What is the focal length equivalent for an iPhone? Or my Android phone?

That can change from one phone model to the next. The safest bet to get info about your phone is to open one of its photos in a tool that can read exif data.

For example, the iPhone 5 has "Focal length" 4.1 mm and "Focal length (35mm)" 33.0mm. That means that it is roughly as wide as your favourite 33mm prime lens on your FX camera. Or as wide as your 22mm on your DX camera.

A Galaxy S4 has "Focal length" 4.2mm and "Focal length (35mm)" 31mm.

An iPhone 6S plus has a "Focal length" 4.2mm and "Focal length (35mm)" 29mm. The reason the 35mm equivalent is different from the Galaxy S4 is certainly that it the size of the sensor is different.

To read exif data you can use for example:

• Adobe Photoshop
• Adobe Bridge
• Aperture
• Preview (Mac OS X)
• exiftool
• ... and many others.

The only snag is that not all exif-readers display the equivalent value for 35mm, and not all cameras actually store the 35mm equivalent. If it does not work for you, don't be too disappointed. Just make sure you try with at least one of the tools listed above. If you still have no luck, just buy a new phone. There is probably a new model on the market anyhow.

What use is Adobe Photoshop - for a photographer?

Adobe Photoshop CS4 is probably the most powerful image editing tool on the planet right now. It can do a vast number of things and integrates well with other programs like InDesign (for publishers) or Dreamweaver (for web designers).

Some basic functions that apply for photographers is described in the following.

The program Adobe Bridge, which comes with Photoshop, contains tools to display and organise photos of a wide range of formats, including RAW files from a large number of manufacturers. With Bridge one can also initiate actions in Photoshop like stitching a number of pictures together.

From Bridge, one can open RAW pictures in the program Adobe Camera Raw (ACR) which also comes with Photoshop. In ACR one can adjust RAW files, remove noise, change brightness, convert to black-and-white, fix vignetting and chromatic aberration and a ton of other things - much like one can in Aperture, Lightroom, Capture NX or DPP.

Once the image looks good, one can save it in one of several formats or open it in Photoshop. In Photoshop, one can cut and paste pieces of the different photos and mix them. One can add patterns, text and a lot of other things. The final picture may be resized and saved for use on the internet.

With smartobjects, one even mix layers of different colour spaces and file formats.

If one fully masters Photoshop, there is a good chance that one does not need any other image editing or RAW conversion software at all.

To explore Photoshop further, one can often download a trial version from Adobe.

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.

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.

Counting Shutter Clicks on a Nikon DSLR

If you are interested in how many times your shutter has gone off in your Nikon DSLR, you can look at the EXIF data of your most recent picture. The information is embedded there, but it may not be very obvious how to find it. The following has been checked on a D40X, D50 and D300.

If your latest photo is a NEF, open it with Adobe Photoshop. Then go to File > File Info... > Advanced. Expand the schema http://ns.adobe.com/exif/1.0/aux/ . The field aux:ImageNumber contains the shutter count. (If you try opening a JPEG from the camera, that field is not available in Photoshop.)

If your latest photo is a jpeg, and you have a Mac, open the photo with the free EXIF Viewer. The shutter count is in a field called "Camera Actuations".

If your latest photo is a NEF, but you do not have Adobe Photoshop or money to buy Photoshop or any additional software at all, you can convert the NEF to JPEG using ViewNX (which is free) and then open it with EXIF Viewer, and the information will be there, still called "Camera Actuations".

People with Windows seem to often use Opanda for the same purpose.

I have not been able to localise this kind of information in Nikon's own software.

If you have a Mac, the shutter count can be found in Preview: Tools > Show Inspector > I > Nikon.

Things you did not know about Bridge

To open a new window with another folder, command-doubleclick the folder.

You can get a flat view of all images in all subfolders of a folder with the menu View > Show Items in Subfolders.

To skip Camera Raw, shift double-click in Bridge. This will open the file directly in Photoshop.

Photoshop Navigation - things you did not know

A quick way to zoom in to many points in different parts of a picture is command-0 (fit on screen), and then drag with the zoom tool around the part you want to check. Then command-0 again and drag with the zoom tool against another part, and so on.

To cycle through open documents: ctrl-Tab (yes, dear Mac users, not "command"!).

Photoshop: Masks - things you did not know

To toggle between a view of the mask and the image it covers: alt-click the layer mask.

To create a black new mask: alt-click on the "add layer mask" icon.

To delete a mask: drag it to the trash icon.

Photoshop: Warp - things you did not know

If you know what Warp is, you probably know how to access it. In case you don't it is in the menu Edit > Transform > Warp.

Using Warp, you can drag about any point of the warped object. You do not have to click-drag on the corner points or lines. You can click-drag on the vast empty spaces between the lines as well.

If you end up with a Warp grid that goes outside the current window, press command-0 (View > Fit on Screen) to see the entire grid.

Photoshop: Layers - things you did not know

To duplicate a layer press command-J. Another quick way to do it is to press V (activate move tool), and then alt-drag the layer.

To copy part of a picture onto a new layer: select that part and press command-J.

To find out which layer contains a visible part of an image: command click on the image. The layer will be highlighted in the layer palette.

To display one layer at the time: alt-click on the eye-icon.

