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Old Jan 27, 2004, 9:06 AM   #1
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Default Toning down digital noise

Here's a trick for reducing noise in Photoshop:

(1) Switch to Lab Mode
(2) On the Channels palette, click on the "a" channel and then apply enough Gaussian blur to make the dots pretty much disappear.
(3) Now choose the "b" channel and press Ctrl-F to apply the exact same amount of blur to that channel.

When you return to RGB Mode, you'll find that the noise has been vastly reduced or, in some cases, apparently eliminated.
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Old Jan 28, 2004, 2:40 AM   #2
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Default Re: Toning down digital noise

Quote:
Originally Posted by bcoultry
Here's a trick for reducing noise in Photoshop:

(1) Switch to Lab Mode
(2) On the Channels palette, click on the "a" channel and then apply enough Gaussian blur to make the dots pretty much disappear.
(3) Now choose the "b" channel and press Ctrl-F to apply the exact same amount of blur to that channel.

When you return to RGB Mode, you'll find that the noise has been vastly reduced or, in some cases, apparently eliminated.
So with this... I could fix the noise in some of my pictures taken with my Canon A70?
shutter speed would have been 2 seconds at F6.3, ISO 50, max optical telephoto, no flash.
actual capture was more like 1/40 second at F4.8 (or 2.8 or between depending on my telephoto) and ISO 400, no flash, with serious editing to bring the images out of the darkness.
Or is there a better way to take night action shots without the flash? the no-flash requirement is mandatory - my flash isn't broken but I don't like blinding people.
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Old Jan 28, 2004, 12:34 PM   #3
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I don't know that you could totally fix the noise because it depends on just how much noise there is. I used it the other day on a photo that was literally half noise. The process ended up cutting the noise level down to about a quarter.

Hopefully, someone with the same camera as you have will spot this post and give you specific advice. Each camera seems to be different, with differing levels of noise. Also, I don't often take action shots.
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Old Jan 29, 2004, 1:05 AM   #4
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hmm...
I would like a way to take no-flash action shots at night or from far away or in a dark to medium lit room. If I get another camera < $500 in about 8 months to a year what would be a good one to get? I would like to be able to make prints with a resolution of around 400-500 dpi at 4"x6" (5MP or 6MP - 8MB like Sony DSC-F828 might be ok too). Also I want to be able to take pictures (in daylight - don't know how to get good clear nighttime pictures..) at distances of, say, 250 to 500 feet, maybe. I have a 1GB CF card but with whatever I get I would want to be able to hold at least 500 pictures at the highest res and highest quality setting (if uncompressed, maybe 200-250 or so).
What would be some good types / brands / models to look at? I probably won't get one for at least 4 to 6 months unless a really good deal on a good camera in my price range (which would be considerably lower if I got one sooner) comes my way.
Maybe I should post this in a different forum, though...
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Old Jan 29, 2004, 8:09 AM   #5
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Quote:
I would like a way to take no-flash action shots at night or from far away or in a dark to medium lit room.
If you're referring to doing this without flash, so would we all, so would we all. I'm not sure, but I think this camera has yet to be invented.

Quote:
I would like to be able to make prints with a resolution of around 400-500 dpi
If you're referring to the resolution the printer is using, then that's essentially a separate issue from the photo's resolution, which is measured in pixels, not dots. For printing to an inkjet, you shouldn't need more than 300ppi, and often you can actually go with less without any degradation.

Quote:
at distances of, say, 250 to 500 feet
You'll want as much zoom as you can get (all of us want that), but just make sure it's optical, not digital, zoom.
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Old Jan 29, 2004, 9:31 AM   #6
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pianoplayer88key

You are asking for the impossible. I agree with bcoultry, everyone would like a camera that could do what you describe.

I don't believe that many printers will print at over 300dpi... you'd have to spend a lot of money to get something that will. Most will just down-sample the resolution and print at its max DPI. but it isn't necessary. If you can print at 300dpi, you'll get a very good print. Note that a pixel turns into multipel dots on the paper.

To take a picture of a subject 250-500 feet away is possible with any camera... it's just that the subject will be very small. What are you taking the picture of? People? If so, they will be very small. You realize that is over the length of a football field? Have you ever seen the equipment that photographers use on the sidelines of soccer or football games? Huge lenses. 3-7 thousand dollar lenses. And even then they still only take pictures of people about... 30-50 feet away.

You question about number of pictures on a card I can answer. I have a 6.1MegaPixel camera (Canon 10D) and I use a 1G flash card. I believe I get a bit over 400 pictures per card at the highest JPG setting. Maybe more. I don't think I get to 500, but it's close. So if you went with a camera that was 8MP, you won't get 500 at the highest setting.

Yes, I'd suggest you ask as a separate post, but I'd also suggest you reassess your needs, as nothing will satisfy them.

