How can I rotate my digital "Negatives"

[ShutteringFocus]

Is there a way to rotate JPEGs without recompressing them?

If I rotate them in camera do they get recompressed?

It's not a big deal if they don't get rotated...but it's getting hard to flip my computer screen over everytime I want to look at the portraits :roll:

[Canuck]

You should have an option in photo editing program to rotate 90 or 180 degrees. You shouldn't have to recompress the pics, it is a matter of rotating. The other question I had was if you were talking about incamera? If that is the case, you can tun the auto rotate on or off from the camera menu.

[ShutteringFocus]

No auto rotate in the D30...

And in Paint Shop Pro I have to resave the photos after a rotate...so...that's recompressed right?

[Canuck]

Sri, I didn't see that you have a D30. I wasn't paying attention. I am on the same time as it is posted with the posts. I can't speak for PSP but it is my guess that it compresses again everytime you save. I use the PSE 2.0 that came with the 10D that I have and it does it w/o haivng to do a resave.

[PacAce]

Most of the better photo editor should be able to rotate the images without lose of quality since all it does is a bit for bit rotation. You might want to check to see if that's the case with your software.

[Belmondo]

If you save the images in TIFF format before you do anything, there will be no degradation of the image. Once you have it the way you want it, save it in JPEG. After that, lock the file, and it won't be re-compressed each time you open and close it.

[scottbergerphoto]

Just to elaborate a little on what Belmodo said, all JPEGS out of the camera should be converted to TIFF (or other lossless format like PSD) and worked on in TIFF until you never plan on editing them again. Each time you edit and resave a JPEG, you lose data. The same loss doesn't occur with TIFF.
Regards,
Scott

[Belmondo]

Just to elaborate a little on what Belmodo said, all JPEGS out of the camera should be converted to TIFF (or other lossless format like PSD) and worked on in TIFF until you never plan on editing them again. Each time you edit and resave a JPEG, you lose data. The same loss doesn't occur with TIFF.
Regards,
Scott

Yup, that's what I meant to say. I'm actually a little anal about this business; I save the RAW images on a CD just as they come out of the camera. I same them again after I convert them to TIFF. Finally, with these two archived copies, I save them a third time, again on CD, after they've been converted to JPEG. These are lessons I've learned the hard way, but blank CDs are inexpensive enough that this degree of overkill still isn't financially punishing.

[ShutteringFocus]

How do you lock a JPEG so it wont be compressed any more?

Is it a left click...then properties or something?

[PeterS45]

BreezeBrowser rotates both RAW & JPEGS without any loss in quality.

This is from BreezeBrowser's helpfile:

This rotation is lossless and so the image will not be degraded however many times it is rotated

[Jesper]

There's a free and good program, IrfanView (http://www.irfanview.com), which can also rotate JPEG's without recompressing them. You need to install a plug-in with it (can also be downloaded on the IrfanView website) - choose Options / JPG Lossless Operations in the program.

[CyberDyneSystems]

I'm guessing Irfanview is like ACDSee in this respect?

ACDSee has a lossless file rotation utility that is great.. yiou can open the file browser to thumbnail view,. select all the portrait oreinted images and click one button to rotate the whole lot of them.

[robertwgross]

Some of us are blessed with having a lossless-JPEG compression scheme, however, I feel that as an archival file format, JPEG is not the way to go. There are too many variations and implementations of JPEG.

I file away RAW files that I think of as "digital negatives" that can't be tampered with. Then I file away TIF files that I think of as the main library image files. I only use JPEG files for web publishing and for sending as email attachments.

---Bob Gross---

[kfong]

I'm not sure on the loss of information on multiple re-compressions on jpeg file. I'm no expert in the field of compression, but as I'd understanding, jpeg uses wavelet transformation for compression. It's similar to passing your bitmap through a low pass spatial filter. Now after the first compression all the high frequency components are removed, and the remaining data is transparent to further filtering, providing the compression parameters aren't changed.
To test this further, I did a little experiment. I draw in PS a little black rectangle inside a 300X300 white background, using 100 pixel/inch. I'd then rotate it 90 degree CW and then SaveAS jpeg with a compression quality of 5. Close the file. Open the file agin, measure the color bleed across the edge of the black rectangle and repeat the rotation, saveAS ...
Here is the result:
no. jpeg compressions - transition region thickness (inches)
0____________________0
1____________________0.161
2 ___________________0.153
3____________________0.162
4____________________0.165
5____________________0.160
6____________________0.161
7____________________0.159
8____________________0.146
9 ___________________0.165
10___________________0.159
I got bored and quit afterwards.
As the result shows, the 2nd and subsequent recompressions do not degrade the sharpness at all.
If one can generate a MTF bitmap and repeat this again it should be able to eliminate the subjectiveness in establishing the border thickness.

Ken

[robertwgross]

I'm no expert on compression either, but I don't think that JPEG uses wavelets. Otherwise, what you stated about the low pass filter is correct. JPEG has a lot of variables, and you can make it tightly compress (throwing away lots of detail), or you can make it save with little or no compression. In general, when JPEG is done inside a device like a camera, the user is given no option about the JPEG variables. Inside a computer, the good editor programs allow the user to set the compression rate.

Another interesting experiment is to take your favorite image in TIF format, and fool around with a copy of it. Convert to different degrees of JPEG and watch how the file size varies. In some cases, you can throw away a lot of data and still have an image that is respectable, but that depends on whether you have a photographer's eye or a computer geek's eye.

Just to date myself, we were fooling around with medical image compression on a PDP-11 more than thirty years ago.

A friend of mine just got his PhD, and his thesis was on JPEG 2000, which is not sure to catch on.

---Bob Gross---

[kfong]

I'm no expert on compression either, but I don't think that JPEG uses wavelets.

Just to date myself, we were fooling around with medical image compression on a PDP-11 more than thirty years ago.

---Bob Gross---

I stand corrected. Just read up on JPEG compression, it uses discrete cosine transform. And the high frequency components are selectively throw away by scaling them down and rounding off to zero. My assertion about image being not degraded by multiple recompression still stands.
As for reminisce about the old days, the first "computer" I can get my fingers on was a PDP-8. (The IBM-360 was hidden behind a guarded room, where no mortal were allowed entry). The bootstrap loader is loaded in by flipping some toggle switches for several hundred different combinations, then the "OS" is loaded with paper tape. With a core memory of less than a kilobyte, you can forget about doing imaging, or doing anything at all useful. PDP-11 was a godsend afterwards.

Another sign of old age is that my 50mm F/1.8 lens is a Mk 1. serial number with UA prefix, but heck, it's still the sharpest lens in my collection, L glass included. Sadly the same cannot be said of my Mk 1 eyeballs :cry:

Ken

[robertwgross]

Just read up on JPEG compression, it uses discrete cosine transform. And the high frequency components are selectively throw away by scaling them down and rounding off to zero.


Yes, DCT is the same principle that was used over thirty years ago, and it seemed like forever for me to get my brain wrapped around that concept then. These days, we just say "convert to JPEG" and we don't think much more about it. Ahh, the marvels of modern technology.

---Bob Gross---

[pradeep1]

Breezebrowser (www.breezesys.com) has a lossless rotation built in. It automatically saves after rotation. If you have the orientation sensor in your camera, then is automatically rotates according to orientation tagged information in your files.