AF fine tune question...

Discussion in 'Lens Lust' started by ciscopro2000, Aug 20, 2008.

  1. I had a chance to play around with this today and found that some of my lenses needed to be adjusted. My methods were far from scientific, just quick focus charts/tripod and some water bottle tests. They seem to work pretty well.

    My question is, if you find that you need to Fine Tune a lens, does it mean there is a problem with the lens (or the body)? Should I contact Nikon and have them take a look? I have never sent equipment to Nikon, so do they also use the Fine Tune feature to adjust the body/lens or do they have a different method? I guess in an ideal scenario, I would have preferred the combinations to work PERFECTLY without any adjustment. :smile: For those that have multiple camera bodies and have Fine Tuned lenses, do the adjustment levels vary between the bodies (example, a lens might be +5 on one body and is +10 on another body)? I am just trying to get a clearer understanding on this. Thanks everyone.
     
  2. Others should reply that might know more of the tech side, but I'm under the impression that there is a slight variance in every camera/lens combo. The AF Fine Tune process just takes that issue out of the mix.

    I set up all my lenses and (as a rule) there just does not seem to be any rhyme or reason to the adjustments, just that the sharpness at the focus point can sure be better after it's adjusted.
     
  3. TimK

    TimK

    Apr 17, 2006
    Hong Kong, China
    I think if the adjustment is within +/- 5 it is probably OK. Sometimes strange things can happen too - My TC20 needs -20 to work with the 500mmVR but almost perfect with my 400/2.8. Both lenses are within a few steps when they are used without TC.

    Unless you are in a studio in real life it is very difficult to get focus locked on the single point you want!
     
  4. Hi Mark,

    I have been dealing with AF fine tune now for several months, both with my previous D300 & new D3. Adjustments did vary between camera bodies.

    Needing an AF fine tune adj. does not mean anything is wrong with camera or lens. Unless of cause, the problem is so severe that the lens might need to be repaired.

    Lastly, only adjust if you feel that an adjustment is needed governing by your normal everyday shooting with that lens. I, and many others, have found that focus test charts, water bottles, etc. are not the best way to tune the lenses. Tune the lenses at the focal length that you use the lens mostly at. I have found that testing focus accuracy with measurements, very often do not reflect your real world shooting.

    mike
     
  5. lmorgan

    lmorgan

    300
    Jun 27, 2008
    NCentral IL
    Don't mean to hijack your thread, but I also have the same questions about fine tuning. I have found through shooting and the angled focus test chart that my 50mm 1.8 is front focusing. Is there a better test than the 45 degree angle test chart to use the fine tune?
     
  6. Mike,
    What other tests do you or others suggest? In real world shooting, I've always thought my lenses were sharp as heck. Only after some focus charts/tripod tests did I find that they needed fine tuning. Any insight you provide will be greatly appreciated. Thanks.
     
  7. I didn't have any luck at all using the charts at an angle. The system and the process worked. I was able to get the best focus point set to zero, but darn if my photos looked off when I used the lens in real world photos. Something didn't translate from the adjustment to the way I actually shoot pictures. This was more noticed as I did portraits and used one eye as a focus on my higher end prime lenses. I would lock in on the eyes (and did it by moving the focus point not the camera) but darn if the nose wasn't perfect and the eye was off a bit.

    This is important because with some of the lower light prime lenses they have to be REAL close to perfect. For example, a subject 5 feet away at 85mm F/1.4 on a D3, the depth of field (area in perfect focus) is only from 4.96 feet to 5.04 feet (giving you only .08 feet of room to miss the focus point - source). So if you shoot different than how a perfect focus chart sets your camera, you are outa luck.... I guess I'm one of those people, cause I just could not use the angle charts.

    Adjusted 85mm at F/1.4 and about 5 feet (but on a D700)
    [​IMG]

    I ended up going to a focus chart flat on the wall (or I now use a detailed book cover) and comparing each shot to the next and checking which is best (like playing the game of guessing a number between +20 and -20).

    Once you get use to doing it and use + or - 5 to get a range, it's easy to lock in on a setting that works for the way you shoot.
     
  8. Bottom line. Look at your real world images. Tune to the length and zoom range that you are shooting. Do not tune to close range test charts, unless you are shooting fairly close range.

    Very closely inspect your images as shot...preferably at F2.8, or widest Aperture(1.8, 1.4) Look for evidence of front or back focusing. You should be able to see this.

    If I am shooting a horse race. I look for blurred hoofs that I did not intentionally lower my shutter for that effect...this may signify back focus. I make sure that I am seeing sharp dirt where it should be sharp in front of the race horse. Too much sharp dirt may signify front focus.

    Inspect closely at ALL zoom ranges.

    For Prime lenses, don't inspect at all zoom ranges:smile:

    mike
     
  9. lmorgan

    lmorgan

    300
    Jun 27, 2008
    NCentral IL
    Thank you Kap. I'll have to try that out this weekend. My real world test was strapping my 2 year old in her car seat so she couldn't move. The focus fell on her forehead on all the shots at 1.8, but finally got tack sharp eyes at 2.8 (as well as a tack sharp forehead). I really appreciate your help.

    And your model has beautiful eyes! :) 
     
  10. PedroS

    PedroS

    259
    May 4, 2008
    Portugal
    There's a real nice thread at Nikonians about fine focus tunning.

    I have spent hours from several days apart from each other to fine focus my lenses.
    Almost all of them needed some fine focus (I use a paralel target, not a 45 degree one).

    Then I start shooting all my lenses in real life and tested them. After some 400 plus photos I have returned everything to zero and forget it since then.
    My photos are tack sharp when they are correctly made. That's the hard lesson learned - take correct photos!:tongue:

    By the way, nothing is wrong about fine focus, I just realize that my life was easier and smoother without thinking about it!:smile:
     
  11. btg1

    btg1

    28
    Jun 20, 2008
    USA
    I am really putting off this whole fine focus project, it is just another way for me to not be out shooting the real photos (and not test photos).
    It also occurs to me that if I don't check/fix this I could have 1000's of pictures out of focus.. and with the D700 (and trying to learn all the various AF focus modes) this could be a long project (of trying to figure out if it is the mode of focus or the fine-tune of focus)....
    What ever happened to the old days of setting ISO, Aperture, Shutter and either Manual focusing or using one focus spot?
     
  12. http://www.nikonians.org/forums/dcb...140459&prev_page=show_topic&gid=140459#141121
    I believe this is the Nikonian thread mentioned above. Thank you.
     
  13. Very understandable. And there is nothing wrong with "the old days of setting ISO, Aperture, Shutter and either Manual focusing or using one focus spot". And I do also use manual focus on my D3 at times.

    The D700 offers many choices, and if you feel the need to use any of these well, there are many here such as myself who have already spent countless hours in understanding and using these focus features to assist in making photographing even better. So if you feel the need to get involved, many of us can assist if need be.

    mike
     
  14. btg1

    btg1

    28
    Jun 20, 2008
    USA
    Thank you for the offer! I may just have a few questions soon! But right now I am enjoying the manual focus of 135/2 DC lens and too confused with all the options to even think about it!

     
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