First L :) Quick Question.

amd is the best wrote in post #7924104
20B = Awesome! Congrats on the new lens as well.

Thanks, hope you enjoy the lens as well.

I love rotaries, they got that distinct sound.

I'm gonna be an ass, but isn't there a filter FAQ thread?

rklepper wrote in post #7923957
Also you need a filter to complete the weather seal on L lenses.

Not true.
Not on the 70-200/2.8 IS, not on the 24-70, there are a few others... You have the 70-200, you should know. There is no space between the front element and the barrel (like on the 16-35 or 17-40). Even w/o a filter water, steam, moist, air cannot enter at all. So what exactly do you have to seal with a filter ?

I don't use an UV filter routinely. I have one to fit every lens of mine and certainly would use one if circumstances dictated, but I can't recall the last time I when that was. I use only quality Heliopan or B+W filters.

I use protective filters on all my lenses, i use ones that are glass only with no effect or surface treatment as not to change image quality however they still fully protect the frontal elements of the actual lens. i also shoot with a lens hood for extra protection regardless of the shooting enviroment

Rodinal wrote in post #7924353
So what exactly do you have to seal with a filter ?

Canon recommends a filter to complete the weather sealing of some of their lenses. That certainly dosen't mean all the time. A filter, I don't care how good, can affect IQ.

jr_senator wrote in post #7924406
Canon recommends a filter to complete the weather sealing of some of their lenses. That certainly dosen't mean all the time. A filter, I don't care how good, can affect IQ.

Just like you said: "On some L's."
Not all L's, like that user implied.
In this particular case, a filter doesn't help at all at waterproof sealing. The lens is sealed as it is. If the owner wants to get a filter, it's good to know that sealing isn't part of the benefits list.

I've had nothing but problems with filters, primarily increasing flare. When I bought the 135L, I thought I better get a good filter because of the size of the glass. It lasted 1 day. Someone will get a bargain on the Sell forum, because I'm done using them. Hoods for me.

Josh101 wrote in post #7924402
I use protective filters on all my lenses, i use ones that are glass only with no effect or surface treatment as not to change image quality however they still fully protect the frontal elements of the actual lens. i also shoot with a lens hood for extra protection regardless of the shooting enviroment

No coatings ? That will surely affect contrast and increase flare considerably.

Your sensor is not sensitive to UV, film was and is. If you use this lens occasionally on a film camera outdoors sure get one.

UV is just outside visible light, to block it or any other visible (or near visible) light you have to put a coating that blocks frequencies somewhere in the middle of what you want to block. However in order to be effective it will have to block some neighbouring frequencies also and some of those may be visible light. At the end of the day its another piece of glass, so it will take something away. Is that something quantifiable is a matter of opinion.

With a film camera the trade off is probably worth it even with a low quality filter as you can gain more than you loose by using it. With a sealed lens on a digital body you have nothing to gain, and depending on the quality of the filter probably quite a bit to loose. I'm sure there are some great UV filters out there that offer little IQ loss, but the good ones also offer plenty of $$$ lost on buying them. $$$ cost versus benefits is something more quantifiable.

As someone who understands some aspects of material hardness, I'm not worried about scratching the front element. In the same way you need diamond to cut diamond, you need something "harder" than glass to scratch it. Wood splinters, regular plastics can't scratch glass. Some metals can, diamonds can, and some ceramics. How often do I get metal shavings or ceramic dust on the front element? Never!

I don't do weddings so I don't have to worry about diamond rings Then again, if I did I'd have my gear insured anyway