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04-03-2011, 10:36 AM   #46
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QuoteOriginally posted by Raybo Quote
So is this about lenses or cameras?
All your reference seems to be double talk?

Use your filters HT, I choose not to use them at all.
What double talk? Someone implied that lenses are what remove UV light. I pointed out that it wasn't the lens' job at all. I use UV filters for protecting the lens, not for UV blockage. But I could just as easily use a clear filter for the same task. Using a UV filter gives me a warm fuzzy feeling of knowing that the filter actually does some kind of filtering.

04-03-2011, 05:44 PM   #47
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QuoteOriginally posted by Hound Tooth Quote
Someone implied that lenses are what remove UV light. I pointed out that it wasn't the lens' job at all.
Consider the filtering of UV light as an unintended consequence of the types of glass they use in lenses these days, and the intended consequence of modern lens coatings.

QuoteOriginally posted by Hound Tooth Quote
Using a UV filter gives me a warm fuzzy feeling of knowing that the filter actually does some kind of filtering.
It also gives you a warm colour cast (depending on the filter) that can just as easily be simulated through shooting RAW and modifying the white balance.
04-03-2011, 10:49 PM   #48
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QuoteOriginally posted by Digitalis Quote
It also gives you a warm colour cast (depending on the filter) that can just as easily be simulated through shooting RAW and modifying the white balance.
I've never met a UV filter that gave any kind of color cast whatsoever, even in the uber-cheap crap.
04-03-2011, 11:21 PM   #49
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QuoteOriginally posted by Hound Tooth Quote
I've never met a UV filter that gave any kind of color cast whatsoever, even in the uber-cheap crap.
I have a Hoya Super HMC UV filter that gives a slight yellow tint to images, it's very small but it is there.

The cheaper ones tend to produce a slight blue colour cast.

but then again I could be wrong, both my eyes perceive colours in a slightly different way.

04-09-2011, 12:48 PM   #50
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QuoteOriginally posted by Raybo Quote
Care to share some hi-res images?
Please tell me which of these was taken with a UV filter and which one without:
Name:  uvfiltercomparo.jpg
Views: 1994
Size:  152.5 KB

parameters:
- 31mm FA Limited
- F8.0
- 1/60 shutter speed
- manually focused on a tripod
- year-old battle-scarred UV filter (Hoya HD)
- 100% crop of center of the frame
- no post-processing except the very minor default sharpening applied by my RAW processing software

I would LOVE to know where I supposedly lost contrast and detail.

Last edited by Hound Tooth; 04-09-2011 at 12:53 PM.
04-09-2011, 03:03 PM   #51
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Right half is "with", left "without"
04-09-2011, 08:38 PM   #52
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QuoteOriginally posted by maciek_w Quote
Right half is "with", left "without"
Think I would agree with that ... a very slightly 'colder' (blue) look and a minute loss of detail (look at the grey stone in the centre).

I almost never use filters but if that was the only degradation then it wouldn't prevent me using them if I needed / wished to.
04-09-2011, 08:44 PM   #53
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sorry, left is with UV filter and right is without.

04-09-2011, 09:37 PM   #54
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QuoteOriginally posted by Hound Tooth Quote
sorry, left is with UV filter and right is without.
Like to explain the anomaly then ? If you can't then it must have been user error because you can't get a sharper shot with a filter on than without !
04-09-2011, 10:21 PM   #55
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QuoteOriginally posted by Frogfish Quote
Like to explain the anomaly then ? If you can't then it must have been user error because you can't get a sharper shot with a filter on than without !
no anomaly. You're confusing contrast and sharpness. Typical mistake. Remember this is a 100% crop. Both images have exactly the same sharpness, but the one with the UV filter gained a tiny bit of contrast for some reason. Maybe the overcast sky was slightly thinner at that very moment. It's perfectly normal for there to be such a small brightness difference in outdoor conditions. Especially in Manual mode when I make no adjustments. It did take me 3 seconds to remove the filter, and then another 3 seconds for the self-timer to elapse.

edit: I also forgot to set a manual white balance. These were shot with AWB, which might explain whatever "bluish cast" you people are seeing (which, btw, I don't see at all... maybe the right side of your monitors are messed up). The images above were developed "as shot" and not with a specific WB profile.

