D700 and autofocus

Discussion in 'Nikon' started by stevenseelig, Nov 17, 2008.

  1. I have been using my D700 a couple of months now and it seems that it has difficulty in finding the autofocus under conditions that would
    have been fine with my D200. At least subjectively this seems to be the case.

    I was trying to understand the 51 AF system a bit better this morning and any of the points off the center one at least with some images
    will focus quickly in one orientation and not in the other (vertical vs horizontal). I mostly do portrait work and place my focus point on the
    eye typically (in focus eyes is 'good' but also it tends to be an area with a fair amount of contrast to work with). Unlike the D200, I find
    myself on target, ready to go, but the D700 can not find the focus point. So I have to reset and by that time, may have lost the shot. I
    almost always use spot focus for this type of work and I have noticed the problem within my studio where the lighting is not dim
    particularly.

    So my questions are: 1. Have other people noticed this? 2. Are there camera settings that I should consider changing to help out? 3: Are
    there techniques to determine whether the speed of autofocus is ok (not actual autofocus)?

    Any suggestions or ideas would be deeply appreciated.

    Thanks, Steven
     
  2. I wish I could share the experience, if for no reason other than to see if I could help. My D700 focuses just fine, but I have the
    sneaking suspicion that in your case, you are not aware which of the 51 points are cross-focusing points (I'm not sure about the
    term, but you get my drift). Of the 51, only around 16 or something have the capability to focus in both directions, not all 51.

    But what you say about the D200 is not entirely true - it had less cross-focusing points than the D700 - chances are you were
    simply more accustomed to using those. I know cause this happened to me as well the first time I used my D700 and I know for a
    fact a friend of mine (who also bought a D700 after his D80) managed to shoot an entire event with EVERY single shot being
    completely out of focus because he failed to learn to use the new equipment properly.

    Personally, whenever I shoot portraits I always use the center point, focus and then recompose my shot...
     
  3. ShunCheung

    ShunCheung Administrator

    Overall speaking, the D700's Multi-CAM 3500 AF module is far superior to the D200's Multi-CAM 1000. I have both cameras. The D3 and D300 also use the same Multi-CAM 3500, but it is optimized for sports photography. The Multi-CAM 3500 has 51 AF points and 15 of those 51 are cross type. Those are the more sensitive ones. Please see the attached image showing where those 15 cross-type AF points are and I would try to use those as much as you can.
    The problem on the D700 (and D3) is that all 51 AF points are concentrated in the center, especially the 15 cross type ones. Therefore, when you shoot portraits, there are no good AF points near the top of the frame, especially where the subject's eye tend to be. Therefore, you need to experiment more with you new D700 and work around this issue.
    [​IMG]
     
  4. Can I say that I am a portrait photographer, have had a D700 for a month now, and share exactly the same focussing
    issues as Steven. I came from a `D2x which would acquire the focus almost instantly, and find that the D700 hunts for a
    second or two or four, even using good studio lighting (ie not dim light). I always focus on an eye, and use the centre AF
    point (focus and recompose - I am an old lag) and for me this is my one big problem with the D700. In the last two jobs I
    have become more and more frustrated at losing good poses because the AF does not find the focus fast enough. I
    have done loads of comparisons with my old D2x and I am becoming increasingly irritated with the D700. To be honest I
    thought it was just me, because I have not heard anyone else complain till now. In fact I was considering selling the
    camera because of this issue.

    I have this with my new 24-70, and my well used 85 1.4.

    If anyone has any thoughts on this - maybe there is a problem with my (and Steven's) camera...
     
  5. ShunCheung

    ShunCheung Administrator

    David, the big difference is that the D2X is a DX body and therefore the AF points cover a much higher percentage of
    the entire frame. Additionally, the D2X has 9 cross-type AF points that are very well positioned for the DX sensor.

    AF point position for portrait photographers is certainly a weakness on both the D3 and D700. I have clearly pointed
    that out in the up-coming D700 review here in photo.net. Generally speaking, on full-35mm-frame DLSRs, the AF
    points are too concentrated in the center of the frame. The Canon 5D and 5D Mark II as well as the Sony A900 all
    have the same problem.

    Hopefully Nikon will redesign the AF module in the future, but there seems to be some technical difficulties when the
    frame size is much bigger than DX.
     
  6. Hi Shun and thanks for the reply.

    I understand what you are saying, but I presume the centre AF point (which I use almost exclusively) should be perfectly
    usable for my needs. The fact that horizontally or vertically it is very slow to 'find' focus is disturbing, irritating and
    ultimately loses me shots.
     
  7. ShunCheung

    ShunCheung Administrator

    I own a D700, a D300 and have used two different D3 bodies extensively. At least in my experience, on any one of those bodies, all 15 cross-type AF points work very well under indoor, dim-light conditions.
     
  8. I was partially aware that not all focus points were created equal, but the magnitude of the inequality is more striking
    then I thought. Shun's diagram is very useful as it is those focus points that function extremely well no matter what I am
    looking at. The reminder have variable focus capabilities depending on the content of the image at the focal position.

