Bill58
Native Texan
pesphoto said:
Easy on the lens cleaning--you (and your coating) would be better off just blowing off the stuff that often gets on it unless you touch or drool on it.
Bill
To Filter or NOT to Filter - That is the question
- Thread starter dcsang
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Easy on the lens cleaning--you (and your coating) would be better off just blowing off the stuff that often gets on it unless you touch or drool on it.
Bill
MacDaddy
Certified Machead
Ahhh! The voice of wisdom! thanks Frank!
Ahhh! The voice of wisdom! thanks Frank!
My $.02— While trying to go down a slippery, wet set of rocks to photograph a dam (dam photo op!) two years ago, I slipped on the rocks and banged the end of a $1200 lens on the rocks—HARD. When I worked up the courage to look at it, the only damage was the badly cracked 77mm polarizer FILTER on the end of the lens. I keep it as a reminder what I need to do to protect my lenses! Your mileage may vary! 8o)
Ahhh! The voice of wisdom! thanks Frank!
My $.02— While trying to go down a slippery, wet set of rocks to photograph a dam (dam photo op!) two years ago, I slipped on the rocks and banged the end of a $1200 lens on the rocks—HARD. When I worked up the courage to look at it, the only damage was the badly cracked 77mm polarizer FILTER on the end of the lens. I keep it as a reminder what I need to do to protect my lenses! Your mileage may vary! 8o)
jaapv
RFF Sponsoring Member.
MacDaddy said:
Last time I did something like that the lens was undamaged but I sprained my ankle. Would a filter have helped prevent that? 😉 😀
I forgot to metion, the lens that wears a UV filter quite often is my Elmarit 90 2.8. It is quite prone to UV flare, as it is the only current Leica lens without kitted elements, so there is no Absorban layer, thus no UV protection...
narsuitus
Well-known
Only use a protective filter when I am shooting in a hostile environment.
FPjohn
Well-known
UV, yellow, no obsessive...
UV, yellow, no obsessive...
Hello:
I avoid obsessive cleaning of lens surfaces and filters which are always present as a yellow or UV. Minolta antireflection uv filters are nice when you find them.
yours
Frank
UV, yellow, no obsessive...
Hello:
I avoid obsessive cleaning of lens surfaces and filters which are always present as a yellow or UV. Minolta antireflection uv filters are nice when you find them.
yours
Frank
Rafael
Mandlerian
dcsang said:
That's always been my reasoning.
jaapv
RFF Sponsoring Member.
First: I am not against the use of protection filters, nobody should be, as there are many circumstances where it is wise to do so and everybody is totally capable to judge the way in which he/she wants to use his/her equipment. Some people wear away the paint on their car by polishing it every day, others never even wash it, causing it to corrode away. Both are equally wrong 😉
I already posted part of this some time ago; it has been expanded.I put it into another thread first, but moved it here.
Any lens has internal flare because of reflections. The better the coatings of the lens, the smaller the intensity of the reflections and with that the degradation of the (theoretically possible) image. One would think that the addition of two reflective surfaces to an optical system with, say, six elements is not that bad, but unfortunately the number of reflections is governed by one of the optical laws of the 17th century Dutch astronomer/physicist Snellius which is R=N(N-1)/2 where N is the number of air/glass surfaces. So a Summicron with 6 elements and 12 surfaces has 66 [ 12(12-1)/2 = 132/2 = 66 ] reflections. If you add 2 surfaces you will have 91 reflections [14(14-1)/2 = 182/2 = 91 ]!Just try stacking filters and adding four or even six surfaces in this formula. Depending on the situation this may really influence contrast. Lenses with more elements and/or less effective coatings will be even more at risk. This is about the type of flare called veil, which usually can only be seen in direct comparison, as it is an overall degradation of the image. The type of flare that produces "UFO's" or diaphragm reflections, is of course well known, but it follows the same laws. Then there is direct reflection of the filter called ghosting, which will result in highlights being reproduced once at a certain distance of the original image, often upsidedown. We had some beautiful examples of that in the RD1 forum a while ago with a Summicron 35 and Hoya filter. Not the worst combo by any means. All these types of flare will be reduced by modern coatings and will only be apparent in adverse circumstances, that is high contrast situations and photographing against the light. It is wise to take a protective filter off any lens in those conditions.
