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05-22-2008, 10:48 PM   #1
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FA 50mm f1.4 images

hi. I have a k10d and just purchased a new FA 50mm f1.4 pentax lens recently. It is my first experience with a lens with such a wide aperture and it is amazing. I have noticed some abnormality in colors in some of the pictures however, with and without the uv filter I purchased with it. because of my limited experience I was wondering if anyone could help me determine if something is wrong. the last photo in the series has light artifacts in the sky and was taken with the uv filter on, is this normal? thanks!









Flickr: hsuperb0i's Photostream

05-22-2008, 10:54 PM   #2
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That last one wasn't taken through a window was it, looks like reflections of some sort?
If that's not the reason, must be UFO's.
Gary
05-22-2008, 11:02 PM   #3
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haha. it was shot through a window, but with the window open. so i guess it wasn't shot through the window. that was shot with just my uv filter on. do other uv filters normally do this? (i.e. filter out the uv lights such that ufo's become visible)
05-22-2008, 11:11 PM   #4
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Wow, that last one kinda reminds me of the pictures of Baghdad during the Gulf War air war....

They could be caused by dust on the filter...

BTW- Welcome to the forum!

05-22-2008, 11:15 PM   #5
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Those are reflections off the (non multicoated) UV filter. You have lots of little light sources in the scene, and some of them are at the right angle to cause this. Best to not use a filter unless there is an over riding need to use it.
05-22-2008, 11:22 PM   #6
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thanks for the replies and welcomes. So i checked my uv filter and there was dust on that. so i shall clean that up.
in regards to the first three images, there are some areas that are more purplish, or greenish than others and none of these were taken with the filter. is something up?
05-22-2008, 11:23 PM   #7
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QuoteOriginally posted by hsuperb0i Quote
haha. it was shot through a window, but with the window open. so i guess it wasn't shot through the window. that was shot with just my uv filter on. do other uv filters normally do this? (i.e. filter out the uv lights such that ufo's become visible)
In my experience, UV filters have no effect on UFO visibility. However, cheap uncoated UV filters can cause flare and reflections.

As for the odd colours, you're shooting a night cityscape with a million points of light, all of them different colours, being scattered by atmospheric haze. Consider it part of the mystery of night shooting.

In the day shot, the green and purple you're seeing in the vents are a flavour of Chromatic Aberration (CA). All lenses display CA to varying degrees, and in this regard, most lenses perform their worst wide open and in high contrast situations.
05-23-2008, 02:48 AM   #8
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LOL yes - thank you for posting the UFO photo, because it makes obvious what is hidden most of the time - reflections and flare from off frame sources affecting the photograph. The flat surface of the filter simply catches the reflections - it will do so during the day as well - but so will the non-filtered front surface of the lens.

Which is why multi coating exists, on lenses and (especially, based on your example) on filters. And why lens shades are a good idea, even at night.

Like Groundloop says, the color variations are due to different types of lighting in the scene. The white balance for the photo can only make one type of light neutral, all the others will have a color cast in one direction or another.

BTW I like the scene, especially the first pic - the bridge reminds me of pearls, or christmas lights...

05-23-2008, 07:58 AM   #9
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Hi,

are you living in Trump Village in Brighton Beach?

the view and some details of the window really look like my inlaws place.

Just a curiosity.

Giovanni ( from Italy ).
05-23-2008, 11:19 AM   #10
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its actually outside my window in the bronx facing the bronx state psychiatry center building and the throgs neck bridge. pretty good that you got nyc right.
05-23-2008, 12:30 PM   #11
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I had the exact same experience with a cheap filter on the same lens.
Just take the filter off for any shots that contain a light source -- or buy a multi-coated filter.

I purchased a Hoya 49mm UV (Ultra Violet) Multi Coated filter from Adorama for less than $20 and I don't see this problem any more. The filter which gave me the trouble was a Tiffen 49mm Digital Ultra Clear WW filter.
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