UV filters on a Canon 100mm Macro

[William Michael]

<p>JDM: No not Irony - but an honest comment.<br>

Sarah: is smokin' hot. I wanna rummage through the disposal bin.</p>

<p>The end.</p>

 

[jeff_livacich]

<p>Whew!<br /> Wow...well, I'll just say this. I have never normally used filters for protection. I don't particularly want that extra piece of glass on the front. But I doubt that a <em>high quality</em> multicoated filter will have much effect on the final image in most cases; it would probably be indiscernable in most cases and might cause some extra flare in some situations. I shoot with the sun in the frame a lot and prefer to not have one on. I do wonder if the flat surface might reflect directly back into the lens more than a curved one.<br>

<br /> But I think if it gives peace of mind, or you think damage could happen, use one. Most people using B+W film use filters a lot and don't sweat it.<br /> Hoya has come out with a protective filter of tempered glass which is highly resistant to impact, so should reduce the likelihood of a shattered filter scratching the glass.<br /> <br /> I consider a protective filter absolutely necessary when the wind's blowing sand at me in the desert, and salt spray and/or sand at me at the ocean. I use one in wet weather. I also used one recently while photographing under a cedar tree that was dropping lots of sticky pollen.<br /> The worst for me though was when I was taking pictures at an air show where I was positioned at the end of the runway where the planes were taxiing into position to take off. Lots of prop/jet wash when they revved. I positioned myself to the side some to avoid it, but didn't consider that they might rev while turning onto the runway. I got blasted by a P-51's prop wash and I did not have a filter on the lens. I covered the lens with my hand as soon as I heard the engine rev up and avoided damage to the glass, but had to clean and relube the focusing helicoid when I got home. I was picking grit out of my right ear for days. I can definitely state that if you're a gearhead, until you've been right behind a Merlin engine in full song you haven't lived.</p>

<p>So, I say use one for sure when the lens could be damaged. It makes no sense to worry about filters degrading an image while allowing a bunch of crud to get on your lens.<br /> The rest of the time do what you want. I prefer to not use them. If you puts your mind at ease or simplifies things or whatever, use them. If you're concerned about the filters' effect, do some tests. You will then know what's best for you in any given situation.</p>

[peter_kervarec]

<p>A good quality lens hood will suffice, even excel and will give more protection than a filter can. The lens hood will absorb much more shock than a filter . Long narrow objects will also be prevented from hitting the front element by the hood. If I am paying thousands of dollars for super sharp lenses , I am certainly not putting images through glass that I would get from consumer grade lenses. But then I love sharp so I may be over the top !</p>

[danielleetaylor]

<p><em>A good quality lens hood will suffice, even excel and will give more protection than a filter can. </em></p>

<p>Hoods do not stop wind driven sand or rain, splashed water, or saltwater spray from crashing waves. Nor can they completely prevent head on impacts.</p>

<p><em>If I am paying thousands of dollars for super sharp lenses , I am certainly not putting images through glass that I would get from consumer grade lenses. But then I love sharp so I may be over the top !</em></p>

<p>Tell me please which side was shot through a filter.</p><div></div>

[peter_kervarec]

 

<p><em>A good quality lens hood will suffice, even excel and will give more protection than a filter can. </em></p>

<blockquote>

<p>Hoods do not stop wind driven sand or rain, splashed water, or saltwater spray from crashing waves. Nor can they completely prevent head on impacts.<br>

Of course you are right Daniel but commonsense must be used as well. I was referring to a lens hood and impacts such as dropping or hitting, the others are obvious if you are in blowing sand or salt spray etc.</p>

</blockquote>

<p><em>If I am paying thousands of dollars for super sharp lenses , I am certainly not putting images through glass that I would get from consumer grade lenses. But then I love sharp so I may be over the top !</em></p>

<blockquote>

<p>Tell me please which side was shot through a filter.<br>

Both look like they were taken with a poor quality lens.</p>

</blockquote>

 

[jeff_livacich]

<p>I would say the left was shot through a filter.</p>

[danielleetaylor]

<p><em>Both look like they were taken with a poor quality lens.</em></p>

<p>LOL! I don't think you have a clue what you're looking at here. These are 100% crops from a pair of test shots made with a Canon 7D and a Canon 85 f/1.8 USM at f/5.6 (tripod mounted, MLU, LiveView focusing). The test target was a subset of a Rand McNally world map. At the distance the target was shot printing patterns and ink bleed are clearly visible. At an average screen resolution this is like printing the shot to over 60".</p>

<p>More telling, you haven't a clue which side was shot through a Hoya S-HMC filter and which was not.</p>

<p>Here's another similar test for detail retention with a 300 f/4L IS. Target magnification is higher than in the 85mm test, and again we see patterns from the printing process and ink bleed. The slight inconsistency of black ink coverage in this target is also apparent. (Good luck finding a sensor/lens combo in small format to yield more detail with the same target magnification.) Please tell me which side was shot through a filter.</p><div></div>

[danielleetaylor]

<p>Jeff - I'll reveal both after Peter guesses (if he cares to).</p>

[sarah_fox]

 

<blockquote>

<p>Jeff - I'll reveal both after Peter guesses (if he cares to).</p>

</blockquote>

 

<p>[chuckling] OK, I get to guess too. My two coin flips say the filters are both on the right-side images. I figure I have a 25% chance of being correct.</p>

<p>Seriously, it would be fun to have a "Find the Filter Challenge," in which enough pairs choices are put up on a web page to determine a correct response probability. A simple "signs test" could be applied to assess whether the responses were significantly different from random, and scores could be plotted in a histogram to keep track of how well or badly everyone scored. I suppose to be fair to the participants, a variety of shooting conditions would need to be represented, including the more challenging ones (like shooting into lights).</p>

<p>It's quite far from being the first and foremost priority on my list of things to do, but it sure would be a smart thing for the various filter merchants (e.g. filterhouse and 2filter) to develop.</p>

[danielleetaylor]

<p>It has been long enough that I'll post the answers: filter was on the left in the first pair, and on the right in the second. The second one is a good one to throw people because the filtered shot is actually the very slightest bit sharper for some reason. (Not likely the filter, just some variable in the whole process.)</p>

<p>I agree with you about the Find the Filter Challenge, but it would probably only benefit B+W and Hoya, and then only their higher tiers of filters.</p>

[JDMvW]

<p>Well, later on, I am really pleased that this didn't come down to my having to post the Tru-Scru again. By the end here, there is almost civility. eh?</p>