Filters - Advice Please

I've just bought a Canon 400D with a Sigma 17-70mm lens and a Canon
50mm lens. I have read a little about how useful lens filters can be,
and would appreciate some advice.

What are the essential filers? Polariser, UV, Fluorescent? I saw a
gallery of beautiful landscape shots the other day and the
photographer used an "ND Grad" filter on all his shots. I think there
are many different types.

What filters are essential, and which ones are a nice extra?

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Advice appreciated.
Thanks

On Sun, 14 Oct 2007 10:37:46 -0000, colly wrote:

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Some expensive filters are also "false economy". I've tested some of the most
expensive polarizers for uniformity of the polarizing substrate as well as
polarizing strength from various companies. Some of the most expensive ones over
$80 and up were worse than $12 generic specials of the same diameter. Failing in
uniformity, strength, or both. Typically both. They must feel they can get away
with that because few people know of a simple way to test them.

Use a known good polarizer and cross it at 90-degrees to the unknown. The
unknown will usually show defects clearly in the form of banding, spots and
gashes of lesser strength, and brighter lights showing through easily overall.
It should appear nearly black (slight tinge of blue or purple) and uniform when
crossed with another good one. I use a lab-grade polarizer for this simple test.
Two of those crossed at 90 degrees to each other extinguishes nearly all visible
light and show zero defects.

About the only time where I have found that cost really matters is when buying
close-up filter sets (typically sold in +1, +2, and +4 diopter sets). They need
to be multi-coated or else that many glass/air surfaces when used in a
stacked-fashion rob too much light and contrast from your image. Multi-coated
close-up filters cost a bit more and are well worth the expense. (Not speaking
of special achromat close-up lens add-ons, usually at +8 diopters strength and
up in a single configuration.) Otherwise all other filters are a crap-shot on if
they are worth the extra money or not. The adage of "you get what you pay for"
has never held less truth than when buying filters.

On Sun, 14 Oct 2007 10:37:46 -0000, colly
wrote:

What filters are essential, and which ones are a nice extra?

No filter is essential. A polariser is sometimes useful.

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Yes. Buy only those you *need* and buy the best you can
afford.

--
John Bean

a uv filter can be useful to have on the lens all the time - not
photographically but more to protect the front element of the lenses -so
that when your camera falls against a wall the filter gets damaged but not
the expensive lens. I know - it has worked for me when out in the
countryside one day trying to clamber over a drystone wall ;-((


"colly" wrote in message
oups.com...
I've just bought a Canon 400D with a Sigma 17-70mm lens and a Canon
50mm lens. I have read a little about how useful lens filters can be,
and would appreciate some advice.

What are the essential filers? Polariser, UV, Fluorescent? I saw a
gallery of beautiful landscape shots the other day and the
photographer used an "ND Grad" filter on all his shots. I think there
are many different types.

What filters are essential, and which ones are a nice extra?

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Advice appreciated.
Thanks

On Sun, 14 Oct 2007 12:39:39 +0100, "kamerakid"
wrote:

a uv filter can be useful to have on the lens all the time - not
photographically but more to protect the front element of the lenses -so
that when your camera falls against a wall the filter gets damaged but not
the expensive lens. I know - it has worked for me when out in the
countryside one day trying to clamber over a drystone wall ;-((

Use a good lens hood to protect the lens, not a UV filter. A lens hood
not only protects the lens, butalso keeps out stray light, improving
contrast. Filters cost money, collect dust, can cause vignetting, and
give ghost images in high contrast scenes.

If you are going to use a filter to protect the lens, make sure you
put one on the back of the lens too, in case it falls on the back.

Ed

Better is a lens hood *and* a front clear filter. The hood protects the
front of the lens and acts as a shade for extraneous light, but the clear
filter protects the front element against dust, splashes, etc. I find that
after several years I need to replace the front filter from those inevitable
cleaningS out in the field--much better than replacing the front element!

In terms of the filter degrading the image: I have done some fairly
extensive tests with and without filter and find that the degradation is
imperceptible at 100% magnification. This is with a garden variety MC clear
filter. The smallest bit of focusing error has a much greater effect on the
final sharpness than that extra piece of glass. There are cases where you
will get extra ghosting when you have very bright lights shining in the
lens, but in that case it is easy to take the filter off for a few
minutes...

BTW high quality filters are much more important with very long lenses. With
a 50 and a 17-70 you don't have to worry.

You don't need any CC filters with digital, as all color correction can be
done with a decent graphics app. A polarizer is very valuable, as it cuts
non-specular reflections, making colors richer, as well as doing the famous
darkening-the-sky bit. Make sure to buy a circular polarizer, so as not to
screw up the metering and/or focusing of your digital camera.

