What really are the effects of UV/protectors on actual image quality?

[mukul_dube]

<p>"Again, if you use one filter and can see a quality drop, IMO you are using a bad filter, or perhaps you have super-human vision..." is objectionable. You are implying that your testing is more reliable than that of others. I have a pair of old eyes which have had cataracts removed. I <em>did</em> see a difference at my last test three years ago.</p>

[ShunCheung]

<p>Mukul, I have made it very clear that people should do their own tests and draw their own conclusions. After all, it is your own photography and you should do whatever you prefer. In your particular case, I think it is apparent that you were using a low-quality or defective filter.</p>

[mukul_dube]

<p>"In your particular case, I think it is apparent that you were using a low-quality or defective filter."</p>

<p>Even if we assume that <em>all</em> the tests I have done since the early 1970s involved bad filters, we are left with several other posts, in this thread and in earlier ones on the subject, in which many people have said that filters do have an undesirable effect. Can it be that they were all using "low-quality or defective" filters?</p>

[andylynn]

Another two cents for not being able to see a difference if it's a good filter. I used to buy less expensive ones and be

careful about bright lights in the frame, but now all the ones I use are either multicoated B+W or the Calumet ones

that are made by B+W. (That's not entirely rational because there are other brands that are good, but I'm sticking with

what I know works.)

[Peter_in_PA]

<blockquote>

<p>Can it be that they were all using "low-quality or defective" filters?</p>

</blockquote>

<p>Perhaps they are, who knows... but let's remember a few things.</p>

<p>1. I think that digital may "mask" some of these "defects" differently than film did.</p>

<p>2, Also, often when people do tests like these, they have a pre-determined bent one way or another for how they are going to turn out. Those who think filters are great are less likely to see problems, I think.</p>

<p>3. And... if you test into a light source, the picture without the filter will win every time (but that's already been discussed and admitted here by those who like to use filters).</p>

<p>My own personal tests (with my D90) were with filters that are "mid-grade". NOT really expensive ones. I only made a handful of images (which I didn't keep I don't think) and found no discernible difference on-screen or in print between images with and without filters (none of my images were shooting into the light). So I don't plan to bother with a test like this again.</p>

[ShunCheung]

<blockquote>

<p>Even if we assume that <em>all</em> the tests I have done since the early 1970s involved bad filters, we are left with several other posts, in this thread and in earlier ones on the subject, in which many people have said that filters do have an undesirable effect. Can it be that they were all using "low-quality or defective" filters?</p>

</blockquote>

<p>Well, this is the internet and a lot of people make a lot of claims. I am a firm believer that "talk is cheap." I would challenge people to go out and make A/B comparison tests and post their results here for everybody to see. Please also specify exactly which filter you use.</p>

<p>I have read many cases where people buy those cheap $15 single-coated filters and they indeed degrade image quality. The lack of multi-coating also introduces flare and ghosting. Some people posted their results here and the problem is obvious.</p>

<p>On that old thread in 2009: <a href="00UNFa">http://www.photo.net/nikon-camera-forum/00UNFa</a>, I explained how my comparison was done and I posted results for everybody to see. But I did not only use one Nikon L37C filter; I stacked three of them together to exaggerate any negative effect.</p>

<P>

<CENTER>

<IMG SRC="http://static.photo.net/attachments/bboard/00U/00UOM5-169641684.jpg">

</CENTER>

</P>

<p>Who is willing to take my challenge?</p>

[tom_mann1]

<p>It is so ridiculously easy for any photographer to perform definitive flare tests on their own particular camera / lens / filter combinations that I'm baffled why endless discussions / debates on this subject continue on. Perform an appropriate test on your own equipment, and you will have a nice quantitative, essentially un-debatable answer about the flare for that particular combo. You then will have the info you need to perform a logical risk-benefit analysis as I suggested earlier in this thread.<br /><br />Go to: http://www.photo.net/nikon-camera-forum/00VRbW . This is a thread on this topic from 2010. Search for my name, "Tom Mann", on that page. This should bring you to my first post in that thread (Jan 8, 2010 at 2:32 PM EST). In that post, I describe how to set up a simple controlled environment to quickly check how much a particular filter degrades the performance of a specific lens (...at a given zoom FL, at a given f-number, at a given off-axis angle, at a given degree of over-exposure, yada, yada). All of these variables may have an effect on the result, some larger, some smaller, so all should, at least initially be observed, and, if necessary, controlled.<br /><br />My test sets up a nearly worst case scenario for producing flare and ghosting by having a single, highly overexposed, off-camera strobe (on manual) pointed directly back at the camera (also on manual) in a dark room. In that thread, I posted one example of one such a test done on a Nikon 28-70/2.8, with and without a UV filter. <br /><br />Above, I mentioned several different parameters that all affect flare and ghosting, both with and without the added filter. In principle, one should investigate many different combinations of FL, f/number, off-axis angle, etc. However, in practice, just a few important combinations of parameters will give you a good overview of that combination of hardware, eg, wide-open and f/11, zoomed all the way in and all the way out, and just one angle, say, with the light source 1/3rd the way out towards the most distant corner of the frame (at each zoom setting). The single most important factor is to keep the degree of overexposure constant, say, 5 stops. If it varies between tests, you will be comparing apples to oranges.<br /><br />Once you have done such tests on your own equipment, you'll be one of the few people with real data on the subject, and you can then safely ignore the religious wars that regularly break out between the "always use one" and "never use one" factions. :-)<br /><br />By the time of the thread I cited, I had done hundreds of tests on various combinations of filters, lenses, f-stop, angle, etc. The results can be summarized as follows: Using high quality filters on high quality modern lenses, with few exceptions, flare and ghosts were always at least 6 to 8 stops below the intensity of the bright point source, and often darker than that. However, with lower quality filters and/or older lenses, the situation was not so good & varied greatly from situation to situation. <br /><br />In the final analysis, these results are entirely in agreement with the conclusions and recommendations of people (such as Shun) who have done similarly well controlled experiments, and who recommend:</p>

