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Circular polariser and noise

leongu
Posted 18/10/2010 - 23:41 Link
First of all, forgive the ignorance but I've only recently used a circular polariser. What it is is that I've noticed increased noise in my photos whilst using a circular polariser. I would love to post and show sample images, but I'm not sure I can with no website to link the photos to.

2 of the photos I've taken have the following specs:
1. with cpolariser and more visible noise
24mm, f/22, 1/60s, ISO 200

2. no cpolariser less noise
50mm, f14, 1/200s, ISO 200

Appreciate if someone could advice if the use of a cpolariser has a direct impact to camera noise. I thought it was a bit odd to find noise at low ISOs especially on a K-x. Also note that the photos haven't been processed yet. So you can just imagine that noise would get worse post levels and contrast adjustments.

Thanks for your help.
Leon
K-x, K100D, DAL 18-55, DAL 50-200mm, Tamron 70-300Di, SMC M28/2.8
fatspider
Posted 19/10/2010 - 00:19 Link
Can't answer you question Leon but I have experienced similar problems, I just put it down to using a cheap polarizer, what are you using?
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link
leongu
Posted 19/10/2010 - 00:24 Link
I'm using a Hama, Alan. And yes it's a cheapo. Quite disappointing really as I thought it would improve my photos.
Leon
K-x, K100D, DAL 18-55, DAL 50-200mm, Tamron 70-300Di, SMC M28/2.8
fatspider
Posted 19/10/2010 - 00:26 Link
Dont be dissapointed, a bit of noise ins't the end of the world and its soon cleaned up with the right software link
My Names Alan, and I'm a lensaholic.
My PPG link
My Flckr link
K10D
Posted 19/10/2010 - 00:55 Link
leongu wrote:
First of all, forgive the ignorance but I've only recently used a circular polariser. What it is is that I've noticed increased noise in my photos whilst using a circular polariser. I would love to post and show sample images, but I'm not sure I can with no website to link the photos to.

2 of the photos I've taken have the following specs:
1. with cpolariser and more visible noise
24mm, f/22, 1/60s, ISO 200

2. no cpolariser less noise
50mm, f14, 1/200s, ISO 200

Appreciate if someone could advice if the use of a cpolariser has a direct impact to camera noise. I thought it was a bit odd to find noise at low ISOs especially on a K-x. Also note that the photos haven't been processed yet. So you can just imagine that noise would get worse post levels and contrast adjustments.

Thanks for your help.

f/22 with a polariser and 1/60 sec. Just how bight was it or were you covering arc welding?

Some thing does not gel here.

Best regards
Inspiration is rarer than a plate glass camera.....
leongu
Posted 19/10/2010 - 21:59 Link
hahaha It wasn't quite arc welding Gary. I managed to link the sample photos and I hope it will make more sense.

1. shot with cpol
Comment Image


2. shot with uv filter
Comment Image
Leon
K-x, K100D, DAL 18-55, DAL 50-200mm, Tamron 70-300Di, SMC M28/2.8
Anvh
Posted 19/10/2010 - 22:25 Link
This might explain the difference, looking at your photo link
Stefan
Comment Image

K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Edited by Anvh: 19/10/2010 - 22:25
leongu
Posted 19/10/2010 - 23:10 Link
Woh that's bit too technical Stefan, but I think I'm getting it now. So objective is to avoid underexposure which would lessen noise as well. I completely forgot that I lose 2 stops when using a polariser. Hence I should have compensated with an increase in f-stop or slow down shutter speed. I was shooting on Av mode and thought the camera was compensating on shutter speed automatically. Or did it?
Leon
K-x, K100D, DAL 18-55, DAL 50-200mm, Tamron 70-300Di, SMC M28/2.8
johnriley
Posted 19/10/2010 - 23:35 Link
Yes it did compensate. The only thing here that I can think might influence noise is that the polariser has darkened some areas, as it should. Darker areas will show more noise.
Best regards, John
leongu
Posted 20/10/2010 - 00:10 Link
Thanks very much for the help and clarification John and Stefan! Good night!
Leon
K-x, K100D, DAL 18-55, DAL 50-200mm, Tamron 70-300Di, SMC M28/2.8

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