Filed under: portal.xn--b8qr95do2b.com — admin @ March 22, 2010 edit
I am referring to filters to protect your lens. I just purchased a Canon 100-400 and ordered a UV for the end. In talking to a relative about my purchase (he's an avid bird photographer)was ask why I would want to use a filter as they tend to block a certain amount of light entering the lens. When doing some reading I realized that depending on the filter you buy you could be losing up to 7% of the available light. I tend to use a filter on all of my lenses for the protection that they offer. How bout everyone else ? Do you have a filter on your lenses ? If so which do you use for this purpose ?um...i'm not sure if i'm on the same page..but wouldn't a lens hood reduce that? I know it does for my 12-24.
It would for some situations, but not when the light source is in the center of the frame :) Sometimes I actually want the light source in the pic. Wierd how sometimes I get the refraction, sometimes I don't... I've noticed faster shutter speeds tend to cut it down a LOT as the refractions end up being very faint, but long exposures (as noted above) give them time to burn into the image and become much more prominent.
--IllahKind of off topic, but what is that then? And how can one avoid or reduce it when it happens (besides pointing the camera elsewhere of course :) )? I notice that from time to time with my lenses, with or without the UV filter.
--Illah
There isn't any way to avoid it. You're getting a tiny little image of the sun refracted from each element of the lens. Oddly, Photoshop has a filter you can use to add it to images that don't have it. Go figure.I have some UV filters for protection, a polorizer for outdoors and a Cokin P121 grad for landscapes... that last filter is orgasmic :DPirate, I always purchase a good quality filter (usually B+W) to put over my lenses. There are those who argue that putting another piece of glass over your lens will reduce picture quality, but is the best protection against damaging the actual lens: As long as it is a quality filter. A lens hood is good protection, (and I always use those as well) but I'd much rather loose a $150 filter than a $1500
But if you pay $150 for a UV filter, you get ripped big time!i have a haze (UV) filter on all of my lenses. I don't notice much loss at all, and i'd much rather mess up a filter than the precious lens glass.I had substantial lens flare in identical long exposures (+30 secs) at night, though that may have been uniquely to the angle of one street light I was shooting. I took it off and that fixed it.I have a UV filter on every lens. Never had to clean a lens. Never had a front element scratched [had UV's scratched -- replaced them.] Never saw any difference in prints taken with and without the filters. Time period: 50 years or so.When shooting outdoors, I use a polarizer....but it does block a stop of light or more.
A lot of people use UV filters for protection...I would, if I had an expensive lens. I don't know how much light, if any, they block...but I don't think it's very much.
On the other hand, a good solid lens hood offers protection against bumping, scratching, even dropping...unless something small comes directly at the lens.I use a circular polarizer. I also have a UV filter but I don't use it very much anymore. I have noticed that the UV filter produces allot of lens flare in night shots.I rarely use filters. I have 2 IR filters (B+W 092 & B+W 093) and a Circular Polarizer (B+W).
As far as lens protection, I just try to be careful. I suspose that if I had to deal with blowing sand or something like that I would get a UV filter.I only use a UV filter if its crazy windy and i'm worried about soil messing my glass. I do use CPL filters for landscapes, a ND filter for longer exposures, and a gradiant ND filter for landscapes where I have unbalanced lighting from a brighter sky and a dim landscape.Some UV's block up to 7% as well, not just skylights, but I think it's more accurate to think of them 'reflecting' rather than 'blocking'. Cheaper, non-coated UVs are the ones that 'block' the 7%, as they basically just reflect back some of the light. Hoya MC and SMC filters only block 1-2% and 0.3% respectively as the coatings cut down on reflective-ness.
As for me, I always use a UV, but I got a Hoya SMC. Not cheap, but I didn't want to put crap in front of a $500 lens. Ideally I'd shoot without it, but I'm not that confident yet (and especially in crowds and parties I need all the protection I can get from drunk people). I can't tell any difference with or without, even when considering flare issues, so it doesn't hurt.
--IllahPirate, I always purchase a good quality filter (usually B+W) to put over my lenses. There are those who argue that putting another piece of glass over your lens will reduce picture quality, but is the best protection against damaging the actual lens: As long as it is a quality filter. A lens hood is good protection, (and I always use those as well) but I'd much rather loose a $150 filter than a $1500 lens.
