CHOLLY Loc: THE FLORIDA PANHANDLE!

When using film, UV filters are essential. :thumbup:

In the case of digital sensors however... not so much.

lighthouse Loc: No Fixed Abode

CHOLLY, you are a curve fitter who massages the data.
Which leads you to tell lies.

wj cody Loc: springfield illinois

i think we disagree again. i've no use for uv filters, only haze filters. if digital imaging devices have problems with ghosting, i'd say the issue lies with the digital imaging device senor and not the filter. perhaps the digital body manufacturers might want to take measures to alleviate that.
otherwise, it's not a matter of film vs digital, but it does regard what the lens perceives, and how it is translated to the film or sensor. and herein may lie the issue. if the sensor is not able to resolve what the lens is transmitting, then i do believe the issue, as noted above, lies with the sensor in the digital imaging device. which is odd, considering digital imaging is constantly touted as superior to film - really strange, that.

CHOLLY Loc: THE FLORIDA PANHANDLE!

Haze filters in fact work by filtering several wavelengths of ultra violet light...the source of haze... and they are in fact, UV filters. ;)

And ghosting is caused by the combination of refraction and diffraction of light as it passes from one medium (the air) to another (the glass of the filter) then another (the air between the filter and the front element of the lens) then another (the glass of the lens). Light bends each and every time it passes from one medium into another... and in optical systems, the result is flare, ghosting, and a reduction in contrast.

Lenses are designed to compensate for diffraction and refraction and most modern lenses have multiple coats of materials designed to either reduce the effect of these physical processes, or the reflection(s) of light through the imaging array that result from them.

Digital Sensors, ESPECIALLY those found on modern DSLR cameras and most point and shoots, have multilayered UV filters built onto them, essentially eliminating the need for an external "haze" filter.

A UV filter on a digital camera is like breasts on a bull; unattractive, unable to function, and completely unnecessary. :lol:

And since UV filters were NOT designed to provide any protection (and hence, are made of thin, cheap glass or plastic) there is ZERO reason to have one, and lots of reasons to avoid them. ;)

mechengvic Loc: SoCalo

Speaking specifically of B+W filters:

"B+W uses Schott German optical glass..."

http://www.vistek.ca/buyingguides/filters/manufacturers.aspx

"The optical glass most often used for making instrument lenses is Schott BK-7 (or the equivalent from other makers), a very finely made borosilicate crown glass."

http://en.wikipedia.org/wiki/Borosilicate_glass

"Borosilicate glass is about 2,3 x the hardness of plate glass. On the Moh's scale plate glass has a hardness value of about 5,7. Glass is harder than most grades of unhardened steel. "

http://www.roymech.co.uk/Useful_Tables/Matter/Glass.html

"Each filter is interferometrically tested for plane parallelism which is the same process that is routinely used by the world’s leading lens makers. B+W has also developed a line of filters that have a Multi Resistant Coating (MRC) that eliminates surface reflections on both sides of the filter. This maximizes light transmission and offers an extraordinary hardness that minimizes scratching and facilitates cleaning as it is water and dirt repelling."

http://www.vistek.ca/buyingguides/filters/manufacturers.aspx

Higher quality filters (I will now speak in general terms, just like ALL of your comments on the matter) are made with the same glass that is used in lens manufacture and made to the same specifications. If you continue to read the links you will see I'm right. (It's ok, I know you won't)

So, while your comments may be correct when you speak of the properties of refraction and diffraction, and haze and UV, and other assorted phenomenon, your generic statements about filters and their lack of quality are severely biased and not based in fact. The fact is that the high quality filters that you speak so poorly of, are made to the exact same standards as the individual elements in the lenses that you praise. That my captain, is a contradiction borne of opposing sentiments, and what we call in the scientific world an opinion. The beauty of them is that you have every right to have one. But passing off your opinion as fact???? Not so much.

lighthouse Loc: No Fixed Abode

Very good post Victor.
Such a pity all the facts presented in it will be dismissed and ignored.

mechengvic Loc: SoCalo

Thanks, In a way I'm glad CHOLLY is so adamant in his opinion because it has made me do more research and I'm learning all kinds of cool things!

CHOLLY Loc: THE FLORIDA PANHANDLE!

Victor, while I do recognize the basis of your argument, I must pick one SERIOUSLY LAAAAARRRRRRRRGGGGGGGEEEE nit from your comment:



I have REPEATEDLY referred to cheap UV lenses and so-called "protective" filters with thin glass.

