View Full Version : uv or skylight


Michael Buendia
December 25th, 2002, 07:18 PM
what would you recommend: a uv filter or a skylight for pure protection on the gl2 lens?

Jeff Donald
December 25th, 2002, 08:11 PM
It really makes no difference for video. If you put it on your lens and leave it on for protection, you'll be (or the camera will be) white balancing through the filter. This will compensate for the slight magenta cast of the skylight filter. Skylight filters are designed to filter out excess UV (blue cast) on film. This is accomplished by tinting the skylight filter slightly magenta. The magenta is neutralized by your cameras auto white balancing (AWB).

Jeff

Frank Granovski
December 25th, 2002, 08:24 PM
A UV might cost less. I'd just get a UV to protect the lens, and a polarizer to cut glare on sunny days. A softening filter is also nice to have.

A Cokin UV is like 10 to 15 bucks. That's my favourite UV. My expensive Heliopan UV suffers from glare. $65 Canadian Bucks down the tube.

Don Palomaki
December 26th, 2002, 04:39 AM
Be aware that in part to the great depth of field potentiql of the GLx series, you may encounter shooting situations where you can actually see the dust on the filter in the image. So keep any filter clean.

Mark Härtl
December 26th, 2002, 04:59 AM
can i use a uv- and pol-filter at the same time? or do i need a mattebox for this? what about a wideangle-converter or the lens-hood (what i want to ask is can you screw other things on a filter)?

Jeff Donald
December 26th, 2002, 05:37 AM
It depends on the filter. Most are made with threads at both ends. This allows for attaching filters, hoods and other accessories. However, many of the filters marketed as suitable for wide angle lenses employ a thinner mounting ring. The thinner ring prevents (in most cases) the filter from protruding into the scene. This protruding, by normal filters, produces a condition know as vignetting. Vignetting is seen as a moderate to severe darkening of the corners of your image. The thinner mounting ring, in many cases, does not have a threaded outer portion. The lack of threads prevent the attaching of additional accessories, including other filters.

Jeff

Frank Granovski
December 26th, 2002, 05:51 AM
The slim line B+W / Heliopan does have the outer threads.

* The Cokin UV has less reflective coating(s) than the Heliopan. This is probably why I get the refections with the Heliopan, but not with the Cokin.

Frank Granovski
December 26th, 2002, 05:57 AM
Polarizers are usually also UV. (At least some polarizers are.)

I'd try to avoid using more than 1 filter at a time. With more glass the image is going to be less clear.

Then there is the matter of linear verses circular polarizers.

Some ND filters are also polarizers, yet others are are both polarizers and softeners.

It's a big filter world out there. I'd just stick with a UV and a polarizer to start.

Mark Härtl
December 26th, 2002, 03:11 PM
thanks jeff & frank, you've helped me a lot - as always. good for my knowledge; am just getting into these things...

Charles Papert
December 26th, 2002, 05:48 PM
Frank:

I am truly surprised to hear that a top-end company like B&W is producing a filter that causes more flare issues than a cheaper filter. Especially, as you say, one that has more coatings designed to reduce this...! For instance, in a really difficult situation like shooting scenes by candlelight, does the Cokin produce less secondary images of the candles than the Heliopan?

Also I am curious about your description of combination filters that combine Polarizers with ND or image softening effects. The only variations I have seen in Polas are linear vs circular and an 812 warming filter+pola sandwich. Which manufacturer is making these other combos you describe?

Frank Granovski
December 28th, 2002, 07:06 PM
The UV which causes flaring on my MX300 is the Heliopan. I kid you not. So I bought a Cokin UV, and found it caused no flaring. So..., I think it's always a good idea to try an expensive filter in the shop first before learning the hard way. Expensive doesn't mean better, in this case. Or, maybe I got a defective Heliopan UV?

About combos, I'll look through my filter catalogs to tell you which one.

Jeff Donald
December 28th, 2002, 08:53 PM
I've used Heliopans off and on for 15 years and never had a problem with flair. I would suggest that you have a defective filter. Of course getting the Germans to admit it will be another thing. I wonder if the glass element is not held by the mounting ring properly. I would send it to Heliopan with a video sample of the flair and see what they say.

Jeff

Don Palomaki
December 29th, 2002, 05:48 AM
> My expensive Heliopan UV suffers from glare.

Where did you buy the bad heliopan? At $65 vs. $12, some one could have swapped the glass and returned it for a refund and net gain of $51.

Frank Granovski
December 29th, 2002, 05:34 PM
I bought it at Leo's, in Vancouver. I'm sure the glass was not switched. Also, the filter is screwed in correctly. Perhaps the coatings cause the light to flare.

At first I wanted to buy a Leica UV, but the Leica threads are different and only fit Leica cams or certain Leica cams. Go figure. I'm happy with my Cokin. It's even made will real glass.

Jeff Donald
December 29th, 2002, 06:01 PM
I'm sure you have the filter screwed in correctly. What I was suggesting is, the glass element is not parallel to the lenses because the element is not seated in the mounting ring properly. It could have been caused by the spanner ring not being tight enough or even too tight. It's possible the element wasn't coated properly, but I think that is highly unlikely.

The coatings to the glass element (both surfaces) are anti reflective coatings and are designed to reduce flair.

Jeff

Michael Buendia
December 29th, 2002, 08:26 PM
the glass on the heliopan is top notch but the coating leaves much to desire. i called a local nyc photo shop and they told me that for the nyk marathon a number of b+w & heliopans were ordered (one of the sponsors had multiple still cameras to cover the event) and they eventually sent them all back and went with hoya shmc uv filters. no glare or reflections reported as opposed to the b+w & heliopans.

if you want the best glass and construction (brass rings) got to go with the germans. what i most care about is reducing glare/reflections and that is done via multiple layers (on both sides). since i don't plan on using the uv filter 24-7 i don't stress over the where the glass came from or if they use brass or aluminum rings. the japanese have good glass, maybe not as good as the german schott (zeiss), but they are very high quality.

that's why i went with one of the originals (not the inventor) = pentax smc filters (7 per side). i believe hoya might cut the glass for them but the coating is all pentax (highly respected in 35mm & medium format lenses).

mb4

Jeff Donald
December 29th, 2002, 08:41 PM
I would take what a New York photo shop tells you with some skepticism. Or for that matter almost any retailer today. The general lack of knowledge in the sales staffs is appalling.

Pentax is the inventor of multi coated photo optics. They make great filters and lenses. A very good choice to minimize flare and reflections.

Jeff

Michael Buendia
December 29th, 2002, 08:43 PM
true, true, true!!!!!