JCGuys, the UV filter is nothing but plain old flat ground clear optical glass. It may be possible to measure some light loss through a UV filter but I can guarantee you it is impossible for anyone to see any such loss. 3% or 7% would be way, way, way, way off base. It blocks some invisible UV light simply because all glass does that. It doesn't block very much, actually. The glass from which your lenses are made does the same thing so you can view the UV filter as an additional lens element with no lensatic characteristics if you like. Its purpose is to protect the front lens element, not to filter anything.
Haze filters and skylight filters have a tiny bit of coloration and block a tiny bit of visible light but you can ignore any affect they may have on exposure. Their effect rounds out to zero. It is nowhere near 3% or 7% either.
After running extensive tests on filters some years ago, I concluded that there is no downside at all to using UV filters to protect your lens. Not even a little. A panel of pro photographers couldn't tell the difference between shots made with or without a UV filter in a controlled test. We were never able to produce flare or any loss of contrast for any reason. There just is no visible downside. Every lens I own has a UV filter all the time which is removed only if I want to attach a different filter.
There is some downside to stacking filters so just use them one at a time. UV protection filters are a good idea.UV filters do not block any visible light. So there is no f-stop penalty.
Polarizers block up to 2.5 stops of light (depending on your setting).
Any optical filter blocks UV light (in addition to it's specific function). I.o.w. you need never combine the UV filter with others ('stacking'). In fact, stacking is counter-productive since it only serves to add 2 more refracting surfaces to the lens array: more risk of flare and glare.I wonder if we are using the term flare the wrong way. If you mean the little string of dots of light you see in the frame when your lens is pointed into the sun, that isn't flare. Flare is hard to see. It reduces contrast in a manner similar to pre-exposing film. It is something like a mild optical "fog." You can see it in finished transparencies when it is present, but it is nearly impossible to see in a viewfinder.Kind of off topic, but what is that then? And how can one avoid or reduce it when it happens (besides pointing the camera elsewhere of course :) )? I notice that from time to time with my lenses, with or without the UV filter.
--Illah
um...i'm not sure if i'm on the same page..but wouldn't a lens hood reduce that? I know it does for my 12-24.An $80 - $100 high quality UV filter will still degrade the image some. It may not be noticeble by most people, but the extra glass will do so just the same. 40 years in photography and never a problem with a damaged lens for lack of UV filter.
I know this is the common belief among photographers and it was my belief for about 40 years also. However, it doesn't appear to be true. Our tests were pretty scientific. Our entire panel of pro photographers agreed on the conclusions 100% to a man. The other common belief is that expensive UV filters are better than cheap ones. That isn't true either as it turns out, except that the expensive ones might have better mounting rings (important to be sure.)http://www.thkphoto.com/products/hoya/coatings.html
There's the hoya page that refers to a filter's reflectiveness and thus light transmission. Like you said, it's not like they block any appreciable amount of light, and even when the HMC reflects back 3% or so that's roughly 0.06 stops - more or less immeasurable. I think I read somewhere the standard one can refelct back up to 7% (doesn't say on the site), which is still only 0.14 stops, which may or may not be picked up by an in-camera lightmeter with a 1/3 stop (0.33) step-range.
So I would say that one is right to say *some* light is blocked/refelcted/whatever, but you are also right to say that it makes close to no difference in the real world.
--IllahOther than a circular polarizer, and ND filters I do not use them. The proper Solid lens Hood on the lens ALWAYS!!! Even for indoor shoots.
I do have a high quality UV filter for all my lenses, but I only use them when shooting in bad conditions, high wind, wet weather etc. An $80 - $100 high quality UV filter will still degrade the image some. It may not be noticeble by most people, but the extra glass will do so just the same. 40 years in photography and never a problem with a damaged lens for lack of UV filter.
The camera and lens that got ran over by that truck about 12 yeas ago couldn't have been saved by a filter, trust me. That is another story.If you mean the little string of dots of light you see in the frame when your lens is pointed into the sun, that isn't flare.
Kind of off topic, but what is that then? And how can one avoid or reduce it when it happens (besides pointing the camera elsewhere of course :) )? I notice that from time to time with my lenses, with or without the UV filter.
--IllahDepending on the source, all filters reduce light to a certain degree, UV can be anywhere from 1 - 3% while a skylight for example can go to 7% depending on brand and coatings. I do tend to agree that the light loss is not that significant, and probably not noticable to the average eye. But that does not change the fact that they do offer some loss.#If you have any other info about this subject , Please add it free.# |
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