MacrophotographyFDCC - January 2012

Macrophotography

Strict definition - From life size to limit of unaided visibility

Loose definition - about 1/3 life size to limit of unaided visibility

Magnification

Magnification is usually represented as a ratio:

Life size = 1:1Half life size = 1:2Twice life size = 2:1

A lens’ magnification is based on a full-frame sensor/film camera

On a crop camera, the perceived ratio is magnified

Canon 1.6 crop = 1.6:1 ratioNikon 1.5 crop = 1.5:1 ratio

Curvilinear Distortion

The outer surface of all distal lens elements are curvedThis curvature results in slightly different focal distances to the sensor planeFor objects feet or more away, this has no discernable impact on focusHowever, for macrophotography it can have a dramatic impact on focusing

Focus on center, periphery is out of focusFocus on periphery, center is out of focusDedicated macro lenses are corrected for this phenomenon

Tools of Macrophotography

Conventional lenses with macro capabilities (i.e., close focusing)

Dedicated macro lenses

Extension tubes

Bellows

Macro ring flash

Macro rail

Nikon Micro105mm f/2.8 VR

Sigma 150mmf/2.8 Macro

Kenko extensiontube set

Velbon Macro Rail Canon MP-E 65mm f/2.81x to 5x magnification

Nikon E-TTLring flash

Nikonbellows

Zeiss 50mm f/2Makro-Planar T*

Conventional Lenses

Many conventional lenses have macro capabilities that provide up to 1:2 (half life size) magnification

Generally, they tend to suffer optical distortions at macro settings

However, they are typically inexpensive

Sigma 17-70f/2.8-4.5 Macro

Dedicated macro lenses

Usually provide 1:1 magnification to infinity focus

Have high-quality lens elements specifically designed for high magnification

Tend to be extremely sharp

Many portrait photographers use macro lenses

Fixed focal length

Substantially more expensive

Pentax 100mmf/2.8 Macrowith hood

Tamron 60mmf/2 Macro

OLD macro lenses

Usually provide 1:2 magnification to infinity focus

Have high-quality lens elements specifically designed for high magnification

Tend to be extremely sharp

Many portrait photographers use macro lenses

Fixed focal length

Substantially less expensive

Some require mount adapter

Pentax 100mm f/4 Macro SMC Takumar

Extension tubes

Fit between camera body and lens

Have no optics

Increase the distance of the lens to the sensor, thus increase magnification

Lose infinity focus

More expensive ones maintain electrical communication between camera and lens

Maintains autoexposure, focus and TTL flash

Kenko extensiontube set

Bellows

Similar to extension tubes, but variable extension

Do not maintain electrical communication between camera and lens

Lose autofocus, autoexposure and TTL

Generally not used today

Nikonbellows

Macro Ring Flash

Magnification reduces the amount of light that strikes the sensor, thus flashes are often needed

Shoe-mounted or pop-up flashes cannot illuminate a macro subject because the lens impedes the light path

Macro ring flashes mount on the end of the lens to provide flash illumination

Some provide E-TTL, while others do not

Sigma EM-140Ring Flash

Macro Ring Flash

Conventional flashes can be used with brackets and diffusers

Need off-camera cable to preserve E-TTLAllows for diffused light source

Delta Flip FlashBracket II

Aperture Diffraction

Aperture diffraction occurs when the aperture is very small

The result is softness of the image

This phenomenon is magnified with macro photography

The greater the magnification, the more diffraction

Thus, the optimal aperture for most dedicated macro lenses is around f/11 for crop sensor cameras

Larger apertures have thin focal plane, thus have narrow depth of field

Smaller apertures have diffraction, thus the image is soft

Purchasing Macro Lenses

Optically, all dedicated macro lenses will be about the sameThe differences in prices include:

Brand nameFast autofocusing (ultrasonic motors)Internal focusing (lens does not change length)Included accessories

Lens hood

Case

Tripod collar

Macro Technique

Stationary object

TripodMirror lock-up

Manual focus

Rails help significantly

Moving object

Monopod or free-hand

Rails often of little use

Manual focus

Focus on a point, then move towards that point

• Repeat

Focus stacking

A lack of depth of field is the principal problem with macro photography

Focus stacking is the process of taking several shots at different focal planes, then using the in-focus regions of those images to make a single image that’s in focus throughout

Avoid changing the lens’ focus as this also changes the magnification

Helicon Focus is a software package that provides this technique

Focus rails are excellent for stacking