The only software I have for processing and resizing images is Canon's Digital Photo Professional. The first thing I do is resize the image to 720 pixels. Next I change the file size to get the file below 200KB. This is done on a scale of 1 to 10 and usually a setting of 7 to 9 will get the results I need.
On flora and Macro this works fine, however if I try to post a landscape type photograph I cant get the file size down to 200KB until I adjust the scale half way down to 5.
First is there another way to go about this without additional software?
Second will the image quality be to poor to post an image at 50% of it's original size?
Third, why does it allow me to keep my image quailty at a higher setting with a close-up photo such as a flower but not for a landscape style photograph?
Thanks for any help you can give. Also I have a Canon 7D and shoot most images RAW and convert to JPEG, if that info helps any.
John
Posted by Lon Overacker on July 14, 2010 at 11:01 PM
John,
I can't speak to your software program, nor can we speak exactly without the examples, but IN GENERAL, many of the Flora or Macro images you have uniform, out of focus backgrounds, shallow depth of field etc. This should be pretty consistent across software programs, but again, in general, when you have color and tone that have continuous and uniform color/contrast, the compression algorithms are more easily able to compress an image to a small size. An extreme example would be: An image with just a blue sky, no clouds, no land, just blue would probably compress down to about 20K at 720px. On the other end, a landscape image with trees, leafs, textures in the rock, clouds, mountains, etc. etc. etc. contains so many unique pixels of color and contrast that these programs can not easily compress them - UNLESS they start removing pixels and cause image quality to degrade. That's where the 1-10 scale comes in. You could save that blue sky image at a quality of 10 and easily get below the 200k. A landscape or any image with tons of detail... a setting 5 might be the norm to keep under the 200k. I routinely have to use settings of 6 (well, 60% in Photoshops Save-for-web dialogue... same thing)
So, at the end of the day, there's nothing you're doing wrong or that your Canon software is doing very different than Photoshop, Elements or any other program. The bottom line is HOW MUCH data and information is in your image. Lots of detail, less compression, bigger file size. Smoother backgrounds, smoother color transistions, fewer colors, then much more compression can be done without losing quality. In other words, one last example, if you have that blue sky or any continuous color and lets say there's a string of 50 pixels where the color is exactly the same. Well, these programs can remove 49 or those pixels and represent the same information with just 1 pixel (generalized to hopefully provide an example.)
Confusing? probably. Did I help much? probably not... Hope it helps a little anyway.
Lon
Posted by Dan Borzynski on July 14, 2010 at 11:47 PM
Lon's answer is correct in a non-technical way. The technical answer is his reply with math.
John - To get a little more specific than Lon, for a 720 pixel image, a setting of 5 won't be the best, but should be perfectly acceptable. You might also want to check an see if there's a way in DPP to save without the embedded meta-data and color profile info. That can also save a good bit of size.
Lon: Yes I do understand what your saying and what's even more scary is that's kind of what I was thinking. With the shallow DOF I probably would have less data in my image compared to that of more detail such a landscape. I just didn't know if I was missing another step someplace. So, is it safe to say that the other photographer here with higher resolution cameras are decreasing their file size to 50% to 60%?
David: Thank's for your help once again, you've helped me out with other questions in the past as well. I will check next time I get a chance to see if I can save images without the embedded meta-data or color profile.
So, is it safe to say that the other photographer here with higher resolution cameras are decreasing their file size to 50% to 60%?
Now maybe someone more technical than me... can explain this better, but essentially, NO, just because someone has a bigger sensor doesn't mean they have to compress more to get to the same 720/200k file - assuming you're shooting the same scene with the two different sized sensors. If that was the case, I'm shooting the near equivalent of a 60MP camera... so with that thinking I wouldn't be able to get my scans down to those dimensions and file sizes.
It's not the original capture, sensor or file size, but HOW MUCH data is contained within that 720px dimension. An image of just blue sky will have much less data than a field of flowers and grasses. I may have more data in my original file than say a 5DMIII and that may have more pixel info than your 7D, but my assumption is that if we all took the same picture and all used the same processing to resize our files to 720px, same profiles, srgb, etc., remove meta data.... etc. etc., that we would all have approximately the same file size and have to use the same jpg quality settings. IT's not where you start, but it's the output, image dimensions and where you finish.
Am I close folks? I'f I've got this backwards, I'll retract.
