Add a comment. Active Oldest Votes. Improve this answer. Guffa Guffa Testing focus with a ruler is prone to error because you can't guarantee what part of the scene the autofocus sensor is triggering on.
To avoid this, use one of the focus charts suggested by other answers. Reid: Good point. I just set the center point to be the only active sensor, so that I know what it is focusing on. It's more than that - sensors aren't necessarily active exactly where they show in the viewfinder. So for example you could think you're focusing on the 30mm mark but in fact your sensor found the 34mm mark, which will show up as back focus but in fact isn't.
That's the reason good focus charts have a clear, unambiguous thing to focus on. Reid: That is not a problem, as the area that I am focusing on is a lot larger than the sensor, and it's nearly parallel with the focus plane. I am of course focusing on the box, not the ruler, that's the whole point of having the box there in the first place. OK, that's fair. I still submit that a good focus chart is better, because it reduces the fiddliness of one's setup and comes with clear directions to follow.
For example, if one did a similar setup but the side of the box was visible, that could capture the focus, or if you used a battery a common focus target there's no guarantee where on the curved surface the focus hits, or if you're not lined up exactly perpendicular with the box, there's a source of error. Another consideration is that a focus chart will give you numbers for both sides of the frame. Show 2 more comments. Rowland Shaw Matt Bishop Matt Bishop 3, 2 2 gold badges 22 22 silver badges 33 33 bronze badges.
Matt, the link seems to be dead. Can you see if you can find if it's moved? I found this link which looks good, but not sure if it's the same information - regex. MikeW I've substituted for an archived version of the webpage for the time being This archived link doesn't work properly. Autofocus works till certain distances on various lenses, but stops working at greater lengths.
Autofocus then keeps hunting to autofocus subject. Is it autofocus sensor problem or lens calibration? Your email address will not be published. We are always looking for more interesting and insightful photography tips and techniques to share with our readers. We would love to publish an article by you if you are interested in writing for us.
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Related Articles. If the camera and the lens are set separately for tolerance and it has to be , then the spec should be cut in half for both. That way when a camera and lens are matched and each is at the opposite far end of the spectrum, the combination still falls within spec. They are creating the problem themselves.
Thanks for this awesome resource! I agree with Nikon on this one. If it is new, it might be worth taking back. These kinds of misalignments are not very common but they are more common in prime lenses than zooms. You have a prime so it might just be a bit of bad luck.
Thank you! I checked it against two of my other prime lenses 50, 85 , and both of those checked out fine. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. Our mission at BorrowLenses is to advance photographic and cinematic dreams by providing access to superior, cutting-edge gear and expert advice.
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See her lighting tutorials here. She learned about lighting and teaching while modeling for photographers such as Joe McNally and has since gone on to teach lighting workshops of her own in San Francisco. See her chiaroscuro-style painterly portraits on her website. December 17, at am. Bernard DeGruchy says:.
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