Eric
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Old Jan 29, 2004, 4:37 PM   #7
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Quote:
Originally Posted by bcoultry
Quote:
I would like a way to take no-flash action shots at night or from far away or in a dark to medium lit room.
If you're referring to doing this without flash, so would we all, so would we all. I'm not sure, but I think this camera has yet to be invented.
--------------------/

What about a camera with night vision mode? For some night shots I might be willing to accept pics with a different color scheme than you get with normal daytime shots. (for example the Sony DSC-F828 I think has a night vision mode, doesn't it? except that it won't fit in my pants pocket (even though I'm sure a Canon G5 would fit in there fairly easily))

-------------------\

Quote:
I would like to be able to make prints with a resolution of around 400-500 dpi
If you're referring to the resolution the printer is using, then that's essentially a separate issue from the photo's resolution, which is measured in pixels, not dots. For printing to an inkjet, you shouldn't need more than 300ppi, and often you can actually go with less without any degradation.

Quote:
at distances of, say, 250 to 500 feet
You'll want as much zoom as you can get (all of us want that), but just make sure it's optical, not digital, zoom.
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Old Jan 29, 2004, 4:47 PM   #8
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Quote:
What about a camera with night vision mode? For some night shots I might be willing to accept pics with a different color scheme than you get with normal daytime shots. (for example the Sony DSC-F828 I think has a night vision mode, doesn't it? except that it won't fit in my pants pocket (even though I'm sure a Canon G5 would fit in there fairly easily))
Night vision is a good point. Hadn't thought of that.

I'm not sure how many cameras can shoot in infra-red, but I bet there are a few out there. Wait a sec... I think I've read NHL say that the Minolta D7 family can. They are a bit expensive, but you also get a lot for your money. Good cameras. I think they have decent (optical) zooms as well. You might want to check out Steve's reviews of the cameras, there are several:

http://www.steves-digicams.com/2001_...s/dimage7.html (2001)
http://www.steves-digicams.com/2002_.../dimage7i.html (2002)
http://www.steves-digicams.com/2002_...dimage7hi.html (late 2002)

I don't know if they all can do IR photography, but they might. Try posting a question speficially about what cameras do infra-red photography and you might get some answers... I've never tried it.

It should be said that none of the D7 family will fit in your pocket either.

Eric
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Old Jan 29, 2004, 4:52 PM   #9
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Quote:
Originally Posted by eric s
pianoplayer88key

You are asking for the impossible. I agree with bcoultry, everyone would like a camera that could do what you describe.

I don't believe that many printers will print at over 300dpi... you'd have to spend a lot of money to get something that will. Most will just down-sample the resolution and print at its max DPI. but it isn't necessary. If you can print at 300dpi, you'll get a very good print. Note that a pixel turns into multipel dots on the paper.

To take a picture of a subject 250-500 feet away is possible with any camera... it's just that the subject will be very small. What are you taking the picture of? People? If so, they will be very small. You realize that is over the length of a football field? Have you ever seen the equipment that photographers use on the sidelines of soccer or football games? Huge lenses. 3-7 thousand dollar lenses. And even then they still only take pictures of people about... 30-50 feet away.

You question about number of pictures on a card I can answer. I have a 6.1MegaPixel camera (Canon 10D) and I use a 1G flash card. I believe I get a bit over 400 pictures per card at the highest JPG setting. Maybe more. I don't think I get to 500, but it's close. So if you went with a camera that was 8MP, you won't get 500 at the highest setting.

Yes, I'd suggest you ask as a separate post, but I'd also suggest you reassess your needs, as nothing will satisfy them.

Eric
Ok, so maybe I don't really need all that nice stuff, but... what could I get with, say, a decent 5MP, 6MP or 8MP camera, a 7x or better optical zoom, aperture F2.0, etc.? I don't like cranking my Canon A70 above ISO 50 (ISO 100 if I have to, although I HAVE done 200 and 400 on a few occasions), but if my next camera is better at image noise rejection than my A70 that would be nice. (for example ISO 200 or even 400 on that camera would be comparable to ISO 50 on my Canon).
Also it'd be nice to have something that fits in my pocket (for example a Canon G5 I'm sure would fit with a little bit of room to spare, with the lens retracted. A Minolta S404 does just fine in there. Do you think there's any chance that a swivel lens camera like the Sony DSC-F828 might fit?
So being realistic, what can I expect to get for $500, $750, or $1000? (at the highest price levels I would want it to include the lenses if it's a dSLR, and include at least one 2GB flash card (or 4GB if it supports it and the prices have come down by then). I'm thinking about getting one sometime maybe as early as May or June, but probably not till August or Oct or Nov, or even early December 2004. Is there a chance that there might be a good camera that maybe isn't announced now that might be in my price range then, or should I wait for the prices on current cameras to come down, and how much should I expect the prices to drop on, say, Canon, Minolta, Sony, any other good brands?
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Old Jan 29, 2004, 5:04 PM   #10
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I'd suggest you look at the various possibilities in cameras at the stores that sell them such as B&H. For a thousand dollars, you aren't going to see accessory lenses included in a dSLR package, nor are you going to see whopper CF cards. If you look at the packages being sold, you'll get a realistic idea of what you get in the basic package and what you'll have to spend to get the rest of the stuff you want. Start doing this now before you end up deeply disappointed.
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