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View Full Version : Digital photos, ISO and noise


Mike Landi
February 23rd, 2006, 06:22 PM
A question for you.

Do you lock the ISO of your G6 to a certain quality or do you leave it on auto?

Judy G. Russell
February 23rd, 2006, 10:43 PM
I lock it at 50 and move it up only when I have to. There's a lot of noise as you move up to higher ISO, and I personally find it easier to stabilize the camera (tripod, etc.) to use a longer exposure than to get rid of the noise.

Mike Landi
February 24th, 2006, 10:34 AM
I lock it at 50 and move it up only when I have to. There's a lot of noise as you move up to higher ISO, and I personally find it easier to stabilize the camera (tripod, etc.) to use a longer exposure than to get rid of the noise.

Interesting. I've wondered just what the Auto setting does. Does the computer first open the appature, then slow the shutter, then raise the ISO to set the camera? I like the Auto setting when I need to hand the camera to someone else for a shot, but I always wondered what the decision order is for the on board computer.

I know the camera gets noisy over ISO 100, but I thought 100 was still good.

Judy G. Russell
February 24th, 2006, 02:03 PM
I've never been entirely sure how the Canon selects the ISO, so I never use auto mode; I use program mode instead. It's as handy as auto for handing the camera off to someone else, but allows you to select ISO, flash mode, etc. Remember that most Canons are a bit off in ISO -- what Canon says is ISO 50 is what most cameras define as ISO 100. So ISO 100 is really closer to ISO 200, and you can pick up some serious noise there. I still use it, at times, when ISO 50 is just too slow, but it can be noisy.

Mike Landi
February 24th, 2006, 02:27 PM
I've never been entirely sure how the Canon selects the ISO, so I never use auto mode; I use program mode instead. It's as handy as auto for handing the camera off to someone else, but allows you to select ISO, flash mode, etc. Remember that most Canons are a bit off in ISO -- what Canon says is ISO 50 is what most cameras define as ISO 100. So ISO 100 is really closer to ISO 200, and you can pick up some serious noise there. I still use it, at times, when ISO 50 is just too slow, but it can be noisy.

I use Program mode most of the time. I just checked the review I read when I bought the G3. They said that the Canon ISO 50 is more like a ISO 80.

I've kept my G3 locked on 50 for years, but I wondered if I was making the right choice. Seems like I did. <g>

Judy G. Russell
February 24th, 2006, 06:44 PM
I've kept my G3 locked on 50 for years, but I wondered if I was making the right choice. Seems like I did. <g>Yup. Now, mind you, there are circumstances where upping the ISO makes sense. For example, you're in a low light situation where you have no choice but to hand-hold the camera. And there are noise-removal programs that will help. But it's always best to go low ISO when possible. This is particularly true when shooting kids, since you don't want a great amount of sharpness in shots of kids (soft is made for kids) and any noise removal system depends on sharpness.

Gary Maltzen
February 24th, 2006, 08:45 PM
But it's always best to go low ISO when possible. This is particularly true when shooting kids, since you don't want a great amount of sharpness in shots of kidsHmm, at first glance seems a bit counter-intuitive to someone who has been shooting film for years - drop the ISO, increase the exposure time resulting in a less grainy image.

Mike Landi
February 24th, 2006, 09:24 PM
(soft is made for kids)

<g>

Depends on the kids. Sometimes, mine need a hard bit of sharpness.

Mike Landi
February 24th, 2006, 09:26 PM
drop the ISO, increase the exposure time resulting in a less grainy image.

Always. The lower the ISO, the slower the film, the more light needed to expose it, but the more detail (less grain).

Dan in Saint Louis
February 25th, 2006, 09:33 AM
Always. The lower the ISO, the slower the film, the more light needed to expose it, but the more detail (less grain).
There is a tradeoff here.

Slower film, smaller grain, thus more detail.

Slower film, slower shutter speeds, thus more blur. Wider aperture, thus less depth of field.

In practice, I have not found grain to be objectionable except in very large prints; so the higher film speeds actually provided sharper pictures. (Of course, some of my favorite subjects move around in the vcinity of 200 MPH http://landiss.info/racing/1975AprilMay/Scan027_jpg.html (http://landiss.info/racing/1975AprilMay/Scan027_jpg.html).)

Judy G. Russell
February 25th, 2006, 10:56 AM
Hmmm... the way I said it, it really didn't come out right. What I mean is, you don't want a lot of graininess in shots of children. You want sharpness of detail, yes, but not grain. When you're talking digital, grain = noise, and the higher the ISO, the more noise.

Judy G. Russell
February 25th, 2006, 10:57 AM
A little difference between those sorts of photo subjects and, say, a small child! (Who only moves at 199mph!)

Judy G. Russell
February 25th, 2006, 10:58 AM
As in "sit down and STOP THAT!!!"?

Mike Landi
February 26th, 2006, 09:37 AM
I tend to crop and enlarge lots of my photos, so I notice grain quickly.

I'll have to experiment a little bit.

