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10-02-2006, 09:02 PM   #1
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*ist DS and Sigma Problems

This is my first post after many visits, thanks for all the great info

Question #1

I am using the Sigma 50-500mm on my DS and are finding alot of noise in the photos when shooting in Raw. When i switch the camera to record in jpeg the problem seems to disappear. I have changed to my other lenses but this problem seems to only occur with the "Bigma"

Camera setting problem or is it the lens? The lense is less than a month old.

Question #2

I use Elements4 for my raw conversions.I have just checked the photo file properties of 2 different lenses and compared them.

With a 100-300mm sigma f6.7 - elements4 lists lens type as the 70-200 sigma f2.8. With the Bigma it lists lens type as a sigma with no other data, except focal lenght.

The photos convert fine with Elements4 when using the 100-300mm but its the Bigma that seems to be noisy.

Is this case of the lens and the camera not "talking" and getting their identities mixed up? And could this "mis-information" be the reason?

Any thoughts??

10-02-2006, 09:12 PM   #2
Ole
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1. Do you compare at the same ISO setting?

2. The jpeg setting could perform noise reduction, RAW not? I'm guessing here.
10-02-2006, 09:20 PM   #3
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I assume you have the camera set to Auto ISO. Have you tried to compare with ISO 200 fixed?
10-02-2006, 10:45 PM   #4
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Hi,
Most conversion software can't tell what Sigma lens is attached. It seems to happen with sigma lenses mostly. I Don't know why though.

I wouldn't have thought that would have anything to do with you getting noise in your bigma pics. I would try Raw shooter for conversion and see if you're getting the same noise in your pics....if so, then it's possibly the lens.

10-03-2006, 01:42 AM   #5
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Can't see how a lens could produce noise. Haven't heard that before.
10-03-2006, 05:33 AM   #6
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A couple of thoughts on this:

If the images are a bit under exposed and you correct them in the raw conversion, this can cause noise to appear.

All raw conversion software does the conversion differently. When I run into a 'difficult' image', I convert using the Pentax software, leaving all settings at neutral. I then work the image in post processing. The Pentax software pl2 or pl3
works better for me on the difficult (not quite right) shots
10-03-2006, 12:41 PM   #7
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I also have the Sigma 50-500mm and do not find noise to be a problem unless I am shooting into shadows. At this point being a slow lens, my ISO usually defaults to 800 or 1600 which adds noise. Not much you can do with this lense when it is a shady day as it is slow. Shooting jpg or raw makes no difference except for better control of the final output for me.
10-03-2006, 02:17 PM   #8
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Thanks for your thoughts.

I always shoot at a fixed ISO 200 or sometimes 400 if the light is low.
All noise reduction in the camera is turned off for shooting jpegs so its not that.

Its strange thats why i asked the question incase its not an isolated problem with the bigma on a *istDS.
The other 100-300mm lens was 1/5th the price if the bigma and i hadn't noticed the excess noise after conversion with it, possibly i am expecting to much in regards to quality from my new lens.

10-03-2006, 02:42 PM   #9
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ts strange thats why i asked the question incase its not an isolated problem with the bigma on a *istDS.


I shoot a sigma 170-500mm on a Ds. iso 400 or 800. There are times that noise is noticeable with the lense. Mostly in shadows as the other poster mentioned. I also shoot a Tokina 400mm atx, the noise is noticeable with it also at times. The same lenses shoot fine on my D. I won't say any more or I'll get flamed :-))

Neat Image is a program I use to clean up the noise. There's a good article at dpreveiw or steves that talks about using the 'Component Veiwer' tool in neat image. Doing the adjustments in the component veiwer gives great results over just the auto settings.
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