Should I use UV Filters?

[Keith Diefendorff]

...

Image degradation due to change in index of refraction is matter of
physics, and is not subject to conjecture. There is 4%
transmisivity loss at each transition between optical media (e.g.,
air to glass). Of this there is no question (cf., Fresnel).

Oh yes there is.

If every surface of a lens lost 4%, a 21-element (15-group) 70-200VR lens would transmit only 29% of the light entering the lens (0.96^(2*15)). (That's assuming no glass-air interfaces within a group. If there are air-glass interfaces at each of the 21 elements then transmissivity would be only 18%.) Either is ridiculous. The net transmissivity of the 70-200 is certainly nowhere near this bad, meaning 4% per surface can't possibly be correct.

And its not. Fresnel reflection off a lens surface is 4% only when the index of refraction of the glass is 1.5. But modern lenses and most UV filters are coated with low-index coatings to reduce Fresnel reflection. Good lenses and filters are multicoated with 1/4-wavelength coatings that further cancel reflection by shifting it 180 out of phase with the incident wave. A multicoated lens surface easily has a reflection loss more like 0.5% and a good one is more like 0.25%. Either is a lot different than 4%.

At 0.5%, the transmissivity of the 70-200 would be 86%, which is still pessimistic but certainly closer to reality than 29%. Adding a good B+W multicoated filter would change that from 86% to 85% at worst.

You think you can tell the difference between a 21-element 70-200 at 86% transmissivity and and a 22-element 70-200 (with MC filter) at 85%? I think not, in general. Surely there are certain intense specular lighting situations where even a small reflection can flare or reduce contrast. But if I were you I wouldn't put much money up against Phil's bet.

--
Keith

 

[luxun54]

LOL, Yellow-billed Hornbill, South Africa.

Like Morris (and many others), I keep a UV filter on my 18-70 and
80-400VR for protection; I use only quality UV filters (B&W and
Nikon) and I have never been able to detect any distortion. I do
not use a filter on my Nikon 105mm macro because (a) for close up
work, you end up magnifying even a very slight distortion; and (b)
the lens is recessed into the housing, and therefore less exposed
to being damaged.
--
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Kind of a scruffy looking crow there!!
--

Cheers!!
Vernon
Great photography is know where and when to stand!

--
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[Old Ed]

Hey Kriss, would you use a Polariser for your landscape shots?

Certainly. I have a Kaesmann B&W MRC CP.

...that anything bad done to your image by a UV filter
could also be done by a polarizer (of comparable quality).

Regards,

Kriss

--
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Check out my photo site if you have some time!
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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220,
Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head,
Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not
like the passengers in his car'...

 

[Bill E(UK)]

The end of your lens gets subjected to all sorts of hazards from salt in the air, physical crashes, stuff falling onto the glass, people and animals coughing stuff over it etc.

A good quality filter (I use Hoya) will protect you valuable lens from almost all of these hazards and I have yet to see an image degraded by a filter.

All of my lenses are fitted with a dediacted UV or skylight filter. This is something I have always done from my earliest days with a Zorki 4 rangefinder, a Zenit E, Pentax K system, and now all my Nikon kit!

Think of it like all the modern day ads for condoms, slip one on and you are protected! You are at risk without it!
--
Bill Ellingford
Forest of Dean, UK

 

[AWT]

I can't see any loss of detail.. The sky has gone darker blue for the same shutter/aperture as you would expect..

 

[Bill E(UK)]

Your insurance policy is not going to help you if you damage a lens in the field when on an assignment expecially a news shoot! You only get one chance to capture the story so, the answer is use the sacrificial filter. As Phil says, you can always remove it at times it may affect a shot.

What will an editor say if you walk into his office and say, couln't get the shot, they were too far away and I had scratched the glass on my 300!
--
Bill Ellingford
Forest of Dean, UK

 

[Kriss001]

But I wouldn't leave a CP on my lens all the time.

Regards,

Kriss

--
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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[Kriss001]

Just curious. Have you ever known anyone who has scratched their lens? I never have. I know a lot of photographers including the ones here. Has anyone here actually scratched their lens? I would like to hear from just one person who has. I might consider changing my stance on the issue if someone could tell me they did.

Regards,

Kriss

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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[light_bouncer]

When I once ended up with a serious smudge on an UV filter, I tried using a LensPen to clean it - and I couldn't get rid of some remaining lines... very fine ones but they were visible. I also tried Eclipse fluid on another UV - guess what, it dried out leaving fluid drops! No idea what I could do better - and that's why I'm afraid to leave the lens without UV filter.

--
If everyone cared and nobody cried,
If everyone loved and nobody lied,
If everyone shared and swallowed their pride,
We'd see the day, when nobody died

 

[Kriss001]

I think they call that a point and shoot. Hehehe.

Regards.,

Kriss
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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[Kriss001]

I always have my lens cover on when not shooting. Always.

Regards,

Kriss

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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[raymondox]

I've heard both ways:
1. Get a UV filter for each lens for the protection. Cheaper to get
a new filter than a new lens, etc.

2. Don't get a filter. The lens has the right coatings already, UV
shouldn't be a problem, and you are more likely to get flair.

I'm new to DLSRs. Would appreciate your advice.

I have dropped or banged the front of my D70s twice, the filter took the damage so the lens still looks like new.