The next problem is especially with wide-angle lenses: The light travelling at right-angles to the filter will have a considerably smaller distance to go through the filter than light striking it at an acute angle, resulting in a difference in refraction and with that in loss of sharpness. It is a widespread misconception that a planparallel surface is not a lens. This is incorrect. It can easily be demonstrated by standing at the middle of the long side of a swimmingpool and looking in. If you have removed your kids from the water and there is no wind, this will form an ideally flat surface, comparable, even superior to, the filter in front of your lens. Now look at the bottom. Instead of the rectangle it is, you will see it distorted into a barrel shape. That is caused by the centric perspective of your eyes turning it into the equivalent of a concave lens. The same thing, and similar effects, happen with anything photographed at distances closer than infinity through a filter which is exactly what one is doing with wideangle lenses. It interferes with the rectilinear rendition your lens is trying to achieve, throw the corrections designed into the lens out and will introduce chromatic aberration as well, as the distortion is wavelength dependent.
Do lens manufacturers do something about this? Mostly the effects are small and hardly noticable, so only some of the very best -and expensive- lenses have been designed with this aspect in mind. A few Leica R wideangles have a built-in filter turret and no filter thread, enabling the designer to compensate fully but the most interesting examples are, of all things, Leica's top tele range. Take for instance the 280 apo 4.0. A fully diffraction corrected lens. Any interference with the path of the light would throw the correction out. So Leica made the front element the least expensive and a fixed protective one, fully correcting for it in the design and added a filter-holder at the rear of the optical system, which must hold a filter - any filter but normally a clear one, at all times to maintain the full correction of the lens.
In my opinion and experience a lens hood and lens-cap when not in use offer far more protection than any filter without having the chance of degrading the image and as a last resort there is always insurance. But, in the end, if one feels more comfortable with a "protective" filter and is happy with the results, what reason would there be to do otherwise? As long as one is aware of the theoretical considerations, that , as always, must be subject to the final result. And remove the filter and use a lens-hood in any high-contrast situation.
The reason for using a lenshood, apart from the obvious advantage of reducing the amount of light that shouldn't be entering the lens in the first place, is that it cuts off a proportion of the so-called "skew rays", that is rays that enter the lens at an oblique angle to the optical axis. Those are the most difficult ones for an optical designer to compensate for and thus the hardest for the lens to handle. Using a lens hood will improve lens quality in all cases, even when one thinks it is not needed.
Just for completeness sake, a filter for UV protection is not needed with nearly any post-1960 lens, as the lens kit in the kitted elements will provide adequate UV protection. Except the 2.8-90 Elmarit, which has no kitted element and is protected by coatings only. That one will benefit from a UV filter in the mountains and on the beach, as may some lenses from other makes that I do not know about.
I already posted part of this some time ago; it has been expanded.I put it into another thread first, but moved it here.
Any lens has internal flare because of reflections. The better the coatings of the lens, the smaller the intensity of the reflections and with that the degradation of the (theoretically possible) image. One would think that the addition of two reflective surfaces to an optical system with, say, six elements is not that bad, but unfortunately the number of reflections is governed by one of the optical laws of the 17th century Dutch astronomer/physicist Snellius which is R=N(N-1)/2 where N is the number of air/glass surfaces. So a Summicron with 6 elements and 12 surfaces has 66 [ 12(12-1)/2 = 132/2 = 66 ] reflections. If you add 2 surfaces you will have 91 reflections [14(14-1)/2 = 182/2 = 91 ]!Just try stacking filters and adding four or even six surfaces in this formula. Depending on the situation this may really influence contrast. Lenses with more elements and/or less effective coatings will be even more at risk. This is about the type of flare called veil, which usually can only be seen in direct comparison, as it is an overall degradation of the image. The type of flare that produces "UFO's" or diaphragm reflections, is of course well known, but it follows the same laws. Then there is direct reflection of the filter called ghosting, which will result in highlights being reproduced once at a certain distance of the original image, often upsidedown. We had some beautiful examples of that in the RD1 forum a while ago with a Summicron 35 and Hoya filter. Not the worst combo by any means. All these types of flare will be reduced by modern coatings and will only be apparent in adverse circumstances, that is high contrast situations and photographing against the light. It is wise to take a protective filter off any lens in those conditions.
