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Digital pictures that are a little too dark or have bad "white balance" (look overall too yellow or too blue) can be easily adjusted in a digital photo editing program.  I use Google's Picasa, which is free and easy to use.  There are lots of other choices.  Here are the controls in Picasa that you can use to adjust a photo in seconds:

Fill Light: This is the most common Fix.  It makes the whole picture lighter, but it may also reduce contrast.  Use this when the whole picture looks a little too dark.  If the picture is way too dark to begin with, it will help but make a washed-out result. Highlights: Makes light colors even lighter (adds contrast while also adding brightness to the whole picture).  Use sparingly, and not if parts of the picture are already very light. Shadows: Makes dark parts darker.  I never use this for pictures of LEGOs. Color Temperature: You can try this if the Neutral Color Picker doesn't work well (also adjusts the white balance), but your results will vary widely.  I rarely use this. Neutral Color Picker: Used to adjust the "white balance" (overall too yellow or too blue look).  Click on the eye dropper button then click on something in the picture that is supposed to be pure white (such as the NXT brick).  The whole picture is adjusted to try to make what you clicked on white (instead of slightly yellow or blue).

Not all lighting problems can be fixed with digital editing, though.  In particular, a picture that is too light (overexposed) is hard or impossible to fix without losing details, pictures that are way too dark will look washed out or grainy when adjusted, and some white balance problems cannot be fixed with the controls shown above.  If you cannot get a good enough result with some simple adjustments, you should re-take the picture with different lighting or different camera settings.

An example of these adjustments used successfully is shown below.

Before: A little dark, and a little too blue	After: Fill Light and Highlights added, Neutral Color set on NXT brick

If you simply turn on a point & shoot camera in full automatic mode, hold it up to your robot until the robot fills the frame and press the picture button, the result is something like this:
 

Canon A570 in full automatic mode (with flash), no zoom (wide angle)

• Parts of the robot are too bright, but other parts are too dark

• The front of the robot is in focus, but the back and top are out of focus

• The perspective is distorted

• Some edges are fuzzy and some surfaces are grainy

These problems are all caused by having the camera (and the flash) too close to the robot.  Given the size of a typical LEGO robot, if you leave the camera at the default zoom (wide angle), then position the camera until the robot fills the frame, then you are only about 1 foot from robot (and if you try to get even closer to try to show a close-up of an area, it will get even worse).  At this distance, the following things happen:

• The light from the flash overwhelms the front of the robot, but the flash itself does not have a wide enough angle to reach the sides, and by the time the light gets to the back, it is much dimmer than the front.

• Because the relative distances from the lens to the front and back of the robot are so different (back of robot is twice as far away), the camera cannot keep all of the robot in focus at the same time while still letting enough light in.  Also note that a camera can only focus so close, and many cameras cannot focus closer than about 1 foot without using a special "macro" mode, so you might even end up with the entire robot out of focus.

• The extreme wide angle distorts the perspective (making the angles appear unnatural) because it shows a view from about 1 foot away, although when the resulting digital picture is viewed at a typical size on a computer screen, the apparent distance is much greater.

• The typical exposure settings for automatic flash photography cause the darker parts of the image to be grainy and the edges between bright and dark to be fuzzy.

These problems cannot be easily fixed by a digital editing program, so we need to take the picture differently.

Simple Fix: Step Back and Zoom In

The simple fix is to stand back about 3 feet and use the camera's (optical) zoom to get the robot to fill the frame.  The result is as follows:
 

Canon A570 in full automatic mode (with flash), at 4x zoom

Note that most point & shoot cameras have both an optical zoom (typically 3x) and then a digital zoom that will take over once the optical zoom is maxed out and zoom in even more (by using only part of the digital sensor and stretching the result).  For this fix, do not exceed the optical zoom.  You only need to get about 3 feet away to get a much better result, which is about a 3x zoom for a typical-sized LEGO robot.  

For an SLR camera with a zoom lens marked in mm (focal length in millimeters), use something around 70mm.

Close-Ups

If you want a close-up of part of the robot, instead of getting closer or zooming in even more, try staying at about 3 feet away then crop down the result afterwards in a digital photo editing program.  You will have plenty of pixels to work with (even the full-sized pictures on nxtprograms.com are all downsized to less than 1/2 of a Megapixel, and all the close-ups are done by cropping), so feel free to crop away.   If the result is too fuzzy or grainy due to lack of sharpness in the image, then you need to look at the improvements in Stage 2.

Using Walls to Reflect the Flash

The improved photo above also shows using a second simple trick to get better flash photos.  Putting the robot in the corner of a room near two white walls and taking the picture diagonally into the corner will allow the flash light to bounce off of the walls and help light up the sides and the back of the robot.

Nikon D200 in full automatic mode, with built-in flash, zoom lens at 36mm
(The camera chose f/4.2 for 1/60 sec at ISO 100)

• The picture is overall too dark.  In order to avoid over-exposing the bright white NXT parts with the flash, the camera ended up under-exposing the whole picture.  This is actually a good choice in a tough situation, because moderate under-exposure can be repaired in a digital photo editing program, but over-exposure usually cannot.

• Parts of the robot are in focus, but parts are not.  This is a depth of field problem caused by the f-stop that the camera chose (here f/4.2) combined with the large diameter of an SLR lens.  This problem is not fixable in a digital photo editing program, so we will have to change the camera settings.

The results of adjusting just the lighting of the above photo in a digital photo editing program produces the following:
 

Nikon D200 in full automatic mode, with built-in flash, zoom lens at 36mm
(The camera chose f/4.2 for 1/60 sec at ISO 100),
adjusted in Picasa to add fill light and highlights and pick the neutral color

Increasing the Depth of Field by Setting the f-Stop

The term depth of field refers to how much of the photo is in focus, and it is directly related to the f-stop (how far the lens aperture is open) used.  Sometimes a narrow depth of field (only parts of the photo in focus) is used for artistic effect, but for pictures of LEGO creations, you will usually want a wide depth of field to get the whole model in focus.  This requires using a manual or semi-automatic (e.g. "Aperture Priority") mode that allows you to set the f-stop.

To increase the depth of field, you want to increase the f-stop number (which results in a smaller lens opening).  A smaller lens opening results in less light reaching the camera's sensor, though, so how far you will be able to go depends on how strong your flash is and how well lit the room is to start with.  If you go too far, the picture will come out too dark, or too grainy if the camera boosts the sensor's sensitivity too far to compensate.

The built-in flash on the Nikon D200 is strong enough to take a good picture in this situation with the f-stop increased all the way to f/16, which results in sharp focus across the whole model.  Some cameras will not be able to go this far on the f-stop without the result being too dark or grainy.  Try starting at f/8 and working your way up to find the best setting. 

Using f/16 and also applying the other general Stage 1 fixes of stepping back and zooming in, and using walls to reflect the flash results in the following photo:
 

Nikon D200 in Aperture Priority mode with f-stop set to f/16, built-in flash, zoom lens at 70mm
(The camera chose a shutter speed of 1/60 sec and sensitivity of ISO 220)

Nikon D200 in Aperture Priority mode with f-stop set to f/16, built-in flash, zoom lens at 70mm
(The camera chose a shutter speed of 1/60 sec and sensitivity of ISO 220),
adjusted in Picasa to add fill light and highlights, and pick the neutral color

Crop picture afterwards to get close-ups instead of getting closer or zooming in more

Use digital photo editing software to adjust the lighting afterwards if necessary

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