Can I use 1.25" inch filters with a 2" eyepiece/socket?

[Trevor Blacklock]

Hi, I'm quite new to astrophotography and am looking to invest in some filters, I found very quickly that they cost a lot of money to buy even one narrow band variant. I would like to purchase an h-alpha filter because of my light polluted city but I'm wondering if I can buy a 1.25" filter to fit in a 2" to 1.25" adapter. I'm unsure if this will cause vignetting or loss of detail but I would like to know if I can use a 1.25" filter in a adapter that changes my telescope from a 2" to a 1.25". If i took pictures through this would there be any downsides?

[Geordie mc]

Can you give a bit more info on the camera you intend to use and your general setup please. Thanks