Visit The night sky in the World for this data – see two examples of their maps – The World Atlas of the Artificial Night Sky Brightness and North America (notice how polluted the night sky on the eastern side of the US is).

Armed with this knowledge, you can then decide on your exposure (how long to keep the shutter open, what ISO) and stacking / blending (normally done with Photoshop) strategy.

From my limited cruise experience, I’d say that if you’re trying to document the entire experience, you’ll definitely want the flash at least for:
* Shots in the ship dining rooms
* For fill to get some nice portraits at the ship railing with, say, a sunset background.

The lighting tips and sample photos are superb too.

The f: in the term stands for fraction. A f:2 setting would have a diameter 1/2 the focal length of the lens, a f:8 setting would have a diameter 1/8 the focal length of the lens. Thus in a 50mm lens the f:2 opening would be 25mm in diameter and at f:8 the opening would be 6.25mm in diameter.

Graystar adds the concept of geometry to the explanation, along with a diagram.

Graystar also explains what doubling or halving the amount of light (equivalent to a full f-stop) means:

Take a 50mm lens. At f/2 we have a 25mm diameter aperture. At f/2.8 we have a 17.86mm diameter aperture. If you were to calculate the area of these two diameters you’ll that one is roughly double or halve of the other.

So for a 50mm lens we have…
f/1 = 1963.5 mm^2
f/1.4 = 1001.8 mm^2
f/2 = 490.8 mm^2
f/2.8 = 250.5 mm^2
f/4 = 122.7 mm^2
and so on.

The F-Numbers have been rounded to make them easier to manage.

dradam simplifies it further: “The standard fstop scale runs: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22″, and provides the mathematical basis of the series:

Yes, this is a mathematical series. If you want it really spelled out it is 2^(n/2) where n starts at 0. So yes, each stop is 1.414 (or square root 2) times higher than the previous. And yes, if we square the whole thing we get 2^n, the series you list above.

If you dont feel like multiplying by 1.414 you can just try and remember this trick (it’s always what I’ve done). Just remember 1 and 1.4, every subsequent number is double the number two before it.

1, 1.4, 2 (twice 1), 2.8 (twice 1.4), 4 (twice 2), and so on.

One more by dradam, on how Pi cancels out in the formula F# = Focal length/diameter:

Given a focal length, going up and down one stop goes as doubling or halving the inverse of the area which follows from multiplying or dividing by the inverse of the inverse of the squre root of 2 (A=pi*r^2 therefore r = (A/pi)^(1/2)). Pi is simply a constant and as A = 2A or A/2 you end up with a series of the powers of root two. This is where you get 1, 1.4, 2, 2.8 etc.

Ian shows examples from:

• Panasonic Lumix DMC-G1.
• Olympus E-30.
• Panasonic Lumix DMC-ZS3 / DMC-TZ7.
• Motorola Moto ZN5 camera phone.
• Canon EOS 50D, EF 400mm f/5.6L IS USM lens.

This post will forever be incomplete, and more information will be added in time.

Lighting is important

I always like some light to come from the windows or doorway from behind or the side of my daughters. This is a personal preference. I’ve tried with direct sunlight falling on their faces, but the photographs somehow aren’t to my tastes. So, I frequently incorporate a degree of rear or side-lighting.

To illuminate their faces, I either use whatever indoor lighting that’s bouncing around, or I use my Nikon SB-800 flash.

If I decide to go with ambient lighting, I’ll try to get a spot meter reading of their face, and throw in an EC of +0.3 or +0.7. Or I’ll just do a trial and error by taking a test shot with the camera in matrix metering plus some EC. With my D70, I invariably have to put the camera into +0.7 EC to avoid having the photo come out on the dark side.

If I use the SB-800 flash, I’ll put the diffusion dome on the flash head and point the head at the ceiling. I tend to always use bounced flash as much as possible.

The use of a minimum of two sources of lighting is important to me. Consider the two photos below (straight from the camera, only resizing and sharpening was done in Nikon Capture 4.4.2).