What I want to know is: where are these glaring differences that other people were warning me about in this thread? I thought I was supposed to expect a significant degradation in quality here, not some barely-noticeable nit-picks that could be caused by anything.

Sounds like made-up stuff to me. Some unfounded claim to suit the theory that adding a glass element in front of a lens MUST affect it negatively.

Last edited by Hound Tooth; 04-09-2011 at 10:56 PM.
04-10-2011, 07:22 AM   #56
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Just teasing you a bit, you know?
04-10-2011, 11:00 AM   #57
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QuoteOriginally posted by maciek_w Quote
Just a silly question: would the designers REALLY NOT THINK that people WILL PUT filters on their lenses? Why is there a filter thread on EVERY Ltd lens out there? Surely the optical design must accomodate - at least partially - for this, doesn't it.
The FA and older series lenses were designed for film. Using filters on film is the norm, especially for b&w. Some Pentax lenses whose design made a filter ring impossible, had built-in filter dials. On top of that Pentax used to make its own SMC and non SMC filters.

So if filters were factored into a lens design back then is hard to know. Iím sure the Pentax lens designers assumed that you would use a filter on their lenses and always had that in the back of their mind. They just hoped you would pick a Pentax SMC filter.

Phil.
04-10-2011, 11:38 PM   #58
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QuoteOriginally posted by gofour3 Quote
The FA and older series lenses were designed for film. Using filters on film is the norm, especially for b&w. Some Pentax lenses whose design made a filter ring impossible, had built-in filter dials. On top of that Pentax used to make its own SMC and non SMC filters.

So if filters were factored into a lens design back then is hard to know. Iím sure the Pentax lens designers assumed that you would use a filter on their lenses and always had that in the back of their mind. They just hoped you would pick a Pentax SMC filter.
My SMC Pentax-F* 250-600mm f/5.6 has a filter tray at the camera side, and the use of a filter in that tray is mandatory. I.e. the lens is not designed to work without one.
04-13-2011, 09:42 AM   #59
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QuoteOriginally posted by Hound Tooth Quote
no anomaly. You're confusing contrast and sharpness. Typical mistake. Remember this is a 100% crop. Both images have exactly the same sharpness, but the one with the UV filter gained a tiny bit of contrast for some reason. Maybe the overcast sky was slightly thinner at that very moment. It's perfectly normal for there to be such a small brightness difference in outdoor conditions. Especially in Manual mode when I make no adjustments. It did take me 3 seconds to remove the filter, and then another 3 seconds for the self-timer to elapse. Possibly - however magnifying it further only highlights the difference of the Left side over the Right side. Maybe you would like to check the originals further because it certainly doesn't look like just contrast. Other than that my best guess is that either a) the focus was changed slightly when you removed the filter (or refocussed) or b) something caused some camera shake ... mirror, passing traffic or whatever. Logic dictates without must be sharper and unless there were clouds hurtling across the sky just a few seconds shouldn't have made that sort of difference to exposure either.

edit: I also forgot to set a manual white balance. These were shot with AWB, which might explain whatever "bluish cast" you people are seeing (which, btw, I don't see at all... maybe the right side of your monitors are messed up). The images above were developed "as shot" and not with a specific WB profile. Ha Ha ! No definitely a very slight blueish cast on the right

What I want to know is: where are these glaring differences that other people were warning me about in this thread? I thought I was supposed to expect a significant degradation in quality here, not some barely-noticeable nit-picks that could be caused by anything.
Really this could vary according to subject and conditions .. no ? And certainly the quality fo the filter.

Sounds like made-up stuff to me. Some unfounded claim to suit the theory that adding a glass element in front of a lens MUST affect it negatively.
There are far too many accomplished photographers across the whole spectrum of photographic sites, for this to be either made-up, a conspiracy of sorts or wrong !
I made my comments above HT. In bold.
04-16-2011, 11:29 PM   #60
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QuoteOriginally posted by Hound Tooth Quote
sorry, left is with UV filter and right is without.

How would we know that you are telling the truth HT?
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