Mike Landi
February 26th, 2006, 09:38 AM
<LOL>

Yup!

Judy G. Russell
February 26th, 2006, 10:26 AM
For those times when you NEED it (when you have to shoot at a high ISO then need to clean up the noise), consider Neat Image (http://www.neatimage.com/).

Mike Landi
February 26th, 2006, 09:01 PM
You've recommended this program to me before.

Maybe I'll grow a brain and try it....

Judy G. Russell
February 26th, 2006, 10:24 PM
It does quite a nice job -- one of only a handful of programs I'd recommend unhesitatingly.

Mike Landi
February 27th, 2006, 08:26 AM
It's on my "check it out list", which will probably be looked at this week.

Quite week at work here. Everyone, including the boss, is on vacation. (The boss is at Key West!)

There is no one here bu me!

Judy G. Russell
February 27th, 2006, 12:00 PM
Quite week at work here. Everyone, including the boss, is on vacation. (The boss is at Key West!) There is no one here bu me!Which means, of course, you should be at least twice as productive as usual -- it's all the interruptions that slow down the work flow!

Mike Landi
February 27th, 2006, 01:06 PM
<ROFL!>

Productive....yeah.

Lots of coffee and I'm still getting sleepy staring at the monitor.

Judy G. Russell
February 27th, 2006, 03:05 PM
I do that when my boss is around too!

Mike Landi
February 27th, 2006, 03:45 PM
It does quite a nice job -- one of only a handful of programs I'd recommend unhesitatingly.

Okay, add another to the "I should have listened to Judy earlier" list. :o

That is some program!

Which version do you use? Is the 16-bit function important? I could take or leave the plug-in stuff, I have no problem launching a stand alone program.

Judy G. Russell
February 27th, 2006, 04:06 PM
Which version do you use? Is the 16-bit function important? I could take or leave the plug-in stuff, I have no problem launching a stand alone program.At the moment, I'm just using the garden variety Home version. The 16-bit function isn't important unless you work a lot with the RAW files. I've found that, for the most part, I get enough detail by converting from RAW to JPG (or for a less lossy conversion to TIFF) and then working with the JPG (or TIFF) file.

Mike Landi
February 27th, 2006, 09:27 PM
The 16-bit function isn't important unless you work a lot with the RAW files.

Thanks, that's what I was wondering about.

...off to spend $ for a very good program! <g>

Judy G. Russell
February 27th, 2006, 11:48 PM
You'll have fun with it... it works very nicely indeed.

Mike Landi
February 28th, 2006, 08:25 AM
Now, I have to learn how to use this thing.

Judy G. Russell
February 28th, 2006, 05:12 PM
Now, I have to learn how to use this thing.Gee, ya think so? Don't suppose you might, like, maybe, read the... no, never mind...

Mike Landi
February 28th, 2006, 06:30 PM
Did you just imply that this software cannot be figured out by fooling around with it?

...maybe I should ask for a refund. <g>

Judy G. Russell
February 28th, 2006, 08:03 PM
Did you just imply that this software cannot be figured out by fooling around with it?Would I do such a thing????

Mike Landi
February 28th, 2006, 08:20 PM
<g>

So, you know what all of those sliders do?

Judy G. Russell
February 28th, 2006, 10:55 PM
Nope. But I play with 'em until I get the image looking the way I want, anyway.

Mike Landi
March 1st, 2006, 09:01 AM
...and I thought I was the only one who did that. <g>

Judy G. Russell
March 1st, 2006, 09:47 AM
Hardly. I suspect everybody who's ever had a complex software program of any kind does that pretty routinely. After all, we can't possibly (gasp) read the... no. Not us!

Mike Landi
March 1st, 2006, 10:03 AM
we can't possibly (gasp) read the

"the"...?

When does software require reading something? <g>

Judy G. Russell
March 1st, 2006, 08:18 PM
Believe it or not I've occasionally read the #$%ing manual. I don't think I've ever understood one, even one purportedly in English. But I have occasionally read one!

Mike Landi
March 2nd, 2006, 06:25 AM
Believe it or not I've occasionally read the #$%ing manual. I don't think I've ever understood one, even one purportedly in English. But I have occasionally read one!

I started to look at the Neat Image manual, and decided that I really did not know what it was talking about. <g>

Judy G. Russell
March 2nd, 2006, 09:12 AM
Truthfully, I don't understand most of it either. But playing with the settings and looking at different advanced options tends to get me a result I'm happy with.

Mike Landi
March 2nd, 2006, 09:23 AM
I'm stunned at just what it can do. I have to try to create a noise profile for my A310 and my scanner. I think I will get a lot of use out of this program.

Judy G. Russell
March 2nd, 2006, 09:57 AM
Particularly for anyone who shoots digital, it's a must-have. How it manages to clean up the noise, I don't know -- but it does!

Mike Landi
March 2nd, 2006, 12:41 PM
How it manages to clean up the noise, I don't know -- but it does!

Some mathematic genius created equations, I assume.