[pete_pf]

i was looking at a polarizing filter and maybe a 8x macro filter (just for kicks) but not sure which lens to put them on. i have the 18-250 and a 50mm, curious if there are any reasons for or against putting certain filters on certain lenses?

[Canada_Rockies]

i was looking at a polarizing filter and maybe a 8x macro filter (just for kicks) but not sure which lens to put them on. i have the 18-250 and a 50mm, curious if there are any reasons for or against putting certain filters on certain lenses?

Nope. I would simply buy the filter that fits the largest filter ring on the lenses and a step up ring so that you can use it on the other as well. There will be occasions where you want to use the polarizer on either lens. Make sure that you buy the absolutely best polarizer that you can, and preferably the even more expensive thin ones. You will need it at 18mm on the zoom.

You might want to try them in a shop if you can to see what the vignetting is like on the 18-250 at the wide end. If you get vignetting, you might be able to reduce it by getting an even larger filter and a step up ring to get the filter further to the side of the lens. This will, of course, make your lens hood not work properly, and you might need to get a larger diameter hood as well.

It's easy to spend your money like this!

[pete_pf]

awesome, didn't know about step up rings ..... *writes "get step up ring" down*

[pete_pf]

wondering now if i should look into getting a 77mm filter and step up rings hehe

[Canada_Rockies]

wondering now if i should look into getting a 77mm filter and step up rings hehe

Would you have enough cash after paying for a top flight thin 77mm circular polarizer to pay for the step up rings?

[Venturi]

You might also want to consider going with a rectangular slide-in filter system like Cokin. The P-series will work with 48mm thru 82mm filter sized lenses & the Z-Pro series goes from 49mm to 95mm.
I switched to them when I started pricing non-budget 77mm filters myself.