I think NO filter is the best. Just be careful with the lens, for the 1855 there is a lens hood given so use that as protection but if you really want to use, please get one which is real expensive and not some cheapo filter. See here...

http://digital-photography-school.com/read...s-if-you-please
http://photofocus.com/2011/10/31/the-probl...-camera-lenses/
http://www.lensrentals.com/blog/2011/06/go...ith-bad-filters
http://www.flickr.com/photos/54355875@N04/7310401002/

Read the links i gave. Details there.

Do you know what cpl is for and when you use it? If not, better skip any filters for now, just use and enjoy the camera.

Otherwise if you really really want to get a filter, you ned to get those in the range of hundreds, not some cheapo filters which might cause image quality issues.

Bring a calculator convert the $$ and compare on the spot 
good stuff ? LA-EA2 ? to use SAL lenses.

or the electronic view finder ?

only if u go to right shop then cheap

good stuff and must have while in Japan? not sure woh.
I will shop lotsa films since I'm in it 

Aiyah I mean this film lah 

50mm on NEX will give you effective focal length of 50x1.5=75mm (based on 35mm format)
85mm on NEX will give you effective focal length of 85x1.5=127.5mm (based on 35mm format)

The focal length is like zoom. The longer it is, then you can shoot faraway objects easier but the field of view is much narrower. E.g. if you want to take photo of lion in Africa, you won't want to use 24mm... You use 200-300mm or even more. If you want to shoot a school photo for example, you can't use 50mm unless you stand really really really far away. If you stand near, you'll probably only get the photo of one person or 2-3 max. You'll probably want to use 24mm or maybe even lower.

read here... fantastic tutorials...
http://www.cambridgeincolour.com/learn-pho...hy-concepts.htm

The Sony NEX sensor is APS-C sized, and there is a crop factor. Most lens spec is listed based on 35mm standard. E.g. the kit lens 18-55mm and 16mm, combined with the crop factor gives you the effective focal length of 27-82.5 and 24mm respectively.

See here for illustration:
http://digital-photography-school.com/crop-factor-explained

Additionally, focal length (50mm or 85mm) doesn't determine how pricy the lens would be. For example a cv 50mm is more expensive than a cv 75mm. if both lens construction is similar, then the price difference is due to aperature size. the longer the focal length, the more difficult it is to construct a lens to have a bigger aperature (lower f number) thus the price.

a simple way to understand is take for example a normal zoom lens SEL18200. Wide open aperature at 18mm is 3.5 while wide open aperature for 200mm is 6.3. so different focal length even tho the physical aperature opening might be the same, the f number will change. (this is not the case for those constant aperature zooms)

Of course there are more reasons to why certain lens are more expensive. what i am trying to point out is that for the same f number but different focal length, do expect price to be higher for longer focal length lens coz of the difficulty in having a larger physical aperature to gain the same f number. confused already? 

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Added on July 25, 2012, 5:00 pm
focal length doesn't add up just like that... it depends on your crop sensor... nex crop multiplication factor is 1.5 compared to a full frame sensor size (simply means full frame sensor is 1.5 times larger than the nex sensor... adapter thickness is only used to have the image formed optimally on the sensor when using a non native mount lens on to your camera...

hopefully it is layman enough...