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RobertLynn
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p.1 #1 · UV Filters and Flare? Come on!


In the past, I've said that UV filters do not degrade IQ. I still stand by that, to a degree. My point has always been, that they in theory do lower the IQ, however I cannot see it with my eyes.

The one thing I have noticed was a little bit more flare. It's not often, so I generally haven't worried about it.

Well, I went out to do some night photography, and have no need for the filters on. However, I didn't take them off (I don't use mine for UV, I use them because I don't like to touch the front element of my lens. Yes, that's my personal choice, you may not like it that way, but I do, so don't try to change my mind on it).

So, I took some shots, and was looking in the LCD, I noticed I had flare. I took the filter off, and viola, flare vanished. Now these were on long exposures (5+ seconds), but still there.







This is a full image, after the filter was taken off. The above is a 100% crop of the upper right corner of the image when the filter was on.







I want to say that I eat crow here, however I've always said that they make you more prone to flare...I didn't even consider it at night time.

Aug 01, 2008 at 09:10 PM
jcolwell
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p.1 #2 · UV Filters and Flare? Come on!


Crow is much tastier than most would think. Plus, it's nutritious. I should know, 'cause I eat it frequently.

Were you using a hood ?

Edited on Aug 02, 2008 at 01:56 AM


Aug 02, 2008 at 01:55 AM
RobertLynn
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p.1 #3 · UV Filters and Flare? Come on!


Yeah, I was using a hood. I'm such a clutz, even though I haven't smashed anything yet, I'm so afraid that I will...even at 3AM I used a hood

Aug 02, 2008 at 03:22 AM
jcolwell
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p.1 #4 · UV Filters and Flare? Come on!


RobertLynn wrote:
...even at 3AM I used a hood


Good, keep it up!

Aug 02, 2008 at 03:25 AM
RobertLynn
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p.1 #5 · UV Filters and Flare? Come on!


I actually asked myself "wth do I need this for, it's 3AM".

Aug 02, 2008 at 05:24 AM
AJ Nadershahi
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p.1 #6 · UV Filters and Flare? Come on!


A few years ago there was a thread from the owner of a new 70-200vr zoom lens who was complaining about poor focus of the lens and lack of contrast in his images. The samples he posted were taken indoors in his living room lit by normal tabletop lamps.

After much debate on the possibility of quality control issues with his new lens and confirming his capture style and use of a solid tripod, he mentioned how careful he is with his equipment - even using UV filters on all of his lenses. He was asked to perform the same tests without the filter. Guess what? It turned out his lens was in perfect working order...


Edited on Aug 02, 2008 at 05:43 AM


Aug 02, 2008 at 05:41 AM
dcains
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p.1 #7 · UV Filters and Flare? Come on!


There's no bigger scam in the photo business than vendors sellng UV filters, and not too many things that will degrade image quality as much. You'd have to hold a gun to my head to get me to use a UV filter on any of my carefully selected glass. Just say no. Either that, or show me a case where a UV actually improved digital IQ.

Aug 02, 2008 at 09:23 AM
RobertLynn
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p.1 #8 · UV Filters and Flare? Come on!


dcains wrote:
There's no bigger scam in the photo business than vendors sellng UV filters, and not too many things that will degrade image quality as much. You'd have to hold a gun to my head to get me to use a UV filter on any of my carefully selected glass. Just say no. Either that, or show me a case where a UV actually improved digital IQ.



I explained my reasoning for it, I just don't want to touch my front element. I haven't had a detrimental effect on my photographs YET (if I do, I'll eat some tasty crow), and I don't expect an improvement if I use one.



Aug 02, 2008 at 09:03 PM
dcains
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p.1 #9 · UV Filters and Flare? Come on!


So the flare in the first pic you posted is not a detrimental effect? Why did you start this thread then?

Edited on Aug 02, 2008 at 09:27 PM


Aug 02, 2008 at 09:11 PM
RobertLynn
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p.1 #10 · UV Filters and Flare? Come on!


dcains wrote:
So the flare in the first pic you posted is not a detrimental effect? Why did you start this thread then?


It is, and it is not. I know that with a filter on my lens, I am more prone to flare (did you read my OP?) and when that happens...filter comes off. Arguably flare is a component of image quality. However, when I say detrimental effects, I mean I don't notice my images color off, or sharpness down, or any missed focuses increasing because of the filter. I notice flare occasionally.

If you read my title if said about flare...then I posted a shot taken at night time. Basically it's a way of saying, that yes, the lens is more prone to flare with a filter, so use them with that caveat.

If you can take my cameras, or anyone for that matter, and show me FLARE ASIDE, my IQ improving, I'll consider taking the filters off. Yes, I understand in theory, the IQ is degraded, but in practice, I just don't see it...Even after reading the tests online, http://photo.net/equipment/filters/

There's another one I have bookmarked on my other computer, but it actually shows images with reduced quality. However, I cannot duplicate this on my images.

One instance of where a filter has saved me some grief is, I had like a rub mark or something on the front of my 24-70L, 3 weeks into owning it, and rest assured I BABY my equipment (i'm not wealthy enough to bang the stuff around and buy more when it's bad), though it came out, it freaked me out. I popped a filter on it, and I later noticed the rub mark on the filter (which consequently buffed out). Here the lens cap had a defect in it, and it would run the lens when on (never noticed it, and Canon replaced it).

Aug 02, 2008 at 09:35 PM
JohnJ80
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p.1 #11 · UV Filters and Flare? Come on!


I haven't confirmed this, but I believe replacing the outer most lens on a Canon lens is not all that expensive (the number I recall is $75). If that is the case, then since you have to buy top quality UV filters, and they go for $49 or so, if you have say more than one lens (and many of us have a lot more), the cost of possibly replacing a lens element vs buying UV filters is far cheaper.

