Posted by Patrick Nixon on December 21, 2007 at 2:29 PM
I shoot a lot of landscapes. While the minimum ISO for the D70S is 200, that is also coupled with 3008 x 2000 pixels. With this number of pixels, what is the general opinion about shooting at ISO 100 or even 50? Is there any real advantage? While I view mostly on-17-inch-computer-screen, I occasionally print large (up to 18") and I might want to project. Or, for ISO less than 200, should I carry my former N8008? I have a backpack large enough to carry that camera body as well as my D70S. Another alternative would be to carry my much smaller Nikon Coolpix 5600 point-and-shoot which can shoot down to ISO 50.
Patrick, this is really camera-dependent. Each type of sensor has its own "sweet spot", which may be 50 or 100, or 200 etc. The best thing you can do is experiment: shoot the same scene in multiple settings, then enlarge to represent your intended print size and decide whether results are acceptable to you.
The film camera and P&S will not give you any advantage in this case. One will exhibit grain at high resolution scans, and the other will be inherently more noisy since it uses a much smaller sensor.
Guy
Posted by Ed Cordes on December 21, 2007 at 8:11 PM
It was my understanding that Canon's "sweet spot" is ISO 100 and Nikon's is ISO 200. However, the other part of your question is how is it useful. I occasionally use ISO 50 to get longer shutter speeds for water/waterfalls.
Posted by ian dugdale on December 22, 2007 at 1:09 AM
I use Nikon P&S cameras for digiscoping and have tried increasing the ISO from 50 (64 for the new models) in limited light but have never kept any of the images due to unacceptable graininess. The camera's software must be aware of this too as auto-ISO never leaves 50 either.
Posted by Patrick Nixon on December 22, 2007 at 12:44 PM
I interpret the responses as saying that resolution (inherent graininess) is controlled by megapixels, thus no improvement in shooting at lower ISO. So, even if another camera were able to shoot at lower ISO, it would not produce a "less grainy" (higher resolution) image unless the megapixels were greater. Correct? On the other hand, shooting at any ISO greater than the sweet spot requires amplification, which introduces noise -- which many people see as graininess. Bottom line for me: ISO 200, 6 mpx with my D70S is fine 99% of the time. But for prints greater than about 8 x 10, I would need to upgrade to more megapixels (not lower ISO)
Posted by David Bostedo on December 22, 2007 at 2:30 PM
Patrick - Two suggestions :
1) Using the term "graininess" to mean resolution isn't really common - the resolution of your camera never changes. It's always 6 MPs. When you talk about "graininess" most people are going to think you mean the noise in your images (which make them appear static-y or grainy). This may change the "apparent resolution", but it's still 6 MPs and most people don't talk about it that way; Just use the term "noise". This is largely controlled by ISO, with lower usually better. Typically, it doesn't get any better at ISOs below the base - so for you ISO 50 and 100 won't be noticably better noise-wise than 200. Instead, they allow exposure changes for using slower shutter speeds or larger apertures.
2) You should easily be able to get good prints larger than 8x10 if the subject is properly exposed and you use good processing technique. I have a 5 MP camera, and have printed quite a few images, like this at up to 12x18 or slightly larger. If you search here, you can probably find several threads about printing large.
Posted by David Bostedo on December 24, 2007 at 3:55 PM
This is a test of linking, since Patrick had some email questions and couldn't seem to resolve them...I'm posting three links to images in my portfolio on Photoportfolios.Net.
This one is a copy of the url found if I just browse to my images via the photographer index :
Hopefully they all work...otherwise, we'll know which don't...
Posted by Kent Staubus on December 24, 2007 at 6:41 PM
Resolution (megapixels) does not seem to be directly related to grainyness (noise at higher ISO.) Resolution has to do with how fine a detail can be rendererd. Grainyness has to do with background noise. Someone correct me if I have it wrong.
Consider this. The actual size of the sensors do not seem to be getting physically larger. To get more dots in the rectangle, they are simply making the dots smaller. Size of the dot (pixel) is called "pixel pitch." Generally speaking, the smaller the pitch, the more noisy a sensor is likely to be. Thus, one number to look at when it comes to noise is NOT megapixels, but pixel pitch. Bigger pitch is better. However, the bigger the pixel the fewer that can be crammed onto a sensor. Any more, the gains in noise reducing software do seem to be effective in countering the noise from the smaller pixels, although that too seems to depend on the specific camera model.
Really, I don't pay much attention to megapixel count. The places I send my photos tell me a camera that generates around 10 MP is plenty good enough. I often use ISO 800 and even 1600 when I have to. A slightly noisy photo will sell. A slightly blurred one will not.
I'm with Kent. In general terms I pick aperture first to achieve the minimum DOF needed, then adjust shutter speed for subject and camera motion. If I can't get a fast enough shutter speed at that aperture, I start cranking up the ISO so I can increase the shutter speed. I'll take noise over undesirable blurring any day.
