Cracked filter: replace or not?

**wedge** · 03-11-2014, 06:05 PM

I've got a Tamron 28-75/f2.8 that has basically become my "everyday" lens. I bought it used about 2 years ago and it came with a slim Kenko UV filter, which I've left on it 95% of the time. Well, my rig took a spill off a pinball machine over the weekend. Thankfully, the only damage (at least all I noticed) was a crack in the filter glass.

In my mind, the filter did exactly what I'd hoped it would do: sacrifice itself so as to avoid paying to have the front lens element replaced. I should note that the crack is quite small and at the edge of the filter, so it doesn't appear to affect image quality at all. What I'm wondering, though, is if I should apply the child safety seat rule here. For those who haven't ever had to buy or know anything about child safety seats, the basic rule is that once one has been through an accident (of any kind, even a minor bump or fender bender), they need to be replaced (the theory being that the trauma of the accident has "compromised" the integrity of the seat.

So, since that filter has survived a fall and saved the lens in the process, should I assume that it's no longer fit for that purpose and replace it? Or should I just continue using it as-is? Or take it off and (possibly) enjoy slightly improved image quality?

FWIW, about 75% of the shooting I do with this is indoors, but, as I know now, there are just as many potential dangers indoors as out. If I replace it, should I get another UV filter or go with a totally clear one? It looks like prices for both are all over the place, but I'd like to keep any investment in the $25 or less range.

**ramseybuckeye** · 03-11-2014, 06:40 PM

I would not replace it, the image quality degradation can be severe. In most cases the hood will be more protection, and really, just be more careful (easy to say!)

**jatrax** · 03-11-2014, 06:54 PM

Personally I am in the `no filters unless there is an optical reason` camp. But if you feel better with a filter that`s your business.

In this case I would say any crack in the filter glass renders it unfit. Toss it and get a new one. I would be worried about glass shards ruining the lens coating if it takes another hit.

kev.pride · 03-11-2014, 07:15 PM

Originally posted by jatrax

Personally I am in the `no filters unless there is an optical reason` camp. But if you feel better with a filter that`s your business.

In this case I would say any crack in the filter glass renders it unfit. Toss it and get a new one. I would be worried about glass shards ruining the lens coating if it takes another hit.

+1.

UV & supposedly clear filters were useful in film days but only degrade image quality now. Only filters I ever use now are for effect eg. Circ Polariser.

Kevin

**dms** · 03-11-2014, 07:37 PM

It seems unlikely the filter strength will be reduced by the crack. It is a risk vs cost question--what is the liklihood it will strike the same place when you drop it next time and then it will fail, but wouldn't have failed if you replaced it.

Your call--but I think the risk is hardly changed. For that matter maybe this filter is better than a new one that you replace it with--after all it seemed to work .

AquaDome · 03-11-2014, 08:46 PM

I put filters on everything. Throw it away. You don't need it and now that its cracked, its a prism refracting light in crazy directions. The glass is gonna fall out and get all in your camera bag.
Whether you choose to put another on it is your business. I certainly would, but only because I LIKE the front of the lens to look showroom-new; not because it adds anything to photography.

03-11-2014, 06:05 PM	#1
wedge Site Supporter Join Date: Jul 2009 Location: Montco, PA Photos: Gallery \| Albums Posts: 154	Cracked filter: replace or not? I've got a Tamron 28-75/f2.8 that has basically become my "everyday" lens. I bought it used about 2 years ago and it came with a slim Kenko UV filter, which I've left on it 95% of the time. Well, my rig took a spill off a pinball machine over the weekend. Thankfully, the only damage (at least all I noticed) was a crack in the filter glass. In my mind, the filter did exactly what I'd hoped it would do: sacrifice itself so as to avoid paying to have the front lens element replaced. I should note that the crack is quite small and at the edge of the filter, so it doesn't appear to affect image quality at all. What I'm wondering, though, is if I should apply the child safety seat rule here. For those who haven't ever had to buy or know anything about child safety seats, the basic rule is that once one has been through an accident (of any kind, even a minor bump or fender bender), they need to be replaced (the theory being that the trauma of the accident has "compromised" the integrity of the seat. So, since that filter has survived a fall and saved the lens in the process, should I assume that it's no longer fit for that purpose and replace it? Or should I just continue using it as-is? Or take it off and (possibly) enjoy slightly improved image quality? FWIW, about 75% of the shooting I do with this is indoors, but, as I know now, there are just as many potential dangers indoors as out. If I replace it, should I get another UV filter or go with a totally clear one? It looks like prices for both are all over the place, but I'd like to keep any investment in the $25 or less range.

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03-11-2014, 06:40 PM	#2
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,295	I would not replace it, the image quality degradation can be severe. In most cases the hood will be more protection, and really, just be more careful (easy to say!)

03-11-2014, 06:54 PM	#3
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Personally I am in the `no filters unless there is an optical reason` camp. But if you feel better with a filter that`s your business. In this case I would say any crack in the filter glass renders it unfit. Toss it and get a new one. I would be worried about glass shards ruining the lens coating if it takes another hit.

03-11-2014, 07:15 PM	#4
kev.pride Veteran Member Join Date: Feb 2008 Location: Modbury North, South Australia Photos: Gallery \| Albums Posts: 351	Originally posted by jatrax Personally I am in the `no filters unless there is an optical reason` camp. But if you feel better with a filter that`s your business. In this case I would say any crack in the filter glass renders it unfit. Toss it and get a new one. I would be worried about glass shards ruining the lens coating if it takes another hit. +1. UV & supposedly clear filters were useful in film days but only degrade image quality now. Only filters I ever use now are for effect eg. Circ Polariser. Kevin

03-11-2014, 07:37 PM	#5
dms Site Supporter Join Date: Aug 2011 Location: New York, NY Photos: Gallery Posts: 2,192	It seems unlikely the filter strength will be reduced by the crack. It is a risk vs cost question--what is the liklihood it will strike the same place when you drop it next time and then it will fail, but wouldn't have failed if you replaced it. Your call--but I think the risk is hardly changed. For that matter maybe this filter is better than a new one that you replace it with--after all it seemed to work .

03-11-2014, 08:46 PM	#6
AquaDome Veteran Member Join Date: Jan 2014 Location: New Carlisle, IN Photos: Gallery \| Albums Posts: 1,475	I put filters on everything. Throw it away. You don't need it and now that its cracked, its a prism refracting light in crazy directions. The glass is gonna fall out and get all in your camera bag. Whether you choose to put another on it is your business. I certainly would, but only because I LIKE the front of the lens to look showroom-new; not because it adds anything to photography.