Updating metadata in a CR2 file

To find images quickly using a disk search tool, like Mac OS X' Spotlight, you can update the metadata of the images. You can for example set the description to "Holiday in Sverdlovsk". Searching for that string in Spotlight will quickly show you all the images.

For JPEG files, you can use for example Adobe Bridge to quickly do this. I assume Lightroom also works.

However, when it comes to RAW files, like NEF and CR2, Bridge adds the metadata in a separate xmp file. When you search for the string using Spotlight, you will find the xmp files but there will be no preview of the image in the search result.

Bridge itself finds the data of course, but you may have moved the files to a computer without Bridge installed.

To update the Description field you can use View NX (free) or Capture NX for Nikon's NEF files. For Canon's CR2 files, however, it seems like it is not that easy.

One solution is to use Aperture.

1. Open the file in Aperture.
2. Click on Metadata and choose the "General" set.
3. Update the field "Caption". That is the field that other applications usually call "Description".
4. Go to File > Export > Master...
5. Enter the data as you want, but make sure the option Include IPTC is set.
6. Save.

You can of course export several images at the same time, and even mix different formats.

There are other solutions than Aperture, I am sure. It should for example be possible to use the utility exiftool which is free. However, Aperture is the most convenient solution I found so far.

Which Nikon camera settings matter when you shoot RAW?

Almost all the settings in a Nikon camera matter when you shoot JPEGs, as a JPEG is supposed to be good enough for immediate use.

When it comes to RAW/NEF files it is a little more complicated. Some settings matter a lot. Some settings do not matter at all. For some settings it really depends. There does not seem to be any exhaustive list of which settings matter and which can be ignored - probably because it is so complicated. The following list is not exhaustive.

Shutter speed is important, as it obviously cannot be changed in software.

Aperture is equally important, as it cannot be changed in software.

ISO is less obvious, but it is also important. ISO is not just a matter of how bright the picture is, but it sets the physical light sensitivity of the sensor. The incoming light is amplified by hardware. When a lot of amplification is needed (high ISO), the system is more likely to introduce noise. Even if my explanation may not be one hundred percent clear, a simple experiment can show that a NEF taken with long shutter speed (much light) and low ISO has less noise than one with short shutter speed (little light) and high ISO.

Long Exposure NR seems to matter. There is no way to undo it even in Nikon software.

White Balance can in theory be ignored, but it is practical to give it a correct value. It is visible to virtually all RAW conversion software, and it can be changed freely in most software. However, some software is unable to correctly adjust bad White Balance, like Picasa or the Finder previews in Mac OS X.

Exposure compensation does not really matter on its own. However, it affects shutter speed and aperture, so it indirectly matters what you set it to.

Active D-lighting is not clear cut. The setting seems to be ignored by Adobe software. At the same time, it cannot be switched off in Capture NX, if you use that software. Anyhow, when you switch it on, it will change images to a somewhat darker exposure by changing shutter speed or aperture, so it indirectly affects the image.

Picture Controls can safely be ignored. They can be changed freely in Capture NX and View NX, and they are not even visible to non-Nikon software like Adobe Camera RAW, Lightroom or Aperture. This is the reason why a black and white NEF file is displayed in colour in Photoshop.

What use is Aperture? Or Adobe Lightroom?

Apple's Aperture is a RAW converter and image management system for Mac OS X. It is a high end program with a vast amount of options and functions. It supports RAW files from a large number of manufacturers, but not as many as the competitor Adobe Lightroom.

As so often, it is very difficult to tell which program is "best". If one of the programs does not support your camera, you should clearly stay away from that program. If you have Windows, you do not have to consider Aperture, as it is Mac OS X only. If you need to batch process files, either program will do fine. If you need to script a program, Aperture can be scripted with AppleScript, but it seems like Lightroom 3 still has very limited scripting capabilities.

Aperture uses the same RAW converter as Mac OS X, which means that any image that can be opened in Aperture, also can be opened in Preview or Quick Look. Lightroom uses the same RAW converter as Adobe Photoshop and Adobe Camera Raw, even though the version may differ.

Both programs have the following main purposes:

• Adjust RAW files.
• Sort and manage images.

If one already has other programs that do this well enough, one probably does not need either of the programs.

Both Adobe and Apple often have trial versions of the software to download to further explore the programs.

Using "hidden" NEF data in Photoshop or Aperture

If you shoot raw nef files with your Nikon camera, you may have camera settings that are not readable by non-Nikon applications. One of the most striking ones is if you choose to set the picture controls to create a black-and-white picture. When you open that nef file in Photoshop or Aperture, for example, the colour will come back.

To see this kind of information in non-Nikon applications, you will have to convert the files in a Nikon application. You can for example batch process all your nef files to jpeg or tiff format using View NX (menu File > Convert Files...) or Capture NX (menu item Batch). Then import the tiff files to the other application.

But don't forget that conversion from nef to both jpeg and tiff will lose some data. Tiff is a lossless format, but the only thing that is lossless is what is visible. In the nef file you can always go back and change the picture controls to some other setting. However, there is no way you can get the colour back in a black-and-white tiff file. In other words, it is always good to keep the nef as backup, in case you need to make some other modifications.

Bridge's raw xmp files

Whenever Adobe Bridge updates a raw file, it stores the data in an external "xmp" (Extensible Metadata Platform) file with same basic file name as the original. If your raw file is called "sunrise.nef", then the corresponding xmp file is "sunrise.xmp".