Posted by Basil Greber on December 25, 2007 at 5:18 AM
The D70 base sensitivity is ISO200. This is where the sensor produces the best image (best signal to noise ratio). So, going below 200 won't give you a better image on this camera. Maybe an EOS 5D at ISO100 gives the better image (definately), but for the D70, 200 is the best.
An example nicely illustrating this is the D300. It has a base sensitivity of ISO200. ISO100 is accessible via LO-1 option - but according to Nikon, ISO200 is where you find best picture quality.
So, bottom line, lower ISO does not always equate to better image quality, and when you start comparing DSLRs to film and P&S cameras, things get messy....
I interpret the responses as saying that resolution (inherent graininess) is controlled by megapixels, thus no improvement in shooting at lower ISO. So, even if another camera were able to shoot at lower ISO, it would not produce a "less grainy" (higher resolution) image unless the megapixels were greater. Correct?
Not exactly.
For starters, digital capture doesn't have grain, it has noise artifacts. They look similar but it's an important distinction. Grain comes from actual light-sensitive particles in film (the lager they are, the more visible the grain). Noise comes from electronic sampling (the better the sample, the less noise).
Many factors interfere with accurate sampling. Most prominent is the physical size of the sensor, so a camera with a smaller sensor will generally be more noisy than one with a larger sensor (e.g. a P&S camera will have more noise than a DSLR at the same ISO rating).
Other factors are exposure (if there's not enough light to be sampled, e.g. at night or in dark shadows, the results will be noisy), sensor technology (CCD vs. CMOS), heat (longer exposures will generate heat which will create noise), and the effectiveness of the specific camera's software in cleaning noise artifacts.
So, at the same ISO you can get vastly different results from different cameras, regardless of resolution.
Guy
Posted by Patrick Nixon on December 26, 2007 at 6:58 PM
This is turning out to be an interesting (and hopefully informative) thread. My thanks to all for their insightful comments. The fundamental question was whether lower ISO would produce a "less grainy" image (potentially influencing a photographer of landscapes to purchase a camera capable of lower ISO). In film cameras, the "grainyness" of an image was predominantly influenced by the film, notably the size of the particles in the emulsion. To obtain a "less grainy" appearance, a photographer had to purchase a film designed for lower ISO, normally with smaller particles in the emulsion. Exposure did not directly affect "grainyness", although some photographers believe "grain" is more noticeable at lower film exposures because the human eye is more sensitve to shadows than highlights.
What I seem to hear commenters saying here is that, in DSLRs, the "appearance" -- meaning the impression of "grainyness" -- is controlled by TWO factors: (1) resolution and (2) electronic noise. Even if there were no electronic noise whatsoever, it seems that a digital image would appear "grainy" if the resolution were poor, i.e. pixels too large or not enough pixels to record variations in light. Noise seems to be related primarily to sensitivity, as expressed by ISO. The "grain" produced by this factor can be noticeable in even moderately-sized images. But any "grain" attributable to resolution does not become noticeable until the image is greatly enlarged, as with large format photo printers or when editing on-screen at large magnifications.
Based on all this , I'll stay with my D70S (minimum ISO 200) and not move up to D80 (minimum ISO 100) or better merely because it is capable of lower ISO. There just isn't enough difference. On the other hand, the D80 probably is capable of producing "less grainy" images because it is capable of 10 MP instead of 6 and its "sweet spot" is at a lower sensitivity, thus requiring less amplification. But if I were producing larger format images, or if someone one day produces a sensor requiring much less amplification for only a few hundred dollars more ........?
Posted by David Bostedo on December 26, 2007 at 10:56 PM
Actually, Patrick, there's still possibly some clarification (although I think you mostly get this by now). As you increase the number of MPs a certain size sensor can record, you shrink the physical size of the pixels. The smaller the pixels, the more prone to noise they are. This is why point and shoot sensors are noisy - they cram 6-10 MPs into a tiny sensor. So the 10 MPs will get you a larger print at native resolution, but won't necessarily be less noisy. Less noise in an image almost always requires larger individual pixels.
For a good example, look at the noise characteristics of the Nikon D3 and Canon 1Ds III. You might get a cleaner print from the D3 due to low noise, but it will lack resolution that the Canon has. Given the same scene and print size, there's no definitive way to say which print would be better. Unless you're maybe talking 20x30 inches or something really large like that, in which case the Canon probably has an advantage. But with good upressing, not always.
I also think you're confusing a lack of resolution when you try to print/view really large, and "grain" or "noise" inherent in the capture. Usually these are treated separately, and it can be confusing to try to lump them together. Noise is inherent in the image file, in the data that was captured. The other problem you're referring to is "pixelation" caused by viewing a digital file too large. This can be mitigated by up-ressing in many cases.
Discussion
12 repliesThe film camera and P&S will not give you any advantage in this case. One will exhibit grain at high resolution scans, and the other will be inherently more noisy since it uses a much smaller sensor.
