Archive

Posts Tagged ‘Dx Format’

Choosing A DSLR Camera – Some Considerations

October 1st, 2011 No comments

There are a wide range of options and features available for DSLR (digital single lens reflex) cameras and it can be confusing if you are buying this type of camera for the first time. This guide will help you decide which features are important to you and hopefully help you to choose your ideal DSLR camera.

Price

A major factor in your decision is, of course, the price. DSLR cameras start at about $400 and can be as much as $8000 for a top of the range camera. A camera of between $400 to $1000 would probably be a good choose for a newcomer. Lenses tend to be expensive and can cost more than the camera body do make sure you take this into account when you make your budget.

Format Size

There are four format sizes at the moment for 35mm DSLR cameras.

Full Frame

This format, with a sensor size of sensor size is 36mm x 24mm, is found on most higher end cameras and is the same size as that used in 35mm film cameras.

APS-C

On a Canon camera this format has a 15mm x 22.5mm sensor and on a Nikon 15.6mm x 23.7mm. This format is used by most DSLR cameras except some higher end cameras and Olympus makes. Nikon call it a DX format.

APS-H

This format is only found in a few cameras such as the Canon EOS 1D MkIII and has a 18.7mm x 28.7mm sensor.

Four Thirds

This is a smaller format at 13.5mm x 18mm and is found on Olympus and Panasonic cameras. The aspect ratio is 3:4 unlike other cameras with an aspect ratio of 2:3.

All of the formats will give a good print out up to 11″ x 14″ which is the largest most amateur photographers will usually need. Most cameras below about $1000 dollars use the Four Thirds or APS-C format so the choice is usually dictated by the price rather than performance.

Image Stabilization Systems

Systems for image stabilisation vary between manufacturers. Some systems are mounted in the camera body others on the lens itself. Nikon and Canon use a lens based system and use gyros on the lens to sense movement and keep the optical groups stable. Gyros mounted on the camera body are used by Sony, Panasonic and Olympus in a stabilisation system called a sensor shift. The sensor shifts to compensate for any movement. Although both systems perform equally as well the lens mounted systems need to be included on every lens which adds to the cost. In addition not all lenses have the system included especially prime lenses under 200mm.

Size and Weight

Cheaper cameras tend to be smaller and lighter although, as no DSLR camera is going to fit into a pocket anyway, the size is not of primary important.

Pixel Count

DSLR camera start at about 6 mega pixels (MP) and can be as much as 22 MP for a high end camera. The pixel count will dictate the size that a print can be blown up to and you need to decide how large you would like your prints before you decide on which model to buy. 240 pixels per inch will give a very good quality print so a 6 MP camera will be adequate for a high quality 8″ x 10″ print.

If you need larger prints a 10 MP camera will be capable of producing a good print at a size of 11″ x 14″. A top of the range camera with a pixel count of 22 MP will give excellent 11″ x 14″ prints.

ISO Settings

ISO ranges between 100 and 1600 are found on most lower end cameras. Mid range cameras may have settings up to 6400 and a high end camera can reach as high as 25,500 and as low as 50. Most DSLR cameras will give pictures with low noise at ISO settings between 100 and 800 but the noise dramatically increases above this. The noise at the higher levels can vary considerably between models so, if possible, try to see images taken at higher setting with the cameras you are considering.

Noise

All digital images will have some noise which will be more noticeable at higher ISO settings. Noise comes from the electronics and sensor when the digital signal is produced from the analog signal. All DSLR cameras have noise filtering systems but this works less well above an ISO setting of about 800. Noise reduction softens the image so try to see images taken in low light if you will be using the higher range ISO settings.

Autofocus

Autofocus systems vary a great deal between manufacturers. All auto focus systems work well for static images but can vary a great deal for moving subjects, especially in low light. Check reviews of specific cameras for information on how well auto focus works for the model you are considering.

Janet Ashby
http://www.articlesbase.com/computers-articles/choosing-a-dslr-camera-some-considerations-712261.html