I dropped my Pentax Z1 onto concrete, it hit the front of the lens. The filter cracked the lens stayed perfect.

a £100 invetments across my lens is good value when I have £2000 worth of cameras.

--
Bluenose

 

[Kriss001]

Filters are notoriously hard to clean. Lenses don't have the same coatings that filters have. I clean mine with a microfiber cloth. If I had to use something to get a stubborn spot off, which I've never had to do, I would use a optical cleaning solution, NOT ECLIPSE. Something made for fine eyeglasses. I would only put a drop or two on the cloth, not the lens.

Regards,

Kriss

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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[Kriss001]

I think if I were to drop my D70 and 70-200VR lens onto concrete, lens first, no filter made of anything would prevent it from breaking. I am very careful with my equipment and I know I don't want $2,000.00 of lens to fall on anything. I agree, accidents do happen but they are the exception rather than the rule. Just my $.02

Regards,

Kriss

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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[tko]

Of course, if it's a high contrast backlight or other difficult situation I just take 'em of, that's only common sense. But witha $20, optically piece of flat glass you shouldn't really see a difference unless it's a reflection or something.

But it's so easy to test, why fight? Take a pictue with, one w/o and post them. I've never seen such a test, which makes it hard for me to believe there is a difference.

A flat piece of glass will transmitt, what, 99% of all light? So, if the reds are blocked twice as much as the blues, that's a 0.5% difference? And I'm using very conservative numbers. So where are these differences coming from?

 

[Bill Karadimos]

Hey Kriss, would you use a Polariser for your landscape shots?

Certainly. I have a Kaesmann B&W MRC CP.

...that anything bad done to your image by a UV filter
could also be done by a polarizer (of comparable quality).

One thing you are forgetting, There is a benefit with a CP and not the UV picture wize...lol Regards...

Regards,

Kriss

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D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220,
Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head,
Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not
like the passengers in his car'...

--

Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming - ' Wow! What a ride!'

 

[light_bouncer]

Filters are notoriously hard to clean. Lenses don't have the same

Interesting. I thought e.g. B+W MRC have some kind of strong resistant coating which is supposed to keep the moisture etc away easily, and any foreign objects should get of easier - but they apparently don't.

coatings that filters have. I clean mine with a microfiber cloth.
If I had to use something to get a stubborn spot off, which I've
never had to do, I would use a optical cleaning solution, NOT
ECLIPSE. Something made for fine eyeglasses. I would only put a
drop or two on the cloth, not the lens.

Thanks for tip, I will get some optical cleaning fluid. For a little OT... got a nasty dust drop on the CCD today, then got back home, tried to blow it off with a blower bulb and got 6 more Damn, looks like wet pecpad cleaning is in order tomorrow... I'm too tired to do that today. I hate what blowers do to CCD - who ever said they can blow things from the sensors? I for one never succeeded.

LB

Regards,

Kriss

--
See if I'm online, ICQ# 1326088
Check out my photo site if you have some time!
http://voyager01.deviantart.com/gallery/

D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220,
Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head,
Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not
like the passengers in his car'...

--
If everyone cared and nobody cried,
If everyone loved and nobody lied,
If everyone shared and swallowed their pride,
We'd see the day, when nobody died

 

[Rod Harris]

Right on Phil...

 

[Kriss001]

The only time I've had good luck with the blower was for blowing the dust off my lenses. The one exception to that is after I do a CCD cleaning with PecPads and Eclipse I frequently find one little piece of lint or fluid left on the sensor. Holding the camera upside down, I give it a few puffs with the Giotto rocket blower. 99% of the time that's all it takes and my sensor is beautiful again.

PS, I prefer to use the blower on my lens caps and my lenses when I take the caps off. They stay pretty clean for me. Just my $.02

Regards,

Kriss

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Check out my photo site if you have some time!
http://voyager01.deviantart.com/gallery/

D-70, Kit, 50/1.8, 70-200VR, 200f/4AFED, SB-800, GitzoG2220, Bogen/Manfrotto 3245 Auto Monopod, Bogen 322 RC2 Grip Head, Canon500D Close-up Filter, Nikon 6T Close-up Filter.

'I want to die like my grandfather, peacefully in his sleep. Not like the passengers in his car'...

 

[Phil Youngblood]

How about broke half in two? A filter would not have prevented that little episode, though.

Major scratches can and do happen but that's not how most are damaged. The primary problem is the minute scratches caused by improper and/or too much cleaning. That degrades the coating on the front of the element causing a gradual loss of contrast over time. It can increase flare after the coating is worn very thin. Many think the coating is very durable and it is to a certain extent but is easily worn down by improper cleaning. If it's as durable as many think, why did Nikon just develop a new, more durable coating. Very few lenses have it at this point.

I shoot a LOT and under adverse conditions at times so there is NO doubt using a high quality UV filter extends the life of my lenses and preserves rather than hinders image quality. Someone not shooting as I do may not benefit as much as I assuming they always use a lens hood, always have the cap on when not shooting, and always clean their lenses properly. Disregard any of the three and you're better off with a protection filter. You just have to be aware of when a filter can cause a problem and take that puppy off for the shot.

Did you notice there were a few wanting to give lip service to my bet regards image quality but there's no takers?

Phil