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.

Nikon's Active D-lighting - what is it?

"Nikon has gone through great pains to promote this feature without telling anybody what exactly is going on."

Frans Waterlander

I have no idea who Frans Waterlander is, but I think he was spot on in a discussion forum. This blog post lists some known facts and some important guesses - if you switch Active D-Lighting (ADL) on.

ADL is a technology Nikon uses to handle pictures with big contrast - a lot of light and a lot of darkness in the same photo.

To make it work properly, use Matrix metering.

Switching on matrix metering on a Nikon D300.

ADL is not the same thing as D-lighting. D-lighting does about the same thing - it reduces shadows and highlight, but it is made after the picture is taken. Active D-lighting is made while the picture is being taken.

How it is done, no one seems to know. One theory is that it is done by the camera sensor itself. Another is that it is a setting applied to the RAW camera data.

You cannot change the level of ADL in Capture NX or View NX. Normal D-lighting can be changed in those products.

It is rumoured that ADL does not work when you take pictures in Manual mode in the camera.

When you use ADL in A, P or S mode, it makes the general exposure slightly darker.

From experiments it seems like Adobe products ignore ADL in NEF files completely. In other words: if you shoot RAW and use Adobe products like Lightroom or Photoshop, Active D-lighting will serve no purpose.

Normal D-lighting can be applied in the retouch area of the camera in many models. It can also be applied in Capture NX and View NX.

My own strategy currently is to switch ADL off. It is complicated to handle, it takes time to switch on and off, there is a risk factor that you do something wrong, and life is too short to learn all the aspects. If there are high contrast images to take, they can often be handled by post processing anyhow.

What use is Capture NX?

Capture NX 2 is Nikon's high end RAW converter. It opens NEF, JPEG and TIFF files and also saves in those formats. It has many more adjustment options than View NX, and it can add and remove them in a way that is similar to Adobe Photoshop's adjustment layers.

The most unique feature of Capture NX is probably the "Control Points" that let you easily make adjustments to areas of the picture that are similar.

When it comes to high end RAW converters, like Capture NX, Adobe Camera RAW, Adobe Lightroom and Apple's Aperture, they all have their strengths. It is very difficult to tell which one is "best". Someone who masters any one of them, can usually do what s/he needs to do with that program. Anyone who does not fully master any one of them will probably not achieve the best possible result.

Capture NX is not an image editing program. You cannot use it to paste a face from one person onto another. Neither can you render patterns or add text strings to a picture. For such tasks, you need to use a tool like Adobe Photoshop or the gimp.

Capture NX can perform batch jobs on several pictures at once. However, it is not scriptable with any internal macros or AppleScript.

How do the Selection tools in Capture NX work? Can I modify selections?

The Selection tools in Capture NX may at first look a little confusing. This is where I would like to say, "but it is really simple..." That would be lying however. It is confusing. In the following, I will try to make it a little clearer.

First a rule to make life easier: Get the Selection right from the beginning.

The easiest thing is if you first select exactly what you want to apply an adjustment too. Then you apply the adjustment, and you are done.

If you make a mistake, you can always delete the adjustment and start from the beginning. You can also "revert" adjustment or selection, but that may be confusing, so wait with that until you really need it.



Now, let's assume that you have applied an adjustment, but you were not happy with the selection. You can do the following things.

Revert the selection. Once you have clicked on the revert or delete button for the selection, the adjustment will apply to the entire picture. Adding a selection again using the Lasso tools will not bring the adjustment back, but do not panic.

This is how the different tools work after an Adjustment selection has been deleted:

The Selection Control Point will add a new selection, and it will apply the adjustment to the selection.

The Lasso, the Polygon Lasso, the Rectangle Marquee and the Oval Marquee will create a selection without adjustment. The entire picture will be without adjustment. However, you can later fill in the selection using the next tools.

The Selection Brush will add a selection where the adjustment applies. However, if there is a previous selection from one of the lasso and marquee tools, the Selection Brush will only add the adjustment to areas which were already selected.


The logic of the Selection Gradient is identical to the Selection Brush. It will add a selection where the adjustment applies. However, if there is a previous selection from one of the lasso and marquee tools, the Selection Gradient will only add the adjustment to areas which were already selected.

The Fill / Remove Tool is arguably the silliest "painting" tool of all. It does not matter where in the picture you click. If you use the Fill tool (with the plus sign), all selected areas will get the active adjustment. If you use the Remove tool (with the minus sign) selected areas will not get the active adjustment, but other areas will.

This is very confusing. As it does not matter where in the image you click, this should be a simple command, not a tool you have to click on twice (on the tool and on the picture) to activate.

Nevertheless, it is very useful, just like the other selection tools, once you have spent some time understanding how they work.


In the example picture above, a blue Color Balance adjustment has been applied to the following selection: Top left - a rectangle with a cut out oval. Top centre - a selection control point based on the colour of the waves. Right - an oval selection filled with a gradient selection. Bottom left - text scribbled with the selection brush in a selected rectangle.

View NX is working with Snow Leopard - finally

The below text is now luckily obsolete. After almost half a year, Nikon finally fixed their applications so they can run with Snow Leopard.

If you launch ViewNX 1.4 under Mac OS X 10.6 (Snow Leopard), all text labels may be replaced by strange strings like IDS_MENU_FILE and a lot of other strings beginning with IDS. There are apparently problems with Capture NX 2 as well.

Your system is fine. The problem is with the software itself, and we have to wait for an update from Nikon.

There is a web page from Nikon that clarifies the situation. It is not very flattering for Nikon.

