Pulling the trigger tomorrow 60D or 7D(w/micro adjust)?

Started Jan 5, 2011 | Discussions thread
riknash
Veteran MemberPosts: 3,189Gear list
Like?
Re: MA counts, speed too, as does AF
In reply to ToddF, Jan 9, 2011

You need to be confident and competent with evaluating a lens in about 60 minutes.

There are many things you need to do and this a partial list.

-If possible, purchase a used lens that is less than a year old where the seller also provides you with the original sales receipt. This provides a bit of insurance should something go wrong during the remaining warranty period. Lenses out of warranty should be slightly less in price. Examine the production date code (do Google search to learn how to read it) stamped on the lens mount and verify its age.

-Physically examine the lens closeup for any abrasions to the exterior, chipped paint, or scratches on the lens elements, mounting ring must have no dings to it.

-examine gold electrical contacts at mount and verify they appear smooth with no damage.

-make sure a UV filter can screw on and off easily. If it has one on, remove it to examine front element.

-Look for dust in the interior of the lens by shining a small flashlight through it.
-operate all switches, ensuring they slide correctly and not loosely.

-operate focus ring and verify the travel is smooth without any signs of internal binding.

-mount lens on your camera and verify that it is not loose when mounted. Attempting to rotate it while mounted shouldn't present any jiggle-slop (as I call it)

-verify that switch functions perform as required. That is, the IS turns on only when it is selected, minimum focus distance limit switches work to limit focus range.
-listen to the IS motor and evaluate the noise. Does it sound smooth or rough?

-focus tests at various zoom lengths. With continuous focus, aim at various near to far objects and confirm that focus tracks quickly and smoothly. Do this at shortest, mid and longest focal lengths.

-sharpness tests. You need to find something like a parked car's license plate at a reasonable distance which you must use the liveview to zoom into maximum to examine the sharpness of the letter/numbers. With IS on, shutter speed 1/1600, holding very steady, center point focus, shoot handheld at the licence plate using shortest, mid and maximum focal lengths. Verify the letters have little to no blur on their edges.

-mount on tripod and shoot same licence with IS off and verify the sharpness of letters on licence plate.

-shoot a few images on tripod using liveview contrast detect focus and compare sharpness.

-although difficult to verify on-camera display, at maximum zoom of display, check corners of images and confirm they appear as sharp with no chromatic aberations, blur or unusual vignetting (darkening in the corners).

-with sunlight to your side, center focus point on road surface and confirm images are in focus at the center point and not in front or behind that point. Look at the gravel and their side-shadow and decide where it looks the sharpest. Is it exactly on the point you focused or somewhere else? Do this at minimum, mid and maximum focal lengths. Set lens focus to infinity and force the camera/lens to focus on point on the road and shoot the picture. Zoom in and examine. Does the point on the road appear to be the sharpest point or somewhere else?

The above gives you a rough idea how to verify a used lens or even a new lens you purchase at a camera store for a good copy. It's not a guarantee but at least a reasonable effort to verify that the lens checks out.

ToddF wrote:

riknask wrote:

Redarding the note:
" The only hard part is making sure you are buying a good copy."

Can you tell me how I make sure I get a good copy? I am not sure what test(s) I need to do to make sure I get a good copy. I see some used 70-200's for sale however I am concerned these might not be good copies hence why some are for sale.

Thanks.

 riknash's gear list:riknash's gear list
Canon EOS 7D Sony Alpha NEX-7 Canon EOS 5D Mark III HTC One
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow