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Do you use focus fine tune?


Ian Rance

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<p>And if so what camera and lens combinations required it?</p>

<p>I am loathe to fiddle with it and found that the one time I really did get some off focus (with a D7000 and 50mm f1.8) which was still not right at -20 that after the body was set up by Nikon (I did not supply the lens) it came back resolved. However I do notice that the 50mm 1.4 AF-S I have, when used at wide apertures, gives results that look like they are needing to be focused more forwards than the camera has chosen. Same with a 85mm f1.8 D (but not so much).</p>

<p>Is setting the focus fine tune worthwhile for each AF lens or do you just end up chasing you tail and not really getting anywhere apart from frustrated?</p>

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<p>First - and so far only - lens that required fine tune with all my DSLRs has been the Sigma 24/1.4. Didn't use any specific focus target - used pretty much the same approach that Ilkka describes here (sans the Excel spread sheet part): http://www.photo.net/nikon-camera-forum/00c42t and Nikon here: <a href="https://nikoneurope-en.custhelp.com/app/answers/detail/a_id/51633/~/how-to-use-the-af-fine-tune-function">https://nikoneurope-en.custhelp.com/app/answers/detail/a_id/51633/~/how-to-use-the-af-fine-tune-function</a><br>

<br /> I was considering purchasing the Sigma USB dock in order to be able to tune the lens itself - allowing to enter more parameters at different focus settings - but real world testing with the best value found at a close focus setting revealed that the lens didn't need different values for more distant subjects.<br>

<br /> In particular, comparing images taken with live view on the D810 with those taken the conventional way helped "zeroing" in on the best fine-tune value. Wondering why that process can't be automated directly in-camera: use the on-sensor contrast detect (or, as will likely become more and more common, on-sensor phase-detect) to determine the correction needed for the in-camera AF phase detect sensor.<br /> <br />On the D810, I went through at least two rounds of fine tuning - first was to zoom in on the best value, the second one to finally nail it (changing the AF fine tune parameter by only one in every step). Only needed to transfer images to the computer for the second round - for the first, examination on the back LCD proved sufficient. Not so on the D700 - which due to the lower resolution proved harder to tune - and I needed to examine every image taken on the computer screen. D7100 worked with the D810 procedure, D300 with the D700 one (no real surprise there). All in all, I might have spent about 2 hours tuning that lens on those four cameras (though I might have spot-checked a few while I had everything set up).</p>

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<p>I do it for all my lenses and cameras. In some cases it makes a significant improvement. One must remember that applying a single focus adjustment is not generally a perfect solution. Auto focus errors can vary with focus distance, zoom setting and aperture depending on the lens. The shift with aperture is most pronounced on fast lenses as you noted. So don't let the process drive you crazy trying to get the focus perfect everywhere. It just isn't going to happen with many lenses. The final setting is often an average value biased towards where you use the lens most or where focus is most often more critical.</p>

<p>I have used various methods with different targets and expensive software. I find that I do as well simply focusing on a ruler with at mark in the center placed at different distances or focusing on a carpet or lawn that has distinct texture. I spend about 5 minutes with each camera / lens combination which is time well spent.</p>

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I have used AF fine tune on my d810 and my d800e with all my nikon lenses. I started because I noticed my d800e was

backfocusing with most of my tele lenses. I contacted sites that advised me that sending the camera back to nikon for

adjusting was probably not an option unless I had tried to adjust away backfocusing with AF fine tune. I used lens align

pro to calculate the adjustments needed. I was not happy to find that every nikon lens I owned required an adjustment,

with numbers ranging from a minus 1 to a minus 12.You must calculate a separate number for each lens.

 

My d810 front focuses so I had to do the same for it with all of my lenses. The adjustments for it are smaller but still

needed. Do an Internet search for a simple way to check for front or back focusing. If you discover you have a problem,

then get a product to help you make accurate tests so your AF fine tune adjustments help to solve a problem instead of

creating one.

 

I still do not understand why adjustments like this are needed given the high costs of my bodies and nikon lenses.

 

Joe smith

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<p>One of my top reasons for getting a newer camera than my D200 was because it did not have focus fine tune.</p>

<p>I often shoot wide open with fast lenses, and with the D200 it was frustrating to focus on the eyes with my over $2000 70-200 F2.8 VR lens and then have the persons ears in focus. I got into the habit of focusing on the eyes with that camera then backing up a bit and taking the actual photo (and many photo's if possible) to hopefully get one with the eyes sharp. <br /><br /><br /> Then I learned newer camera's have focus fine tune and I was all over it, having a camera without (and shooting so much wide open) not a feature I can do without. I only did my portrait type lenses (50mm F1.4 and 70-200 F2.8) by finding a paper template online to guide me. I did not do it with my 80-400 VR, 17-35mm F2.8, 18-200, nor 70-300. Those lenses with their rather long DOF and on my newer camera were close I just didn't feel the need.</p>

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<p>I did fine tuning on four lenses -- three Nikon lenses and one Sigma lens. Two of the four required a change, two didn't. I don't know if I can really tell the difference, but upon the metrics involved in the testing I did, one of the lenses (a Nikon lens) was quite a bit off. It took me two hours to set up and do the four lenses.</p>
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I do it with every camera that has the ability and every lens I use, both owned and rented, Canon and Nikon. If nothing

else even when it turns out that no adjustment is necessary for a specific camera and lens combination I know that I'm

getting the best performance out of the pairing.

 

I use the LensAlign Mark II target and the accompanying FocusTune v3 analysis software and follow the same protocol

every time starting with a well lit and perfectly aligned target at 25x lens focal length distance (for zoom lenses Nikon only

allows you to make the adjustment at a single focal length setting while most recent Canon bodies let you set adjustment

for both shortest and longest focal length).

 

My first go around I do it at two adjustment point intervals: -20, -18, -16,....+16, +18, +20 with five frames at each

setting. I also defocus slightly (in the same direction) between frames.

 

I have FocalTune analyse the results and then do a second round bracketing in 1-step adjustment increments over a 10-

increment range. In other words if +3 looks best then I shoot from +8 to -2, again with five frames at each increment.

 

The secret to making work is patience.

 

Now if I am shooting still life I use Live View.

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<p>Like many of the posters here, I think checking and tuning is required if you expect to get a high percentage of close distance shots in focus at large lens openings.</p>

<p>The D800 I used to have did seem to require more compensation than some of the other cameras I have had, my D810 requires less.</p>

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