dSLR fine tuning AF

[RaymondC]

<p>Hi, some of you may recall I had some issues with my D600. I got to Japan on my trip, and got them to check it out for me, within an hour they said it there was no problem but I am not sure if this is due to "being within spec". Thom Hogan has said that with a 50mm lens at a 2m distance +/- 10mm may be considered within spec. </p>

<p>In terms of the technique. Do you use it at max aperture and as close as the lens focuses? I've tried using f/4 and at a 2m distance but the samples were difficult to tell. </p>

<p>What I got in the past is that the eyebrows might be sharper than the eyes. I did use my 50mm lens at 1m distance, at f4 and someone here mentioned that 21cm on the ruler (further away) was shaprer than the point set at 13cm. Angled 45 deg on a biscuit box on the a table ..... </p>

<p>Thanks :)</p>

[pge]

<p>Read this</p>

<p>http://www.photo.net/nikon-camera-forum/00biJz</p>

[mike_halliwell]

<p>+1 Phil</p>

[theodoros_fotometria]

<p>MO is, that automatic systems are improving but are not (can't be) perfect... "doing photography" will still require skills on picture taking and all the "promising specs" are there for the "average user"... I can live with and without AF... but rather prefer the "good old microprism" screen back... either with AF, ...or without it!</p>

<p>These kind of questioning of "automatics" on a camera is well back... from the times that internal metering first appeared. It's not the automatic features of a camera that will make you a better photographer... it's you!</p>

[keith reeder]

<p>Depends <em>entirely</em> on what you shoot, Theodoros. Good luck being consistently successful doing <a href="http://www.capture-the-moment.co.uk/tp/tfu29/upload/moto-x_cambois_acdsee_1.jpg">stuff like this </a>manually - it's not possible.</p>

<p>You <em>might</em> get the odd decent image focusing manually, but good AF will get you far more, and far better, images.</p>

[dan_south]

<p>I test at different distances with the widest aperture, take a lot of shots, and average the results. </p>

[RaymondC]

<p>I have done some tests with my 50 and 85. +2 and a -3. </p>

<p>Can someone give me a low down on the AF Tune settings please? I've read the manual. The saved figure is the no. if you want it to save like +2 or -3 right? Then how does default work then? If you have a saved value and a default value which which one comes first? Does the saved value come first, b/c that was activated by the user right?</p>

<p>Maybe in the past I got the two muddled up, I cleared the saved settings and started again ... </p>

[RaymondC]

<p>Doing a bit of tests just photographing the coke bottle - on the side here they have a printed number on it. -2 adjustments looks good but then at minus 7 it looks a bit better. But minus 3 to minus 6 wasn't that good. Does this sound right? So it's not linear?</p>

[kari_oinonen]

<p>Ray, usually the af correction is for that lens only. If there is a "default" it should affect all lenses you mount to your camera. Those corrections are added together in action.<br>

It is not recommended to tune the af fine tune using a very short distance. You are better off with medium/ normal shooting distance.<br>

( For some good reason newest Sigmas have different af-fine tune values for various (3) different distances.)<br>

A zoom lens might actually need different af fine tune values for different zoom settings - the simplest is to use medium zoom setting to do af fine tune testing. At least to start with.<br>

If you focus on the bisquit box at 2m distance, that is ok. Single area af, center af, camera in fixed position - tripod. Then check what the ruler at an angle can tell you. Put the ruler a bit outside of the focus area so that the ruler is not mixing the focus.<br>

I do not know if those af fine tune values are totally linear, but various values shoud give you only one peak and others around the peak should give you gradually poorer and poorer results.<br>

And you do check the results with your computer monitor?</p>

<p> </p>

[gerard_kopcsay]

<p>Nikon DSLR manuals that I have seen from the D3 to the D800 state that the default AF fine tune value and the AF tune value for specific lenses are not cumulative. In particular, the default value is "used when no previously saved value exists for the current lens (CPU lenses only)." AF fine tune on my cameras seems to behave as described in the manual.</p>

[RaymondC]

<p>Thanks. Yep, I am at the moment just AF tuning my primes first 2x, I also have 2x zooms. Not a collector, lol. Yep I download into Lightroom and compare 2 shots at a time at 100% view on my calibrated monitor.</p>

[kari_oinonen]

<p>Gerard, thank you for the more accurate/ correct infomation wrt. the default value of af fine tune. Not cumulative - ok.<br>

Ray, good luck and have fun!</p>

[sjmurray]

<p>One thing I've run into is that if a lens needs an adjustment for shooting close up, it may not focus well on distance shots. The camera's manual clearly states this. I have a new 18-105 I'm probably going to send back to Nikon for this reason. I shouldn't have to turn the af fine tuning on every time I'm closer than 20 feet, and off when I'm shooting farther out, but that's just what I have to do with this lens. </p>