How to fine tune lenses

<p>I read on these forums a lot about "fine-tuning" lenses so that they can perform to their maximum capabilities. I have checked the auto-focusing of my D300s for all my lenses shooting a brick wall, and they all seem to be spot-on. I know this because when I manually turn the focus ring after autofocusing, the image blurs. But then I read on these forums that "all lenses need to be fine tuned". Is there a better way of doing this?</p>

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<p>But then I read on these forums that "all lenses need to be fine tuned".</p>

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<p>Be sure to check the sign that should be above the door to every forum: <em>"Abandon all hope, ye who enter here."</em></p>

<p>If the internets are to be believed, there is not a single D7000 that is capable of autofocusing, DX dSLRs are useless, the moon landing was faked because the astronauts failed to recover any green cheese, and My Bloody Valentine are releasing a new album.</p>

<p>One of these is true.</p>

<p>Wait! There's no green cheese or they just neglected to bring some back?</p>

<p>Mike : +1 for Lex and Peter ... and also, "if it ain't broke, don't fix it", or, alternatively, "fixate not". </p>

<p>Mike: One of the 'terns around here has just given me a polite 'dope slap' for not answering your Q ... try here:<a href="http://forums.dpreview.com/forums/thread/3377109">http://forums.dpreview.com/forums/thread/3377109</a> it will give you ONE way to do this. Read the whole thread, and you'll learn possibly more that you want about this subject.</p>

<p>Really?<br>

You tested them and they are spot on... But you need to fine tune them?</p>

<p>Forget about it. Go out and make images and don't worry.</p>

<p>did you mean :" fidilly focus:"</p>

<p>this a step beyond one example of a lens being better than another.</p>

<p>mayvbe the problem is not the lens.<br>

maybe it is your grip on the camera.</p>

 

When it comes to stuff like this, my usual order of business is only to run tests after I have found an actual reproduceable

type problem during regular shooting. I couldn't imagine sitting around testing all the focus of my lenses and focus points.

i don't even know how many focus points my cameras have. I just pick the one I want and use it. Go make pictures and

enjoy your cameras and don't worry about this stuff unless the need arises. Just my 2 cents.

<p>Thanks for all your responses. I was mainly just curious how others go about testing the focus of their lenses, whether the camera really needs adjusted or not. </p>

<p>I test the focus of my lenses by shooting photographs.</p>

<p>I didn't worry too much about fine-tuning lenses until the D800 arrived. With both of my primary zooms (24-70 f/2.8G, 70-200 f/2.8G VR II), the D800 autofocuses at a greater distance than the camera to subject distance. If the subject is at 30 feet, the actual plane of focus in the image will be out near 40 or 50 feet without correction. I believe that this phenomenon is known colloquially as "back focusing."</p>

<p>I fine-tuned these lenses using the instructions in the manual. First, I did some test shots with each lens at -20, -15, -10, -5, 0, 5, 10, 15, and 20. I reviewed the results to narrow down where the sweet spot is. For instance, if the sharpest shot is at -10, I would repeat the tests with every adjustment from -5 to -15. Then I would run the same test again, as the sharpest number is not always consistent. On one run it might be -12, and on the next it might be -11. Multiple tests will point to an average value that works well under most circumstances.</p>

<p>It is critical that you evaluate your test shots on a sharp computer monitor rather than on the camera's small LCD screen. For this reason, I suggest that you take a lot of shots under different conditions, load them onto the computer, and then spend some time evaluating each test with the software that came with the camera (e.g. ViewNX 2 for Nikon cameras or DPP for Canon bodies).</p>

<p>Fine tuning is not perfectly precise. The best adjustment at the short end of a zoom can be a few values off from the best adjustment at the long end (e.g. -12 vs. -14). I selected the average of numerous tests at both ends of the zoom and also the middle of the range. There's only one adjustment available for any given lens, so you pick the number that comes the closest for the entire zoom range.</p>

<p>I'm not suggesting that all cameras and lenses require fine tuning. However, in some cases it's necessary, and it's good to know that the feature is available. Fine tuning made a big difference in the case of my D800 and the lenses that I use most frequently.</p>

<p>The D800 yields the <em>most accurate</em> focus when using <em>contrast detection autofocus</em> in Live View. However, this type of AF is slow and will not work well with moving objects. It's important to note that AF fine tuning has NO IMPACT on <em>contrast detection autofocus</em>. It impacts only the <em>standard distance-based autofocus</em> that's available when Live View is not active, i.e. when you compose through the viewfinder. Your fine tuning adjustments are ignored when using Live View, and that's understandable, because the body determines proper focus based on contrast detected in the Live View image rather than on subject distance.</p>

<p>Best of luck, and be sure to evaluate all of your results carefully before shooting an important event or assignment.</p>