So, since a UV filter can't improve the image quality on a digital camera (it can help on film since film is more sensitive to UV), you get better image quality and spend less money (including if you are worried about lens damage) by not using a UV filter.

J.

Aug 03, 2008 at 06:22 PM
bertrum
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p.1 #12 · UV Filters and Flare? Come on!


Just a quick question...does the coatings on the lens front element include UV protection??

Aug 03, 2008 at 07:11 PM
RobertLynn
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p.1 #13 · UV Filters and Flare? Come on!


I'm not sure, but if you check the link posted, UV filters actually don't do much at all for UV. It was surprising, the company that blocked the most UV, also made the filter that did the worst on the tests.

My point is simply this, you're going to be more prone to flare, even at night time.

Aug 03, 2008 at 08:33 PM
HerbChong
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p.1 #14 · UV Filters and Flare? Come on!


every coating on any element blocks UV to some degree. couple that to the sensor IR/UV filter found in almost all cameras and you can effectively say that most modern DSLRs do not respond to UV light in any useful way. read up on http://www.naturfotograf.com/UV_IR_rev00.html#top_page to see what is involved for digital UV photography and realize that the bodies he reviews are older and have less UV and IR filtration than modern cameras.

Herb....

bertrum wrote:
Just a quick question...does the coatings on the lens front element include UV protection??



Aug 04, 2008 at 12:17 AM
dirb9
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p.1 #15 · UV Filters and Flare? Come on!


It is not just the coating, normal glass in itself blocks out most UV light. In my experience (at 10,000 feet), the issue with high altitude UV and film is overblown. There is a reason that companies had to produce special lenses made only of quartz and fluorite for UV photography, like the UV Nikkors.

Aug 04, 2008 at 12:32 AM
dimitris77
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p.1 #16 · UV Filters and Flare? Come on!


JohnJ80 wrote:
I haven't confirmed this, but I believe replacing the outer most lens on a Canon lens is not all that expensive (the number I recall is $75). If that is the case, then since you have to buy top quality UV filters, and they go for $49 or so, if you have say more than one lens (and many of us have a lot more), the cost of possibly replacing a lens element vs buying UV filters is far cheaper.

So, since a UV filter can't improve the image quality on a digital camera (it can help on film since film is more sensitive to UV), you get better image quality and spend less money (including if you are worried about lens damage) by not using a UV filter.

J.


If this can be confirmed then i will be convinced to take my filters off. $75 for the front element of my 85L seems a bit low though...

Aug 04, 2008 at 03:56 PM
bertrum
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p.1 #17 · UV Filters and Flare? Come on!


HerbChong wrote:
every coating on any element blocks UV to some degree. couple that to the sensor IR/UV filter found in almost all cameras and you can effectively say that most modern DSLRs do not respond to UV light in any useful way. read up on http://www.naturfotograf.com/UV_IR_rev00.html#top_page to see what is involved for digital UV photography and realize that the bodies he reviews are older and have less UV and IR filtration than modern cameras.

Herb....



Thanks Herb. That is what I was thinking but couldn't find the info.


Aug 04, 2008 at 04:43 PM
DThom
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p.1 #18 · UV Filters and Flare? Come on!


The graph in this link shows the spectral response of the filter that covers the sensor on canon cameras.

Red line is the stock filter

It is not sensitive to UV or IR. (the blue line is the replacement filter used in astrophotography). I have had UV filters on my lenes for 30 years to protect the front element. I have never scratched a filter. After reading this, I think most of them will go.



Aug 04, 2008 at 05:07 PM
HerbChong
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p.1 #19 · UV Filters and Flare? Come on!


the only time i have damaged a filter in over 30 years was when it wasn't even on the camera. i used a Zeiss liquid cleaner to remove a smear and that is a mistake on high end Hoya filters. they develop spots on the coatings that wouldn't clean off no matter what i did. scrubbing with Kodak lens tissue and a drop of fluid eventually scratched the coating and the marks from the liquid still weren't gone. that's when i started getting rid of my Hoya Super HMC filters. i have two left, a CPL for a specific lens with a non-removable hood so i can't use adapter rings, and an 81A that i use on the rare times when i still shoot slides.

Herb....

Edited on Aug 04, 2008 at 06:47 PM


Aug 04, 2008 at 06:42 PM
sav0320
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p.1 #20 · UV Filters and Flare? Come on!


Dude, you better get that UV filter back on, you made the building lean without it!

Aug 04, 2008 at 06:53 PM
David Baldwin
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p.1 #21 · UV Filters and Flare? Come on!


Robert,

I'd say you've been unlucky, or the problem only appears close up to very strong point light sources. I specialize in night photography, and have done since the early 1980s. I always use UV/Skylights, and can't say I've noticed any flare problems as a result:

www.nightfolio.co.uk

Here in the UK a big problem on long/night exposures is dew forming on the front of the lens. If I use a filter and it fogs up, I simply replace it with a new (warmer) filter from my pocket, and can continue shooting.

As for easily replacing lens front elements I am sceptical. The only time I had a major lens maker disassemble my lens they tried twice to put it back together properly and produce sharp images, and failed. I am very wary about the ability of even authorized lens repairers to do major work to factory standards - perhaps I am just paranoid.

Aug 05, 2008 at 04:45 PM
GeneO
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p.1 #22 · UV Filters and Flare? Come on!


Your seeing reflection of light off of the highly reflective sensor projected onto the flat filter. A well know problem for shooting with a filter on at night with light sources (even for film).

Gene

Aug 06, 2008 at 04:15 AM

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