Home · Register · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Post-processing & Printing | Join Upload & Sell

  

Archive 2015 · Mac reducing file Size

  
 
a2rob
Offline
• • •
Upload & Sell: Off
p.1 #1 · p.1 #1 · Mac reducing file Size


Question.

I have a built in SD card reader on my iMac. When I view the contents in bridge the file size is 24.3 meg which is the correct size for my camera. But, when I save in Lightroom, Camera Raw, or drag and drop the files are reduced to 12-14.xxx. No import processing and in lightroom I have no preset settings active. I thought is was and Adobe problem so I downloaded and exported in Capture One and the same thing is occurring.

Just wondering if there is a MANI setting on the mac that I need to reset. This has just started occurring during one of the mac updates I believe. Just annoying as I'd like to get all of the resolution for larger prints...

Anyone have any idea, searched on adobe forum tried all their recommendations and still nothing!!



Apr 19, 2015 at 04:38 PM
Ian.Dobinson
Offline
• • • • • •
Upload & Sell: Off
p.1 #2 · p.1 #2 · Mac reducing file Size


I don't get this . are you talking about NEF or jpeg? (i see you shoot nikon)

taking any application out of the equation for a moment as you say it happens when you drag/drop in the OS , let me ask for more info .

You say the file size is 24.3 . 24.3 what? if your saying 24.3MB then I'm not sure thats correct if you mean ALL THE TIME as file size changes due to things like ISO and the detail in the scene even when the resolution stays the same .



Apr 20, 2015 at 01:23 AM
lara_ckl
Online
• • •
Upload & Sell: Off
p.1 #3 · p.1 #3 · Mac reducing file Size


Are you saying 24.3MB file changes to 12-14MB?

That's a big change. Some changes are to be expected. A file on a 32GB SD card will show as a different size when copied to a 2TB hard drive. Never noticed such a big change though.



Apr 20, 2015 at 06:59 AM
howardm4
Offline
• • • •
Upload & Sell: Off
p.1 #4 · p.1 #4 · Mac reducing file Size


there might be a difference in the block size of the underlying media but there isn't enough information given by the OP to make that determination.


Apr 20, 2015 at 07:45 AM
howardm4
Offline
• • • •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Mac reducing file Size


you're saving it as a jpeg! of course it's going to be reduced in size, it's a lossy compressed format.


Apr 20, 2015 at 08:07 AM
gdanmitchell
Offline
• • • • • • •
Upload & Sell: Off
p.1 #6 · p.1 #6 · Mac reducing file Size


And, {b]don't do that!

First, keep your original raw files separately from the files you work on in Photoshop. While the analogy isn't perfect, they are the equivalent of your negatives back in the film era. You wouldn't throw away your negatives after making a print — don't discard your raw files.

Second, open your raw files into Photoshop as 16-bit images. This retains the best potential for editing that won't create visible degradation in your final files.

Thirds, save your original size Photoshop files with all edits intact (and done in layers, preferably smart layers or adjustment layers) as either .psd (the Photoshop format) or .tif (the tif format). with all layers intact. These will be big files, but that's life. Do not save your photoshop files as jpg!

Fourth, in order to be extra safe — and not lose image data as you do when you go to jpg — whenever you do further editing for print or web presentation or two resize, etc... work on a copy of the original Photoshop file — not the original.

Dan



Apr 20, 2015 at 08:38 AM
a2rob
Offline
• • •
Upload & Sell: Off
p.1 #7 · p.1 #7 · Mac reducing file Size


Yes, I know I have always saved my .nef files as .jpg and most not all of the D800 file size was kept which was great for me. Now that I have a Sony 24meg camera I knew some of the file information would be loss but over half!

I create a new catalog in LR for each event and have the original file saved. But to upload some files to the lab requires .jpg in which the file is severely reduced.

Thank you for your time and assistance.




Apr 20, 2015 at 09:04 AM
howardm4
Offline
• • • •
Upload & Sell: Off
p.1 #8 · p.1 #8 · Mac reducing file Size


the 'quality' setting of a jpeg, esp at the high/very-high values can have a very big effect on output file size w/o actually being useful (ie. you wouldn't see it on-screen or print).

