Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old May 6, 2012, 1:54 PM   #1
Senior Member
 
Join Date: Aug 2006
Location: Irvine, CA
Posts: 750
Default Photo posting

Hi, I know this has been pounded into the ground but I am hoping for a solution.
I have the new Sony A77 with 24 mp sensor.

I downsized my pics for posting to 884x768, .68mp, 10,368kb, which I think is still to large to retain exif data.
Is the 24mp sensor my problem?

What do I need to do?

Thanks.
__________________
A77, 28-75mm f/2.8, 16-50mm f2.8, 18-250mm f3.5, 70-300mm f4.5G SSM
Flying Fossil is offline   Reply With Quote
Sponsored Links
Old May 6, 2012, 2:25 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

No. It's not the 24MP Sensor.

It sounds like you want to post 884x768 (less than 1 Megapixel) resolution photos, not 24 megapixel photos. ;-)

If you're seeing a file size of 10,368KB (around 10MB), something is *very* wrong with the way you're downsizing them and saving them.

What tool (editor) are you using to downsize them with?

What JPEG Quality setting are you using?

Are you sure you're saving them as JPEG and not TIFF files or some other format?

The file size you get for a given resolution JPEG image will be impacted by the JPEG Quality Settings (a.k.a., JPEG Compression amount) used in the editor you're using to downsize them with.

Usually, a JPEG Quality Setting of around 8 (if the editor uses a 1 to 10 or 1 to 12 scale for JPEG Quality) will get the file size down to within the maximum sizes allowed here for an image downsized to around 884x768 pixels for dimensions. Or, use around 80% Quality using an editor that has a percentage scale instead.

10,368KB file size for an image that's only 884x768 in size? Heck, the full size 24MP images from a Sony A77 are usually not that large.

Checking through the samples in our A77 Preview, only one 6000x4000 pixel (24 Megapixel) JPEG image we posted was that large (the hippo photo). Most of the others were a lot smaller in file size (file size will vary by content with JPEG compression).

http://www.steves-digicams.com/camer...hotos-159.html

Nah... something is *very* wrong with the way you're downsizing them (file type, jpeg quality settings, etc.) if you're seeing 10,000KB file sizes from an 884x768 pixel image, as that's what you'd expect to see for a full size 24MP (6000x4000 pixel) image with good jpeg quality settings and lots of detail.

If you're sure the dimensions are correct (you actually downsized them to 884x768 pixels for dimensions), then the file type is probably wrong (not JPEG), or you're doing something like using a quality setting of 12 or 100% (which means virtually no JPEG compression is being used).

Again, what tool are you trying to use to downsize them with, and have you checked the JPEG quality settings you're using (making sure you're using JPEG as the file type your saving the downsized images to)?
JimC is offline   Reply With Quote
Old May 6, 2012, 2:53 PM   #3
Senior Member
 
Join Date: Aug 2006
Location: Irvine, CA
Posts: 750
Default

Thanks for the quick response.
I made a mistake. the 10, 368kb was the original photo size.
The resize is 342kb. It is a .jpg and I used FastStone Image viewer to reduce the original.

I do not see a quality setting to modify.
__________________
A77, 28-75mm f/2.8, 16-50mm f2.8, 18-250mm f3.5, 70-300mm f4.5G SSM
Flying Fossil is offline   Reply With Quote
Old May 6, 2012, 3:19 PM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

That sounds more likely (384KB). ;-)

FastStone Image Viewer, huh?

When you use the File>Save As menu to save an image you've downsized, you'll see a button or link for JPEG quality settings on the screen that comes up. Click on it (it probably has the default JPEG Quality settings shown, and when you click on JPEG quality from that screen, you'll see Sliders come up that you can use to adjust the quality. It probably defaults to around 90 on a scale of 0 to 100. Around 80 would probably get the final image so that it's file size is smaller than allowed.

