Just like the old “ film compared to digital” or the “ Nikon compared to Canon” debates, lens filters frequently create endless discussions on the Internet. Many people argue that one should never use defensive filters, since it is another piece of cup in front of the lens that reduces quality and emphasizes other optical difficulties such as ghosting / flare, while some argue that filters make it easier to secure the front element of the lens plus make it easier to clean that component. I personally have been recommending use of defensive filters for years, as long as they are of top quality. The filters that I have been making use of do not seem to affect the resolving strength of lenses they are mounted on plus mostly do not seem to heavily impact ghosting / flare either. Getting spent the last couple of weeks in a laboratory testing many lenses, I pondered if I could actually measure the quality of a lens with and without the filter. I recently purchased an used zoom lens that came with a crappy plastic-type filter, so I decided to run 2 separate scenarios – one with no filter, one with a high quality B+W filter (more on B+W items below) and one with a cheap plastic-type material filter. The results of the study turned out very interesting!

Armed with the particular Imatest software, I first scored the sharpness of the Nikon 70-200mm f/2. 8G VR II zoom lens, which is usually my reference zoom lens for telephoto sharpness. The central length was roughly 150mm as well as the aperture was set to f/5. six, which is the sweet spot from the lens. I then mounted a top quality 77mm filter by B+W plus did it again. Here is the result of Imatest measurements:

If you look at the above charts, they will look pretty much identical. There is a minor variance in numbers, but that’ s expected when going in one image to another – Imatest ratings can be slightly different even when you usually do not change anything. Judging from the over case, using a top quality filter does not affect the resolving energy of the lens at all . This is an excellent scientific proof for those that claim that just about all protective filters decrease resolution. Misconception debunked!

Let’ ersus now move to a second case situation. What if you were to use a cheap, lower-quality filter? As I have mentioned above, Recently i purchased an used lens – the particular Nikon 55mm f/2. 8 AIS that came with a cheap plastic filtration system (more on this project on an individual post). So it was a perfect situation scenario to see what the resolution would certainly look like with and without the inexpensive filter. Let’ s take a look at exactly what Imatest measured (shot wide open with f/2. 8):

Now this is an interesting outcome. Looks like using a cheap filter will indeed affect lens resolution. There is certainly about a 10% drop in fixing power across the frame! And I believe, if I were to take this lens plus shoot it against the sun, this specific filter would surely make spirits and flares appear worse.

Summary

It was an interesting study, because it proved that will high quality filters have no affect in any way on lens resolution. If you bear them clean and in good shape, they also do not impact the ghosting and flare properties from the lens. You might see a little more ghosting/flare on some filters, but if this annoys you, simply dismount the particular filter and put it back on when you are done shooting against the sun. It is far from like you would shoot against light every day right? From my encounter, the multi-coated B+W filters have zero affect on ghosting/flare, so I certainly not bother to dismount filters whenever shooting against the sun.

At the same time, make sure that you are not using inexpensive, low-quality filters. As you can see from this post, cheap filters do indeed impact the resolution of the lens and they may seriously affect the ghosting and sparkle properties of the lens. I have observed reduced contrast and really nasty ghosting / flare with cheap filter systems before, so I have learned my training on not buying those.

Filter Recommendations

If you are looking for recommendations on what filter systems to use, I have been a huge fan associated with B+W filter systems . All filters that I purchase (neutral density, polarizing, clear) are usually B+W brand. They are made of top quality glass and they are manufactured in Germany – so you can expect the best performance from their website. A key feature you should always look for within high quality filters is MRC, which usually stands for “ Multi-resistant coating”. Regardless of what brand you go with, always make sure that the particular filter comes with this particular coating. This particular anti-reflection coating is the key to getting little if any additional ghosting/flare in your photos.

The one I usually get intended for pro-grade lenses is the B+W 77mm UV Haze MRC 010M Filter . With $72, it is not a cheap filter, however it is worth it as you can see from the over test results. I have been using this specific filter for several years now. The last thing you should do is mount a $10 filtration system on a lens worth hundreds, otherwise thousands of dollars! There is a new XS-Pro version of the above filter, which is more expensive at $87 (adds nano coating), but I doubt it will make a huge difference. I have bought a couple of those recently and I are not able to say that they are better in any way. Remember that UV protection is not needed upon digital cameras, because sensors have a built/in UV filter. So when you install an UV filter on a contemporary DSLR, it simply acts as a crystal clear filter. So either buy an ULTRAVIOLET or a clear filter – each should be as good.

Certainly, you have to choose the right filter size for every lens you own. The above links are usually for lenses with 77mm posts, so if you need another size, merely type something like “ B+W 67mm MRC” in the search box in B& H and you will find an obvious filter quickly. You will see that as the dimension of the filter get smaller, the cost of the filter is reduced too. For example , a 67mm B+W MRC filter costs around $43, that is significantly cheaper than the 77mm filtration system.

If you do not know a lot about filters, I wrote an in depth article on using lens filters . Provide a read – it is fairly extensive and covers all of the aforementioned filters.