Nikon 18-200 AF Fine Tune on D300: Can somebody figure this out?

<p>I shot both of these photos with my D300 with the 18-200 Nikon lens at 26mm - f/4.5. I tried AF fine tuning on them.<br>

In this first picture (AF tune @ +10) the image is clear towards the right-center but blurry on the left.<br>

<img src="http://i214.photobucket.com/albums/cc152/asusenior/Photography/zDB1_6378.jpg" alt="" /></p>

<p>Strangely, with AF tune @ -5, the clarity is reversed from the above picture. It is now clearer on the left and more blurry towards the right-center. Can anyone figure what's going on? The subjects are far enough away where depth of field should not be an issue.<br>

<img src="http://i214.photobucket.com/albums/cc152/asusenior/Photography/zDB1_6380b.jpg" alt="" width="825" height="548" /></p>

<p>Where is the point of focus? What was your shutter speed? Solid tripod? Exposure delay mode, (mirror up)? Also, I would have stopped down further than f4.5 to take this image.</p>

<p>I focused on the bright building near the center. The buildings are all a few hundred feet away and shot wide angle, so depth of field should be infinite. I wanted to shoot close to wide open in order to tune my lens.</p>

<p>Were you shooting these obliquely through a window pane? </p>

<p>No, there were shot outdoors on my balcony on a tripod.</p>

<p>Hi Paul,</p>

<p>You probably should use a different test subject under better lighting conditions to tune your lens. Sorry I'm not more help. I'm sure someone else will chime in soon.</p>

<p>Oh yes, and be sure VR is off when using the tripod.</p>

<p>VR was off.</p>

<p>The two look pretty much the same to me. The one on the left has a little more coma than the other, but if you look down in the right bottom corner of the sample, they look pretty much the same. The slight variation between them is probably wind or heat rising between you and the bright pinpoint lights.</p>

<p>Good observations, Stephen. There are a lot of possible variables here. Another is the stability of the balcony Paul shot these images from. I live in a 40 floor condominium here in Honolulu and while standing on my 7th floor balcony in my bare feet, I can feel periodic vibrations through my concrete deck. I live close to a freeway and three elevators are constantly traveling up and down within the building.</p>

<p>Also, I would be interested in seeing an enlargement of a similar area on the right edge. I am still bothered by this image being shot wide open and the resulting loss of edge sharpness at this magnification.</p>

<p>The 18-200mm lens is <strong>better</strong> at f8 or f11. Testing at f4.5 may not be so good.</p>

<p> </p>

<p>This sort of result was standard for the 18-200mm AF-S VR I once had...... irrespective of focal length, aperture or support. I hope there is another explanation for the issues you are having here.....</p>

<p>Jerry,</p>

<p>Paul is trying to fine-tune his Nikon 18-200mm f4.5-5.6 VR lens with his Nikon D300 body which is a valuable adjustment option available on Nikon's more advanced camera bodies. Generally, you want to perform this fine tuning at a the widest aperture of a lens. However, I believe Paul should be performing this particular procedure under more controlled circumstances. In Paul's defense, this may be the only convenient opportunity he has to indulge in this sort of thing.</p>

<p><em><strong>"This sort of result was standard for the 18-200mm AF-S VR I once had...... irrespective of focal length, aperture or support. I hope there is another explanation for the issues you are having here....."</strong></em></p>

<p>I can't say that I agree with your experience, Matthew, at least as to the performance of my very early sample of the Nikon 18-200 f4.5-5.6 AF-S VR.</p><div></div>

<p>People probably get tired of me saying how this lens, (Nikon 18-200mm f3.5-5.6 V AF-S), gets disparaged too often on photo.net. As a former professional, I can tell you that if I still had the energy and connections, I could sell the above image, and others taken with this lens, over and over again, paying for the lens, the camera and transportation to and from the site and make a tidy profit for the rest of my life and the life of my heirs.</p>

<p>Granted, had I used a better quality optic, I could have captured an image with better IQ. So what. This lens rocks!</p>

<blockquote>This lens rocks!</blockquote>

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<blockquote>Robert, you have missed my point, your particular copy of the 18-200mm lens might rock - mine did not, in fact it was by far and away the poorest optic I have ever used and I've used plenty! I do not need to be a Pro photog. to know that my copy of the 18-200mm AF-S was a complete and utter dud - even after a warranty repair / fix / fiddle / do nothing by Nikon Australia. My point for the orginal poster is that I hope he has not befallen the same blight that I did with this particular lens by purchasing a dud copy - they (dud copies) do exist.......... </blockquote>

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<blockquote>I know there are plenty of p.net members with glowing reviews of the 18-200mm lens and they are warranted indeed - my experience was something else.......<br /></blockquote>

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<p>I could sell the above image, and others taken with this lens, over and over again, paying for the lens, the camera and transportation to and from the site and make a tidy profit for the rest of my life and the life of my heirs.</p>

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<p>so the 18-200 will support one's retirement fund and support one's offspring's financial needs forever? that wouldn't be hyperbole, would it?</p>

<p> </p>

<p>This is the reason why not to use lenses such as the 18-200 ;-)<br>

It looks like the plane of focus isn't exactly parallel with the lens. It can happen either as a manufacturing defect or something has gone out of alignment later. More tests would be needed, but frankly I wouldn't be surprised if this was the cause.</p>

<p>The building on the left seems to be much further away than the building on the right.<br>

The difference in sharpness between both shots seems greater in the building on the left. The building on the right looks to me almost the same in both shots.<br>

If the point of focus is closer in the first shot wouldn't that account for the difference?<br>

Hard to tell though at this resolution and with my eyes!</p>

<p>Jerry wrote [The 18-200mm lens is <strong>better</strong> at f8 or f11. Testing at f4.5 may not be so good.]</p>

<p>That is the entire issue.</p>

<p>Looks like coma smearing to me. A product of focal length, aperture, and unavoidable overexposure of bright light sources on a dark background placed at the edge of the frame. Seen a lot worse examples than that, including my old 50mm at f1.4</p>

<p>Paul, I would retest your lens capturing images of a flat brick wall. If you want your camera to be absolutely parallel to the wall, tape a small mirror in the middle of the wall and align your camera so that you can see the image of your camera from the mirror when you look thru the viewfinder.</p>

<p>While it may be too much to expect corner-to-corner sharpeness from a lens such as the 18-200, at least it should be even on all corners. If somehow one side is sharp but the other is not, and after you re-focus a different side is sharp, it may be an indication that your lens axis is not totally perpendicular to the sensor plane. That is the symptom that either your lens is not aligned or the mount on the body is not aligned. Once I drop my camera + lens and the mount on the lens is just slightly bent, and that was the symptom I observed.</p>

 

<p>it seems like the d300 is laboring with the af fine tuning feature with the 18-200mm.</p>

<p>Ramon,</p>

<p>With all respect, no. The OP is testing a lens for edge-to-edge focus on a 3D topic shot wide open.</p>

<p>The test is flawed. Follow Shun's advice above.</p>

<p>might have been better if the test/fine tuning subject or center of focus was the wide building with many windows.</p>