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AF Fine Tuning question

Discussion in 'Lens Lust' started by greyhound rick, Oct 3, 2008.

  1. Hello everyone!

    Ive been posting in the "Sports Photography" section with regard to "fine tuning" on my D300 and would like to get your input on my findings.

    Heres what has happened so far with my 85mm f/1.4 lens

    1. Tested it with the Jackson test chart and it showed severe front focusing.

    2. Took some test shots, fairly close up, and saw some front focusing, but not as severe as the test chart.

    3. Photos further away, i.e. photos of racing greyhounds at Phoenix Greyhound Park, came out fine. No front focusing.

    4. Took lens to Tempe Camera and had professionals use their testing equipment to determine if the lens was within Nikon tollerances. The lens checked out spot on according to them.

    5. Took lens to Phoenix Greyhound Park and tried many, many shots with focus adjustment at "0", "+4, 8, 12...." and felt that the shots taken at "0" were much better in terms of focus on the subject vs. any of the "+" settings.

    Conclusion so far:

    After reading about this and communicating with numerous people who know much more about it than myself, I believe that the best way for me to proceed at this point is to tweak the tuning up close and in semi-close shots, but not to do anything for my greyhound photos.

    I have talked with a friend of mine on another forum and he told me that after much analysis, testing and experimenting that he has had the same results and conlclusion as I have. Adjust more in close and less further away, ultimately leaving it at "0" when shooting at a distance that the greyhounds are at.

    Any input you have with regard to this is most appreciated and I want to thank everyone that has helped me so far with this up to this point.

    thanks again and take care,

    my best,

  2. I'd agree with that line of thinking. I adjusted my 200-400 & 600 with a test chart and got it all spot on but then in real world shooting with distant objects I was getting major back focus!
  3. I agree. Real world shooting is the key.

    However, as far as focus deviation between a close up test chart as compared to real world focus, I have found that there is much less chance of deviation with a Prime lens vs. a zoom. Every single one of the Primes that I have, both show focus deviation in the same direction. My final tuning of the AF Fine Tune is done in correlation with real world shooting, and NOT to the charts. This does take time and analyzation though, and an understanding of reading the zone of focus in relation to the DOF.

    I think though in Rick's case, there are a few things going on which deserve attention. Firstly, my assumption is that his test charts are shot at F1.4 and very close up. I believe his real world shooting is at F2.5 or so, plus at a greater distance than the charts. So, the distance to the subject being greater, and the greater F-stop are both adding to a much wider zone of focus. Adding to this, Rick's shooting shows no real defining of an analytical DOF. His greyhound shooting by design shows mostly all motion blur. IMHO, because of these factors incurred with Rick's shooting, it would be very hard for Rick to detect any *real world* FF in his type of shooting.

    I used to own an 80-200AF-D two ring. Known for focus issues close up esp. on the D300/D3. With my lens, any AF Fine Tune at one zoom range, would imbalance the focus at another range. Thom Hogan talks about this phenomenon with AF Fine tuning zooms. The end result was that I fine tuned the lens at the 135mm at F2.8....sweet, sweet, sweet! But...my zoom now turned into a Prime. I had velcro holding the zoom ring at 135mm. I would not dare use it as a zoom any longer. The lens had other issues though, and was eventually replaced by my outstanding focusing 80-200AF-S. Which seems to be on the money with an AF(-4) Fine Tune at all ranges.
  4. Thanks Richard. Do you adjust the AF Fine Tuning for different shooting situations or do you just leave it at "0"?

    I would think that if the distance from camera to subject remains fairly constant that setting the AF Fine Tuning number and leaving it there would be little to no problem....HOWEVER....if these distances are changing during a shoot, I would think that it would be next to impossible to constantly change the AF Fine Tuning between shots.

    How do you feel about this??


  5. Thanks for the input Mike as always!!

    I guess the final determinate in this exercise should be the actual results. After taking many, many shots at the track at different settings I have determined that the best focused shots BY FAR are the ones taken at "0". I would say that that in and of itself should determine the best setting to shoot at. No??
  6. Hi again Mike!

