Do you have to AF fine tune a given lens separately to TWO identical bodies??

<p>I just fine tuned my Nikon 17-55mm f2.8 to my first D300 body. Big adjustment.... +18</p>

<p>Can I put the same value in my second D300 body? Or do I have to do the same test but separately for that other body?</p>

<p>You can try, but I'm almost certain it will NOT be the same adjustment. It's a unique pairing focus-offset that you're entering.</p>

<p>If it <em><strong>is</strong></em> exactly the same, it's a coincidence.</p>

<p>I'd say do the test and come back and tell us..:-)</p>

<p>The simple answer is that you have to do it with both bodies for the best possible results. Been there and done that.</p>

<p>-O</p>

<p>Owen is correct.</p>

<p>ok, I might be having a problem with the second body. No matter what value I put it at (-20 to +20), the focus point is almost indistinguishable. what's up with that? and YES, I do have it set on one point focusing and on a tripod with timed release.</p>

<p>Mike, Owen, and Al are giving you good advice. Any AF fine tune is strictly between a particular combination of one individual camera body and one individual lens.</p>

<p>And the default (bias)value for AF-fine-tune is set accordingly in the other body? It is another/second parameter, that applies to every lens. Probably just summed up together with the first fine tune parameter. I do not have D300 available to see if there are actually both those two parameters in that model.</p>

What kind of target are you using, what is your distance (in multiples of focal length), how many shots are you taking at

each adjustment setting, and how are you analyzing the results?

<p>shooting a ruler vertical to my shooting plane, f2.8 @55mm</p>

 

<p>A good test target can be found by searching "siemens star test target". Some of them can be printed by free. Couple of A4 size prints will give you good tools.<br>

To me these star test targets are far superior to what I used previously.</p>

<p>While rulers can come in many different sizes, typically they are not that big, perhaps a foot long? Unless I am fine tuning a macro lens, I would use a much larger subject and fine tune the lens with a distance that I would typically use that lens from.</p>

<p>For example, the 17-55mm/f2.8 is a typical event lens which you capture people from maybe 3, 4 meters, i.e. 10 feet, 15 feet? I would fine tune it with a subject from that kind of distance.</p>

<p>The default fine tune is only used if a lens-specific fine tune has not been set for a particular lens. The two adjustments are not added up. They may not even have the same units.</p>

<p>With a zoom you should determine the focus fine tune for both the short and long end of its range. If they differ significantly then in practical use there may need to be a compromise adjustment that is used according to your needs. I get different settings for the ends of the range for the 14-24 and 24-70 but the 70-200/2.8II is very consistent and usually requires only a very slight adjustment. If the ends differ then usually I select the value that is 2/3 of the way between the short and long end settings (closer to the long end setting).</p>