Lenses

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Collingwood, 3066

Victoria, Australia

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Creating Complex Imaging Solutions +613 9419 5247

Lenses

Lens focus issues

Images not sharp

There are many factors for images not being sharp and exhibiting in many ways.

Lenses

Back focusing. The focusing is locking on behind the subject

Forward focusing. The focusing is locking on in front of the subject

Edge to edge focus. The edges of the image will be soft.

Softness through out the range. This may be an indication of wear, in need of a calibration or a distortion in the lens assembly

The lens needs a focal calibration

Worn guide rollers

Impact damage

Dusty or smudged lens filter

Lens guide rollers, when theses wear

out it creates sloppiness in the lens

causing resolution issues

Also see camera focal issues

Reducing wear on your lens mount

Attaching, and removing, a lens on a camera causes frictional wear on the lens mount, and is made worse when sand and grit is wedged between camera and lens.

Metal mounts can produce swarf that enters the mirror chamber and become deposited on the CCD/CMOS imager resulting in spots on images, also the AF sensor can be affected by this swarf. The entry level lenses with plastic mounts do not produce swarf but can become rough and raspy. In any case, mount surfaces loose their smooth rotational movement.

Use a clean lint free cloth with a small amount of alcohol, methylated spirits or shellite to wipe the mount and contacts on both lens and body helps to reduce wear. A smear of grease will help reduce wear. Some professional DSLR cameras already have suitable grease applied on the mount as a countermeasure to wear.