Light pollution filter + adaptor help

[Emz]

Having been spoilt with lovely dark skies at the SSP, now I'm back in the city I've decided to invest in a light pollution filter for my Canon 10D (just to do star trails etc, I'm still learning!)... I was going to get this one:

Light Pollution Reduction - Skywatcher Light Pollution Filter

but I think I need to get some sort of step-down adaptor cos my lens is 58mm and the filter is 2 inches (50.8mm)?

I don't seem to be having problem finding 58-52mm adaptors online and I was wondering if that was close enough? Or am I trying to perform the impossible?!

Any tips greatly appreciated,

ta muchly

Emz

[johninderby]

You'll probably have to make up one from two T adapters. One to go from the 2" to a T and then one from the camera to a T. Telescope Service have a huge range of adapters so you should be able to sort something out.

http://www.teleskop-express.de/shop/index.php/language/en/cat/c144_Astrofoto----Adapterringe----Digital.html

John

[NickH]

No, I think Emz is asking about the front lens on the stock EOS, which is threaded AFAIK for 58mm filters. I think her idea is to screw in a 2" LP filter to that. I had a look and could not find something exactly matching, but it would be far cheaper than an EOS clip if one exists

[Psychobilly]

You can get a 58-48mm step down adaptor - Try Bristol camera center... vignettes at wide angle but better than nothing...

http://www.bristolcameras.co.uk/advanced_search_result.php?keywords=58-48mm+step+down

For a cheap solution try the 2" Skywatcher one first...

Peter...

[Carbon Brush]

Hi. Two things to think about. First what optical characteristics are you hoping for? Some filters are better than others and that is reflected in the price. Second, where do you want it to fit? Usually filters are made to fit into 1.25" or 2" eyepieces. some are available to clip into cameras. You can also but the glass blanks from some manufacturers.

Light pollution filters really are a big subject. If you can borrow one or two to try out for a day or two and get a feel for the result, that is much cheaper than buying the wrong one!

I have used a couple of different 1.25" filters for visual use. For photo work with my modified Canon 1000D I use an Astronomik CLS clip in filter.

On the plus side, it gets rid of the orange pollution really well (better than my lower cost filters) and stars come out different colours. Bright nebulae like M42 in Orion are bright red. Well worth the £100 or so cost.

On the minus side, the view through the viewfinder is dim and blue. Another minus is that you can't use your nice EFS lenses with it - they bump into each other. You need to get hold of old (non auto) lenses. But as you aren't using autofocus and auto aperture, that is not an issue. I have a collection of various M42 thread lenses and an M42 to Canon bayonet adapter. Old heavy non auto lenses are usually quite cheap.

I hope this helps. I'm sure many others will be adding their views and recommendations.

[NickH]

I have the SW one, and optically it's pretty identical to the more expensive Baader version (and I also have the CLS for my main TMB imaging setup).

From what Emz has said, she plans just to use this to pull out some light pollution for 60s star trail exposures in urban areas, nothing too fancy. She was doing these exposures at SSP, and the LP levels were quite low, back in the urban environs, it's worse..

plus for £26, that filter is very good value IMHO

[Psychobilly]

Get the adaptor from BCC only £5 got to be worth a try...

Peter...

[NickH]

Digital Cameras at Bristol Cameras - SLR - Camera Lenses and more

Thanks Peter...good link!

[Psychobilly]

They carry a huge range of step up and step down adaptors at good prices..

Clip-ins wouldn't work witht he EF-S lenses anyway... so its really got to be a front filter option...

I have just bought a prism so I can get round to doing some in-scientific comparison tests with my growing range of LP filters... easier than waiting for the 10 mins when the mirror in the bedroom cast a spectrum on the door...

Peter...

[Emz]

WOW I am overwhelmed with how quickly everyone has answered, and with such useful info, thank you!! :-D

Yes, I think as I am quite new to all this the £5 BCC adaptor with the SW filter seems like a good place to start.

Thank you so much everyone :-)

[LukeSkywatcher]

Very informative thread. I also am looking to attach my SW LPF to my 450D.