To Filter or not to Filter
 

I cant seem to get a conclusive answer from my reading and probably wont get a conclusive answer for my question but do you use a filter with all your lenses or just some or maybe just depending on the situation (outside, inside, windy day, no wind etc.). I see people saying you lose IQ and others saying you don't etc. I'm just not sure what is what with filters, I personally own none.

When shooting in sandy or dusty or salt air environment I put a tiffen haze 1 filter infront of my lens. Other times, they are off unless I want to use it for the warming effect.

Some filters have purpose. A tiffen Haze 1 or BW Haze 010 also warms the shot, while most uv protector really do not do anything for the shot and can degrade it.

I ask because I noticed after only a month and a half my kit lens has a small nick/scratch close to the outer portion of the lens, I'd hate for that to happen to an L. Although it is not visible in any photos I've taken.

i personally do not shoot a protective filter. i would put one on if there were any flying debri such as at a motocross, dessert race or something. otherwise i just use the lens hood, i hv never had an issue.

i do use creative filters like circ polarizers and neutral densities from time to time though.

It really takes allot to of dirt or large nick/scratch to the outer element for it to shot in the photo. But if you do take photos at the beach like the ones of your kids, I would put a haze 1 filter in front of it. But for the L lens, I would invest in the tiffen HT haze 1 instead. It has a great multicoating that is very easy to clean. And it is an excellent filter. The BW multicoated would be my second pick for the L. But since the kit lens is only 150 dollars. Get the tiffen and you will be fine. Low grade coating actually can be worst then uncoated glass causing more degradation. Tiffens are uncoated except for the HT line, so they are easy to keep clean. The BW F pro are also good, and are uncoated also.

I agree with Hards,

ND 4 will add 1 stop
ND 6 will add 2 stop

So they are great for adding motion blur. Or when you want to shoot wide open with a slower shutter speed.

Good enough for me, thanks.

I am getting the FZ 35 and for video it seems like one need a ND filter to avoid streaking / blooming. Otherwise I might just add a clear filter to protect the lens and make clean up easier (beach etc).

Every filter decreases image quality - even the most expensive.
I'm using ONLY polarizing filters (circular, each < 5 $) for special purposes.
No ND - for such seldom cases two CPLs are enough and stepless useable.

For protection - how said - a lens hood is enough.

If you're going to use filters, use good ones. A poor filter will noticeably degrade image quality.

And protecting a $100 lens with a $75 filter is a little silly.