<p>Yeah, you can spend 3 hours getting those lenses spot on, then when the shot is taken the animal's eye is in focus but it's snout and everything else is blurred. So close down on the aperture and it didn't matter what adustments to focus were made because now the whole beast is in focus. I use the white line on the road for my test subject. Easy to spot where the focus is on the course bitumen. Of course, when I change my distance it needs another setting.</p>

 

<p>Errmmm...u can perhaps look into buying a lensAlign and Focustune for $100 and follow instructions (a lot of test parameters, distance, constant lighting, etc. etc.) . The AF fine tuning methods described above is okay, but if you need even more precise results for pixel peepers then it's definitely worth looking into it.<br>

I came across AF fine tuning tools out there because of my D800 & D800E too. The high MP make camera shake or AF inaccuracy quite obvious...and I wasnt sure it was the AF or the wide spread "left focus" issue. Spent a lot of time looking into it, sending it to nikon, then testing it blah blah blah.....<br>

Anyways, when AF is properly fine tuned, the accuracy can easily exceed live view contrast detection autofocus, which is a generally a good benchmark to go by.<br>

Another thing I found out is that it's way easier to achieve accurate AF fine tuning with primes than the zooms, which varies according to distance, focal length etc. So after fine tuning everything you might end up with a crazy range for zooms, such as +5 to -10, while the primes are pretty much spot on everytime.<br>

Yeah like everyone else said, just go out and shoot. I have been through all that testing and tuning and it's very time consuming</p>

<p>Mike, as Rick suggested, buying a system like LensAlign is the best way to ensure that your lens(es) are properly in sync mechanically with your camera. Shooting against a brick wall may work in many cases, but an actual alignment system will give you the best results. I never had many (or didn't notice any) problems with my D90 and consumer lenses when I first got started, but when I bought a D300s and the 85 f/1.4 I had all kinds of problems. I thought I had a bad copy of the lens, but when I looked online I saw that the alignment (in addition to using good focusing technique) should be checked before writing the lens off as bad.</p>

<p>I just mentioned this on a post to another user a day ago, but everyone should make sure all of their lenses are aligned with each of their camera bodies. For example, my 14-24 (arguably Nikon's sharpest zoom) was so crappy on my D800 that it needed a -13 adjustment, whereas on my D700 it only needed a -2. My 24-70 needed a +3 on the D800, but a -1 on the D700. Amazingly, my 105 macro didn't need any adjustment on my D800, but a -3 on my D700. This just gives you an idea of the kind of variance you can see once you start doing this.</p>

<p>It does take some time (a couple of hours when done carefully) to get things properly aligned if you have a lot of lenses and a few bodies, but you'll thank yourself later, especially if you have a shoot where you're using an 85mm lens at f/1.4 all day. Things may look great in the viewfinder, but even a +/-1 offset at f/1.4 will make a big difference once you see it on your computer or on a reasonably-sized print. And if you're spending nearly $2000 for f/1.4 or f/2.8 lenses and $2000+ on a camera body, it only makes sense to make sure everything is aligned properly. After that, go out, shoot, and enjoy the fruits of your labor!</p>

<p>Thanks again. Points well taken from all your responses. 1) unless there is an obvious issue that shows up in real photographs, don't go looking for issues and 2) spend less time on photo websites and forums and just get out and shoot.</p>

<p>"I have checked the auto-focusing of my D300s for all my lenses shooting a brick wall, and they all seem to be spot-on."<br>

It appears that you're interested in only absolutely the best. Otherwise you wouldn't have started the thread. After all, "they all seem to be spot-on."<br>

I myself do not want to "get out and shoot" unless I know that I and my equipment are ready. The thing with inaccurate focus goes beyond the issue of image sharpness and often it cannot be "fixed" by stopping the lens down, which in itself has the potential of yielding a blurry photo.<br>

Consider this scenario. You're taking a closeup portrait of a beautiful lady in a studio. The lens is focused on the eye(s), like it has to be. But guess what... your lens backfocuses. On the LCD it all looks normal. You preview, zoom in and check the eyes.. yep.. they're sharp, moving on. Did you check the EARS by any chance? Probably not. If you did, you'd see that they're sharper than the eyes. No idea at this point, though. You have someone else print enlargements and the next day you have to explain to the beautiful lady why her not-so-beautiful ears stand out so much and her NOSE looks funny because it's out of focus. "Dammit... Should have stopped down to f-16".. You'd just probably make her ears even sharper. Bottom line: Missing the focus mark means that what you want to be sharp is soft. And often: what you want to be soft is sharp.<br>

The focus HAS to be spot-on and not just 'look' like it is. And guess what... you may not know it but I do.. NONE of your lenses focuses properly at this point. You can ignore what I just said and "shoot happily ever after" or you can read on.<br>

I've read all of the posts here and the people here fall into one of 3 categories:<br>

1. They don't care about the AF if the pictures look good enough.<br>

2. They care but they can't be bothered with tuning the AF.<br>

3. They know a lot about the AF tuning and AF in general but they don't know a proper technique of nailing it down.<br>

<br />Tuning the AF is A LOT of work. At this point you cannot imagine what it entails. But it can be done.<br>