The screen that loads when you click on JPEG Quality lets you see the final file size when you move the Quality Slider, so you can make sure the size is within the maximum allowed (253.9KB is the max allowed file size for the forums here if you don't want the forums software stripping out the EXIF info and recompressing your images).

Chances are, there is a Global Setting for JPEG quality somewhere in it's setup screens, too. I'm not in Windows right now to load and check it.

But, if memory serves, if you use the File>Save As menu choice after you resize an image, you should see a link on that File>Save As screen somewhere for JPEG Quality that gives you a screen with JPEG Quality sliders for the file you're saving.

Chances are, a setting of around 80% will get you to within the file size limits for posting a photo that's been downsized to those dimensions (approx. 884x768). But, you should be able to see the file size when you move the quality slider with the FastStone Image Viewer. So, just move it until you get a file size that's lower than 253.9KB.

Most other image editors will allow you to adjust JPEG Quality (a.k.a., JPEG Compression amount) when you use their File>Save As menu choice, too. Sometimes you see the slider on the first screen that comes up. Sometimes you see a way to set it if you click on a button for Advanced, Quality Setting, etc.

Some use a 1 to 10 or 1 to 12 scale, some use a 0 to 100 scale, etc. But, they're all doing the same thing, compressing the images more or less based on the jpeg quality settings, which changes the final file size.

The File Size you can expect for a given image size and quality setting will vary by image content (for example, if you have an area with lots of the exact same color, it's going to compress better and give you a smaller file size than an area that has lots of different color shades and details in it).

But, again, around 8 on a 1 to 10 scale (or around 80 on a 0-100 scale) is usually going to be about right for most images downsized to those dimensions. Tweak as needed to get the file size within limits (something the FastStone Image Viewer can show you when you use it's JPEG quality sliders).
JimC is offline   Reply With Quote
Old May 6, 2012, 6:37 PM   #5
Senior Member
 
Join Date: Aug 2006
Location: Irvine, CA
Posts: 750
Default

Thanks for the help.
I will post a shot here to see how/if it works.
Attached Images
 
__________________
A77, 28-75mm f/2.8, 16-50mm f2.8, 18-250mm f3.5, 70-300mm f4.5G SSM
Flying Fossil is offline   Reply With Quote
Old May 6, 2012, 6:48 PM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Worked fine. Image within allowed sizes, EXIF still embedded (meaning the forum software did not modify it).
JimC is offline   Reply With Quote
Old May 6, 2012, 6:53 PM   #7
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

P.S.

As an FYI, I do see where you had the aperture stopped down to f/14 for that image.

Note that you'll start seeing softer images due to diffraction issues when stopping down the aperture that much using a higher resolution APS-C size sensor like the 24MP Sensor in the A77. So, I wouldn't stop down the aperture that much unless you really need more Depth of Field for some reason, as you'd probably get sharper images a stop or two down from wide open with that camera/lens combo.
JimC is offline   Reply With Quote
Old May 6, 2012, 7:21 PM   #8
Senior Member
 
Join Date: Aug 2006
Location: Irvine, CA
Posts: 750
Default

Quote:
Originally Posted by JimC View Post
P.S.

As an FYI, I do see where you had the aperture stopped down to f/14 for that image.

Note that you'll start seeing softer images due to diffraction issues when stopping down the aperture that much using a higher resolution APS-C size sensor like the 24MP Sensor in the A77. So, I wouldn't stop down the aperture that much unless you really need more Depth of Field for some reason, as you'd probably get sharper images a stop or two down from wide open with that camera/lens combo.
Thanks again. Two things that could/should have had a little negative effect were the app. setting and also I was in shutter priority which I rarely shoot.
I took a couple of shots and they appeared pretty good in the view finder shot I stupidly just fired away.
I would normally use Aperture pri. around f/4 for that scene.
I got lucky.
__________________
A77, 28-75mm f/2.8, 16-50mm f2.8, 18-250mm f3.5, 70-300mm f4.5G SSM
Flying Fossil is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 7:46 AM.