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Old Dec 22, 2007, 8:41 PM   #11
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Yah the exposures are different, just wasn't what I expected.

Robert
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Old Dec 22, 2007, 8:43 PM   #12
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I have the cokin Grad. ND filter and like it. It looks kind of old fashioned, but it is suprisingly flexible and easy to use.

Robert
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Old Dec 22, 2007, 10:45 PM   #13
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Digital sensors are supposed to be more sensitive to flare than film is, so some filter manufacturers put extra coatings on the digital filters to try to cut down on it. I'm not sure you would necessarily notice a difference between filters except for times when you would be suseptable to flare. If you aren't going to be using your filters in situations that would create flare you might not notice a difference. I only have a couple of filters and all of mine are from my film days so I can't verify if this is really true or not. I do know that UV filters at night can cause flare and ghosting problems, and I don't use them much any more.
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Old Dec 23, 2007, 2:00 AM   #14
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I use skylight filters as lens protection. Not that I'm especailly afraid of bumping the lens into something, but to protect the front element from being wiped and cleaned by myself. You can use whatever dedicated lens cloth you want, within 10-15 years the lens coating will be affected. An as you know, a quality lens lasts much longer than that.

My A*85mm is very apparently used, the lens barrel paint is worn and there are bump-and-scratch marks all over. But the front element is like on day one. The skylight filter protecting it is not.

Kjell
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Old Dec 23, 2007, 6:11 AM   #15
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bigdawg wrote:
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When you live in a humid enviroment early morning photos with a polorizing filter and either a Skylight or UV filter are a must. They do help cut through the water vapor fog the is so prevalent in North alabama Summer mornings.....The polorizer helps by cutting the reflected light from these morning sunlit vapors and together with the UV or Skylight filter they cut through 80-90 percent of it.
Dawg, very interesting comment because, of course, I share the same conditions in SW Arkansas. I recently picked up a 70-210 Series 1 (one of the good models), and to my surprise, a set of three filters was stacked on the end of the barrell--an ND X 4, a Skylight (1B), and a round polarizer...all of them Hoyas.

Coincidentally, the 67mm filter threadof the Vivitar is shared by my DA*50-135 and my Phoenix 100-400 AF, the lens I use most for birding. Now, I can't wait for one of those misty morning to try your idea.

BTW, I'm one of those who can't wait to get a protective UV lens in front of his good glass....simply for protection.

Paul
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Old Dec 23, 2007, 10:10 AM   #16
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This is what I thought unless you are shooting in conditions that would normally cause flare or other optical problems you probably won't notice the benefit of the additional coatings on the "digital" filters.

I guess then one needs to decide if the "digital" filter for those times is worth the extra cost or if the cost savings for a regular "film" filter is more advantageous. It would be nice if we have one standard filter size so we didn't have buy the filters in different sizes for different lenses. All of my Pentax lenses are 52mm, the Pentax 18-250 is 62mm. Since I plan to use that lenses the most I bougtht the "digital" filters for it and have regular ones for the others.

Now if the Pentax 10-17 only had threads on it.

Robert
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Old Dec 23, 2007, 10:23 AM   #17
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I have mounted metal lens hoods on all of my lenses, it protects the front element without the need for a filter. I always used protective filters as Kjell suggested but lately (possibly because of the sensitivity of the sensor that Harriet mentions) I have noticed that whenever there is a strong light sourse in an otherwise low light scene I get ghosting from filter flare. This only occurs with light sources, such as windows. that are well away from the centre of the frame, but the result is a ghost image at the opposite point in the frame. I will take care to not damage the front elements from cleaning and still use the filters when conditions warrant it (harsh weather etc.)

I was a firm believer in the protective filter and never saw anything that I could recognize as ghosting when I used film.

Ira


Notice I still use a filter on the Sigma (a good quality Tiffen) because it has a wide shallow hood making it more vulnerable.
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Old Dec 23, 2007, 10:28 AM   #18
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The slow rubbing off of the lens coatings is very interesting. I never thought of that. I guess as long as any type of negative effect that can be had from having a "protective" lens on the front can be cloned out if needed then it is probably a good idea. Those special coatings are quite important and are the main reason I waited for the Pentax 18-250 instead of going with the instant gratification of the Tamron 18-250. Pentax has better coatings.

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Old Dec 23, 2007, 11:10 AM   #19
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Don't forget that you can always take off a UV or skylight filter when you don't want it or find you get ghosting. I just didn't realize it would happen when I was out one night with my new K100 and an old 24mm 2.8 lens with a UV filter on it. I got terrible ghosting and now hardly ever use filters. Perhaps I should go back to using them and get decent ones (my old ones are a mixed bag of medium priced, decent Hoyas and cheap consumer ones).
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Old Dec 23, 2007, 8:06 PM   #20
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Robert Barnett wrote:
Quote:
This is what I thought unless you are shooting in conditions that would normally cause flare or other optical problems you probably won't notice the benefit of the additional coatings on the "digital" filters.

I guess then one needs to decide if the "digital" filter for those times is worth the extra cost or if the cost savings for a regular "film" filter is more advantageous. It would be nice if we have one standard filter size so we didn't have buy the filters in different sizes for different lenses. All of my Pentax lenses are 52mm, the Pentax 18-250 is 62mm. Since I plan to use that lenses the most I bougtht the "digital" filters for it and have regular ones for the others.

Now if the Pentax 10-17 only had threads on it.

Robert
As for the differing size of the filter threads the Cokin filter holder uses a screw on adapter that the filter holder just pushes on to and they come in every size needed and cost very little. I have a filter adapter ring for each size lens and the filter holder just moves from one lens to the next in a split second...The A-Series filter holder is good up to a 55.6mm lens size ( I use it on 62mm lenses and have no vignetting yet.) and then you step up to a P-series filter holder that takes you way on up the lens size chart. I actually have a holder adapter that lets my series a Filter holder be used on lenses up to 82mm but with some minor vignetting. See below.








More here...

http://www.geocities.com/COKINFILTERSYSTEM/


Dawg
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