找了个英文的，有对焦测试的步骤，还提供了网上提交测试结果的连接 原帖引用地址 http://focustestchart.com/chart.html#Interpreting
Important!
There are many factors that can lead to erroneous and misleading results when doing this test. Make sure you read these instructions carefully and follow them in detail.
- Print out this document.
- Place the test chart absolutely flat on a level surface. There must be no visible lumps or bumps in the chart. It needs to be flat.
- Aim your camera at 45 degrees to the chart.
- Focus on the centre of the focus line in the focus box at the centre of the chart.
- When shooting your test pics, you need to be close enough that the test chart somewhat more than fills the frame. Get nice and close.
- Ensure that you are not so close that the auto focus system is unable to focus due to you being at the limit of the range of focus of your lens.
You can check this by moving your camera closer and closer to the image and testing when it is no longer able to focus and then making sure that you are set up at least a few inches back from this point. - Set your camera to aperture priority mode (“A” on the rotary dial) and adjust the aperture setting as wide as it will go (lowest f-stop number) for the lens you have on the camera. This gives you the shallowest depth of field, which is crucial to this test.
- Set the Autofocus system to “AF-S” mode (CSM Menu item 2).
- Set the AF-area mode to “Single area” (CSM Menu item 3).
- Ensure that you have the centre focus area selected. If not then adjust this using the multi selector button (up/down/left/right). The focus selector lock switch (just below the multi selector button) must be unlocked in order to change/select the appropriate focus area.
- If you have extra lighting available, use it to light up the test chart. The chart must be lit more or less from the front. I like to use a bright constant light source, like a halogen flood or similar, but the flash seems to work just fine too. If you’re going to depend on the flash then make sure there’s enough ambient light for the auto focus system to work reliably.
- Metering mode and centre weighting is not critical. As long as you’re getting a well lit, bright image out of the camera then it’s fine.
- First shoot an initial pic and have a good look at it before you go further. Make sure the test chart is bright and white. Adjust your white balance and shutter speed to get this right. Use more light and/or the flash if necessary.
- Use either the remote control (if you have one) or the camera’s self timer to trigger the shutter release in order to avoid any camera shake.
- Now go ahead and shoot your test pics.
Interpreting your results
Once you’ve taken a bunch of test pics you’ll want to know what they mean.
When you view your test pic/s, you should be able to clearly see, as in the example on the right, that part of the chart is in focus, and that it gets obviously and progressively more out of focus as you move up or down, away from the in-focus part.
Notice how the sharpest part of the image is in the centre, between the two 2mm marks and how it gets blurry as you move away from the centre line, either up or down. This is as good as it gets. Spot on focus, bang on the centre line, right where the camera was aimed. This represents the ideal.
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| | It’s normal, particularly with longer focal lengths, to see the focused area, or depth of field, shifted slightly rearward, as in the pic on the right. This is not a problem as long as the focus line is still within the area that’s in focus. |
| | If the part of your pic that’s in focus is so far back that the focus line is way out of focus then you have a problem with back focus, as in this example. |
| | If the point that’s in focus is too far forward, as in this example, then you have a problem with front focus. |
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You’re welcome to email me at: tim@FocusTestChart.com.
I’m happy to look at your test pics and to offer an opinion.
By the way: If you happen to measure the spacing of the lines on the chart you’ll notice that they are further apart than the markings suggest. This is deliberate. When the chart is at 45 degrees to your camera, the spacing becomes correct. This is done so that when you see those markings in the resultant image you can read them as-is without having to make extra calculations. They’re pre-compensated.
Tim
The chart
| To get your own copy of this test chart, download this document. Printing this web page directly will not give you a usable chart. |
Simple focus target | To get your own copy of this focus target, download this document. Printing this web page directly will not give you a usable target.
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