Modded my Canon 5D MkII

[patohalmo]

Can't wait for the skies to clear - I've astro-modded my Canon 5D MkII myself today. Only took the UV-IR Cut filter out, leaving the LP1 in.

And my autofocus still work fine! Soo happy that I can still use it for normal daylight shooting in full auto as I have the Hoya UV-IR cut filter for the lens

I hope to get much better images now.

[StuartJPP]

I recently modified a Canon 6D and am also awaiting a "proper" imaging session. I managed to get a bit of imaging time in but not quite what I wanted...I opted for a Baader replacement mod because I almost exclusively image with lenses aka refractors and would require many different UV/IR filters.

I have done a fair bit of imaging with my Canon 5D3 and the lack of Ha will hopefully be overcome, other than the lack of Ha I think it fares pretty well.

Here's hoping we get a chance the next new moon...

[Astroboffin]

Can't wait for the skies to clear - I've astro-modded my Canon 5D MkII myself today. Only took the UV-IR Cut filter out, leaving the LP1 in.

And my autofocus still work fine! Soo happy that I can still use it for normal daylight shooting in full auto as I have the Hoya UV-IR cut filter for the lens

I hope to get much better images now.

I am a bit confused by the mod you have carried out, both of the filters have UV/IR cut, so how can you take daytime pics by just putting an UV/IR cut filter on the lens, if the mod has been done correctly the picture will come out red, as it should on an astro modded camera!!

You need an IR cut filter for digital imaging, that's why one of the filters is left in the camera, if they are both removed that is a full spectrum mod.

It sounds like you have removed the wrong filter for an astro modded camera...,!

Out of the two filters in the camera which one did you remove, the one nearest to the sensor or the outermost one ??

AB

[Astroboffin]

Hi,

Yes I have just checked it should be the filter nearest to the sensor that is removed, the front filter it the UV/IR cut filter, which should be left in, and it can be left in because it allows the Ha OIII and SII signal to pass through, but blocks the UV/IR which is what you need, but then you can't use for daytime pics as the image will come out red, unless you either use a Custom white balance, or buy a special colour correcting clip in filter.

The rearmost filter that should be removed is the colour correcting filter which corrects the colour by blocking the signal especially Ha, that we require for astro imaging.

(hence why that is if you want to use for daytime pics you then need a clip in colour correcting filter)

If you have removed the from filter UV/ IR only, it will make no difference for astro use really......sorry

In fact it could make it worse on a refractor and you will definitely need a separate UV/IR block filter on the camera.

See here

http://www.astronomiser.co.uk/eosmod.htm

AB

[barkis]

This post edited because in effect, it just  repeats what is explained in Astroboffins  post and link.

Ron.

[patohalmo]

Yes, I know they are both UV-IR blocking filters.

One is LP1 and the other LP2. Means lower pass 1 & 2.

The first filter in the optical train is LP1. This is the clear looking one, with piezoelectric attachment for cleaning purposes. This blocks the UV and IR in the lowest and highest wave lengths of light respectively.

The second one in the optical train, LP2 (closer to the sensor) is of blueish colour and blocks the UV & IR further. In case of UV it blocks higher wave lengths, for IR it blocks lower wave lengths.

And this last option is the one that has to be eliminated, as it blocks way too much.

As you pointed out correctly, when this filter is removed, the pictures tend to have a red tinge.

However, you can get filters from few optical suppliers (Hoya, B&W) named UV-IR Cut. These have the same bluish tinge as the LP2 and have similar function. And they are produced to fit over the lens, rather than camera.

This is similar to the Baader mode, when you replace the LP2 with Baader that lets in a bit more "red". But in my case, this wasn't needed since I had this type of filter already (it blocks rather more UV/IR than the LP2) so the mod was only waiting to happen.

When I asked few guys online doing astromodding about the mod, it was either no reply or negative reply due to the 5D MkII being a bit more expensive and if something went wrong... 

I fully understand that, so I just decided to risk it and do it myself. 

I've tested it and works flawless

[patohalmo]

http://www.hoyafilter.com/hoya/products/generalfilters/uvircut/ - this is the exact filter I have for the lens

[Astroboffin]

http://www.hoyafilter.com/hoya/products/generalfilters/uvircut/ - this is the exact filter I have for the lens

Ok, glad it's all working ok

AB