Usually, teh sweet spot for jpegs is 70-80%. the size is also affected by how 'busy' the image is (vs. large expanses of featureless sky or water)



Apr 20, 2015 at 02:51 PM
howardm4
Offline
• • • •
Upload & Sell: Off
p.1 #9 · p.1 #9 · Mac reducing file Size


the 'quality' setting of a jpeg, esp at the high/very-high values can have a very big effect on output file size w/o actually being useful (ie. you wouldn't see it on-screen or print).

Usually, teh sweet spot for jpegs is 70-80%. the size is also affected by how 'busy' the image is (vs. large expanses of featureless sky or water)



Apr 20, 2015 at 02:51 PM
gdanmitchell
Offline
• • • • • • •
Upload & Sell: Off
p.1 #10 · p.1 #10 · Mac reducing file Size


howardm4 wrote:
the 'quality' setting of a jpeg, esp at the high/very-high values can have a very big effect on output file size w/o actually being useful (ie. you wouldn't see it on-screen or print).

Usually, teh sweet spot for jpegs is 70-80%. the size is also affected by how 'busy' the image is (vs. large expanses of featureless sky or water)


True, but that's not the issue here! :-)



Apr 20, 2015 at 08:55 PM
OntheRez
Offline
• • • • •
Upload & Sell: On
p.1 #11 · p.1 #11 · Mac reducing file Size


Rob,

I think we're all confused. Your example shows a Sony raw file of 25.1 MB. You then show a JPEG with a file size of 9.59 MB. So (1) They aren't all the same size as you note in your first post. (2) As noted by others JPEG is a LOSSey format. That means (as Dan explains) there is an algorithm that arbitrarily throws big chunks of your pix away. As Dan suggests I too always keep the originals in RAW and always have a copy of anything complex done in Ps saved with all layers as a PSD. I understand upload limitations very well and yes, all my newspaper submissions have to be jpegs simply to squeeze them thru the skinny wire we have around here. Since they are going out on newsprint, no one can tell the difference anyway. The new online version of the paper is another story, but they stick to the newsprint rules.

Incidentally looking at your two examples above even small and at monitor resolution I can see significant loss of detail and dynamic between the original and the jpeg. Hard drives are dirt cheap these days and if you have a Thunderbolt equipped iMac you can get excellent transfer speeds. My masters live on a SSD dual drive RAID with periodic backup to older platter technology. Anything currently being worked on lives in one of several folders on the SSD in my iMac and is backed up via the Time Machine and a tertiary platter device. Don't ever lose your originals if they are of value to you.

Robert

BTW rather nice shot. Living here in the Sonoran Desert I can't even fathom that much water!



Apr 20, 2015 at 10:33 PM
Ian.Dobinson
Offline
• • • • • •
Upload & Sell: Off
p.1 #12 · p.1 #12 · Mac reducing file Size


a2rob wrote:
Yes, I know I have always saved my .nef files as .jpg and most not all of the D800 file size was kept which was great for me. Now that I have a Sony 24meg camera I knew some of the file information would be loss but over half!

I create a new catalog in LR for each event and have the original file saved. But to upload some files to the lab requires .jpg in which the file is severely reduced.

Thank you for your time and assistance.



I think you are getting File sizes / File types and resolution very confused .

a jpeg as mentioned above is a LOSSY file so some info is chucked away which allows you a smaller file (oh and its only 8bit which again reduces the amount of data) .
But unless you tell the application to reduce the res of the file on export the RESOLUTION will remain the same .