The next problem is especially with wide-angle lenses: The light travelling at right-angles to the filter will have a considerably smaller distance to go through the filter than light striking it at an acute angle, resulting in a difference in refraction and with that in loss of sharpness. It is a widespread misconception that a planparallel surface is not a lens. This is incorrect. It can easily be demonstrated by standing at the middle of the long side of a swimmingpool and looking in. If you have removed your kids from the water and there is no wind, this will form an ideally flat surface, comparable, even superior to, the filter in front of your lens. Now look at the bottom. Instead of the rectangle it is, you will see it distorted into a barrel shape. That is caused by the centric perspective of your eyes turning it into the equivalent of a concave lens. The same thing, and similar effects, happen with anything photographed at distances closer than infinity through a filter which is exactly what one is doing with wideangle lenses. It interferes with the rectilinear rendition your lens is trying to achieve, throw the corrections designed into the lens out and will introduce chromatic aberration as well, as the distortion is wavelength dependent.
Do lens manufacturers do something about this? Mostly the effects are small and hardly noticable, so only some of the very best -and expensive- lenses have been designed with this aspect in mind. A few Leica R wideangles have a built-in filter turret and no filter thread, enabling the designer to compensate fully but the most interesting examples are, of all things, Leica's top tele range. Take for instance the 280 apo 4.0. A fully diffraction corrected lens. Any interference with the path of the light would throw the correction out. So Leica made the front element the least expensive and a fixed protective one, fully correcting for it in the design and added a filter-holder at the rear of the optical system, which must hold a filter - any filter but normally a clear one, at all times to maintain the full correction of the lens.
In my opinion and experience a lens hood and lens-cap when not in use offer far more protection than any filter without having the chance of degrading the image and as a last resort there is always insurance. But, in the end, if one feels more comfortable with a "protective" filter and is happy with the results, what reason would there be to do otherwise? As long as one is aware of the theoretical considerations, that , as always, must be subject to the final result. And remove the filter and use a lens-hood in any high-contrast situation.
The reason for using a lenshood, apart from the obvious advantage of reducing the amount of light that shouldn't be entering the lens in the first place, is that it cuts off a proportion of the so-called "skew rays", that is rays that enter the lens at an oblique angle to the optical axis. Those are the most difficult ones for an optical designer to compensate for and thus the hardest for the lens to handle. Using a lens hood will improve lens quality in all cases, even when one thinks it is not needed.
Just for completeness sake, a filter for UV protection is not needed with nearly any post-1960 lens, as the lens kit in the kitted elements will provide adequate UV protection. Except the 2.8-90 Elmarit, which has no kitted element and is protected by coatings only. That one will benefit from a UV filter in the mountains and on the beach, as may some lenses from other makes that I do not know about.
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rxmd
May contain traces of nut
Err... the difference obviously is that in the pool there is no second air surface that diffracts the light back in the original direction, so the analogy is somewhat flawed.
If you put a glass plate on top of an empty pool I don't think you'll notice much displacement. Theoretically there is some, but if the glass is reasonably thin and the viewing angle isn't too extreme the effect won't be very noticeable to the naked eye, especially in comparison to other factors such as dirt on the glass. Or if you have vertically-opening windows (in the Netherlands they are quite common 😉), open them halfway, look at a vertical object and see if there is much displacement.
One would notice the effect probably if one had a habit of photographing test charts with Summicron ASPHs, but personally there are other, more limiting factors in the overall quality of my pictures, most of which are located between my ears.