"It's not the original capture, sensor or file size, but HOW MUCH data is contained within that 720px dimension. An image of just blue sky will have much less data than a field of flowers and grasses. "
True. If the image is very detailed and/or has a complex pallet of colors, the initial file size will be greater. Upon compression, 'good' data will be eliminated. In order to reach a specific file size (say, 200KB) the algorithm has to discard pixles; so, the more data contained in the image, the greater the amount of compression needed.
"...but my assumption is that if we all took the same picture and all used the same processing to resize our files to 720px, same profiles, srgb, etc., remove meta data.... etc. etc., that we would all have approximately the same file size and have to use the same jpg quality settings. IT's not where you start, but it's the output, image dimensions and where you finish. "
Discussion
6 repliesOn flora and Macro this works fine, however if I try to post a landscape type photograph I cant get the file size down to 200KB until I adjust the scale half way down to 5.
First is there another way to go about this without additional software?
Second will the image quality be to poor to post an image at 50% of it's original size?
Third, why does it allow me to keep my image quailty at a higher setting with a close-up photo such as a flower but not for a landscape style photograph?
Thanks for any help you can give. Also I have a Canon 7D and shoot most images RAW and convert to JPEG, if that info helps any.
John
I can't speak to your software program, nor can we speak exactly without the examples, but IN GENERAL, many of the Flora or Macro images you have uniform, out of focus backgrounds, shallow depth of field etc. This should be pretty consistent across software programs, but again, in general, when you have color and tone that have continuous and uniform color/contrast, the compression algorithms are more easily able to compress an image to a small size. An extreme example would be: An image with just a blue sky, no clouds, no land, just blue would probably compress down to about 20K at 720px. On the other end, a landscape image with trees, leafs, textures in the rock, clouds, mountains, etc. etc. etc. contains so many unique pixels of color and contrast that these programs can not easily compress them - UNLESS they start removing pixels and cause image quality to degrade. That's where the 1-10 scale comes in. You could save that blue sky image at a quality of 10 and easily get below the 200k. A landscape or any image with tons of detail... a setting 5 might be the norm to keep under the 200k. I routinely have to use settings of 6 (well, 60% in Photoshops Save-for-web dialogue... same thing)
So, at the end of the day, there's nothing you're doing wrong or that your Canon software is doing very different than Photoshop, Elements or any other program. The bottom line is HOW MUCH data and information is in your image. Lots of detail, less compression, bigger file size. Smoother backgrounds, smoother color transistions, fewer colors, then much more compression can be done without losing quality. In other words, one last example, if you have that blue sky or any continuous color and lets say there's a string of 50 pixels where the color is exactly the same. Well, these programs can remove 49 or those pixels and represent the same information with just 1 pixel (generalized to hopefully provide an example.)
Confusing? probably. Did I help much? probably not...
Lon
Lon: Yes I do understand what your saying and what's even more scary is that's kind of what I was thinking. With the shallow DOF I probably would have less data in my image compared to that of more detail such a landscape. I just didn't know if I was missing another step someplace. So, is it safe to say that the other photographer here with higher resolution cameras are decreasing their file size to 50% to 60%?
David: Thank's for your help once again, you've helped me out with other questions in the past as well. I will check next time I get a chance to see if I can save images without the embedded meta-data or color profile.
John
Now maybe someone more technical than me...
It's not the original capture, sensor or file size, but HOW MUCH data is contained within that 720px dimension. An image of just blue sky will have much less data than a field of flowers and grasses. I may have more data in my original file than say a 5DMIII and that may have more pixel info than your 7D, but my assumption is that if we all took the same picture and all used the same processing to resize our files to 720px, same profiles, srgb, etc., remove meta data.... etc. etc., that we would all have approximately the same file size and have to use the same jpg quality settings. IT's not where you start, but it's the output, image dimensions and where you finish.
Am I close folks? I'f I've got this backwards, I'll retract.
Lon
True. If the image is very detailed and/or has a complex pallet of colors, the initial file size will be greater. Upon compression, 'good' data will be eliminated. In order to reach a specific file size (say, 200KB) the algorithm has to discard pixles; so, the more data contained in the image, the greater the amount of compression needed.
"...but my assumption is that if we all took the same picture and all used the same processing to resize our files to 720px, same profiles, srgb, etc., remove meta data.... etc. etc., that we would all have approximately the same file size and have to use the same jpg quality settings. IT's not where you start, but it's the output, image dimensions and where you finish. "
This seems logical, to me.
If I am wrong, chew me out, too.
--P