<ul>

<li>(a) Running your own tests on your own specific equipment;<br /><br /></li>

<li>(b) If you haven't done such tests, you will generally be safe if you are shooting with high quality, clean filters and lenses, the sun (or a bright light at night) isn't hitting the front element of your lens, and you are not shooting a scene with unusually deep shadows. Certainly, for front lighting or moderate side lighting, it should be completely unnecessary to remove a good quality protective filter on a high quality lens;<br /><br /></li>

<li>© If you are shooting at night with deep shadows and bright sources of light, or if you need to shoot a high contrast scene with the camera pointed into the sun, attempting to pull detail and retain contrast in the shadows, and particularly, when the sun (or lights) are actually included in the image, and the benefits of getting the shot outweigh possible long term cumulative damage from shooting without a filter, take off the filter. In many cases, you may not need to do this, but, since there is essentially no cost to doing so (because of the assumptions), why not.</li>

</ul>

<p> <br />HTH,<br /> <br />Tom M.</p>

 

[robert_hooper1]

<p>I am reluctant to get involved in this discussion because filter vs no filter threads often create such passionate responses from both sides of the issue. Personally, I always use a protective filter on my lenses while shooting, and this practice has saved some pretty expensive glass as a result. But, I buy the best filters available, and to keep up with coating technology, I replace old filters with upgraded filters, when they present themselves on the market. There are some truly fine filters on the market today. I would never consider using a cheap, poorly coated, or non-coated filter. With such a filter, image degradation is guaranteed.</p>

<p><a href="http://www.kenandchristine.com/gallery/1054387">Here is a filter vs no filter test, (not my own), that I think some will find interesting.</a></p>

[ShunCheung]

<blockquote>

<p>I am reluctant to get involved in this discussion because filter vs no filter threads often create such passionate responses from both sides of the issue.</p>

</blockquote>

<p>Robert, I totally understand, but I hope people won't feel it that way. The objective for this forum is to exchange photography knowledge, especially related to using Nikon equipment. It is normal to have difference experience and opinions. And as I mentioned earlier, I encourage people to perform their own A/B tests with and without protective filters. The filters you use and your shooting environment can lead to different results.</p>

<p>I would also like to make it very clear that those who flame others do not belong to this discussion/debate and perhaps don't even belong to this forum. If one cannot disagree with others in a civil mannger, please stay away from this thread (and perhaps other threads as well).</p>

<p>In my case, I tried an extreme situation stacking 3 filters together; in fact, I also tried stacking 4 of them, but all of those are Nikon's own multi-coated fitlers, and I am convinced that under most situations, even stacking 4 Nikon filters will not degrade my images to a degree that I can easily tell by pixel peeping. Therefore, I am totally comfortable with using one protective filter. Today, I sometimes use filter and sometimes don't, depending on the exact shooting situation. Therefore, at least to me, it is totally expected that the OP does not observe any image degradation when using one B+W MC filter. The difference is so tiny that it is beyond our human vision to discern.</p>

<p>One thing I would recommend is using good-quality filters; they should be multi-coated. It does not have to be something really expensive such as certain B+W. Nikon's own filters are good and so are some higher-end Hoya, Tiffen, etc. If your lens is a $200 18-55mm consumer kit zoom, I wouldn't spend $100 to buy an expensive filter for it. You are better off spending more money towards better lenses to begin with.</p>

[Two23]

<p>I have tried nothing but the very, very best MC coated filters from B+W, Hoya, and Nikon. I still can get loss of contrast & saturation from filter use. I also get ghosting with even the best ones at times. It just wasn't worth it to me to chance losing a money shot like that, so I quit using everything but a polarizer (when needed.) Funny thing is that despite shooting daily outdoors in harsh conditions, I've never once damaged a lens because a filter was not there. I have had severe damage doe to a lens because a filter WAS there. Filter shattered and gouged the lens badly. I see filters as more of a danger than a protection. Sure, when shooting in waterfall mist I still use a filter to keep grit from landing on the lens (a polarizer,) but for protecting the lens I use the lens hood and the lens cap. While thin glass filters shatter pretty easy, the plastic lens cap is almost bullet proof. I have lenses made in the 1800s that never had a filter on them, and the glass is still perfect. Just don't think filters do anything at all to protect under normal circumstances. to put a high quality filter on all my good lenses would cost me MORE than a repair anyway. back to the original question, yes I have had images screwed up because I had a filter on, usually due to ghosting. That's the main reason I very rarely use a so-called "protection" filter. the other reason is from my own experience I've had more damage FROM a filter, as have two of my friends. Nothing scratches glass like broken glass.</p>

<p>Kent in SD</p>