Orion with and without light pollution.

[Nidge]

I'm trying to improve my post processing technique which at the moment is very limited. So a few evenings ago I took a single 10 second frame of Orion with my 600d and "Nifty Fifty". Today I realised a big mistake and that was I'd failed to set the RAW option and shot in JPEG mode instead.

I intend to purchase a CLS filter for the 600D but thought I'd have ago at trying to reduce the light pollution in the post processing stage to see how far I could go before introducing unwanted artifacts, like colour blotching and clipping the blackpoint.

Below are two images, the first as shot and the second after processing.

Regards

Nidge

Otley, West Yorkshire

[Cath]

Quite a few stars there Nidge! .. very nice.

I too was thinking about getting a LP filter but after looking through all the various before and after images people have posted I decided not to bother because the filter doesn't bring out anymore faint detail, it just reduces the orange colour cast from what I've seen. And that can be done very easily in Canon's Digital Photo Professional software (comes with the camera) or in something like Paint Shop Pro or PhotoShop - as you've shown yourself.

[Nidge]

Thank you for the reply Cath.

I have limited knowledge of optical filters and possibly, through my inherent ignorance, I presume they function similar to filters used in radio applications in that they increase the dynamic range i.e. the ratio between the wanted data and the unwanted data.

In radio the shift is moving away from conventioinal hardware filtering and toward digital signal processing (software) driven mainly by the price differential between the two. However, as with image processing in software, it is too easy to get over aggressive with the technique and introduce unwanted artifacts that were not in the original data.

Regards

Nidge

Otley, West Yorkshire.

[Cath]

Yes I agree.

I'd like to see more before/after images really with and without a LP filter to really convince myself either way (on unmodded cameras). A Canon clip filter is not cheap for me.