The page explains what Nikon planned to start with. Capture NX 1 is not part of the software that was supposed to work, and they will not do anything to make it work in the future. Nikon has pretty much abandoned Capture NX 1, so those of us who buy new cameras, like the D5000, have to upgrade to Capture NX 2, which does not work with Snow Leopard, which... Well, the situation is not ideal.

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.

Chromatic Aberration

Chromatic aberration is a consequence of the fact that light of different colours do not focus on the same plane when they go through glass. Think of a simple prism, where white light goes in and a rainbow of colours come out.

Camera lenses are not always good at compensating for this, and the result may be a blue thin line around objects.

To get rid of the line semi-automatically, you can use tools like:

• Adobe Photoshop - Filter > Distort > Lens Correction. Adjust the slides in the box "Chromatic Aberration".
• Adobe Camera Raw - Open the file. (If it is not a raw file, you right-click on it in Bridge and select "Open in Camera Raw..."). Click on Lens Correction. Adjust the slides in the box "Chromatic Aberration".
• Capture NX - In the Edit List, click on "New Step". Select Adjustment > Correct > Color Aberration Control.

You can also manually replace the colour using things like the "Hue and Saturation" adjustment in Photoshop or the Gimp. In Photoshop you can also use Image > Adjustments > Replace Color.

If you do not succeed in getting rid of the chromatic aberration, do not feel bad about it. It is a tricky thing to handle. Good software takes into account the camera and the lens. As an example, Canon's RAW editing software Digital Photo Professional does not make the Chromatic Aberration correction tool available for pictures taken with the Canon EOS D20. Neither does it attempt to correct TIFF or JPEG pictures. This is undoubtedly because Canon knows they cannot make good enough corrections for those pictures.

Wikipedia has a more information on the subject.


The Lens Correction tab in Adobe Camera Raw.


Example of a picture with both green and red chromatic aberration.

Detail showing red aberration on one of the birds.

Detail showing green aberration on another of the birds.

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.

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.

What's that... eh... thing, in Capture NX?

The documentation of Capture NX is not perfect and the usability of the product is far from perfect. Here are a few things I have not found in the documentation.

Sometimes you see a yellow warning triangle in the window title bar.

This triangle stays as long as the the text "updating image" stays in the title bar, so it probably means the same thing. In other words, it does not mean the file is corrupted or contains bad data or too much highlight or that anything else is wrong. It simply means "wait".


When you display the white balance settings for a file in Base Adjustments > RAW Adjustments > White Balance, you may see numbers and letters after the Camera WB. It may be something like "Auto, A3, G2" or "Incandescent, 0,0" or "6000K, A2, G3".

The first information is the white balance type or the colour temperature expressed in Kelvin. The following two numbers are the adjustments you may have done in your D300, under Shooting Menu > White Balance > right arrow.

The first adjustment is the value on the Amber (A) - Blue (B) axis, and the second one is the value on the Green (G) - Magenta (M) axis. Coincidentally, this corresponds to the LAB colour model. The amber-blue axis confusingly corresponds to colour temperature as well, with each step equivalent to about 5 mired. The green-magenta axis is simply an adjustment of green-magenta, like a cc filter (colour compensation/colour correction filter).

What a NEF contains

As a raw nef file is a dump of camera information and not an actual image, it is very different how the nef file is displayed in different applications.

Let's for example assume that you take a black-and-white picture with your Nikon. FastStone, IrfanView and xnview all display the image as black-and-white. However, the gimp, Picasa, Aperture 2.1 and Mac OS X' Preview ignore the tag that says that the image should be black-and-white, so they display the image in colour.

Nikon's Capture NX keeps the camera information, so it appears black-and-white, but one can also go back to the original colours.

1. Go to Base Adjustments > Camera Adjustments > Picture Control.
2. In the dialogue that comes up, change "Non-Picture Control" to "Picture control".
3. Change the settings to what you prefer.

Sometimes it is not obvious to see what changes have taken place in the camera. I for example had a picture where the White Balance was far off. There is no indication in the adjustment panel of Capture NX, that the White Balance had an unusual setting in the camera, so I had to look around for some time, before I found where it was.

White balance is, by the way, one camera setting that Aperture takes into account.

This may appear confusing for a simple reason: it is confusing. Not only are the names for the features sometimes confusing, but the concept itself is confusing.

There are a couple of metaphors one can use.

Think of the raw data from the camera as a Word document. If you switch on Track Changes in Word (or Record Changes in OpenOffice) you can make as much modifications you want. Add text. Remove formatting. Change pictures. You can always select Reject All Changes to go back to the original. You can also reject some changes and keep others. In the same way, you can always go back to the original camera raw data in a nef file, no matter how many changes you have made. You can also revert some changes, even if they were made in the camera, but keep others.

A more real life metaphor is a dinner table. Let's say you change the tablecloth every day. You use different kinds of china and put different dishes on the table every day, so it looks very different from one day to the next. No matter what things you add, you can always remove them at the end of the day. What you are left with is the original naked wooden table. In the same way, you can add effects to a nef file - sharpening, blur, white balance, noise reduction. But at the end of the day, you can remove them all, and what you are left with is the original camera raw data.

Many applications open nef files, but they almost never save to nef format. If you make a modification, you will have to save the image as tiff, jpeg or some other more mainstream format.

Capture NX is an exception, as it saves the modifications in the nef file itself. However, it does not touch the actual raw data in the nef file.

Some of the data that can be stored in a nef without touching the actual raw data.