ND grads are nice, but you can do a lot of that digitally, especially if you
are working with RAW files. The screw-in ones are practically useless, as
you always have the grad transition in the exact middle of the frame. Better
are the Cokins or whatever that can be moved, but the plastic ones scratch
absurdly easily. The Tiffen glass grads are the best I've found, but are
absurdly expensive. Mounting all these movable grads is a pain--unless you
are Ansel Adams and have all day to do one image you will find them a
bother.

Then comes the fact that no matter what, the grad threshold is a straight
line. You also have to decide on the ND factor and whether you want soft or
hard grads (with gradual or sharper transitions). Are they useful?
Absolutely, for some things. Are they a pain? Absolutley, for all things...

If you shoot a lot of red stuff and fall foilage you can consider a red
enhancing filter. This works by notching the orange transmission quite
deeply at one relatively narrow wavelength, so it doesn't screw up the
overall color balance, and this is not something you can do easily
digitally. It has some limited usefulness for some things, but is certainly
not essential.

You can also consider a soft-focus filter (there are many different styles
available that all give slightly different effects) if you like that sort of
thing. The effect is much more complex than just using a gaussian blur in
PS, although with some work you can do nice soft-focus effects in PS.

Finally there are all the cross-filters and gimmick filters that can't
easily be duplicated digitally, but they are all...gimmicky...and you
probably don't need to even consider them unless you need to do that kind of
gimmicky stuff for some reason.

Toby

"EAL" schrieb im Newsbeitrag
...
On Sun, 14 Oct 2007 12:39:39 +0100, "kamerakid"
wrote:

a uv filter can be useful to have on the lens all the time - not
photographically but more to protect the front element of the lenses -so
that when your camera falls against a wall the filter gets damaged but not
the expensive lens. I know - it has worked for me when out in the
countryside one day trying to clamber over a drystone wall ;-((

Use a good lens hood to protect the lens, not a UV filter. A lens hood
not only protects the lens, butalso keeps out stray light, improving
contrast. Filters cost money, collect dust, can cause vignetting, and
give ghost images in high contrast scenes.

If you are going to use a filter to protect the lens, make sure you
put one on the back of the lens too, in case it falls on the back.

Ed

"colly" wrote in message
oups.com...
I've just bought a Canon 400D with a Sigma 17-70mm lens and a Canon
50mm lens. I have read a little about how useful lens filters can be,
and would appreciate some advice.

What are the essential filers? Polariser, UV, Fluorescent? I saw a
gallery of beautiful landscape shots the other day and the
photographer used an "ND Grad" filter on all his shots. I think there
are many different types.

You can simulate the effects of an ND grad filter using digital tools, so
those are nice, but not essential. The most essential filter is the
polarizer, which cannot be simulated digitally in any way. Get a good brand,
as well. I've tried cheaper brands, and they usually fall apart in about a
year. My B&W filters last years.


What filters are essential, and which ones are a nice extra?

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Advice appreciated.
Thanks

"colly" wrote in message
oups.com...
I've just bought a Canon 400D with a Sigma 17-70mm lens and a Canon
50mm lens. I have read a little about how useful lens filters can be,
and would appreciate some advice.

What are the essential filers? Polariser, UV, Fluorescent? I saw a
gallery of beautiful landscape shots the other day and the
photographer used an "ND Grad" filter on all his shots. I think there
are many different types.

Almost forgot; a good multicoated UV filter to keep on the lens at all
times, except when using the polarizer.


What filters are essential, and which ones are a nice extra?

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Advice appreciated.
Thanks

"Kinon O'Cann" wrote in message
news:fmpQi.1506$pl2.1128@trndny09...

"colly" wrote in message
oups.com...
I've just bought a Canon 400D with a Sigma 17-70mm lens and a Canon
50mm lens. I have read a little about how useful lens filters can be,
and would appreciate some advice.

What are the essential filers? Polariser, UV, Fluorescent? I saw a
gallery of beautiful landscape shots the other day and the
photographer used an "ND Grad" filter on all his shots. I think there
are many different types.

Almost forgot; a good multicoated UV filter to keep on the lens at all
times, except when using the polarizer.


What filters are essential, and which ones are a nice extra?

I've found some on ebay that are very cheap, are cheap filters a false
economy?

Advice appreciated.
Thanks


Regarding a UV filter; I have nearly always used one but I've heard the
arguement, "Why pay a lot of money for a Zeiss (for instance) lens and then
crap it up with a dime store UV filter?" Any comments?

In article , Ed Mullikin
wrote:

Regarding a UV filter; I have nearly always used one but I've heard the
arguement, "Why pay a lot of money for a Zeiss (for instance) lens and then
crap it up with a dime store UV filter?" Any comments?

don't put a cheapo filter on an expensive lens. get a hoya or b+w
multicoated filter, not a no-name uncoated questionable quality filter.