Points to check before buying used equipment
If you are not sure you understand the points mentioned below, it is probably best for you to buy new equipment, at the risk of ending up with a used camera in poor condition.
The external appearance of the equipment says a lot about its former owner: shocks / scratches
First of all, examine the equipment carefully from all angles to assess its wear and tear and whether it has been subjected to any shocks.
For digital cameras, look carefully to see if all the buttons are present and working, if the housing shell is not cracked or dented in some places. A simple scratch is sometimes not a problem, but a shock mark, however small, can mean that the case has fallen, and some components inside, that you don’t see, may have been damaged. A quick look at the battery connectors will allow you to see if there are any traces of oxidation. Without a lens, also check if the contactors and the device mount are in good condition, and that there is no dust (or worse, sand) inside the sensor cage. A few dusts on the mirror are generally not a problem (because the mirror protects the sensor from the housing) but it is better to be too demanding than lax and bite your fingers later.
For the lenses, check carefully if there is no dust trapped between the different lenses, if the lens surface is not scratched, and if it is a zoom, if the zoom ring works and is fluid. Tip: Use a flashlight and illuminate the inside of the lens on the side where the lens is attached to the body. This way, you will see all the dust present in the optics.
Ask specific questions about the equipment to the seller
Before buying second-hand equipment, I like to talk with the seller, to know what his use of the equipment has been, how long he has been using it, if he has been satisfied with it, why he sells it,… In short, all these little questions that seem like nothing but that will allow you to check that the person in front of you is really the user of the equipment. If not, think about it, and if in doubt, refrain from doing so, as the dealer may tell you stories.
In general, unless you are comfortable enough to inspect a piece of equipment yourself, or you buy it in a photo shop, talk directly with the user of the photo equipment for sale.
Check the number of trips
If you think that a SLR camera is immortal, you are mistaken: each camera has a shutter that is one of the wear parts that allows you to know how to use a camera. With the number of shots, you can find out if the camera has taken a lot of pictures, and especially estimate how many pictures you have left before the shutter shows signs of weakness (black bars on your picture) or breaks down completely.
To find out how many times a camera has been triggered, the easiest way is to study the EXIFs of the last picture taken with this camera. If your in-house photo software does not allow you to find the number of triggers, download XnViewMP (free) and open the photo using this software.
For information, and depending on the ranges, here is the number of theoretical releases of the boxes before a failure occurs:
- Entry level: 50,000 trips (ex: D3300, 100D)
- Mid-range: 100,000 trips (ex: D7100, 70D)
- Semi-pro: 150,000 trips (ex: 7D, 5D, D800)
- Pro: 300,000 trips (D4s, 1DX)
These figures are not contract values provided by the manufacturers, and if your shutter fails, the repair will only be covered if the housing is still under warranty.
Replacing a shutter costs several hundred euros, depending on the model (the higher the model is, the more expensive it will be to replace). So check the number of trips before choosing a box, and if it is too close to the theoretical limit, ask yourself if you could find another device that is newer and perhaps a little more expensive, with which you would be more comfortable.
Trigger and trigger
For a box, it is essential to perform a few trips to see if the device is working properly. The important points to check here are the exposure cell, autofocus, viewfinder, recording files on the memory card.
To check the exposure cell, disable bracketing and exposure compensation, photograph a bright area several times in a row and check that the exposure is correct and above all constant between the different shots.
Inspect the sensor
The sensor is the centerpiece of a DSLR, and if it is not in very good condition, it is better to stop there in the purchase. Indeed, it is an extremely fragile and delicate component, and a simple cleaning of the sensor without taking precautions can cause stains or even scratches on this sensor, with permanent traces on all the photos you will take later.
To check that the sensor is in good condition, is not filled with dust and has no scratches, here is a simple procedure to carry out with the housing:
- use a manual setting with priority to aperture
- choose a very small aperture type f/16 (do not worry about the shutter speed
- use the widest focal length and focus manually as close as possible
- take a picture of a clear wall, a white sheet of paper or even a blue sky
Take several pictures, and watch them on a large screen (not just on the back of the camera). If you see small dark spots or lines on the image, the sensor is not in good condition. If the stains (dust) can leave after meticulous cleaning (go through a professional or someone who knows what they are doing), the scratches are there to stay, so give up. And if you have your sensor cleaned, a tip: take pictures with the professional to show the condition of your sensor before leaving it, so there is no unpleasant surprise if it turns out that its cleaning has made things worse, or worse, brought a scratch on the sensor.