Those are slot-in square filters. Normally used with an adapted holder that screws onto the front of the lens. You can use up to 3 filters at one time. The cheap knock-off brand would be Tian-Ya. Sells for about RM100~180, for the Filter Holder, Screw adapter, and 3pcs of filters. Depending on which filters you pick up, the price will be different. Better one would be Cokin, but they're quite hard to find nowadays, and way more expensive. About RM50~100 per filter.
The ND filters for the Tian-Ya is not a pure grey, and will have a purplish / magenta color cast.
Added on January 9, 2012, 7:19 pmMain advantage of the NEX series are the interchangeable lenses, and the quality and low-light ability that comes from the APS-C large sensor.
However, since your parents will be using it, do you think they will swap lenses around often? If not, they will only be limited to either the SEL1855 zoom, or the SEL16F28 pancake. Since size is an issue, I will not talk about the SEL18200. If they are not swapping lenses, they will only ever use one lens, and if so, please consider a super zoom instead.
With a prosumer super zoom, you can easily get 28~600mm+ depending on which model you go for, which will be really convenient. Super zooms nowadays are not that large, and heavy, as compared to DSLRs. If you were to pack the SEL18200 with the NEX, it would be much larger length wise.
In short:
NEX
===
+ Quality
+ Low Light
+ Interchangeable Lenses
- Lens /Sensor Maintenance Required
- Learning Curve, ease of use
- Lack of pancake / collapsible zoom
- Longest telephoto zoom is only 300mm (35mm equiv.)
Super Zoom
+ Long zoom (up to 720mm [35mm equiv.])
+ Compact size with telephoto zoom
+ Easy to use
- Fixed Lens
Thanks for breaking down the information for me. Does the 16mm f2.8 pancake prime has shallow dof compare with, let say the A mount 50mm? Worth getting it along with the 18-55mm? Main reason I ask is because I dont think they prefer 18-200mm due to small aperture for longer range.
Mind sharing how much you guys got your NEX-5n with 1855 and 16f28? Any freebies?