How to focus at infinity when lens do not have infinity mark

 

 

<p >HI Friends,<br>

I have D5000 and kit lens 18-55 and 55-200 mm lens. I am learning landscape photography and i have read about hyper-focal focusing and focusing at infinity.<br>

The problem is my lens do not have infinity mark on it so i am not able to focus on infinity. Hyperfocal seems to be impossible thing since i am not able to figure out infinity focusing first.<br>

Any help is appreciated.</p>

<p >Many Thanks,<br />sunil</p>

 

 

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<p>Most zooms and kit lenses, especially of the AF variety haven't got DoF scales, or infinity marks.Which of course negates the ability to hyperfocal focus. All one can do is shoot at small F stops, and hope.</p>

<p>why doesn't the rangefinder work for you? aim at a distant object and watch for the little green dot in the viewfinder... works on old, MF lenses on my D3100 (although, to be honest, it's usually pretty easy to find infinity focus).</p>

<p>Try this site:<br>

http://blog.rv.net/2009/02/hyperfocus/</p>

<p>Youcan also calculate , or have calculated the hyperfocal focus with a tool like DofMaster<br>

Maybe check this out ? : <a href="http://www.dofmaster.com/">http://www.dofmaster.com/</a></p>

<p>The depth of field scale is very subjective anyway. I know there is a precise definition as to what it considers "sharp", but from a practical point of view, I don't think it is that important. I would just use a small aperture and focus slightly back from infinity. How "slightly"? Take trial shots and see what works for you, or use the depth of field preview button (which I don't find all that useful either, I use it more for portraits and the like, to see if an aperture of say 2.8 or 5.6 gives a nicer background at the given distance).</p>

<p>But don't use a REALLY small aperture or you'll get mush. Google "diffraction".</p>

<p>I think those lenses have no distance scale, correct? Sorry, but I think you HAVE to have a distance scale to make this work.</p>

<p>I would think that you can simply auto-focus at the main subject (or any subject that will come to the center of DOF), lock the focus, recompose and shoot. So long as the main subject is far enough and stop down to f8, the resulted images should be fine. If you use tripod, you can use the MF mode and the focus aid function mentioned by William. You can then recompose without touching the focus ring.</p>

<p>Depth of field is a convenient fiction - there is only one plane of sharpest focus. DOF works for photographers in the Cartier-Bresson tradition, for whom sharp images are secondary, but nearly useless for landscapes. If there is a key element in the composition, focus on that object. If the background is important (as in mountain landscapes), focus on the background and stop down. For everything else, including the evaluation of distracting elements, use the DOF preview function.</p>

<p>Edward is technically correct, but the term depth of field describes the range of focus in an image. It means the lens is able to reasonably resolve from this distance to that distance. It doesn't mean the entire image is tack sharp. However it means there is specific information in the field of view that is rendered into focus by the lens using a preselected aperture.<br /> Below is an image I shot with my D700 and the Nikon 55mm f2.8 Micro-Nikkor lens. I shot this photo at f22 to get the bird in the foreground and the ferry in the background in focus. The hyper-focal distance markings on the lens were used to achieve this effect. However if one looks closely, one can see the bird is in sharp focus but the ferry is not. The brain accepts this condition automatically as in real life, one could not focus on the bird and the ferry anyway. You can get a closer look at this image using this link (I think you will agree that the f22 setting on the Nikon 55mm f2.8 Micro-Nikkor produces great results):<br /> http://hull534.smugmug.com/photos/743655311_Q88Xm-XL.jpg<br /> <br /> <img src="http://hull534.smugmug.com/photos/743655311_Q88Xm-L.jpg" alt="" /></p>

<p>How to focus at infinity: <br>

1. auto-focus at the horizon (infinity). <br>

2. if you want to maintain infinity focus, then use small piece of gaffers tape on the focus ring of lens affixing it to the body of the lens, thus preventing focus ring from moving.<br>

3.switch to manual focus (on lens and camera).<br>

4.you are now locked at infinity, you can alter the focus manually from here by removing the gaffers tape if you used it. </p>

 

<p>How to focus at infinity: <br>

1. auto-focus at the horizon (infinity). <br>

2. if you want to maintain infinity focus, then use small piece of gaffers tape on the focus ring of lens affixing it to the body of the lens, thus preventing focus ring from moving.<br>

3.switch to manual focus (on lens and camera).<br>

4.you are now locked at infinity, you can alter the focus manually from here by removing the gaffers tape if you used it. </p>

 

<p>Sounds like you need a couple of good manual prime lenses. Do the research.</p>

<p>You'll need make a judgement, for each photograph you take, as to what technique to use, but I would suggest reading Mertlinger when it comes to focus technique. <a href="../canon-eos-digital-camera-forum/00VMmm?start=30">HERE</a> is a link to a post that I made here about a year ago, where I posted images using both hyerfocus, and infinity focus. As you can see, they both yield great but different results.</p>

<p>You have lots of DOF at 18mm and say F11. Put the focus in manual and focus out 7 feet or so and most everything front to back should be exceptably sharp. As the focal lengths get longer it will be more important to focus on the area you most want to be sharp.</p>

<p>This is a complex and tricky topic, but I thought I'd throw in my two cents.</p>

<p>(1) In lens design, infinity is not really infinity. It's a distance at which you can focus and everything beyond that point will appear to be in focus. (Sharpness of distant objects depends on how much you enlarge the image, but let's neglect that constraint for the moment).</p>

