Skylight 1A filters..necessary on DSLR's?

On Mon, 4 Feb 2008 21:07:05 +0100, "Gary Seven" <G7.TakeThisOut@invalid.net>
wrote:

>Hello everyone. In December I went out and bought the Canon 40D and a
>couple of lenses to go with it (ok, it was a "Kit" purchase so technically I
>only bought one additional lens . Anyway, as I practice and experiment
>with the camera I found myself wondering if the Skylight 1A filters were
>still necessary. I was looking at the 1A still mounted on the 28-105 lens
>that sits unused on my old Canon EOS A2e, and wondered if should go out a
>buy a new one for the newer lenses. I remember being told in Photog 101
>that they were more for protecting the lens glass than anything else,
>although I understand they also help to correct for overblue skies.
>
>Comment anyone? TIA.
>
>/G7

About the only reason to use a skylight filter on a digital camera is
to protect the lens - the other functions and benefits can be
achieved through post processing.

For me, the benefits of using a skylight filter (protection) are
offset by the problem it creates ... flare.

I find a lens cap provides as much protection as a skylight filter. A
rigid lens hood with a Hood Hat not only protects the lens but also
helps to reduce the risk of flare.


TR
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Gary Seven wrote:
> Hello everyone. In December I went out and bought the Canon 40D and a
> couple of lenses to go with it (ok, it was a "Kit" purchase so technically I
> only bought one additional lens . Anyway, as I practice and experiment
> with the camera I found myself wondering if the Skylight 1A filters were
> still necessary. I was looking at the 1A still mounted on the 28-105 lens
> that sits unused on my old Canon EOS A2e, and wondered if should go out a
> buy a new one for the newer lenses. I remember being told in Photog 101
> that they were more for protecting the lens glass than anything else,
> although I understand they also help to correct for overblue skies.
>
> Comment anyone? TIA.
Skylights were really only applicable with slide film, with
colour neg film the slight warming they gave was very easily
applied in printing - conversely the warming they provided
was often reversed in the printing stage.

Likewise true warming and cooling filters (81 82 etc) were
also more applicable with slide than colour neg film due to
the ease of correcting colour in print.

Now with digital - I personally leave a Skylight on all my
lenses, because I still use film. It provides a slight
warming effect, which is basically cancelled out if using
AWB or Manual WB.

But, when it comes to shooting digital, personally I like
leaving my WB set to daylight, and using warming/cooling
filters - I know I could use different WB settings to get
the desired result, but I find the use of filters to be a
more familiar workflow. In this manner of operation, I find
the skylight provides nice colour when shooting in daylight
/ open shade - just like it did with slide.

In theory if you are using in-camera (or post-process)
white-balance to correct for extreme lighting (eg very low
colour temp incandescant), then you are more likely to
posterize or blow one channel before the others. A sensor
will have a certain native white-balance - this would be the
colour of light that will make the different coloured
sensels _natively_ read the same value. In theory then if
colour correction filters are applied to convert the
incoming light to this native white-balance, the camera will
be operating with it's maximum dynamic range in all 3
channels. I don't know how you would test to find a camera's
native white balance - presumably photograph a grey card in
daylight in raw, and look at what the raw RGB values are.
>
> /G7
>
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Gary Seven <G7 DeleteThis @invalid.net> wrote:

> Hello everyone. In December I went out and bought the Canon 40D and a
> couple of lenses to go with it (ok, it was a +ACI-Kit+ACI- purchase so technically I
> only bought one additional lens . Anyway, as I practice and experiment
> with the camera I found myself wondering if the Skylight 1A filters were
> still necessary. I was looking at the 1A still mounted on the 28-105 lens
> that sits unused on my old Canon EOS A2e, and wondered if should go out a
> buy a new one for the newer lenses. I remember being told in Photog 101
> that they were more for protecting the lens glass than anything else,
> although I understand they also help to correct for overblue skies.

> Comment anyone? TIA.

If you don't want to correct for overblue skies and want a protective
lens cap you can shoot through, then you want a clear glass lens
protection "filter", not a Skylight 1A. They're useful in rain, salt
spray, sticky conifer twiggery, and for keeping other people's
fingerprints off your lenses. Outside such special conditions, I find
a rubber lens hood much more useful lens protection, since it also
cushions knocks.

--
Chris Malcolm cam DeleteThis @infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Gary Seven <G7.RemoveThis@invalid.net> wrote:
> Anyway, as I practice and experiment
> with the camera I found myself wondering if the Skylight 1A filters were
> still necessary.

Yes! Absolutely! I have a great deal for you, a Skylight 1A
filter (no-name, used, scratched) for $99.95 (+s&h, just another
$44.95), at only 10.000% mark up, in the wrong size for you.

Please send me the money immediately, I'll send you the filter
as soon as you need it.

> I remember being told in Photog 101
> that they were more for protecting the lens glass than anything else,

There are clear (as in *really* 100% clear) protect filters
available for just that purpose. I would not recoomend them, as
the mark up is lower than with cheezy skylight, haze or UV filters.

