| Author | Thread |
|
|
07/13/2003 05:48:34 PM · #1 |
Over the past few months since I've been participating on this site, I've discovered a few things that allow me to avoid grain in my photos, when that is desired. I'd like to know a few more methods of avoiding grain in-camera, if you have any tips.
Here's one: get the light right! Manipulating images either darker or lighter adds grain, so I've learned to be careful with getting the amount of light I need.
Your suggestions?
Message edited by author 2003-07-13 17:49:06.
|
|
|
|
07/13/2003 05:58:43 PM · #2 |
Originally posted by dsidwell:
Over the past few months since I've been participating on this site, I've discovered a few things that allow me to avoid grain in my photos, when that is desired. I'd like to know a few more methods of avoiding grain in-camera, if you have any tips.
Here's one: get the light right! Manipulating images either darker or lighter adds grain, so I've learned to be careful with getting the amount of light I need.
Your suggestions? |
Setting the correct ISO for the light you DO have. |
|
|
|
07/13/2003 08:16:17 PM · #3 |
| So Pedro (or anyone else), if I set my ISO to say, 400 rather than 100, I'll get a less grainy image if I'm shooting in a darker space, even though 400 is usually grainier than 100? (Just to clarify). |
|
|
|
07/13/2003 08:59:13 PM · #4 |
Originally posted by dsidwell:
So Pedro (or anyone else), if I set my ISO to say, 400 rather than 100, I'll get a less grainy image if I'm shooting in a darker space, even though 400 is usually grainier than 100? (Just to clarify). |
I see what you're saying. I've often thought the same thing. I still get grain on dark shots with a low ISO of say 100. So does low ISO(100) + longer exposure = more grain than high ISO(400)+ shorter exposure? Does apperture play a role as well?
I might start experimenting.
Message edited by author 2003-07-13 21:03:21. |
|
|
|
07/13/2003 09:09:24 PM · #5 |
Yes, I'd think so. Because 400 you won't have to adjust the curve, so even though there's SOME grain, it's a little camera grain. Bumping a curve from 100 would probly add more - would love to test this.
|
|
|
|
07/13/2003 09:29:02 PM · #6 |
I would love to get more info on ISO. I always use 100, I guess I need more info on situations in which to change it.
|
|
|
|
07/14/2003 05:20:49 AM · #7 |
I always used to use AUTO ISO when shooting in the past, so I don't know what the camera usually chose, but when shooting for my "At Work" entry, I put the ISO up to 400, because it was dark, and I remember hearing somewhere that you're meant to use a high ISO for dark conditions. I don't actually know if it did anything, except make my photos very noisey, because I still had to muck around an awful lot with shutter speed and aperture to get any half-decent shots.
Here is a section of the original camera file:
Click to see actual entry.
To reduce the grain showing up on my final entry, I resized using "Soft" resampling, and this eliminated most of it, because it kinda blurred it all out. Then I ran a very very slight neatimage, but the result was hardly noticably different.
I know that wasn't really 'Avoiding Grain' but thats how I reduce it when there is no choice but to have it.
Here is one of my outtakes:
Vocalist (Outtake)
For some reason theres not as much ISO grain on there at all, even though it was taken using the same camera settings (Can anyone shed any light on this?). Neatimage was used a bit more heavily on this one, and you can still see the remainders of the noise on the suit, and the shirt sleeve especially.
Message edited by author 2003-07-14 05:53:37.
|
|
|
|
07/14/2003 05:44:06 AM · #8 |
On my canon, I always use ISO50. I guess this is a bad habit of assuming the lower the ISO is always less-grany regardless of the lighting condition! Someone with experience please enlighten me! Thanks
|
|
|
|
07/14/2003 05:44:13 AM · #9 |
yes, changing to 400 would do something. If you change from 200 to 400, it will be 1/2 as sensitive. 100 to 400 will mean 4 times as sensitive.
With real film, the images would ge granier with increasing film speed, but that was because of the chemistry of the film. I wasn't sure if that pattern has been carried over to digital. Let us know what you get (I guess I could try it myself). |
|
|
|
07/14/2003 06:39:02 AM · #10 |
Originally posted by Konador:
For some reason theres not as much ISO grain on there at all, even though it was taken using the same camera settings (Can anyone shed any light on this?). |
ISO is basically a multiplication table. On ISO 100, the light metered by the imaging chip is processed directly. On ISO 200, the light metered is multiplied by 2 (to compensate for the loss of an EV step), iso 400, 4 and so on.