Apr 21, 2015 at 02:03 AM
a2rob
Offline
• • •
Upload & Sell: Off
p.1 #13 · p.1 #13 · Mac reducing file Size


OntheRez wrote:
Rob,

I think we're all confused. Your example shows a Sony raw file of 25.1 MB. You then show a JPEG with a file size of 9.59 MB. So (1) They aren't all the same size as you note in your first post. (2) As noted by others JPEG is a LOSSey format. That means (as Dan explains) there is an algorithm that arbitrarily throws big chunks of your pix away. As Dan suggests I too always keep the originals in RAW and always have a copy of anything complex done in Ps saved with all layers as a PSD. I
...Show more


Thank you!
Files are only saved .jpg to upload to print lab and archiving to zenfolio..
My work flow includes the raw files of every photo that I have taken for the past years. Just a little confused as to the reduction in files when saved in LR, CO or Camera Raw! I new my D800 threw away some unwanted data but never half the file size. It may just be a Sony thing, since I switched 6 months ago and as I go back and view, most of the files are the same except for the A7r which is a 36mb camera.

Thank you again for your assistance....



Apr 21, 2015 at 06:11 AM
a2rob
Offline
• • •
Upload & Sell: Off
p.1 #14 · p.1 #14 · Mac reducing file Size


Ian.Dobinson wrote:
I think you are getting File sizes / File types and resolution very confused .

a jpeg as mentioned above is a LOSSY file so some info is chucked away which allows you a smaller file (oh and its only 8bit which again reduces the amount of data) .
But unless you tell the application to reduce the res of the file on export the RESOLUTION will remain the same .



Thanks, but I am aware of the compression and difference in the files but this was not the issue...



Apr 21, 2015 at 06:14 AM
atwl77
Offline
• •
Upload & Sell: Off
p.1 #15 · p.1 #15 · Mac reducing file Size


a2rob wrote:
Thanks, but I am aware of the compression and difference in the files but this was not the issue...


Sorry, but you really do not understand compression.

The goal of lossy compression (as used by JPEG format) is to produce as small a file size as possible while retaining as much detail as possible. The difference between the JPG size and the NEF size is, for practical purposes, irrelevant -- only the quality setting when saving the JPG matters.

For the same JPG quality setting, the smaller the file size the better the compression algorithm is -- it doesn't mean that the compression algorithm "threw away" more data.

Try taking a picture of a plain white wall (or plain blue sky), and compare that to a highly detailed landscape. The JPEG of that plain image is going to be much smaller than the detailed landscape, but it doesn't mean that more data was "thrown away"; the compression algorithm was just able to compress the plain image more efficiently than the detailed landscape.



Apr 21, 2015 at 06:30 AM
howardm4
Offline
• • • •
Upload & Sell: Off
p.1 #16 · p.1 #16 · Mac reducing file Size


Why yes! it's well known that a '0' (zero) is fatter than '1' so of course a white wall (255.255.255) would compress better than a black wall, the white is already skinny.


Apr 21, 2015 at 07:44 AM
a2rob
Offline
• • •
Upload & Sell: Off
p.1 #17 · p.1 #17 · Mac reducing file Size


atwl77 wrote:
Sorry, but you really do not understand compression.

The goal of lossy compression (as used by JPEG format) is to produce as small a file size as possible while retaining as much detail as possible. The difference between the JPG size and the NEF size is, for practical purposes, irrelevant -- only the quality setting when saving the JPG matters.

For the same JPG quality setting, the smaller the file size the better the compression algorithm is -- it doesn't mean that the compression algorithm "threw away" more data.

Try taking a picture of a plain white wall (or plain blue sky), and
...Show more

yep




Apr 21, 2015 at 09:02 AM
CAlbertson
Offline
• •
Upload & Sell: Off
p.1 #18 · p.1 #18 · Mac reducing file Size


When you say one file is 24MB and the other 16MB (or number like the) are you comparing the SAME type of files. This means are both files RAW or are both files JPG. I'm betting that the files are not the same type.

A RAW file is just camera data. It is not yet an image and must be converted. It is a good archive format because you can process it any way you like. But JPG is a better distribution format. Think of RAW as the "negative" and JPG as a print. The analogy really does hold up well.

Also of course we assume the smaller image is not a crop or a reduced resolution copy.



Apr 26, 2015 at 10:16 PM





FM Forums | Post-processing & Printing | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username       Or Reset password



This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.