Mike, if you're interested, I will write and post an entire article about tuning the AF. I would do that for you and also to demonstrate to everyone here a very good technique, something they do not have. I had to figure it all out all by myself because NO ONE on the entire internet seems to know how to do it right.<br>

You would need:<br>

1. Your camera (the D300s)<br>

2. A cable release<br>

3. A good tripod<br>

4. A completely manual strobe that you can sync with your camera, a good Nikon speedlight is better. Being able to shoot and sync it off-camera, is preferable.<br>

5. Photoshop.<br>

6. A proper indoor environment to execute the procedure.<br>

If I get a request from you and 2 more people, I will write the article. (Arrogant remarks will not be counted)</p>

<p>I just want to thank Bruce Brown for the link.</p>

<p>It, in turn, led to some other really useful links on fine-tuning focus on both Nikon and Canon cameras with the feature.</p>

<p>I confess, however, that I use all my lenses and cameras "right out of the box" and do not see the problems that so many do. Am I ignorant or just apathetic?</p>

<p>I don't know and I don't care,</p>

<p>I'm just a happy little fool</p>

<p>JDM: I want to thank 'Horshack" ... and buy him a bottle of 'Dom' and dinner!</p>

>>when AF is properly fine tuned, the accuracy can easily exceed live view contrast detection autofocus<<

 

I would love to see 100 percent crops of the tests that you ran to verify this statement.

"Tuning the AF is A LOT of work."

 

Not really. Maybe a half hour per lens and yes in my experience the results have proven to be worth it. I use a LensAlign

Mk II and the FocusTune software.

 

"At this point you cannot imagine what it entails."

 

Following the instructions, shooting the test frames, and then confirming with some real photographs.

 

 

"But it can be done."

 

And it is neither brain surgery or rocket science.

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<p>I had to figure it all out all by myself because NO ONE on the entire internet seems to know how to do it right.<br />You would need:<br />1. Your camera (the D300s)<br />2. A cable release<br />3. A good tripod<br />4. A completely manual strobe that you can sync with your camera, a good Nikon speedlight is better. Being able to shoot and sync it off-camera, is preferable.<br />5. Photoshop.<br />6. A proper indoor environment to execute the procedure.</p>

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<p>Umm, I happen to know quite a bit about technique...thank you very much. ALL of my seven lenses are well aligned with BOTH of my cameras and ALL of my images are TACK sharp. And contrary to what you say, there are MANY consistent messages about how to ensure lenses are aligned properly. The six steps you've outlined are essentially what's already out there in cyberspace. Looking forward to reading your "original" article.</p>

 

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<p>"Tuning the AF is A LOT of work."<br>

Not really. Maybe a half hour per lens and yes in my experience the results have proven to be worth it. I use a LensAlign Mk II and the FocusTune software.<br>

"At this point you cannot imagine what it entails."<br>

Following the instructions, shooting the test frames, and then confirming with some real photographs.<br>

"But it can be done."<br>

And it is neither brain surgery or rocket science.</p>

 

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<p>Ellis, my sentiment exactly. While it's a little time consuming, it ain't hard. I don't know where this dude is coming from...</p>

<p>Well, that's what I thought. You are just the kind of crowd that's not worth arguing with. I wish you happy shooting and I thank you for saving me a whole afternoon of writing a text that would probably not fit on a single page in this forum. I have a better technique than ANY of you has, software or not. It is a lot of work but it ultimately gives the most accurate results. I needed a confirmation that it would be taken seriously or at least read in its entirety. Life has taught me not to waste time on people that ridicule you even before hearing you out. Frankly, having my lenses tuned better than most anyone has them is what matters to me. I'll save this technique either for my blog, my book, my YouTube channel or maybe for all three of them. That way at the least I will be compensated for my labor. Keep liking your AF tuning and forget I ever posted anything in this thread.</p>

I guess the only option then is to allow ourselves to drown in the quicksand of mediocraty in order to prevent us from

feeding the trolls.

<p>This is why photographers don't have to fill out TPS reports. <a href="http://www.break.com/usercontent/2008/4/office-space-i-have-people-skills-488721">Because they have people skills</a>.</p>

<p>David R.E. Speaking for myself, maybe others, apologies, most sincerely. I'm going to be 65 in a week or so, and I still enjoy, HUGE, learning, reading, arguing (used to be on the debate squad in college), and also needleing, teasing, joking, and challenging. Being a United States Marine only adds to it, compounding the effect. That said, I think it's something in the air or Cosmos the last few days ...I am an Astronomy nut also, and I note it's 'the dark of the moon'... my co-workers and the interns have been the same mood the past few days ... it will pass. Don't give up on PNET ... it's the BEST, but, sometimes, you gotta have kind of a thick skin. Stay with us, please. It IS the INFORMATION HIGHWAY.</p>