[geekette]

I have a 52mm Vivitar Polarizing Filter that works fine on my K lenses. I just got a Pentax-M 50/f1.4 (very beautiful lens btw) and it is smaller and won't take the filter. Should I buy an adapter to make the 52mm fit or should I buy another--smaller--polarizing filter?

[boriscleto]

I have a 52mm Vivitar Polarizing Filter that works fine on my K lenses. I just got a Pentax-M 50/f1.4 (very beautiful lens btw) and it is smaller and won't take the filter. Should I buy an adapter to make the 52mm fit or should I buy another--smaller--polarizing filter?

Just buy a 52mm to 49mm step down ring. Duh, 49mm to 52mm step up ring.

[Tom in Delaware]

Yeah you need a step-up ring. Fotodiox sells a whole set of them for not much money. They sell through both Amazon and Ebay.

[MetaD]

Figure out what filter size you are going to use in the future (Pentax most common sizes are 49m and 58mm, but new lenses include 67mm and 77mm). There is no convenient solution, but you don't to pay for and haul around a bag of multiple filters for each lens. A plastic step-up ring is cheap so you can choose 58mm or 67mm, buy several step-ups, and save money for quality filters.

[Ratmagiclady]

Figure out what filter size you are going to use in the future (Pentax most common sizes are 49m and 58mm, but new lenses include 67mm and 77mm). There is no convenient solution, but you don't to pay for and haul around a bag of multiple filters for each lens. A plastic step-up ring is cheap so you can choose 58mm or 67mm, buy several step-ups, and save money for quality filters.

I mostly keep to two sizes, (in my case 55 and 72mm from my old Canon stuff: Canon similarly went from using a lot of 55 down to a lot of 52, and obviously Pentax has lots of 49. ) though I may have to bump the large size up to 77 cause of one lens. I haven't fully replaced my 72mm filter set, which disappeared out of hock some years ago, anyway, *sigh* )

Anyway, it's good to have a small size and a large size of filters, (Assuming, of course, you also have large-filter-sized lenses that you want to put filters on) and then step everything to those: with me, lenses that aren't 55mm thread generally wear a step ring, and a hood that fits *that.* (I like to get matching hoods and step rings from heavystars: he's got about the full line of S&W brand stuff) That way when I want to add filters, the step ring's already there, pretty much no extra fuss. In any event, it's easier to put a step ring in your bag than duplicate filters, though there's a point past which it's just a little awkward to put a huge filter on a small-threaded lens.