The first step
The first thing to do before buying is to find online information about the chosen model: sometimes the market get entire parties of equal marriage, and about the probability to meet such, you need to know in advance.
Do not hesitate to spend on the inspection camera as much time as you need. The task of the seller to sell you the goods, even marriage, but your task is to purchase a serviceable model. Take a camera and carefully inspect the case: there are no scratches, if not touched the screws. Check out the button cover is securely seated battery.
Prepare in advance and bring the laptop with the software installed Exif-O-Matic. Make a test shot, open it in this program and find the Exposure parameter Sequence Number: is the number of captured still images. If the number is small, perhaps the camera was used in the store. But a large number of most likely suggests that the camera bought, used it and then returned to the store. Ask for another copy.
Check for dead and hot pixels. Will expose the following values: shutter speed 1/60 sec, ISO 100. Make the white sheet of paper, consider it on a laptop: if you can see black dots are dead pixels. Then remove the lens, close the camera cover and take another photo: the white dots are all the same dead pixels. Hot pixels can be detected: put alternately a shutter speed of 1/3 second and 2 seconds (if you have the noise reduction feature, this exposure must be made) with ISO 100. Pictures for finding broken pixels need to be considered at 100% magnification. To remove the corrupted pixel in the warranty service, but if their number is large, it is necessary to ask for another copy.
The last thing you need to pay attention – work focus. Usually in stores you can find special charts to check focus, but you can use a regular ruler and a match. The ruler is placed on a white sheet of paper vertically, match – perpendicular to it, in the middle. At an angle of 45 degrees and take a picture of the match line. The focus in the middle or far end of line – focus error. If in focus, as intended, match, pay attention to depth of field: it should be about the same above and below are the matches.
The buying process
The camera is a complex and fragile technique, and the more reliable will be your seller, the more likely to avoid defective or used models, as well as on time and without difficulty to obtain services. In specialized stores, the price of goods is often overestimated, while in hypermarkets of electronics you need to carefully check the camera for defects before buying. Be sure to check the documents and warranty card, appearance of the packaging.
Ordering from an online store will a certain risk: if there is no alternative, do not take the money for the good name of the seller and good courier service.