Nikon AF Point Outline test issue

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Marc H

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I have been using Steve’s target to determine if my AF Point outline was off and following his instructions from his video “8 Common Auto-focus Problems”. I tried with 2 cameras (D500 & D7200) and 2 lenses (200-500 & 500 PF). When I go from the blurry white paper surrounding the target to the target, nothing happens. I barely see the target behind the AF point outline but the cameras do not focus even if I hold the point on the target while continuing to press the back-button. Additionally if I try to focus on the target, I get inconsistent results. Either it focuses, delays focusing (1-5 seconds) or locks in a non-focus mode. I have my cameras set on continuous servo AF, single point AF. I tried using a solid black square as a target. I have the same problem moving from the white paper to the square. However, focusing on the black square is not a problem. Anyone’s thoughts on this would be appreciated.
 
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Marc H said:
I have been using Steve’s target to determine if my AF Point outline was off and following his instructions from his video “8 Common Auto-focus Problems”. I tried with 2 cameras (D500 & D7200) and 2 lenses (200-500 & 500 PF). When I go from the blurry white paper surrounding the target to the target, nothing happens. I barely see the target behind the AF point outline but the cameras do not focus even if I hold the point on the target while continuing to press the back-button. Additionally if I try to focus on the target, I get inconsistent results. Either it focuses, delays focusing (1-5 seconds) or locks in a non-focus mode. I have my cameras set on continuous servo AF, single point AF. I tried using a solid black square as a target. I have the same problem moving from the white paper to the square. However, focusing on the black square is not a problem. Anyone’s thoughts on this would be appreciated.
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How much light are you shining on the target?

The only thing that comes to mind is insufficient light making it hard to acquire the target at f/5.6. Basically any high contrast target (a black cross might be better than a black square) should work for reliably acquiring AF assuming sufficient light. Does it work better if you try this outside in daylight?
 
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Thanks much for responding. I think the light was likely adequate. I did the test outside with auto ISO. With the settings at f/5.6, 1/320 sec, I only had a reading of ISO: 180. I am wondering if I missed something in Steve's video. Why with the setting that Steve used, the cameras/lenses would not focus when the AF point outline went from the white paper to the centered target (or the black square). Separately from the video test, I tried to focus on the target. Strangely, focusing on the target was erratic but I had no problem focusing on the black square. (Both the target and the black square where much larger than the AF point outline.)
 
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It may be your target, I use one of Steve's old targets, I found this one better for my use.

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Hi Nick, Doing the test, I followed Steve's instructions which included using Continuous servo AF and single point AF. I also used the target he mentioned in the video. I believe AF-S would not allow focusing to change from the white part of the test sheet to the target while pressing the focussing button. As I indicated, perhaps I missed something. What is A1?
Thanks for responding
 
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Marc H said:
Both the target and the black square where much larger than the AF point outline.
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That doesn't sound quite right. The AF system needs to see contrast under the Single AF point selected so if the black object is much larger than the focus point you don't really have contrast to detect as much as all white or all black to detect. Ideally you'll be far enough from the target for the focal length being tested that there's actually black and white transitions under the single focus point being tested. IOW, it's high contrast black to white edges that the AF system responds to so make sure you're not so close that you lose those edges under the selected focus point.

Maybe I misunderstood your post, but if the black square is much larger than the single focus point you might do better to back off a bit so there's not pure black nor pure white under the single AF point. That doesn't really explain your problems with the test target that does have fine detail but at least in the case of the black square you don't want it much larger than the selected AF point.
 
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Thanks Soudbyte, The target I used is the one used for determining where and how large is the Focusing point outline compared to what you see in the viewfinder. The target for this is and needs to be a smaller one centered on a white sheet of paper. I have the other target which I will be using to determine how sharp my lens is.
 
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I agree DR Wyoming but it seemed to work. Perhaps my focusing point outline is a bit off. That is what I was trying to find out with Steve's test. I'll look into a bit more tomorrow. Thanks.
 
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I have now seen which target you are using, the one I suggested might work, just, the correct one is obviously much better.
I printed the target on standard white paper, with that installed on a wall I checked my camera with a 24-85 zoom.
It worked for me just as Steve has said in his video.
I had the target inside in poor light and it took some time along with me getting to a close range (less than a metre /3ft) from the target for the check to actually work well.
The closer to the target the better the result for me, perhaps check near the minimum focus range for your lens/es as a start?
Happy to report my camera single point AF outline is pretty much spot on.
 
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Marc H said:
I agree DR Wyoming but it seemed to work. Perhaps my focusing point outline is a bit off. That is what I was trying to find out with Steve's test. I'll look into a bit more tomorrow. Thanks.
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Check your Focus tracking with lock On setting. Possibly set too high. Just a thought.
 
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Well, thanks to Soundbyte, I tried different lenses and determined that I cannot use the test and target at 500 mm on either the 500PF or 200-500. I tried my 70-300 and the test seems to work up to 200mm. I found that my AF point outline is pretty centered but the actual focusing point is a bit larger than the outline Ralph, I did try to mess with the lock-on setting but that did not help. DRWyoming, I was able to focus on the black square without a problem. I had used a black marker to make the square and it had some faint lighter streaks. That probably helped with the focus. Thanks all for your help.
 
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@Marc H Good to know that you have got some results.

I tried my 500mm this morning and found no problems with the test BUT only if the target was in full sun, put it in the shade and nothing worked as expected.

This was my setup with both sun and shade, you can see with the shade shot that the sun part of the image is way brighter.

Target in shade.
Shade_1_BCG.jpg
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Target in sun.
Sun_1_BCG.jpg
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@DRwyoming is I think correct in questioning the amount of light hitting the target, shade or dull artificial light does not cut it.
 
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Palouse said:
I'm confused, isn't the AF point a characteristic of the camera body? How would changing a lens affect its location?
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I don't think anyone is suggesting the AF point moves with different lenses, just that the test is harder to perform with some lenses (smaller maximum aperture) or in dimmer light conditions.
 
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It would seem that the problem was target illumination, not the lens in question.
Certainly in my case the change of lens made no difference that I could make out to the AF point size or location.
In the tests I made with a 500mm it was a lot harder to establish reliable results in comparison with a 24-85mm lens.
Better illumination was the deciding factor to get reliable results with the 500mm.
 
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