> although I understand they also help to correct for overblue skies.

Well, just lower the push for the blue channel, and there you go:
no overblue skies, less noise in the blue channel, and ... oops!
No mark up for me! You really need a half-dozen skylight filters:
if you stack them, the sky will not be overblue and your lens
will be protected multiple times. I can even give you a package
deal if you buy 10 or more: 5% off!

-Wolfgang
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

The short answer is no.

Frankly they were not necessary with film cameras.

In theory they could offer an advantage under some conditions. But in
practice, for all but a very small amount of the most critical work they
don't offer any advantages.

OK I am sure someone is going to ask. Most digital sensors have very
little sensitivity to UV light, but some. Under some conditions it might be
desirable to reduce it even more. I have never seen such a situation.
Much the same way variable strengths (different cut offs) filters were
available. (skylight/UV).

--
Joseph Meehan

Dia 's Muire duit



+ACI-Gary Seven+ACI- +ADw-G7+AEA-invalid.net+AD4- wrote in message
news:60p9jcF1r0c3kU1+AEA-mid.individual.net...
+AD4- Hello everyone. In December I went out and bought the Canon 40D and a
+AD4- couple of lenses to go with it (ok, it was a +ACI-Kit+ACI- purchase so technically
+AD4- I
+AD4- only bought one additional lens . Anyway, as I practice and experiment
+AD4- with the camera I found myself wondering if the Skylight 1A filters were
+AD4- still necessary. I was looking at the 1A still mounted on the 28-105 lens
+AD4- that sits unused on my old Canon EOS A2e, and wondered if should go out a
+AD4- buy a new one for the newer lenses. I remember being told in Photog 101
+AD4- that they were more for protecting the lens glass than anything else,
+AD4- although I understand they also help to correct for overblue skies.
+AD4-
+AD4- Comment anyone? TIA.
+AD4-
+AD4- /G7
+AD4-
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Mr. Strat <rag.RemoveThis@nospam.techline.com> wrote:
: In article <60p9jcF1r0c3kU1.RemoveThis@mid.individual.net>, Gary Seven
: <G7.RemoveThis@invalid.net> wrote:
:
<snip>

: Oh God! Another one...

Huh?
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

"Gary Seven" <G7.TakeThisOut@invalid.net> wrote:
> Mr. Strat <rag.TakeThisOut@nospam.techline.com> wrote:
> : In article <60p9jcF1r0c3kU1.TakeThisOut@mid.individual.net>, Gary Seven
> : <G7.TakeThisOut@invalid.net> wrote:
> :
> <snip>
>
> : Oh God! Another one...
>
> Huh?

I read in a book once, "Don't put a filter on a camera that you don't need
for the image." I think that's what he's refering to. :O)

I also read that lens caps work quite well for protecting lenses. However,
if you're like me, you lose them on a regular basis while wandering about
the woods, and should by stock in a lens cap company!

Have fun,
Dave
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

In article <60rq3nF1rpgklU1 DeleteThis @mid.individual.net>, Gary Seven
<G7 DeleteThis @invalid.net> wrote:

> Mr. Strat <rag DeleteThis @nospam.techline.com> wrote:
> : In article <60p9jcF1r0c3kU1 DeleteThis @mid.individual.net>, Gary Seven
> : <G7 DeleteThis @invalid.net> wrote:
> :
> <snip>
>
> : Oh God! Another one...
>
> Huh?

It seems like a week doesn't go by without someone asking if they
should keep a UV/skylight filter over their lens. I guess it's too
tough to read previous posts.

And there's nothing I'd rather do than stick a cheap piece of colored
glass in front of my lens.
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Joseph Meehan <sligoNoSPAMjoe.TakeThisOut@hotmail.com> wrote:

> OK I am sure someone is going to ask. Most digital sensors have very
> little sensitivity to UV light, but some. Under some conditions it might be
> desirable to reduce it even more.

Pray tell, which of your lenses do not cut out enough UV?

-Wolfgang

PS: Please refrain from top posting --- this is usenet, not
jeopardy, and people read top to bottom when reading English.
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's? 

Gee. That is why I wrote "it might..." I have never had the need. I
would expect it to be a very unusual situation indeed.

--
Joseph Meehan

Dia 's Muire duit



"Wolfgang Weisselberg" <ozcvgtt02 DeleteThis @sneakemail.com> wrote in message
news:v6ho75-3fu.ln1@ID-52418.user.berlin.de...
> Joseph Meehan <sligoNoSPAMjoe DeleteThis @hotmail.com> wrote:
>
>> OK I am sure someone is going to ask. Most digital sensors have very
>> little sensitivity to UV light, but some. Under some conditions it might
>> be
>> desirable to reduce it even more.
>
> Pray tell, which of your lenses do not cut out enough UV?
>
> -Wolfgang
>
> PS: Please refrain from top posting --- this is usenet, not
> jeopardy, and people read top to bottom when reading English.
 >> Stay informed about: Skylight 1A filters..necessary on DSLR's?