Introduction:
You just bought that dream lens that you have had on your wish list. You have a Wedding to shoot in one week and want to use your new tool. What do you do next?
How to test your new lens:
1.Examine the Lens. Generally inspect the lens for proper fitting of the focus ring, any physical damage and general build quality. Is anything loose? Are all of the screws there?
2.Does the barrel slide back and forth easily?
3. Check the operation of the focusing motors. Do they sound okay? Is it's operation smooth?
4.Check the lenses for scratches or any damage.
You are not finished yet. You must do the following for each camera body that you own.
Check the Lens for Front and Back Focusing Issues.
A lens should focus exactly at the point of focus. For example, put a one meter yard stick on the floor. Set up a tripod and you will focus at say the 18 in mark. You need to do this at the min and maximum F stops. If you find that the lens is focusing in front of your target, then it is front focusing. If it is focusing behind your target, it is back focusing.
The reason we do this is simple. We want to be absolutely certain that when we shoot the brides eyes, or groups of people, that we get them in focus. At low F stops, like F2.0 to F1.2 we do not have a large depth of field. For that reason, we must calibrate our equipment for each lens in our kit. Remember that I said that "I would not buy a camera body that didn't have a Auto Focus Micro Adjustment in it?" (ie: Canon 60 D and Nikon D600). This is why. With the built in tool, you don't have to send your body and lens back to Canon or Nikon for adjustment. Not having this feature in any new upper end camera body is quite frankly an insult to the buyer. The manufacturer is simply saying, " We don't care about the quality of your photos". I can see leaving this feature off on consumer models as a way to get people to buy the semi-pro equipment.
Here is a link to down load a chart that you can use to test your lens.
Here are some examples of tests:
- Example 1
- Example 2
Summary:
Modern manufacturing processes should not produce Cameras with a large standard deviation in the tolerances. In Japan, they hold an annual event for companies with the best or lowest number of defects. America was offered this approach to manufacturing after World War II and refused to partake in it. Japan readily accepted it. In the early 80's North America finally accepted their mistake and started to use this approach. Even with this improved manufacturing method, error or deviations in production can produce camera/lens combinations that require calibration. Camera bodies that have this Auto Focus micro adjustment were a leap forward in design that allowed us to produce beautiful sharp in focus pictures. If the picture is out of focus, there is nothing that you can do to bring it back into focus that I know of at this time.
Masters-Tip: Check all of your lens/body combinations and calibrate to ensure that the AF system is working properly.
Masters-Tip: Only buy camera bodies that have an Auto Focus micro adjustment built in.
Kirk is a Professional Wedding Photographer in Windsor Ontario Canada. In appreciation if you would be so kind as to give a G+ and a Facebook Like KW Masters Photography on his Facebook page. You only have to do this once and add your likes and G+ per post.
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