Buying the 100-400L......

sandpiper wrote in post #5885944
That is all I put on mine, too. Lens hoods offer far more protection against knocks than filters do, although filters can be useful in conditions of blowing sand or fast flying stones.

I have given my 100-400 many bangs which would have broken a filter, but not affected the front element (which is much tougher), so I have had no damage. A filter only protects against flying debris, if you knock the lens it does nothing to protect it and the filter can break and the broken glass can scratch the element, thus doing more harm than good.

Filters for protection are simply not economical for me, I have several lenses so that adds up to several expensive filters. buying that many filters would cost me far more than replacing a front element, and would be a definite cost whereas the element is only a possible cost that probably will never happen. For me, spending several hundred pounds to avoid the possibility of a £150 or so repair bill isn't an option, I could have another whole lens for that.

In over 25 years of photography, during which I have ill-treated my gear in many ways, I have never damaged a front element. I do have two lenses with severely deformed filter threads, due to knocks that would have certainly shattered a filter, but they still perform flawlessly and without a mark on the glass. I couldn't fit a filter on them now though, even if I wanted to.

For every lens I have seen that has been 'saved' by a filter, I have probably seen another one that has been damaged by broken filter glass.

There is no right answer though, there is an eternal argument on here between the filters / no filters brigades. You just have to decide what to do that is best for you.

The 100-400L is known for wanting high quality filters though. There have been a few threads on here by people complaining that their 100-400L is very soft, only for them to find that it became sharp once they took the filter off.

did read the whole thing (im editing - you know how that is)
I just figure everyone knows a lens hood is a given, it also off improved IQ by not allowing stray light to enter from angles on the side of the lens and or out of your angle of view. I hear what your saying but things happen (ie sand rocks hehe) also one branch on a tree facing you will go right through the lens hood and scratch your coating on the front element, thats a hefty fix out of warranty, not too bad IF you even have to replace the 80$ filter

For me its a piece of mind that i can focus more on what im doing and not falling on slippery rocks and running through low bushes while no worrying about where my lens is in relation to my direction

I don't think I've seen this yet.......For me, the 100-400 is the only lens I've owned that seemed to have a problem with filters, so I simply didn't use one.
With a filter on (and I tried two different high quality UV's) the contrast suffered and the lens was softer. I don't know why, all the other lenses I own or have owned get a minty fresh Kenko or Hoya MRC or pro1 UV...Just not the 100-400. I also use the hoods on all.
The one thing I like about UV's is the protection they give you...not in the classic sense, but I like the fact that my glass is just like the day I bought it, forever, or until I sell it

I use a B+W MRC F-Pro UV Haze filter on mine.

I haven't got mine yet but have a question, Will the autofocus and IS work if I use the canon 2x on the 100-400L?

Borderline whether AF will work at all on a 40D with the 2x TC, officially not. Even if you tape the pins they both get slowed down and hunt around on AF. With AF off and IS on and manually focusing, IS is fine, but don't forget you are wagging around up to 800mm on FF, and up to 1280mm on 1.6 crop , making it pretty near impossible to handhold unless you get really high shutter speeds, but that won't be so easy either because you are starting out from f/9 to f/11. In short, preferrably whack it on a tripod with an Anglefinder C or LiveView, turn AF and IS off, MLU enabled, and if you get a good copy of the lens you can get some good shots. I've even stacked the 2x and 1.4x TCs and got a few shots I liked getting.

Hmmmm.......having just purchased a 100-400mm lens, I find the comments enlightning. I tend to be clumsy at times so I afford myself all the protection I can grab onto. I always include a hood and a good (Hoya, B+W or Heliopan) filter. On this lens I have a Hoya Pro 1 clear filter. So my question to the naysayers and knowledgeable alike is...does the problem come from the uv aspect of the filter or just 'cause another piece of glass is not needed? Thanx

.............old

Glass, two outer and two inner surfaces, coating or no can reflect, plus the optical quality of the glass. Digital cameras have no need for UV filtration. Another way to put it is that whatever you put over the front element of the lens, anything it adds to the optical path gets magnified by 400mm and more.

I'm not going to get into the "protection paranoia", but I have seen enough evidence that "protective filters" affect images from not noticeable to light "fogging" to glaring reflections of things outside of the image frame. All my lenses go naked, unless I need a filter to filter something.

...BTW, modern front element coatings are pretty tough compared to those of a decade or two ago. If you buy a Porsche, drive it like a Porsche, but if you are scared to death of getting a scratch on it, either improve your driving skills or get a Yaris.

John_T wrote in post #5901719
Glass, two outer and two inner surfaces, coating or no can reflect, plus the optical quality of the glass. Digital cameras have no need for UV filtration. Another way to put it is that whatever you put over the front element of the lens, anything it adds to the optical path gets magnified by 400mm and more.

I'm not going to get into the "protection paranoia", but I have seen enough evidence that "protective filters" affect images from not noticeable to light "fogging" to glaring reflections of things outside of the image frame. All my lenses go naked, unless I need a filter to filter something.

John, do you have any dust issues with your glass? The only lens I use without a filter has a veritable warren of dust bunnies in it.
So what I'm asking is, does a filter seal out dust?

Nothing abnormal. If you mean in the lens, I think one has a speck or two, but that doesn't affect the image at all. The front element is sealed on most lenses, so you'd only be keeping it off the front element. There are a couple, I forget which where under extreme conditions of wind, rain and/or dust where a filter will help. On most lenses, dust might possibly get in, but not through the front element. Sometimes there might have bee a speck or two that was somewhere in the innards of the lens that gets shaken onto an element, but that is strictly internal and unpreventable.

It would take a lot of dust on the front element plus freak light from an angle to affect an image, though even then it would be doubtful you could nail it down to dust. The lens hood is there to prevent such possibilities. I rarely need to clean a lens, just puff it off front and back with a bulb blower. Salt spray or blowing sand, puff it off throughly, maybe a light brushing with a sable or old sensor brush and then maybe a gentle cleaning with lens cloth and a optical quality, anti-static liquid lens cleaner. I never touch the lens with a cloth that's not dampened, as the liquid is a good lubricant to prevent any mineral dust from scratching. Really, overcleaning is a much greater sin than undercleaning. The last lens I saw that might have suffered from cleaning was over thirty years old.

That all said, on the average monitor and average printer your aren't really going to see anything due to dust, unless it was on the sensor. I have a pair of Eizo CG241W monitors and an Epson Pro 3800 printer where nothing escapes my evil eye, and I have yet to see any results attributable to dust, unless it was on the sensor. The only real concern on dust is not letting it get on the rear lens element or mirror where it can get past the shutter and flipped on the sensor. The bulb blower is your best friend, not a "filter", IMHO, of course...

John, I'm not concerned about dust affecting IQ,, the only thing it effects is reasale value!

Well, I haven't sold anything ever, only passed a few things along and never heard any complaints. As I said, I only have one lens with two tiny, tiny specks in there you have to look hard to find, and I'm pretty sure they were in there when the lens was new. If some buyer rejected the lens for that, I would just consider him unknowledgable. Anyway, the lens is a keeper and I sure would prefer a couple of specks of dust, or even a scratch or chip on the front element, to front focusing, backfocusing, loose element, funky AF or any of the many other things that can fault an image or the smooth operation of a lens. Sorry, can't say much otherwise to the question of resale.

Got mine last night and it looks like its a sharp one. WOOHOO!

yay!

I got a sharp copy as well earlier this year. As for filters, I have a high quality Hoya UV filter (S-HMC) and haven't noticed any IQ issues (the filter cost me fifty bucks, it better not suck )

Kimberwhip wrote in post #5926890
Got mine last night and it looks like its a sharp one. WOOHOO!