Why do lenses focus past infinity
Further away is better, but for a wide-angle lens, you should be able to focus at infinity with an object that is at least ft or m away. Some planets are quite bright and can be used for focus. If Venus, Jupiter, Mars, or Saturn is in the sky, these planets are going to be brighter than stars, which are generally too dim to focus on.
There are a couple of methods to use planets to focus to infinity. Place your camera in live view and point your lens at the brightest planet that you can find. In live view, zoom in to your focus point to the maximum available, then move your focus point so that it is directly over the bright planet.
Turn the manual focus ring until the planet or bright star is in precise pinpoint focus. It requires a very small movement of the focus ring and is very obvious when it is in focus. It will help if you zoom in on the bright planet or star in live view using live view zoom controls.
Some very recent cameras can auto-focus on planets or bright stars. I can only speak to the low-light capabilities of the new Nikon Z6 and Z7, but those two cameras do have a low-light AF mode that you can turn on. The focusing speed in low-light situations is not particularly fast, but it does work on bright planets. Once again, zoom in on the focus point and place the focus point on the planet. Engage auto-focus and wait for a second or two and it should autofocus on the planet.
Then turn your lens to manual focus. You snapped a photo of your focus ring at infinity focus like I described above, correct? Dec 27, as a reply to Skul's post I have in front of me three Nikkor manual focus lenses.
El Duderino wrote in post Is there something beyond infinity? Madweasel Madweasel Cream of the Crop. Jump to forum Not a member yet? Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more Don't be a stranger - register now and start posting!
Dec 27, 1 Is there something beyond infinity? Dec 27, 2 Hahaha. Dec 27, 3 I'm not totally sure but as i recall it seems to have something to do with the way the AF mechanisms work.
Dec 27, 4 It is regarding the expansion of materials on the lens in warmer temperatures that would make it hard to focus at infinity if they did not account for it by providing the 'beyond infinity' focus point. Dec 27, 5 Obviously you're not a fan of Buzz Lightyear, who taught us all that indeed there is something beyond infinity. Dec 27, 7 for temperature tolerances I've heard but mostly so the AF mechanism doesn't get hammered when racking back and forth around infinity.
Dec 27, as a reply to plasticmotif's post 8 as I remember, it's made for infrared shooting purpose Dec 27, 9 Russo09 wrote in post If they ever put "Beyond" on a lens that focuses passed infinity I will buy it no matter how much it costs or how much I'll use it bobble. Dec 27, 10 According to a Canon rep at a local photo and imaging show recently it's so the AF mechanism can focus on infinity perfectly by minute adjustments backwardds and forwards. Dec 27, 11 Agree with Newworld Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers.
It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. On the kit lens that came with my Nikon D I have noticed that when trying to focus on infinity for shots in dark conditions star-trails, etc the lens tends to move past infinity out of focus and need to be brought back a little to get a clear infinity focus point.
It is not just cheaper lenses. Many modern lenses, especially Auto Focus zoom lenses have this characteristic. There are several reasons for it:. Even with manual focus prime lenses, some designs are susceptible to focus shift at different aperture settings. Although focus shift will be more noticeable at the minimum focus distance and other shorter distances, the lens may still need a little wiggle room at infinity focus to allow for adjustment depending on the selected aperture.
The best way to get clear focus for astrophotography is to use Live View at high magnification to manually focus the lens, then leave the focus set at infinity and turn off Live View. Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Pretty much all Nikon AF-S lenses can focus beyond infinity. Some people say this is so that the AF system can have the lens go just past infinity and then come back but I've heard others say that it is because the focus point of ED lens elements varies with temperature so the infinity mark varies with temperature. Thanks for the helpful explanations. The question was actually prompted by a comment on this thread about Voigtlander manual focus lenses.
If this is a common feature of autofocus lenses, would it be necessary to use DOF preview to check infinity focus as a routine? Sounds like Buzz Lightyear's classic line "To infinity and beyond! It is often a feature of more expensive lenses, which need to have the capability for expansion in warmer temperatures.
You mention the issue in conjunction with AF lenses If you want to check infinity focus, go out on a clear night and focus on the moon or a bright planet or star. SCL , Jan 11, It is far better for a lens to be able to focus slightly beyond infinity than to not be able to reach infinity focus at all i. Hence, the tolerance in many lenses that permit you to focus past infinity to make allowances for thermal expansion, etc.. One should not rely on the focus limit stop as a means to determine sharp infinity focus, particularly with zoom lenses that may be varifocal focus shifts slightly with varying focal length.
Michael R Freeman , Jan 11,