<p>(2) Let's say that for a particular lens that infinity is 30 feet away (9 meters). You have several choices.</p>

<p>(2a) Focus at 30 feet (mathematical infinity for the lens).<br>

(2b) Focus closer than infinity (e.g. at 20 feet).<br>

(2c) Focus FARTHER than infinity (e.g. on an object that's 50 feet away).</p>

<p>If you choose the 50 feet option, the distant object will be sharper than with other options, but closer objects will be more out of focus.</p>

<p>If you choose the 30 feet option, a.k.a. infinity, the distant object will not quite be in focus, but it will be close.</p>

<p>If you choose the 20 feet option, the distant object will be noticeably out of focus to some degree (a lot or a little).</p>

<p>(3) But there is another distance - let's say for example that it's at 24 feet - where for a given f-stop (e.g. f/16) the distant object will look NO LESS SHARP than if you had focused at infinity (30 feet). THIS distance (24 feet in our example) is the hyperfocal distance for this lens at f/16.</p>

<p>(4) Given that you have verified with a DOF calculator that 24 feet is the HFD for your lens at f/16, you don't need a DOF scale to shoot at the HFD. You could</p>

<p>- measure 24 feet from the camera with a tape measure<br>

- place an object at that distance<br>

- focus precisely on that object at that distance<br>

- set your aperture to f/16<br>

- shoot</p>

<p>RESULTS: The sharpness of the distant object should be no worse than if you had shot at 30 feet @ f/16. And as a bonus, more of your foreground (items close to the camera) will be in focus.</p>

<p>(5) However, the sharpness of the distant object would have been even better if you had focused (manually) on the full 50 feet to the object's location.</p>

<p>(6) When autofocus focuses on a distant object, it's usually focusing at the lens' infinity setting. Depending on your level of skill, you might get a sharper photo if you override this setting and focus manually on the subject. But you'll lose sharpness in the foreground, so it's a trade-off. There's no such thing as a free lunch.</p>

<p>(7) The composition and the photographer's artistic intentions for the shot will determine whether the HFD is a better choice than focusing on a particular object (near or far).</p>

<p>(8) If you need better near to far sharpness than is possible with the HFD, you'll need to use tilt or swing movements or combine shots into a "focus stack."</p>

<p>(9) The small apertures required to use HFD focusing may add diffraction effects to the image. Diffraction renders the image LESS sharp. Be aware of this trade off before shooting at f/16 and higher.</p>

<p> </p>

<p>I think you might have lost him with your post, Dan..But an excellent essay nevertheless.<br>

Range of best sharpness: F8, and on your DOF scale, Infinity to 2m centered. All should be sharp from 2m out...maybe F11 just to be sure.<br>

The trouble with kit lenses is that you are not supposed to do any of this stuff. A curse on Nikon for gelding their newer lenses. How is someone meant to learn? One good thing though, this will keep the prices up for earlier lenses.</p>

<p>Well, I HAVE to throw in my 2¢.</p>

<p>Although it's hard to use technically-correct hyperfocal distance technique if you don't have distance markings on your lens, you can adapt the technique just by knowing that you have less depth of field in front of your focal plane than behind it.</p>

<p>So (I use this, but it's imperfect), if you choose to focus slightly closer than your key subject and use a small aperture, you will sweep up your subject in the apparent sharp area.</p>

<p>It's not exacting like hyperfocal, but it's handy.</p>

 

<p>Hi All,</p>

<p>Thanks a lot for your replies... in short distance mark is the minimum criteria to go for hyperfocal focusing. Now i wonder why nikon decided not to include this in kit lenses.</p>

<p>@Dave<br>

Sunil sorry for the interruption but Dave I think I took a shot of the exact same bird at the exact same location (well almost same bird^^).<br>

The bird is a rare species: Fry Catcher :-P<br>

http://whschroeder.com/html/animals_9.html</p>

 

<p>If your talking about the 18-55mm f/3.5-5.6G ED II, on page 18 in your manual, it states<br>

Closest focus distance: 0.28 m (0.9 ft.) at all zoom settings. So you know it is about 1ft out to infinity. HFD is used more for a wide than, say 55mm. The basic idea is that at a wide angle, something that is closer (x) thought to infinity looks sharp. Mostly for the things that are closer and follows out, like for example a rock that is near and the mountains that is far.<br>

Take this for example, I know it is not fair that I used a older manual 24mm lens that has the scale, but you will get the point. <a href="../photo/11935551">http://www.photo.net/photo/11935551</a><br>

Taken at F11 with the post at about 1FT away from the lens. The tripod is set low to the ground to make the post larger. In this example, the post is sharp. The building looks sharp, it is not. This was mentioned above. <br />So (in manual mode), if you simply (looking down on the lens while its on the body) Turn it all the way to the right until it stops, that is infinity, then turn slight to the left about 1/4". Then use F11, take the shot. Look at it in your software and you should see where it is sharp. You just need to find a subject like this image, that has something from near to far. Do the same for F16. These test shots will let you know, is it 1ft, 1.5ft or 2 ft. Then all you have to do is memorize the spot. Maybe make a mark on your lens so you know how far to turn it. Remember, the HFD is differant for F16 and F11, this just gives you two chocies.<br>

This is not exact, but it will work without a scale. there are factors, DOF and HFD is subject to the eye of the beholder and how large a print and how far one stands back to view the image. Given an 8x10 and standing about 6ft to view it, what I think is the field of focus will be different than what you will see as the field of focus. But, that is the whole complicated thing about this, also mentioned above. Hope this helps.</p>