As you should know, ONE of the things any good researcher has to deliberately avoid during the course of data analysis is allowing (a) personal bias to cause them to either ignore unwanted results or in this case, what has been actually stated by me on this subject REPEATEDLY.

And while you may be correct about high quality, expensive filters, it is my considered opinion that the overwhelming majority of the people who responded positively about filter use for protection in this thread DO NOT EMPLOY SUCH HIGH QUALITY FILTERS. Rather, they use the junk and garbage given to them in package deals or sold to them by salesmen padding their quota.

It is a FACT that even those VERY EXPENSIVE high end filters you reference are STILL by necessity, thinner than the front element of almost all lenses, and in fact, ANYTHING capable of damaging said lenses WILL NOT BE STOPPED BY A FILTER.

That, sir, is NOT an opinion, but rather is fact in deed. ;)

And as you know, eventually people decide that a preponderance of evidence and repeatable results move ideas from "theory" to "law". That's where I am with this filter issue, having been a serious photographer since 1978 and a dedicated filter user with film, but discovering that UV filters were not necessary for digital imaging and that "protective" filters do NOT protect any better than a lens hood/cap and proper precautions.

I have also discovered that filters DO degrade image quality. That is in FACT, what they are designed to do; FILTER.

So it's REALLY cool that you are doing the research. Just be sure you analyze the data with an open mind. ;)

wj cody Loc: springfield illinois

having, for the last 60 years, used filters on lenses from 35mm to 8x10 view camera lenses, i have never had the problems you seem to experience. having traveled the world, in peace and war time, in places safe and not so much, neither i nor any of my compatriots has ever had any issue with their haze/uv filters. so, i guess we must be a very fortunate group.

tradergeorge Loc: Newport, Kentucky

Having followed this whole thread, and having traveled as wide, if not as long as you, I tend to agree with you. What we have is the THEORETICAL possible effects of these filters vs what people have encountered in real life over long experience. The argument is put forth that anything that would damage a lens would destroy these filters. This is a specious and ludicrous argument. Most protective devices are not meant to ward off the disastrous, but rather the long erosion over time. A water droplet is no immediate danger to a rock, but over time can carve a canyon. I dare say a piece of "Saran Wrap", as was put forth, would ward off this damage for a long time if properly placed....I use the extreme to illustrate the normal....The point is that a filter WILL protect the lens and coatings from everyday wear and tear, and absorbs a lot that would be detrimental.

mechengvic Loc: SoCalo

As I have stated on previous threads covering the same subject, threads started by neither of us... :roll: , I respect your opinions and continue to do so. And I agree with what you say, being a technically minded person myself, you just don't argue with the physics.

But on your comment I quoted it reads like you're talking about all filters and in looking back to everybody else's comments, they mostly refer to high quality filters...

The truth is I appreciate the opportunity to hash these topics out because like I said, I am learning a lot!

tradergeorge Loc: Newport, Kentucky

You want to talk physics? If so, you would have to agree that the lowest quality filter someone could put on a lens would slow down the impact force of something, say a rock, that impacted it. If this impact was enough to say, crack it, but not penetrate, it would have done its job of protecting the front
element of the lens. This is not even going to the FACT that it being a tight cover, it would keep out dirt, grit, etc, and absorb all the effects they would inflict....The facts of physics say that it is a worthwhile endeavor, notwithstanding the specious arguments made here against them......I have been using them for almost 50 years and have not noticed any detrimental effects on my photos. I will not "Appeal to Authority" by stating with seeming sage knowledge that everyone I have known over the years have used them, but it remains that a lot of smart people use them religiously...

mechengvic Loc: SoCalo

I don't argue with those physics either that's why I DO use filters on my lenses... :mrgreen:

rook2c4 Loc: Philadelphia, PA USA

From my experience, the front element and its coatings are far more resistant to scratches than some people make them out to be. I have lenses that I've used for many years (and used by my father before that), and they are no signs of scratches or other forms of damage on these lenses. I think most scratched lenses are the result of either reckless abuse or cleaning them with not-so-clean cloths that contain sand particles etc. When I am using my camera, I take extra care that I don't slam the camera into hard objects and that absolutely nothing touches the front element. Naturally if I were out shooting in a desert sand storm or in a dense jungle, I'd want some kind of protective filter. But in most other situations, I just don't find it to be a great necessity.

CHOLLY Loc: THE FLORIDA PANHANDLE!

My daddy was a country boy but one of the smartest people I ever knew. He told me when I was 6 years old "Boy, try to learn at least ONE new thing every single day."

When I turned 12 it was "Boy, try to learn at least TWO new things every single day..."

There is NO joy like the joy of discovery. :thumbup: