Week 4

Close up photography (and macro)

Focal length definition

"The distance from the surface of a lens or mirror to its focal point. Also called focal distance, focus."
http://www.answers.com/topic/focal-length#ixzz1GiM255vk

-Focusing changes the distance between the lens and sensor (lens moves, sensor is fixed)

-The closer the image, the bigger the distance needs to be between the lens and the sensor

-200mm = distance between sensor and lens is 200mm (closer)

-50mm = distance between sensor and lens is 50mm (further)

-A normal lens not described as macro will focus at about 0.4m to 0.5m at closest

-Distance from lens to film gets bigger the light intensity drops

-"Macro is when the image on the sensor is bigger than the object is in real life'

-Use smaller apertures to get the most depth of Field

-Always use a tripod

-Use mirror up function to minimise  camera shake (canon can do this in the menu somewhere...)

Equipment

-Close up lenses screw on like a filter. They are like glasses. "A screw on magnification glass". they are the cheapest option but the lowest quality.

-Tiny bellows

-Extension Tubes, simply push the lens further away from a camera. Bought as a set. Can attach 1 to the other. Has no glass so no degradation! May push lens into something it cant handle optically. Geoff says they are a good alternative.

-Macro Lens

 -the front element extends more that a usual lens

 -optics are designed for close up

 -scale for magnification is written on the lens so you can choose magnification.

 -try to move the object so you know what magnification you have.

-Life size converter

 -joins onto macro lenses to make 1:1 magnification

-magnification is measured in image size divided by object size.

Lighting

-Fiber optic lights - tungsten. Handy for small objects. Can't use in conjunction with flash because of white balance problems.

-Ring flash- perfectly flat, even, lighting. Not exciting, not powerful, designed for really short distances,

-Working small means BIG softboxes aren't really appropriate

-Use backlighting for small, thin objects

-Microscopic stuff is usually back lit.