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09-09-2010, 01:01 PM   #1
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Resolution question

My K-x camera gives me in raw,a resolution of 4288x2848.
My screen resolution is 1920x1200.
I resize my pictures using Irfanview.But why is it that I can view the raw image that fits my screenwithout changing the resolution,or is that just in the photo editor that I am using.
I keep changing the resolution down to my screen size.
Confused about this!

09-09-2010, 01:32 PM   #2
Ash
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Hi there.
The resolution of your original image stays the same and your software simply downsizes it visually in order to fit in the screen, effectively scaling the down the image. You should see this somewhere on the title bar of the window, showing the percentage reduction required to fit it on the screen.
09-09-2010, 01:39 PM   #3
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QuoteOriginally posted by Ash Quote
Hi there.
The resolution of your original image stays the same and your software simply downsizes it visually in order to fit in the screen, effectively scaling the down the image. You should see this somewhere on the title bar of the window, showing the percentage reduction required to fit it on the screen.
I do see the scaling so I understand that now.
Why should I not have my camera take pictures at 1920x1200 if that is the best I can view?
I do not print images,only view them on my computer.
09-09-2010, 01:51 PM   #4
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QuoteOriginally posted by TWN Quote
I do see the scaling so I understand that now.
Why should I not have my camera take pictures at 1920x1200 if that is the best I can view?
I do not print images,only view them on my computer.
I like to keep the picture above what my computer monitor can see, because I want the option to be able to crop the picture. I can always resize it afterwords.

Caveat: I do sometimes reduce the picture size in the camera options for certain situations: Sport events, wildlife in flight, etc... so I can take faster shots. But for family/portraits/landscape/etc, I perfer the best picture the camera can take.

My 2 cents.

09-09-2010, 01:54 PM   #5
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QuoteOriginally posted by TWN Quote
I do see the scaling so I understand that now.
Why should I not have my camera take pictures at 1920x1200 if that is the best I can view?
I do not print images,only view them on my computer.
Good question, and based on what you do now, you're correct.

However:

Don't you believe that in the future, you will capture special pictures that you DO want to print? And the only reason you won't be able to us because of...wait:

For what reason? To save space on your card and/or computer?

But there's another reason to shoot in higher resolution:

Once you get into even semi-serious retouching in post processing, like Photoshop or other, in MANY retouching tasks, you want to be able to magnify your image on screen 200, 300, even 400% to be able to properly work on that given segment of the image. If your image is the size you're suggesting, you can't make it greater than
100% without it turning to blocks of garbage.

An example of this would be a full body portrait of someone--but he has red-eye and you want to zoom
in and select the red area to fix. You need the resolution in the original file or it's next to impossible to properly select the edges of the red area and not also select the areas that DON'T need fixing.
09-09-2010, 01:57 PM   #6
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QuoteOriginally posted by chalion Quote
I like to keep the picture above what my computer monitor can see, because I want the option to be able to crop the picture. I can always resize it afterwords.

Caveat: I do sometimes reduce the picture size in the camera options for certain situations: Sport events, wildlife in flight, etc... so I can take faster shots. But for family/portraits/landscape/etc, I perfer the best picture the camera can take.

My 2 cents.
Image size has nothing to do with image quality, unless you're printing at a size where it matters--and it doesn't always.
09-09-2010, 02:23 PM   #7
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Best colours and sharpness are my concerns.

I have enough disk space where that is not an issue.

I was more curious than anything else.

This is just one of those times where I needed an explanation as to why doing something this way was better than doing it that way.

Thanks for the help.
09-09-2010, 02:35 PM   #8
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QuoteOriginally posted by TWN Quote
Best colours and sharpness are my concerns.
I have enough disk space where that is not an issue. I was more curious than anything else .This is just one of those times where I needed an explanation as to why doing something this way was better than doing it that way.
Thanks for the help.
Totally understood, and like I said, you asked a very good question. But I hope that I properly explained that image size has little to do with image quality, and you're not printing the file.

