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02-18-2016, 02:05 AM   #1
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I took a knife to the front element of my lens!

I wanted to see just how tough the coatings are on my 18-50 kit lens, so I took a knife to it and also used a paint marker. I was surprised that there was no damage. This is why I do not worry about having a protective filter on all my glass.

Take a look at the video I made showing the abuse:


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02-18-2016, 02:30 AM - 1 Like   #2
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Good stuff. Selling "protective" filters is one of the biggest scams in photography.
02-18-2016, 05:23 AM   #3
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Good! you would have taken a pic with the lens, while still the smiley marks on the lens. Would love to see the photo it takes :-)
02-18-2016, 05:35 AM   #4
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QuoteOriginally posted by Sandy Hancock Quote
Good stuff. Selling "protective" filters is one of the biggest scams in photography.
Uh huh. Pick up a 50mm f/1.2 lens circa 1980s 1970s (if you don't have one) and repeat the same test.

02-18-2016, 05:43 AM   #5
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QuoteOriginally posted by Sandy Hancock Quote
Selling "protective" filters is one of the biggest scams in photography.
All I know is that when my 18-250 took a hit, the filter was smashed and the front element was not. I don't want to think about what would have happened if the filter had not been on. It may be a scam, but my experience tells me it can help. I am not a poor man, but I don't want to spend hundreds to replace a lens when I could be spending tens to replace a filter.
02-18-2016, 06:14 AM - 1 Like   #6
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QuoteOriginally posted by Albert Siegel Quote
I wanted to see just how tough the coatings are on my 18-50 kit lens, so I took a knife to it and also used a paint marker. I was surprised that there was no damage. This is why I do not worry about having a protective filter on all my glass.

Take a look at the video I made showing the abuse
It's an interesting test and it does show that the coatings are tough... However, moving the knife blade side to side on a smooth glass surface isn't a particularly stringent test, with all due respect. I have personal experience, some years back, of scratching the front element of a lens by wiping it clean while at a windy beach to get rid of salt water deposits. Grains of sand or grit can *definitely* scratch the coating of a lens when pulled across it with a microfibre cloth (you might like to try that on the lens if you don't mind the potential damage). And that's why, when conditions warrant it, I *do* use a protective filter on all my glass. I'd rather accept a minor risk of degradation of IQ in those situations than risk another scratched lens...
02-18-2016, 06:26 AM   #7
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Well. I dont put a filter on our DA 35 2.4 which is on my wife's camera all the time. I did put a hood on it so I thought it was protected. She still managed to scratch it. But it hasn't affected IQ at all.
02-18-2016, 06:29 AM   #8
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Give it a real test......put a pea sized dab of peanut butter on the front element and let a hungry squirrel give it a shot.....




Good luck!

02-18-2016, 07:13 AM   #9
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Steel is rarely harder than glass, so it will not scratch it.

Small little tiny f0cking stone, on the other hand... can do the job pretty well...
02-18-2016, 08:27 AM   #10
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QuoteOriginally posted by tgchan Quote
Steel is rarely harder than glass, so it will not scratch it.

Small little tiny f0cking stone, on the other hand... can do the job pretty well...
This!

Don't forget a granule or two of sand.
02-18-2016, 09:16 AM   #11
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And just to demonstrate the effect of sand or grit, as opposed to a steel knife...

This is an exercise I did just now, to show why - in the right circumstances - a protective filter is anything but redundant. I took an old, irreparable lens, then got a small piece of grit from the soil in my garden, and gently wiped it back and forth on the front element with a lens wipe (as soon as I applied light pressure, the grit broke down into a number of really tiny particles - just the size you might expect to get on your lens on a windy day at the beach, or if you dropped your camera while walking through the woods - into a muddy puddle, for instance ). Now imagine that this is your lovely DA or FA Limited lens! Of course, careful removal of debris before using a lens wipe, lens-pen or cloth should avoid this kind of thing happening... but what if just one tiny grain of dirt remains? I'm not saying everyone should use protective filters - but this is why I always will (and yes, I choose to remove them when conditions allow or there is significant chance of flare)...
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02-18-2016, 07:20 PM   #12
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That's quite an example you made! :-) Still though, I do not claim the the lens to be indestructible, I only show that a modern lens coating can take more abuse than expected. While a lens protector is reassuring to many people (myself included at times), I'm only saying that I don't lose any sleep over some of my lenses not having them.

For example, I do use protective filters on my zooms, but don't bother with my primes. I can get into dirty situations with the zoom, so it's easier to just take off the filter and clean it directly. As for my primes... while usually not a problem, there have been times when there have been undesirable effects due to the filter, so I do not use them on primes since I only use primes when I want the very best image quality I can get.

Just for the sake for clarity... I am not expressing my view as the best way. I only do what works for me. If someone does or does not like filters, well... that's really a personal decision that I don't comment on. All that matters is that one is happy with their decision and enjoys their hobby or work. Also, this is not directed at anyone. I'm just sharing my thoughts. :-)

Last edited by Albert Siegel; 02-18-2016 at 07:20 PM. Reason: Added smile at end. :-)
02-18-2016, 08:58 PM - 1 Like   #13
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Generally, I don't put filters as well, but I never go out without a hood.. But I always give my front elements a thorough "air bath" from the rocket blower every chance I've got when outside.

The only lens I occasionally use with a filter is my 18-135. It's my go anywhere/sacrificial/lens cap lens
02-19-2016, 01:34 AM   #14
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QuoteOriginally posted by Albert Siegel Quote
That's quite an example you made! :-) Still though, I do not claim the the lens to be indestructible, I only show that a modern lens coating can take more abuse than expected. While a lens protector is reassuring to many people (myself included at times), I'm only saying that I don't lose any sleep over some of my lenses not having them.

For example, I do use protective filters on my zooms, but don't bother with my primes. I can get into dirty situations with the zoom, so it's easier to just take off the filter and clean it directly. As for my primes... while usually not a problem, there have been times when there have been undesirable effects due to the filter, so I do not use them on primes since I only use primes when I want the very best image quality I can get.

Just for the sake for clarity... I am not expressing my view as the best way. I only do what works for me. If someone does or does not like filters, well... that's really a personal decision that I don't comment on. All that matters is that one is happy with their decision and enjoys their hobby or work. Also, this is not directed at anyone. I'm just sharing my thoughts. :-)
Albert - I actually really enjoyed your post; your demonstration was very useful. And I appreciate you weren't trying to be evangelistic At the same time, my reply to you wasn't meant to be dismissive of your preference for not using protective filters. I only intended to provide an alternative view point for anyone reading. Like you, I have - on a few occasions - had undesirable effects from filters, but find Hoya HMC UV(C) Slim Frame to be consistently good, with little or no degradation in IQ (even with flare, unless shooting direct into the light). Even so, I remove my filters in certain circumstances
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