If you're buying a camera or lens, it's a good idea to give it a try. Here's what to check for.
Checking That a Camera Works
For all their technical complexity, there's a huge amount of things that can not be done with a digital camera: if it works, it works; if it does not work, it does not work. There's not much middle ground.
Look it Over Visually
The first step is to look over the camera. Are there any cracks, dents, breaks, or bad scuffs? You should expect a little, but nothing too bad.
Open the battery and SD card hatches. Do they open smoothly? Do the battery and memory card go in and out smoothly? What about the pins? Are they clean and undamaged?
Have a look at the lens and in particular the contacts that send information to a lens. Are they in good condition? Attach a lens to the camera. Does it go on smoothly? Is there any play between the camera and lens or does it have a nice, tight fit? Does the camera show a warning?
What about the hot shoe or built-in flash? Do they work? Do they look damaged?
Push all the buttons and turn all the dials. Is anything stuck or catching? When you adjust things, what does it do for you?
Have a look at the tripod plate. Is it damaged?
Check the diopter. Does it adjust properly?
It should not take more than a few minutes to complete your camera, poking and prodding and making sure it looks right.
Check the Shutter, Mirror, and Burst Mode
With the externals being over, it's time to pay proper attention to the internals. Remove any lens that's attached to the camera and look at the mirror. Is there any apparent damage?
Select a shutter speed of about 1 / 3rd of a second. Is the mirror action smooth? Does the shutter action look good? It will move fast, so it's hard to tell, but if it's a problem you might see it or hear it.
Select the maximum shutter speed, put the camera in burst mode, and hold down the shutter. Is the shutter action smooth and continuous? Do you hear anything weird or catching? The camera should happily shoot until you fill the buffer.
Check the Lens Controls
Attach a lens that you own and trust to the camera. Select a few different shutter speeds and apertures and take a few shots. Do they look like you'd expect?
Select the narrowest aperture, look down the barrel of the lens, and hold the depth of field preview button. Did the aperture blades close smoothly? Is the aperture symmetrical?
Check the Autofocus
Manually select at autofocus point, select a wide aperture, focus on something, and take a picture. Inspect the image to check that the point you focussed on is actually in focus.
Check the Sensor and LCD
If the camera has Live View, turn it on and make sure the screen looks good. Take a totally overexposed image and a totally underexposed image: they should be pure white and pure black. Inspect them on the back of the camera looking at each other.
Transfer the images to a computer and give them another quick look over. Does it look like it should?
Check the Shutter Count
Camera shutters fail over time. They are usually rated for between 100,000 and 300,000 actuations, depending on whether it's an entry-level or professional camera-you can find it out from the manufacturer's website.
RELATED: How to Check a DSLR's Shutter Count (and Why You Should Care)
Use your laptop to check the camera's shutter count. If it's less than 50,000 or so, then the camera has lots of life left in it. As the number gets higher, the more likely it is to need a shutter replacement in the future. Checking That's A Lens Works
Like cameras, there's a whole lot that can not go wrong with a lens that doesn ' t leave it very interesting broken. Here's how to check one over.
Look It Over Visually
Look the lens over visually. Make sure the glass is not badly cracked or scuffed. Look through the lens and make sure there's no dust or fungus caught between the elements. Have a look at the filter ring, too. Do the threads all look okay?
What about the lens mount? Do the contacts look good? Does it mount solidly to your camera? Are there any errors?
If it's a zoom lens, does it zoom smoothly? Do all the switches and dials work without catching?
Check the Focus
Attach the lens to your camera, select an autofocus point, and take a photo. Check the image to see that where you are focussed is actually in focus. Repeat the process with different points of focus, apertures, and subjects.
View and find the camera in manual focus mode. Focus on a few different subjects and take a photo. Do they look like they should? Did the lens focus adjust smoothly?
Check the Aperture Controls
set your camera to the lens' minimum aperture, look through the lens, and press the depth of field. Do the aperture blades move smoothly? Is the aperture symmetrical?
Check the Image Stabilization (If It Has It)
If the lens has stabilized, it shifts to slow shutter speeds. Does it seem to be working? Put the camera in live view, and hold the lens next to your ear. Can you hear the IS motor working as you move about?
Buying used camera gear is pretty safe, especially if you buy it from a reputable source. Cameras and lenses are not in good shape, or they're paperweights.