Guy
1) Using the term "graininess" to mean resolution isn't really common - the resolution of your camera never changes. It's always 6 MPs. When you talk about "graininess" most people are going to think you mean the noise in your images (which make them appear static-y or grainy). This may change the "apparent resolution", but it's still 6 MPs and most people don't talk about it that way; Just use the term "noise". This is largely controlled by ISO, with lower usually better. Typically, it doesn't get any better at ISOs below the base - so for you ISO 50 and 100 won't be noticably better noise-wise than 200. Instead, they allow exposure changes for using slower shutter speeds or larger apertures.
2) You should easily be able to get good prints larger than 8x10 if the subject is properly exposed and you use good processing technique. I have a 5 MP camera, and have printed quite a few images, like this at up to 12x18 or slightly larger. If you search here, you can probably find several threads about printing large.
This one is a copy of the url found if I just browse to my images via the photographer index :
This is the page
This one is a copy of the url I get when using the "members.photoportfolios.net/dbostedo" link to find an image :
This is the page
If I'm logged in, I see this as the url :
This is the logged in page
Hopefully they all work...otherwise, we'll know which don't...
Consider this. The actual size of the sensors do not seem to be getting physically larger. To get more dots in the rectangle, they are simply making the dots smaller. Size of the dot (pixel) is called "pixel pitch." Generally speaking, the smaller the pitch, the more noisy a sensor is likely to be. Thus, one number to look at when it comes to noise is NOT megapixels, but pixel pitch. Bigger pitch is better. However, the bigger the pixel the fewer that can be crammed onto a sensor. Any more, the gains in noise reducing software do seem to be effective in countering the noise from the smaller pixels, although that too seems to depend on the specific camera model.
Really, I don't pay much attention to megapixel count. The places I send my photos tell me a camera that generates around 10 MP is plenty good enough. I often use ISO 800 and even 1600 when I have to. A slightly noisy photo will sell. A slightly blurred one will not.
Kent in SD
An example nicely illustrating this is the D300. It has a base sensitivity of ISO200. ISO100 is accessible via LO-1 option - but according to Nikon, ISO200 is where you find best picture quality.
So, bottom line, lower ISO does not always equate to better image quality, and when you start comparing DSLRs to film and P&S cameras, things get messy....
Basil
Not exactly.
For starters, digital capture doesn't have grain, it has noise artifacts. They look similar but it's an important distinction. Grain comes from actual light-sensitive particles in film (the lager they are, the more visible the grain). Noise comes from electronic sampling (the better the sample, the less noise).
Many factors interfere with accurate sampling. Most prominent is the physical size of the sensor, so a camera with a smaller sensor will generally be more noisy than one with a larger sensor (e.g. a P&S camera will have more noise than a DSLR at the same ISO rating).
Other factors are exposure (if there's not enough light to be sampled, e.g. at night or in dark shadows, the results will be noisy), sensor technology (CCD vs. CMOS), heat (longer exposures will generate heat which will create noise), and the effectiveness of the specific camera's software in cleaning noise artifacts.
So, at the same ISO you can get vastly different results from different cameras, regardless of resolution.
Guy
What I seem to hear commenters saying here is that, in DSLRs, the "appearance" -- meaning the impression of "grainyness" -- is controlled by TWO factors: (1) resolution and (2) electronic noise. Even if there were no electronic noise whatsoever, it seems that a digital image would appear "grainy" if the resolution were poor, i.e. pixels too large or not enough pixels to record variations in light. Noise seems to be related primarily to sensitivity, as expressed by ISO. The "grain" produced by this factor can be noticeable in even moderately-sized images. But any "grain" attributable to resolution does not become noticeable until the image is greatly enlarged, as with large format photo printers or when editing on-screen at large magnifications.
Based on all this , I'll stay with my D70S (minimum ISO 200) and not move up to D80 (minimum ISO 100) or better merely because it is capable of lower ISO. There just isn't enough difference. On the other hand, the D80 probably is capable of producing "less grainy" images because it is capable of 10 MP instead of 6 and its "sweet spot" is at a lower sensitivity, thus requiring less amplification. But if I were producing larger format images, or if someone one day produces a sensor requiring much less amplification for only a few hundred dollars more ........?
For a good example, look at the noise characteristics of the Nikon D3 and Canon 1Ds III. You might get a cleaner print from the D3 due to low noise, but it will lack resolution that the Canon has. Given the same scene and print size, there's no definitive way to say which print would be better. Unless you're maybe talking 20x30 inches or something really large like that, in which case the Canon probably has an advantage. But with good upressing, not always.
I also think you're confusing a lack of resolution when you try to print/view really large, and "grain" or "noise" inherent in the capture. Usually these are treated separately, and it can be confusing to try to lump them together. Noise is inherent in the image file, in the data that was captured. The other problem you're referring to is "pixelation" caused by viewing a digital file too large. This can be mitigated by up-ressing in many cases.