I do appreciate plain glass ("UV") filters since a friend accidentally dropped his Kiev 88 with my Mir-36 wideangle lens while doing field research in Egypt. The usual argument is that a hood fulfils the same function, but obviously you can't always have a hood on your camera, unless you're seriously into pinhole photography.
Philipp
jaapv
RFF Sponsoring Member.
rxmd said:
The second surface does bend your universe back into shape, sure, otherwise a filter would produce barrelshaped distortion as well. But my experiment does prove, and that is what it is meant to do, that a flat surface has a very clear effect on the path of the light and is not "optically inert". Your welcome clarification emphasizes the reason why the thickness of the filter is important too. As for the last sentence, I tend to get lenshoods that are adapted to the lens that I use.😉
And may I quote myself?
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dll927
Well-known
Each of my Leica lenses sports a 39mm Leitz filter. Do you suppose they would ever have marketed those filters if they thought they would degrade images?
CraigK
Established
Every hunting season I get whacked in the eye with a damn willow branch at least once a day as I walk through the grouse woods.
After one particularly unpleasant visit to the doctor for some ointment and an eye patch that I had to wear for a week, I bought a pair of shooting glasses. I never go into the woods without them now.
As a pro, my photo gear is in and out of bags, cases and pockets constantly, and I am very often all thumbs when it comes to putting lenses on and off bodies in a hurry.
I put UV filters on all my 35 and medium format lenses and change them when they begin to show the wear and tear I subject them to.
On the other hand, my large format work is done at my leisure, no quick changes during a press conference, no shooting from a dangling crane in a steel mill, just me, mother nature and some FP4.
So the lenses go commando.
jaapv
RFF Sponsoring Member.
Err...yes, as customers want to buy them, they would provide the best they could find at a considerably higher price than B&W who make them.dll927 said:
colyn
ישו משיח
I never use a UV filter..in fact I seldom use filters at all.
If I need to enhance clouds in a blue sky I'll use a yellow filter or polarizing filter to eliminate glare.
If I need to enhance clouds in a blue sky I'll use a yellow filter or polarizing filter to eliminate glare.
dogbunny
Registered Boozer
Hi,
I'm also trying to learn a bit more about filter use. I never realized this was such a heated topic. My major interest is in photo results.
I hope you don't mind, but I attached this photo I took a while ago climbing Mt. Fuji. I didn't use any filters at all. How could a filter have helped me here? I don't mean to sound like a total noob, but I am 🙂 It was a foggy day, I guess I was hoping my photo could have a bit more clarity and less glare.
If any of you could point me toward some kind of filter tutorial, that would be cool too. Thanks.
I'm also trying to learn a bit more about filter use. I never realized this was such a heated topic. My major interest is in photo results.
I hope you don't mind, but I attached this photo I took a while ago climbing Mt. Fuji. I didn't use any filters at all. How could a filter have helped me here? I don't mean to sound like a total noob, but I am 🙂 It was a foggy day, I guess I was hoping my photo could have a bit more clarity and less glare.
If any of you could point me toward some kind of filter tutorial, that would be cool too. Thanks.
Attachments
iml
Well-known
I shoot by the sea a lot. Not having UV filters is a recipe for sand, grit, and salt blowing onto the lens front element, so I always use them.
Ian
Ian
jaapv
RFF Sponsoring Member.
dogbunny said:
That is a photo of a desperate photographic situation. If any filter would have helped, there must have been some sunlight behind that mist. In that case a polfilter-maybe. But in Black and White, a red filter would be great here.
R
Robert
Guest
I have a skylight filter on all my lens . Any problems with lens detail would be insignificiant if the lens got scraped or damaged. A filter can be changed a lot easier than the lens.
Nachkebia
Well-known
Yesterday I bought 39 and 46 Leica UV filters to project my lenses, I can not afford sctraching my lovely 50 lux asph 😀
jan normandale
Film is the other way
Dave I didn't vote because like Rick Moranis said in "Spaceballs" .. "smoke 'em if you got 'em" Same for me, if I got 'em I use 'em. If I don't, I don't.
dspeltz
Portsmouth, NH USA
Now we have to add IR protection filters for M8 users.