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