For example, if your camera allowed you to shoot a 72 by 150 image, you understand that this would be worthless in
many ways, allowing you a 1 inch by about 2 inch
viewable image.

It will still look GREAT at that size, but that's about it,

09-13-2010, 11:45 AM   #9
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Ira is quite right, as always. (He's right about everything except M42-PK adapters, but that's another story.) Perfection does not lie within resolution; art does not rely upon pixels. And virtually EVERY image you see on a computer has been processed and resized. Net/Web image resolution (pixel density) is 72 dpi. Consider that the overwhelming proportion of images shown on the Net/Web were shot at densities MUCH higher than 72dpi. Measure your own 1920x1200 screen to see how many inches it has and thus its display density.

It's generally a Very Good Thing that (taken) image densities are much greater than (displayed) image densities, because non-perfect pictures shown at 100% reveal their non-perfections, whereas downsized images hide those realities. Shown small enough, almost anything can look good; and shown huge enough, almost anything can look bad. Example: Keep hitting the '+' button on your image browser till you hit 1000%. Tell us how good the results look, eh?
A penny saved is a penny.
09-13-2010, 01:25 PM   #10
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QuoteOriginally posted by RioRico Quote
Ira is quite right, as always. (He's right about everything except M42-PK adapters, but that's another story.) Perfection does not lie within resolution; art does not rely upon pixels. And virtually EVERY image you see on a computer has been processed and resized. Net/Web image resolution (pixel density) is 72 dpi. Consider that the overwhelming proportion of images shown on the Net/Web were shot at densities MUCH higher than 72dpi. Measure your own 1920x1200 screen to see how many inches it has and thus its display density.

It's generally a Very Good Thing that (taken) image densities are much greater than (displayed) image densities, because non-perfect pictures shown at 100% reveal their non-perfections, whereas downsized images hide those realities. Shown small enough, almost anything can look good; and shown huge enough, almost anything can look bad. Example: Keep hitting the '+' button on your image browser till you hit 1000%. Tell us how good the results look, eh?
A penny saved is a penny.
Would it be safe for me to say that the larger the number of pixels then the better the quality/sharper of picture?

I'm legally blind so it's harder for me to focus my camera therefore I need to take advantage of any tricks,like shooting in the highest camera resolution poosble or not to be concered about that because computer screen resolution negates any benifit of higher camera resolution.

My screen magnifier is 6X magnification so I do see a lot of imperfections
09-13-2010, 08:45 PM   #11
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QuoteOriginally posted by TWN Quote
Would it be safe for me to say that the larger the number of pixels then the better the quality/sharper of picture?
Well, we *could* say that, ALL ELSE BEING EQUAL, more megapickles mean a sharper picture. But all else are rarely equal. When more pixels are scrunched into a small sensor, the result is more noise. On another forum is a debate over whether M4/3-system users are more noise-tolerant because those tiny sensors (about 1/2 of APS-C size) are cruddier. In general, with similar sensor density, more megapickles give better detail and greater dynamic range. The advantage mostly appears in closely-inspected enlargements.
09-14-2010, 06:29 AM   #12
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The "What resolution is good enough?" question is hard to answer without understanding the questioner's purpose. Here's a good example - the fuzzy photo has better resolution than the sharp one - which do you prefer? Which would you prefer if your purpose was only to read the chart?


The above image is from a good article by Ben Wells on the topic.

Regarding the OP's question, I suspect that so long as the camera's resolution (ie pixel count) is greater than the display's resolution (pixel count), a small change in camera resolution won't be noticeable. Extra sensor resolution would allow cropping if desired, but not add much to a non-cropped image.

Good display contrast at the 1-2 line per mm level for viewing at 30mm or so is apparently what we like as casual viewers; I'm not sure how that translates into sensor resolution, but suspect it is something like a 50% MTF at the equivalent sensor resolution. This implies a sensor pixel count about twice that of the display pixel count?

