Shortcuts and Rules of Thumb

Written by: Tiffany Joyce

Following are a few shortcuts and rules of thumb that help me in my day-to-day photography needs. Since I refer to them often enough myself, I thought I would pass them along to you.

Using a Teleconverter

Keep light loss in mind if you use a teleconverter in combination with your lens. In general, adjust the light levels one stop for each level of magnification. For example, if the magnification is 1.4x, adjust the light level by one stop. If the magnification is 2x, adjust the light level by two stops. This translates to stopping the lens down one or two stops to improve sharpness. For example, an f/2.8 lens becomes f/4.0 when used with a 1.4x teleconverter. An f/2.8 lens becomes an f/5.6 with the use of a 2x teleconverter. To accommodate this, you will also need to slow the shutter speed down, or increase the ISO, to allow more light in.

Correctly Exposing the Moon

When photographing the moon, set the f-stop to f/16 and set the ISO to 400. Set the shutter speed at 1/400 for a full moon, 2/400 (or 1/200) for a gibbous moon, 5/400 (or 1/80) for a quarter moon, and 10/100 (or 1/10) for a crescent moon. This formula works no matter which ISO you choose – if you’re working with ISO 200, the shutter speeds would be 1/200, 2/200 (1/100), 5/200 (1/40), and 10/200 (1/20).

Sweet Spots

Here is a table of aperture vs. shutter speed “sweet spots”. I actually printed a copy and stuck it in my camera bag.

Shutter speed = 1/2; Aperture = F22
Shutter speed = 1/4; Aperture = F16
Shutter speed = 1/8; Aperture = F11
Shutter speed = 1/15; Aperture = F8
Shutter speed = 1/30; Aperture = F5.6
Shutter speed = 1/60; Aperture = F4
Shutter speed = 1/125; Aperture = F2.8
Shutter speed = 1/250; Aperture = F2.0
Shutter speed = 1/500; Aperture = F1.4

Printing vs. Pixels

Following is a table comparing photograph size to the equivalent in pixels, which is helpful to understand when you’re printing photographs yourself.

Wallet size = 142 x 218 pixels
4×6 = 512 x 768 pixels
5×7 = 768 x 1153 pixels
8×10 = 1024 x 1536 pixels

Helpful Links

I find myself going back to these links every now and then:

- Matt Cole’s Handy Guide to format sizes, image areas and “normal” lens focal lengths.
- The Ultimate Exposure Computer.
- 78 Photography Rules for Complete Idiots. It’s tongue in cheek, so don’t take it seriously! Though, there are actually a few good tips in there. It just made me laugh.

Do you have a rule of thumb or easy-to-remember formula to share with us? Leave your tips in the comments!

Photo credit – “Crescent Moon” by Luis Argerich on Flickr Creative Commons.

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