The first picture is of Renice with the use of only bounced flash. When the camera is in portrait mode (held vertically), bounced flash tends to create a shadow to the side. If the subject is close to the background, the shadow is more obvious, and ugly. I find this photo uninteresting from a lighting perspective.

Full EXIF:
Nikon D70
Focal Length: 50mm
Optimize Image: Normal
Color Mode: Mode Ia (sRGB)
Long Exposure NR: Off
2007/02/23 10:29:36.8
Exposure Mode: Manual
White Balance: Flash +3
Tone Comp.: Auto
Bounce
JPEG (8-bit) Fine
Metering Mode: Multi-Pattern
AF Mode: AF-S
Hue Adjustment: 0°
Image Size: Large (2000 x 3008)
1/60 sec – F/2.8
Flash Sync Mode: Front Curtain
Saturation: Normal
Exposure Comp.: 0 EV
Auto Flash Mode: Balanced i-TTL
Sharpening: Auto
Lens: Nikkor 50mm F/1.8 D
Sensitivity: ISO 400
Auto Flash Comp: 0 EV

The second is again of Renice, but this time, sunlight is streaming into the room from a window behind her. Notice the formation of “rim light” on her hair and left shoulder. This makes for a more interesting photo, from a lighting perspective. To illuminate her face, I used the SB-800 in TTL-BL mode (this Nikon technology attempts to balance the illumination from the flash with the ambient lighting to create a mild fill-flash effect). If you’ve read Thom Hogan’s Nikon field guides, you’ll know that he recommends that the EC on the flash be dialed down to -1.7 to ensure that the fill-flash effect looks even more natural (that is, as if there was no flash used at all) – I sometimes forget and leave it at zero – that’s OK because my wife prefers her children’s face to look bright in photos . Also, the background is relatively far away, so you don’t notice any shadows behind her. You’ll need to experiment a lot to develop a feel for when and under what circumstances the shadow appears – you can only get better with lots of practice.

Full EXIF:
Nikon D70
Focal Length: 50mm
Optimize Image: Normal
Color Mode: Mode Ia (sRGB)
Long Exposure NR: Off
2007/02/23 10:30:22.8
Exposure Mode: Manual
White Balance: Flash +3
Tone Comp.: Auto
Bounce
JPEG (8-bit) Fine
Metering Mode: Multi-Pattern
AF Mode: AF-S
Hue Adjustment: 0°
Image Size: Large (2000 x 3008)
1/60 sec – F/2.8
Flash Sync Mode: Front Curtain
Saturation: Normal
Exposure Comp.: 0 EV
Auto Flash Mode: Balanced i-TTL
Sharpening: Auto
Lens: Nikkor 50mm F/1.8 D
Sensitivity: ISO 400
Auto Flash Comp: 0 EV

Camera Settings

The image processing engine in the Nikon D70 produces somewhat less-than-satisfactory JPEG files in default settings. I’ll list some of my oft-used settings that represent an attempt to work around these issues.

White Balance

I’ll use Auto White Balance -2 or -3 most of the time. Automatic White Balance at zero tend to result in photos that look too cool – the really bad news happens when photographing people – they tend to come out looking less than healthy in your D70 pictures. Again, practice and getting to know your camera is the key. You’ll find that for some pictures, auto WB at zero actually produces the (artistically) better picture.

Here’s a pic taken with Automatic WB at 0:

And one with Auto WB at -2:

Notice how the second picture looks “warmer”? Look at the skin, and the subjects in the background. Whenever you hear people commenting about dull or gray-looking D70 pictures, Auto WB 0 (and EC 0 – more on that later) is normally the culprit.

Auto White Balance can sometimes go all over the place though, depending on the lighting and the positioning of the subjects, so I sometimes just select one of the presets. If I’m using the SB-800 flash, I’d use Flash 0 or Flash +3 for the white balance. Why Flash +3? Well, Flash 0 sometimes result in pictures that are too warm, so your photographic subjects come out with an orange or pinkish tint. So Flash +3 “cools” things down a bit in the color temperature department. Incidentally, I used Flash +3 in the two shots of Renice – I like it, but some of you might even think that it’s a bit too “warm”. To each their own, really.

… more to come.