To fill the current layer with the foreground colour: press alt-delete. To fill the current layer with the background colour: press command-delete.

To load layer transparency as a selection: command-click the thumbnail.

To quickly change Blending modes: press V (activate move tool) and then press shift+(plus) or shift+(minus). For the each of the blending modes, there are shortcuts beginning with shift-option, like shift-option-F for Soft Light or shift-option-M for Multiply. They can all be found in the manual under the title "Keys for working with blending modes".

To change opacity: press V (activate move tool) and then type a number. 1=10%, 2=20% and so on. You can also change some of these methods.

To merge all visible layers to a new layer above the currently selected layer: Shift-option-command-E (or alt+ Layer > Merge Visible). This can be useful if you have smart objects, whose pixels you cannot edit directly.

To create a new layer from another image: drag the other image to the current one. To make sure it is centred hold down the shift-key as you drag.

Photoshop: Channels - things you did not know

To display only one channel at a time, type command-3, command-4, command 5. You can also drag the eye from one channel to another. You can also alt-click on the thumbnail - not the actual eye, to deselect all other channels.

To make a selection from a channel: command-click the thumbnail.

Photoshop: Curves - things you did not know

To get a fixed point in a curve from a picture: click on the hand tool in the curves dialogue and then command click on the picture. That will fix a point at that particular colour.

Photoshop: Gradients - things you did not know

To apply a gradient exactly horizontally or vertically: hold down the shift-key, as you create it.

Photoshop: Brushes - things you did not know

When the brush tool is active, you can hold down alt to make it to a colour picker, so you can change colour of the brush by clicking on the image.

To change the colour of the active brush from the current image: hold down alt to temporarily make it to a colour picker, and then click on the colour in the image.

To change the opacity of the active brush: just type a number. 1=10%, 2=20% and so on. Or use one of these methods.

To get a straight line with the brush tool: click on one place - shift click on another, and the line will appear between the two. If you go on shift-clicking somewhere else, you get another line, which makes it easy to make a polygon.

Usability trap: In the Brushes palette, you can activate a feature, like Scattering or Noise by clicking on the checkbox next to its name. However, this will not display the options for that feature. You have to click on the feature name to see the options.

When you create a Brush (Edit > Define Brush Preset...), it does not matter if you leave white space around the brush, as all white will be discarded. This is different from when you create a pattern, where the white space is taken into account.

To change the size of a Brush there are two shortcuts: Method 1: Press [ or ]. Method 2: Hold down ctrl+alt and drag horizontally. To change the Brush softness: Command + Ctrl + Option + click-drag.

Photoshop: Selections - things you did not know

To fill a selection with the foreground colour: press alt-delete.

To fill a selection with the background colour: press command-delete.

Photoshop: Eyedropper - things you did not know

To choose foreground colour from an image, use the eyedropper tool (I) and just click on a part with the desired colour. To choose background colour from an image use the eyedropper tool (I) and alt-click on the desired colour.

To select a colour on the screen outside an image: click and hold down the colour picker and drag it to the point on the screen with the desired colour.

To swap foreground and background colours: press X. To set the default foreground and background colours to black and white: press D.

Photoshop: Numeric values - things you did not know

To change numeric values in most dialogues in Adobe Photoshop, you can use one of these methods.

• Type a new number.
• Click on the label for the number and drag horizontally.
• Command click on the number field itself, and drag horizontally.
• Put the cursor in the number field and press or hold down arrow-up or arrow-down.

Photoshop - things you did not know

I will soon add a number of "things you did not know" entries about Photoshop. They will not constitute a manual in any way, but they will contain small tips and hints, which are not always obvious. If something is useful, but it is so well hidden that a user may miss it, it fits the concept. Some of you will obviously already know some or most of them, but some of you may not.

The option/alt/⌥ key is consistently called "alt".

The command/⌘ key is consistently called "command". The Windows equivalent is almost always ctrl.

Doing the Impossible with Smart Objects

Before CS3, there were plenty of things you simply could not do in Photoshop. With CS3 and the introduction of Smart Objects, a lot has become possible.

One (almost) obvious thing is that you can apply lossless filters. Just create a layer to a Smart Object and apply the filter. You can add loads of filters and remove or activate them, and of course edit them with Layer Masks.

Smart Object layer in Adobe Photoshop CS4

But not only that - you can now mix layers of different kinds. You can have one layer as a 16 bit image in LAB colour space, while you have another in 8 bit grey scale, and blend the two layers. You can even add RAW files using File > Place, so you have a RAW file layer, which will open for adjustments in Camera RAW every time you double click on it. This means that you can have an almost endless number of different image formats - all stored in the same file.

And if that is not enough, you can have one Smart Object contain another Smart Object that contains a third one and so on.

To have several instances of the same Smart Object, highlight the layer and press command-J. You can have as many instances of the same Smart Object as you like in a file. You can apply different kinds of layer styles and rotations and transformations of them. If you then update the Smart Object, for example by changing its colour, the modification will apply to all instances of that Smart Object in the file.

To replace the content of a Smart Object: Go to Layer > Smart Objects > Replace Contents....

You cannot edit the individual pixels in a Smart Object (unless you open it). However, you can make a copy of the Smart Object, for example with merging all visible layers to a new layer above the currently selected layer with Shift-option-command-E (or alt+ Layer > Merge Visible).