Technique: Use Continious Release for Sharpness

Continuous release isn’t just useful for fast moving subjects, it’s also handy for times when you just barely have enough shutter speed to get a sharp image while hand holding.

Pressing or releasing the shutter button, regardless of how smooth you try to be or what technique you use, you will always move the camera a little bit. However, once you’re holding the shutter release down that motion is gone. In many cases this can make the difference between a sharp image and a slightly blurry soft one.

An example of how low you can go is evidenced here with sharp images being made at shutter speeds as low as 1/80th of a second with a 640mm effective focal length.

Lenses: Magnifications

There are two ways the magnification of the lens is generally described.

• The ratio form gives the ratio of image size to object size. In other words, if a lens has a maximum magnification of 1:4, then at that magnification the object will be 4 times larger than the image.
• The decimal form is simply the decimal representation of that ratio. For example, a 1:4 magnification can also be expressed as 0.25x.

To convert from the ratio form to the decimal form, divide the object size by the image size.

Some Common Magnifications

• 5:1 (5x) – The highest magnification of the Canon MP-E 65mm f/2.8
• 1:1 (1x) – True macro magnification, the image is the same size as the subject was. Most true macro lens support this magnification.
• 1:2 (0.5x) – Half macro magnification, the Canon EF 50mm f/2.5 compact macro and the Zeiss Macro Planar lenses reach this.
• 1:4 (0.25x) – “Consumer Macro”, most lenses that aren’t dedicated macro lenses but are branded as macro reach this magnification.