Dave

PS regarding the "is more better?" question, It seems to me that more is better only to a point of diminishing returns. Say you have a perfect sensor of a particular size and the displayed image is just an enlargement of the sensor's image. Now imagine subdividing the sensor into pixels; 4 then 8, then 16, etc... The image you see will be pixelated until you reach a pixel count that corresponds to something around 2 lines per mm on the enlarged image. How could further subdivision of the sensor improve the image observed?

Last edited by newarts; 09-14-2010 at 06:37 AM.
09-15-2010, 12:05 PM   #13
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QuoteOriginally posted by newarts Quote
The "What resolution is good enough?" question is hard to answer without understanding the questioner's purpose. Here's a good example - the fuzzy photo has better resolution than the sharp one - which do you prefer? Which would you prefer if your purpose was only to read the chart?


The above image is from a good article by Ben Wells on the topic.

Regarding the OP's question, I suspect that so long as the camera's resolution (ie pixel count) is greater than the display's resolution (pixel count), a small change in camera resolution won't be noticeable. Extra sensor resolution would allow cropping if desired, but not add much to a non-cropped image.

Good display contrast at the 1-2 line per mm level for viewing at 30mm or so is apparently what we like as casual viewers; I'm not sure how that translates into sensor resolution, but suspect it is something like a 50% MTF at the equivalent sensor resolution. This implies a sensor pixel count about twice that of the display pixel count?

Dave

PS regarding the "is more better?" question, It seems to me that more is better only to a point of diminishing returns. Say you have a perfect sensor of a particular size and the displayed image is just an enlargement of the sensor's image. Now imagine subdividing the sensor into pixels; 4 then 8, then 16, etc... The image you see will be pixelated until you reach a pixel count that corresponds to something around 2 lines per mm on the enlarged image. How could further subdivision of the sensor improve the image observed?
Well the reason I asked was because I am legally blind and I use my computer screen at 6X magnification,except when I first view a photo at regular resolution,then I increase the magnification to 6X.Details pop out at that 6x mag.But I run a photo screensaver at regular size and can usually make out what am am seeing without any detail.

The on camera display is of no real use to me as it is to blurry and I have to use a magnifying glass to read anything/settings on the camera and on the screen.

None of this is a big deal but I just want to get the best detail/sharpness I can.

Thanks for the reply.
09-15-2010, 03:49 PM   #14
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QuoteOriginally posted by TWN Quote
Well the reason I asked was because I am legally blind and I use my computer screen at 6X magnification,except when I first view a photo at regular resolution,then I increase the magnification to 6X.Details pop out at that 6x mag. But I run a photo screensaver at regular size and can usually make out what am am seeing without any detail.

The on camera display is of no real use to me as it is to blurry and I have to use a magnifying glass to read anything/settings on the camera and on the screen.

None of this is a big deal but I just want to get the best detail/sharpness I can.

Thanks for the reply.
I'm assuming that when you enlarge text by 6x you are enlarging line widths as well as lengths; true?

If so, from the little I understand about normal photographic quality it is a good bet that if an image you magnify by 6X and view from 12-14" appears to have good enough contrast for you, it will also be good un-enlarged for a person who does not use such enlargement to read text.

Do normally sighted viewers say your un-enlarged photos are crisp & sharp?
09-16-2010, 07:25 PM   #15
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QuoteOriginally posted by newarts Quote
I'm assuming that when you enlarge text by 6x you are enlarging line widths as well as lengths; true?

If so, from the little I understand about normal photographic quality it is a good bet that if an image you magnify by 6X and view from 12-14" appears to have good enough contrast for you, it will also be good un-enlarged for a person who does not use such enlargement to read text.

Do normally sighted viewers say your un-enlarged photos are crisp & sharp?

No one sees my computer screen so I can only go by what I see.Everything is magnified 6X.

I can't focus my K-x because the image I see is too small and blurred.I therefore use auto focus.I shoot in raw.

I think I will keep the resolution set to where it is.Maybe sometime in the future when I understand how to operate my camera better I might try a different resolution.

Thank you for your reply
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