Modding a Canon 40D

[Photosbykev]

I've got a 40D gathering dust at the moment and I plan to get it modded for IR landscape and DSO astrophotography.

Looking at the astronomisers website I have the option to remove the IR filter, leaving the front AA filter in place, or removing both filters.

I've already have the EOS Clip CLS filter and would welcome some input on the preferred option for astro work.

[simon84]

Hi Kev,

If you want to use the camera with AF then you will need to replace the filter. I looked heavily into modding my 1000D but I know down the line I will get a good quality CCD so I've decided to not do it.

Manual focus should work with no problems but obviously you will need a custom WB to set the colours right, I'm not sure the impact that this would have on IR landscape photography as I've only ever done it with a non modded camera.

My thoughts were that for £56 and not much faffing about as the camera will already be open you might aswell pop the replacement filter back in there but as you have a nice collection of bodies I'd just go for the removal. I was planning on modding the camera myself as I have access to a clean room at a friends company that build high speed cameras.

Might be worth leaving the AA filter in there though, as it will keep the sensor free from dust, not sure if the 40D has the vibration cleaning system in there but if it does isnt it this front filter that enables it?

I'm going to be trying my non modded 1000D out on M42 soon with a CLS CCD clip filter as I'm interested to see just how much red is cut out, I've seen some images that look very red indeed with a non modded camera.

[Photosbykev]

Cheers Simon,

I'm unsure if the front AA filter was more than just plain optical glass, if it is just plain glass I would get it replaced. However if it does cause any filtering then I will leave it off as the EOS Clip filter will always be in the body anyway. I always shoot in RAW mode so the white balance isn't a problem and rarely use autofocus on any of my cameras

So the question should of been is that front filter just plain glass or is it doing something else other than just protecting the sensor.

[simon84]

If its just there protecting the sensor and dosnt filter anything I'd live it in as those clip filters are ok but there are gaps around the edge of them.

I did find a site once that detailed all Canon models and the filters inside them but do you think I added it to my faves???

[Dangerous-Dave]

If you want to do IR landscape, as well as DSO astrophotography then you will need the filter removal mod. Filter replacement will pass the far red, but not the IR you require for the landscape shots. A straight forward filter removal alters the plane of focus, so autofocus no longer works and the viewfinder is no longer parfocal with the CMOS, you need to ask about the plain glass mod.

[Photosbykev]

Thanks for the advice Simon and Dave, I'll get the IR filter removed and the front glass replaced.

[Photosbykev]

ok too much faffing about deciding on this mod on the Canon 40D so I've asked Andy (Astronomiser) to replace the Canon rear filter with a Baader filter, that mod lets me get into the extended red and the H-alpha range for astro work but not IR.

Removing both the rear and front AA filter would of given me a camera suitable of IR landscape photography but would compromise the astrophotography quality so I decided against it.

I also ordered the DC Pro power supply for the 40D as it has the old style battery and my current DC power supply is only suitable for the newer lithium batteries in the 7D and 5D MkII

[Dangerous-Dave]

Yep, the Baader mod is the better choice for astrophotography. IR light registers as white and the night sky glows with IR.

[Psychobilly]

Which could have been taken care of usign UV/IR Cut... which can be easy to do if its you use the Right LP filters... CLS-CCD or IDAS...

I regret not putting a clear glass back into the 350D so I guess i'll have to get round to doing it....