I'm considering buying a DSLR from a friend. I've read the used lens question elsewhere on this site, but I was wondering what I should look at on the body to assess the condition?
A couple of things:
- Make sure the obvious stuff like autofocus, aperture control, shutter speed actually work.
- Check number of shutter actuations. Most bodies have a mean time between failure (MBTF) number for this, so check how close it is.
- Make sure all connections work. USB, HDMI (if present), Video out.
- Battery, charger. Be aware you might need to replace it, depending on the amount of use it has seen.
- Shutter Actuations. Oh yes. Consumer DSLRs last something like 20-100k. It's a pretty fast thing to hit that. However, that's an estimate. It could go for 10k or 200k, you never know. But the higher the shutter count, the sooner it will fail.
- Check all the things the other guys said: aperture, AF, flash (if it has it), make sure the sensor and viewfinder are free of scratches, make sure the mounting for the lens isn't damaged and doesn't let excess light in.
- Take a picture in a well lit area. Look at it 100% on a computer and check for oddities (scratches, bits missing, etc.)
Just factor in that you'll be buying a battery. But make sure the charger works.
Ensure you test the camera at its highest possible shutter speed. Try this in both single shot and multiple shot mode. Look for any darkening of the frame that could indicate the shutter is starting to fail.
Also closely inspect some shots and look for dots (like dirt) and more importantly streaks (grease or worse scratches) on the sensor. Shooting the sky show these items.
Check that all accessories are present and work.
Consider a refurb -- Adorama usually has a few, and I think you can find them elsewhere, too. Given the rate of "depreciation" for bodies & lenses, these seem to be very good values, and you'll have the assurance that the equipment has been reviewed by technicians. In many cases, you'll also get a warranty on these items on top of the savings.
It's like buying a used BMW. Learn about your seller, and see if they are someone who would baby their equipment. If they have a website, go to the website and look at the photos. If they're a beginner, there is a chance they don't know how to care much for their equipment yet. The perfect person to buy from is a budding intermediate amateur/professional who is upgrading to a professional body, and selling the lower end body to raise funds. Also, a good sign of someone who takes care of their camera is someone who still has the box, receipt, packaging, and manuals.
In addition to the obvious (visible scratches on the body, ability to take pictures and to autofocus), it is a good idea to check for:
Number of shots already taken. A typical entry-level DSLR is tested for about 100,000 shutter actuations. See How many actuations are "too many actuations"? for more details.
Dust inside the body. A quick look on and around the mirror can give you a hint on how well the camera has been treated. Dust does not have to be visible to be harmful, but if it is visible, it's likely to be a problem. Not everybody is as careful as you are when changing lens ...
Dust on the sensor. Be careful: small dust is barely visible on pictures taken at wide aperture (you may not notice it it day-to-day pictures and find out it's a disaster when you take a macro shot for example). Take a shot of at the narrowest aperture of your lens (i.e. the largest possible F-number). As much as possible, shoot a uniform background (e.g. the sky), out of focus (e.g. focus to minimum distance and take a shot of the sky which is at infinity). Then review the whole picture at 100 % zoom. See Why use a small aperture when trying to see sensor dust? for details.
Accessories. The body usually comes with USB cable, TV connection cable, eyecup, battery and battery charger.
Serial number. It should be the same as the one on the bill.
All buttons should work, all memory card slot(s) should work, the flash should work, ...
Note: if you're buying only the body, you'll need a lens and memory card to test the body. Don't forget to carry these when you meet the seller. Ask for a charged battery or you won't be able to test.