    Sorry, but I wanted to ask another question.....

    You stated that my greyhound photos show mostly motion blur. Do you mean the surrounding areas of the photo or the entire photo? I think that for the most part, the subjects are in pretty good focus considering the following:

    1. Low and inconsistant light
    2. Very close camera to subject distance
    3. High speed and erractic moving subjects
    4. Low contrast
    5. Very aggressive panning required

    Let me know what you think about the focus of the greyhounds themselves. I personally think they are in pretty good focus but would like your opinion.


  7. Rick, I think I'll be shooting at or around the '0' setting in future as adjusting between shots could reuslt in missed opportunities. With the 600 objects are usually far away anyway so it's not such a big deal, the 200-400 however could be slightly harder to pinpoint an average focus setting due to the zoom and it's close focus ability.
  8. Rick, here are a few concepts to ponder.

    1)The greyhound is erratic. The entire body is darting, jerking and moving. Even the torso is probably compressing in and out. The legs especially and the head are moving swift. Your shutter, as high as you may thing it might be, is NOT high enough to stop all this motion. Your panning is also very quick with such an animal. Because of these factors, the panning of your subject results in mostly motion blur. The parts that can be stopped by your shutter, will be sharper. Foreground and background results in motion blur also. Probably becasue of lighting dynamics, and/or Front focusing.

    2)If you shoot your test chart at an angle, NOT square, you will notice that one side of the chart is in better focused than the other. This is the same phenomenon that will happen with real world shooting. If you shoot at an angle, and especially using a shallow DOF(wider Aperture), one part of your subject will be in better focus than the other. The Zone of focus is angled. Any item not in the zone, will look Out of focus.

    3)I am hungry and looking forward to my Arby coupon:smile:
  9. thanks for the input!!


    Two questions:

    #1. In your opinion based on my results, would you say its a safe bet to keep the fine tune set at "0" (off ) while shooting the greyhounds since that is where I get the best results?

    #2. If I am shooting with my 85mm and need to shoot a variety of subjects at different distances from the camera would you suggest setting the AF Fine Tuning every time the distance changes substantially or just leaving it at "0".

    I would think for a set distance (portraits) that I might want to find the proper "+" setting ahead of time and just leave it there.....


  10. This is different from my experience with AF Fine Tuning on my D3. I had a front focus error with close subjects using my 85mm f1.4 that required a +7 correction to eliminate. This correction did not introduce focus errors for more distant subjects. My 85 f1.4 now properly focuses at all distances.

    I had not noticed focus errors with distant subjects before making the correction since I primarily use the lens for closer portrait shots. I suspect the error was present with distant subjects as well, but masked by the greater DOF.
  11. Rick, I can lie to you and say simply to leave it at 0. I can also lie and say change the AF Fine Tune for each distance.

    But I will not say the above. I will say though, that I have given you much information that I feel is accurate from experience. Others, including yourself, may agree or disagree. You have my input, I have covered much and am happy to do so. You also have other links which will give you further information.

    I suggest you try and really grasp an understanding of DOF and the zone of accurate focus. You sound like you will not rest until you are given an answer that you want to hear. And because of this, you are shooting darts to find someone to agree with what you want to hear.

    Good Luck,

  12. my d50,d70s, and d200 didn't have this function and i never had a problem....
    I have never touched it on the d3 or d300 and have never had a problem....
    I have alot of glass so I guess I'm just lucky
    I shoot alot of sports and alot of fast moving birds, alot of the time from a moving boat
    Line up the sensor and fire seems to work for me...
    I wonder if lenses really need a user adjustment to focus better
  13. Rick, if I came off a bit nippy in my last reply, please accept my apologies.

    I think this AF Fine Tune thing is an area that is not greatly understood by many. And by no means do I totally understand it myself. Sometimes I question and question what I perceive, and could use further answers myself.

    I also feel since the D3/300 cameras are the first Nikon cameras to utilize this tool, Nikon could have dedicated an area in the manual or on their website to have some tutoring on the subject. The manual does not go into much detail at all.

