-650nm to pass to the sensor while blocking both the UV and IR that the sensor is otherwise sensitive to, so multiple pieces of glass is sort of unnecessary.

My Nikon only had one filter, but the canon I modded had two. interestingly both filtered the light from my NIR optical mouse! (light I can see with my eyes, faintly)

I wonder what target is best for this type of camera... Perhaps a dusty region like the iris nebula or ghost nebula? As those IFN clouds seem to be visible at many many wavelengths.

[ONIKKINEN]

6 hours ago, Spad said:

Number 1

So pretty much useless for astrophotography then!

Also... daylight snaps is quite a narrow view. It far more capable than that generalisation. When yiu start fannying with the on camera white balance, in Photoshop, and shooting at night (not astro). You can get some quite startling and ethereal images.

IR pass filters work great on the Moon. Longer wavelenghts are less prone to poor seeing so you can often find better detail in IR even if shorter wavelenghts have a chance of being sharper due to limits in diffraction.

So not completely useless. If your camera has an uninterpolated video shooting mode like the movie crop in a 550D then you can do some serious lunar work with the camera.

[Spad]

37 minutes ago, ONIKKINEN said:

IR pass filters work great on the Moon. Longer wavelenghts are less prone to poor seeing so you can often find better detail in IR even if shorter wavelenghts have a chance of being sharper due to limits in diffraction.

So not completely useless. If your camera has an uninterpolated video shooting mode like the movie crop in a 550D then you can do some serious lunar work with the camera.

Righto.... I'll point at the next full moon and see what happens!!

TBH... I might just stick a 50mm 1.8 on it, then slap it on my Star Adventurer and see what comes out...

Thanks everyone!

Edited May 19, 2023 by Spad

[michael8554]

"daylight snaps" is quite a narrow view".

Just my poor attempt at distinguishing between night-time astro use,  and daytime use.

Part of the problem with descriptions of the mods is that people say "an IR filter remains on which doesn't make sense."

The retained filter cuts IR.

And "they removed the front IR filter"

The removed filter coincidently filters IR, but it's not designed to filter IR, it's a bandpass filter for the visual spectrum.

That tries to match the R, G, and B sensor's spectral response to the human eye's spectral response.

And is removed because that response happens to attenuate the Ha wavelength.

Resulting in the red caste to daytime shots.

Michael

Edited May 19, 2023 by michael8554

[Albir phil]

Hi I use a mod Canon 750D modified by astronomisser not full spectrum only filter I use is optolong Lpro . I only use it for emmision targets.for other I use a old Canon 1200 D again with Lpro filter for help with contrast and light pollution.