The idea behind this is excellent. The raw file contains exactly the data that came out of the camera and nothing else, and you can trust that nothing has been changed - by Bridge.

The drawback is of course that you have two files that need to stick together. If you move all files created a certain date from a folder, it is not at all certain that the raw and xmp files are created the same date, so they may get separated.

Nikon's Capture NX instead stores all modifications in the nef file itself. That may be seen as a drawback - a raw file is no longer what came out of the camera. However, there are ways inside Capture NX to remove the modifications, so it is not that much of a drawback.

Aperture has yet another approach. It stores the modification in its own database. When you export the Master you get the choice whether you want to include the IPTC data or not. The IPTC is the only data Aperture allows to change in a raw file. The rest of the image is intact, as it came out of the camera. Other changes need to be exported through other file formats, like tiff or jpeg.

Index of NEF files with keywords

There are plenty of good reasons to use RAW file format instead of jpeg. However certain things get trickier. One of them is keywords.

The great thing with metadata like keywords and IPTC fields is that you quickly can search your entire harddisk for files about a certain subject, taken at a specific location or by a specific photographer. You just have to make sure that the information is stored in your files.

That is fairly easy with JPEG files. You update the metadata with, for example, Bridge, and the files can be searched in Bridge itself, in Aperture or Spotlight.

However, if you update NEF files or other RAW files using Bridge, the data is not stored in the files themselves, but in the associated xmp files. This means that for example Spotlight does not find the image, but just the xmp file. Neither does Aperture see the field, if the file is imported to Aperture.

The only way I found to make sure that they keywords are found by both Bridge, Spotlight and Aperture, is to use Nikon's free application View NX to set the metadata.

This is a funny roundabout way of doing things as View NX itself does not have any search engine. In other words: you need to use one tool to set the metadata, and another to look for it. Well, that is how things work today anyhow.

Copyright info and Aperture - EXIF or IPTC

With the firmware update 110 for the Nikon D300 one has the option to add a copyright note in the images, just like one could already before with the Nikon D3.

This is excellent news. It would have been even more excellent news if the information had been easy to find outside the world of Nikon.

There are now three fields to play with in the camera. They are all entered under the Setup menu.

1. Image Comment is entered under the menu heading "Image Comment".

2. Artist is entered under the heading "Copyright Information".

3. Copyright is also entered under the heading "Copyright Information".

If you use low end products like gimp (2.6.1), Preview or iPhoto (7.1.5), none of this information is to be seen anywhere.

The following explains how some more high end applications display the fields.

Image Comment

• Aperture - field not visible.
• Bridge CS2: "Camera Data (EXIF)". Field called "User Comment".
• Capture NX: "Camera Settings" > "Shooting Info". Field called "Image Comment"

Artist

• Aperture: EXIF field called "Artist". It does not seem to be visible unless you go in and customize the Metadata displays.
• Bridge CS2: "IPTC Core", field called "Creator" AND "Camera Data (EXIF), field called "Artist".
• Capture NX: "Camera Settings" > "Shooting Info". Field called "Artist"

Copyright

• Aperture: Field not visible. There is a field in Aperture called "Copyright notice", but it is not filled with the information of the Copyright field in the D300.
• Bridge CS2: "IPTC Core". Field called "Copyright notice".
• Capture NX: "Camera Settings" > "Shooting Info". Field called "Copyright". (It is not under IPTC as it is in Bridge.)

In Nikon View NX all the three fields appear with the same name as in the Camera, but under the heading "File Info 2".

Spotlight finds information in the Image Comment field but not in Copyright or Artist.

Clearly Nikon's own software is the best option to view data entered using Nikon's cameras. If you happen to be somewhere without access to Nikon's software, you can look for dedicated EXIF readers that will fine at least some of the data. For example the free little application EXIF-O-Matic, is able to display the fields Artist and Copyright.

Why is the size in pixels wrong in Aperture?

If you open a RAW file in Aperture and compare the size of the picture with another application, it is very possible that the size is different.

This is not a bug. In contrast to tiff or jpeg, RAW files do not necessarily have the exact number of pixels defined, but small variations can take place.

I did some tests on one particular nef file from a Nikon D300.

First I converted the file to DNG, so I could open it in Photoshop CS2.

I then opened both DNG and NEF in the gimp with UCRaw. Result for both files: 4320*2868 pixels.

I then opened both DNG and NEF in Aperture. Result for both: 4304*2852 pixels.

I then opened the NEF in Capture NX. Result: 4288*2848 pixels.

And finally I opened the DNG in Adobe Camera Raw and Photoshop. Result: 4288*2848 pixels.

As you can see, out of four unrelated applications with different development teams, only two agreed on the number of pixels. And the applications that agreed, opened two different files (the dng and the nef).

Why does not Aperture read my DNG file?

If you have a DNG file that Aperture refuses to open, is it possible that the DNG file is from a camera which has a strange format. Aperture 2.1 has support for DNGs from many cameras, but not all.

In some cases Aperture opens some DNG from a particular, camera, but not all. It then may depend on the lens, like in the case of an Olympus E-P2 ORF file.


Another possible explanation is that the DNG was generated with the "Convert to Linear Image" option turned on in Adobe DNG Converter. It has to be turned off. This is not obvious. The Linear Image option is there to increase compatibility compared to "Preserve Raw Image", but it is increased in a way that Aperture cannot handle.


Wrong setting in Adobe DNG converter.


Then, there is of course also the possibility that you cannot import the file, because you do not have any project, or because you highlight the wrong part of the screen, when you do the import. But in this case no files can be imported, DNG or not.