    Don't forget, it was me who initially brought this AF Fine Tune matter to your attention. You did not search it out because you felt that you had focus issues. Most shooters do a focus test chart *because* they think they might have issues. This was not your case...at least this is my understanding.

    Anyway, your answer may well indeed be to leave things as they are '0', or simply turn off the AF Fine Tune. It appears that you are saying that at the distance you shoot, there does not appear to be a problem....end of story, concentrate on other more important things. Because if the problem was indeed serious, you would not see much of anything in focus, and that does not seem to be the case.

  14. No worries Mike....no apologies necessary. I have thick skin and have no problem with anyone being direct and blunt. Sometimes thats the best way to be because it cuts thru the bs!

    Im not really searching for something I want to hear. Im just trying to be honest and if my honesty seems like Im soliciting someone to agree with me then so be it, but those arent my intentions at all.

    Mike, when you say that I need to understand the "focus field" better what exactly are you saying there? Is it my ability to determine what is in focus and what isnt in a certain photo?

    Maybe Im overly simple minded (not a bad thing mind you) about some things, but I think that you do what you do to get the BEST results and constantly try to improve. Thats my method to this madness anyway. So, for now, I think I'll stick with the "0" setting for the greyhounds and tweak to the "+" side for closer targets.

    Let me know how I can become more educated in this arena and I will glady do the work!! Just not sure how I go about understanding the "focus area" better. Let me know. Thanks
  15. Ive got a friend of mine in The Bay Area that I respect a lot when it comes to photography and Id like to share a couple of quotes (if youve read these before on another thread I apologize) from him in messages he sent to me that I believe are germane to this subject:

    Here they are:

    "Just get ready to head down a path where you may end up taking hundreds of test shots to decide how to set it then starting all over again when you don't like how it works in real-world shots! ha ha ha"

    "Short is I have spent countless hours doing it.. and when all was said and done I learned a lot about lenses and ended up putting my adjustments back to near 0 on all of them. So once you start this process it may take lots of time because when you adjust for what you think is right you end up finding subjects that you made it worse for. Has to do with how the auto focus system works and how some lenses are actually designed to have a certain amount of front or back focus to them!"

    Just an opinion to throw in the mix here. Thought you might be interested in reading......
  16. Very interesting Rick.

    Here is another opinion. I don't know Thom personally, but have purchased the D70 guide from him. Like your friend, Thom is also very well respected in the Nikon community.

    From Thom Hogan in his D300 review:

    "Another nice addition to the AF system is the ability to tune it for individual lenses. If you've ever had a Nikon (or Canon) body that back-focused or front-focused with a lens consistently, AF fine tune is the answer you've been waiting for. In return for a few hour's work, you'll get more precise focus than you had before. A few lenses that I had put off as being good but not great performers suddenly went up a notch after I tuned them on my D300 and D3"

  17. Great stuff Mike!!! (as usual) :smile:

    Im going to try shooting some races tomorrow with a setting at "+2" and "+4" and see what happens. I might have tried to tweak it a bit too much before by jumping all the way to "+10, +12" pretty fast and not giving the minor adjustments enough shots.

    I believe in what you say, Mike, and will continue my quest to find the answer to better focused shots.

    Lets keep in touch and please, dont ever hold back with your comments thinking you will hurt my feelings. I understand that in order to learn from people like you I have to be able to take constructive criticism which I think I do well.

    I have a contact in Australia who is a pro sports photographer there. He lets me have it all the time! One thing hes told me over and over and over again is that you can not buy your way to being a good photographer....you have to work your Arse (is that how they say it in Canada??:biggrin:)  off!! So....thats what Im going to do!!

    take care my friend,

  18. Jeff Jarvis

    Jeff Jarvis

    Sep 10, 2007
    I took my D700 and my lenses to Nikon Service, NIKs Thailand, to have focus fine tuned.
    They have some very impressive equipment set up to calibrate/service everything.
    Great workshop. Great folks to work with too.
    Turns out, the D700 needed an adjustment.
    Didn't ask what they did but my shots are looking better.

    I imagine that equipment coming off an assembly line could all benefit from a technician checking the specs., no?
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