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06-12-2012, 05:23 AM - 1 Like   #16
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QuoteOriginally posted by RioRico Quote
And then the broken filter glass can scratch the front element too. A lens hood offers more protection

I've seen two examples of lens filters able to take direct impacts. One such example... Riding passenger on the back of a Honda Aspencade 1800. Rock strikes lens at 75++mph. Filter cracked but remained completely intact - no glass debris.

I'd much rather always have some sort of protective filter (and preferably lens shade as well) on a lens of any cost.

06-12-2012, 05:27 AM   #17
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QuoteOriginally posted by chesebert Quote
Front Element Scratches

LensRentals.com - Front Element Scratches

Enjoy your scratched-but-it-doesn't-matter lens!
You're supposed to read the replies to questions as well See post #6
06-12-2012, 06:14 AM   #18
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I don't think that it's repairable. Shoot some pics and see for yourself if it affects (share here too). It likely to affect once you stop down to f8 and lower.
06-12-2012, 06:42 AM   #19
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QuoteOriginally posted by Louicio Quote
Get someone to polish the gouges
That could destroy the coating.

The standard repair is matte black paint in the scratches,
which should have only a very minor impact
on the T-value of the lens.

Or magic marker, like RioRico mentioned.

06-12-2012, 07:58 AM   #20
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QuoteOriginally posted by SpecialK Quote
From past examples I've seen, it will have little effect on images. Looks bad, though.
It can cause problems with flair and with low f-numbers so use Rioricco's advies to avoid that.


btw the front element might be replaceable, contact pentax and see what they say.
06-12-2012, 11:43 AM   #21
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Thanks for the advice everybody. I did take some sample pictures and it didn't look very different, but I'm sure that varies depending on the lighting conditions. However, it just...looks...so...ugly like this. The scratches are deep enough to cast a shadow, actually.

As to how exactly the lens cap broke: it wasn't from any particular impact. The camera bag was slung around my shoulder and attached to my belt so it wouldn't move too much. With the camera and the lens attached, it was a perfect fit for the camera bag, not too tight or too loose. However, all the moving around was enough to uncap the lens and it snapped off the flexing part of the lens cap. After riding around for awhile, the edge of the lens cap was rubbing against the front element and resulted in the scratches that you see. I suppose it doesn't take much effort to scratch up those lenses -- it carved it like cheese.

When I took my camera out, I saw a number of white slivers on my camera lens and realized that it was because the lens cap just gouged out my lens.

The camera bag was a model like this in case you are curious: Amazon.com: Tamrac 5683 Digital Zoom 3 Camera Bag (Black): Electronics
06-12-2012, 01:04 PM   #22
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I'd love to see before & after results using lens goo or black paint.

I think chances are good that black paint will give good results. Optical aberrations caused by uneven filling of gaps by lens goo may be worse than simply removing light like black paint.
06-17-2012, 08:26 AM   #23
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QuoteOriginally posted by calsan Quote
Could you please post this image again every time someone says not to use UV / Protection filters? I've lost count of how many times I've read posts here claiming that they're unnecessary.
But in this case, nothing much bad happened? The lens doesn't look as pretty, but so far as anyone can tell (or has said) there is no difference in the photos it takes. The poster is upset because the lens looks ugly now.

Here's a hypothesis: the loss of quality from the scratches is no more than the loss of quality from using a UV filter to prevent scratches. Do we have evidence either way?

06-17-2012, 09:32 AM   #24
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If a scratch leaves shadows on the lens as shown on OP's attached picture then logic dictates that light has been blocked over the scratched area. Am I wrong? Or am I right? By that can we assume that optical properties of the lens has been compromised?

OP might possibly need to retake the test with scene that has more details with a smaller aperture and possibily at different focal lengths to see the damage.

Carl Zeiss did have an article (short one) quite a while back IIRC in regards to getting absolute best performance out of your lens - one of the things they said was to not use a filter and the camera and lens have to be on a very stable platform (i.e. tripod and a remote trigger). But I suspect many here don't alway use a tripod, instead rely on the SR only.

Again, the use of a good filter, I emphasize again good filter and by that definition not cheap, though not perfect in its function (it will add a bit of degradation to the pic but you'll need to zoom a lot to even see it), is still the better option. Would you rather lose a $50 filter or a $500 lens? You still can take it off before you shoot.

So far I've tried and used quite a number of filters and so far find those from Tiffen, Hoya's basic ones like the hmc, Schneider Krezeunach's , Nikon's and Marumi unacceptable. So far they've shown to either have flare or ghosting effect and some soften the images. B+W filters are the ones I'm using now and I find that they're excellent in field use. I have not tried Hoya's top of the line HD ones yet but I will someday. Besides, if someone can confirm me on this, isn't the use of a filter needed to complete a WR lens seal?
06-17-2012, 09:39 AM   #25
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The only lens cap i've on my lenses while transporting is the rear lens cap, i dont use uv filter or lens cap on the front.
There is nothing in the bag that can scratch the lens so why do you need protection?
06-24-2012, 08:09 AM   #26
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QuoteOriginally posted by deanallan Quote
If a scratch leaves shadows on the lens as shown on OP's attached picture then logic dictates that light has been blocked over the scratched area. Am I wrong? Or am I right? By that can we assume that optical properties of the lens has been compromised?
The issue is whether there is any noticeable difference in photos taken. If you compare the area blocked by the scratches with the total area of the lens, the proportion is tiny. Probably less than 1%. So the effect probably won't be visible to the naked eye. Where-as a UV filter might block 3% of the light, across the entire area, so will have more of an effect.

(3% was for the only filter I could find that gave a figure. I couldn't find transmission figures for the B&W filters you prefer.)

QuoteQuote:
Would you rather lose a $50 filter or a $500 lens?
You should compare the certainty of the $50 cost against the possibility of the $500 cost. If you have 10 lenses, you can use the money saved by not buying 10 filters to replace a lens if it does get scratched. In practice, scratches are rare. And as argued above, a scratched lens is still usable, and should still have some resale value if you feel you must replace it.
06-24-2012, 09:51 AM   #27
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QuoteOriginally posted by selar Quote
I'm saying the lens cap came off because it broke. The force that broke the lens cap would have broken the filter as well. The force was from a reasonably pointy surface to break the lens cap in the centre without impacting the filter ring.
Without getting into the filter protection argument, let me point out that the lens cap on my 18mm-250mm (the same type lens as the OP is posting about) has come off numerous times. In fact, I'm on my second cap, having lost the first one. So I do not agree that the cap came off because it broke.
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