Unfortunately, the weaknesses in the imaging chip are also magnified. This is why an image at ISO 1000 will have more "grain" - the differences between the individual pixels become important, as the light available to the camera is only a tenth of what it "needs".
(try darkening an image taken on ISO 100 in Photoshop by 90 %, and then try to lighten it by 90% again. That is basically what happens)
This is where shutter times become important. If the shutter time is long, issues of temperature etc in the camera (which affect how well the weaknesses of the imaging chip show up) become significant. On a shot shutter time, the weaknesses have less time to actually make themselves apparant.
That is why you can get away with shooting with a flash on ISO 400, because the shutter time remains relatively low.
 - haje
|
|
|
|
07/14/2003 07:58:45 AM · #11 |
I dont know that much about ISO (or ASA as it used to be called). For better definition, colour saturation the lower the iso the 'better' the result? Of course the ISO setting is dependent on the amount of light available. I used to use Kodachrome 25 for my slides in extreme sunny conditions and the colour reproduced was outstanding. I would be interested to hear from somebody who really knows about ISO settings
|
|
|
|
07/14/2003 08:05:45 AM · #12 |
There's a really good definition of ISO on DPReview
ISO definition
|
|
|
|
07/14/2003 12:15:16 PM · #13 |
So is it better to capture on low ISO (50) and longer shutter speed, or high ISO (400) to avoid grain in low light situations?
Message edited by author 2003-07-14 12:16:40. |
|
|
|
07/14/2003 01:03:11 PM · #14 |
The best ways to avoid grain:
Expose correctly so you don't have to save the shot in photoshop
(The only 'correct' exposure is the one that you meant) The more you
need to tweak the result in photoshop, the worse it will be.
Use the lowest ISO value you can, that still lets you get the required aperture/ shutter speed
If you need a faster speed, go to a faster ISO.
If you need more depth of field, go to a faster ISO.
Keep your camera cool.
Aperture doesn't change the sensor noise.
Shutter speed does - longer shutter speed == more noise, everything else being equal.
Higher ISO also == more noise, everything else being equal. Typically increasing ISO by one stop reduces the needed shutter speed by one stop - it would be interesting to know if the equivalent noise is the same - I would expect it is, but that assumes the sensor noise is linear with ISO gain and exposure time. It is probably so close as to not be noticeable in real world situations though. |
|
|
|
07/14/2003 01:10:09 PM · #15 |
Originally posted by zerocusa:
So is it better to capture on low ISO (50) and longer shutter speed, or high ISO (400) to avoid grain in low light situations? |
lower ISO and longer exposure will allow more light & information to get to the sensors, thus a richer picture (obvious motion-blur difficulties aside) What Haje said above is bang-on as far as I understand it.
The reason you'd use faster film is because you want to freeze an image and have shorter exposure times. Auto racing photogs often use 1200+ film, which can appear a bit grainy, but have little motion-blur. Many landscape photogs will use really slow film (ISO 25) with 15 or 20 second exposures and get incredibly rich colours and detail.
I'm ASSUMING (I don't really know) that all this translates to digital...I make that assumption since D-cams don't actually use film, so there'd be no reason for such a setting unless they had built in a similar feature to satisfy the film-converts. :)
|
|
|
|
07/14/2003 01:32:06 PM · #16 |
always use the lowest iso you can for the subject.
if it's a still subject you can just use a long shutter speed. this will still be cleaner than a high iso and shorter shutter.
mostly you would switch to higher iso's if you need a faster shutter in the ambient light, to avoid motion blur, ie with moving objects.
|
|
|
|
07/14/2003 02:20:50 PM · #17 |
| Can anybody tell me how to use NeatImage I cant select the whole picture? |
|
|
|
07/14/2003 02:27:21 PM · #18 |
Just select a small area with an average amount of noise. Then click Sample or whatever it says (i cant remember offhand). When you apply the filter it will apply to the whole image anyway.
|
|
|
|
07/14/2003 02:37:47 PM · #19 |
|
|
|
07/14/2003 02:51:27 PM · #20 |
Wow! This has been really helpful so far! Thanks!
|
|
|
|
07/14/2003 07:15:00 PM · #21 |
Originally posted by Konador:
To reduce the grain showing up on my final entry, I resized using "Soft" resampling, and this eliminated most of it, because it kinda blurred it all out. |
Wow, that's quite a noise reduction. What software did you use to do the "soft" resampling? |
|
|
|
07/14/2003 07:36:17 PM · #22 |
Originally posted by heida:
Can anybody tell me how to use NeatImage I cant select the whole picture? |
Run the Neatimage help file. It tells you step by step. |
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 08/27/2025 03:44:54 PM EDT.
- haje