    It appears that lines running perpendicular to the long axis of the focal point box are difficult for the camera to see and in
    when the camera is held in a vertical position, the dominate eye structures....such as eyelid in fact run along the axis
    more difficult to detect.

    I suspect some of my puzzlement is caused by my expectations of more equal performance (particular on faces and
    more complex objects) across the 51 points.

    Below are two images. One taken in the vertical orientation and one taken in the horizontal position with the actual focal
    point shown. With absolute certainty, the 15 centered focal points worked perfectly and instantaneously in either camera
    orientation. Again with absolute certainty, in the horizontal position, none of the focal points outside Shun's red box
    would focus..period...no way. But place the camera in the vertical position and all 51 points focused instantaneously.

    The focal point is very simple so I might expect some problems, but I would not expect it to affect taking portraits.

    Shun, I remember you commenting about the points all being the center of the sensor field... but the constraint of the
    cross hair focus point to the center of the 51 makes it even worse.

    In reflection, i suspect that with the D200, I addressed this problem by simply using the center focus point, locking focus
    and then reframe the composition as desired and when I got 51 points in the d700, I loved it and it worked great..so I
    used it more and more...and had not realized how different the points really were.

    Anyway, thanks for the help..I will need to find a comfortable work around or go back to old ways!!
    Steven
     
  9. Second try to upload the image mentioned above...
    00RWPn-89383584.jpg
     
  10. I would add one last observation. If the camera is held horizontal, the outer points will not focus as described above and
    that is absolute. If one rotates camera about 15-20 degrees in either direction off horizontal, then it begins to find the focus
    and the more one rotates to the veritical position, the 'tighter/faster' the focus finding becomes.....
     
  11. ShunCheung

    ShunCheung Administrator

    Steven, I wonder which AF mode you are using on the D700. If you are photographing a still subject, I would highly suggest using only 1 AF point and specify which one you are using.

    There are a lot of disadvantages of getting all 51 involved unnecessarily, and there is no mode that you can restrict it to only the 15 cross types. If you use Dynamic AF for action photography, you can choose among 9, 21 or all 51 AF points, but never 15. Obviosuly, if you use 21, you have to get some line-type AF points involved because there aren't so many cross-type ones.
     
  12. Shun,
    I am using single point AF for my portrait work.

    Occasionally, I use dynamic focus 9 points when I shoot people in motion.

    Also in my 'laboratory' setting the camera to dynamic focus 9 point did not change the behavior of non-focusing in the
    horizontal position.
     
  13. The D3 has the same problem, and it is the only thing I am not happy with in the camera... Using single point focus, in low light, the D2X can literally focus on things that I cannot see. It is incredible. The D3 leaves a lot to be desired in that way.

    I tend to use continual focus, at f/1.4 on off center points for a lot of 'portraiture' during events... What has helped me the most is disabling the AF when the shutter button is pressed, and using the 'AF on' button only for AF... this allows so much better control of the focus that I can recompose if I need to (at 1.4 i generally dont) and has helped with the issue... its not that it makes the focusing better, but it allows you to control it better and get more successful shots, in my experience.

    The D3's smaller focus points allow much more control, though, as I can focus through people's glasses on the eye itself, where the D2X's sensors were so large that doing things like that are impossible in many cases. It definitely teaches you exactly how to find contrasty areas when you need them, too...

    One last thought: I belive the last firmware update for the D3 involved AF tweaks... We used to have an issue where it just would not fire, despite simple conditions, for a second or two, like an AF confirmation delay... it was annoying as anything, but it seems to have gone away... I am not sure of the D700 firmware status, but if there is an update and you have not done it, that may help.
     
  14. ShunCheung

    ShunCheung Administrator

    As far as I know, the latest firmware version for the D3 is 1.10 for A and 1.11 for B, introduced back in April 2008, which was several months before the introduction of the D700 on July 1, 2008. Nikon has not issued any firmware update for the D700 so far.
     
  15. Robert.... I am curious as to why you feel use of the AF button rather than the shutter release gives you more control. I
    tend to use the shutter release 1/2 way down. Also, how 'good' are the images in continuous focus mode as I would
    suspect that does not help achieve a better focus..but at least you could release the shutter.

    Also the Firmware on my D700 is 1.0 for both A & B.

    Finally, out of curiosity, what is the reason that the cross hair focus applied to the middle 15 points is not applied to the
    outter autofocus points. And, on single spot AF how 'big' is the area used for auto focus calculation?
    Thanks
     
  16. in general, the size of the indicator in the camera is a close approximation of the AF area. The D2X sensors were a little bigger than the rectangles in the camera, if I recall correctly, but those points in the camera are a good base for the size...

    The AF button thing give me better control because I can use continuous focus if something is moving, but then also prefocus and shoot whenever exactly I want if the subject is still, all without fumbling for buttons or switches, as my thumb is always near the AF on button. In the studio thats kinda nice, espeically when shooting at f/8 or f/11, because the exact focus point isnt super critical and the camera is a lot more responsive. At an event, it allows me to focus using one of the cross sensors if necessary, in continual mode with a less still subject, then quickly recompose without the focus changing to snap of a shot... it works less well if the aperture is wide open, and it works less well if you introduce camera motion blur into the shots (i do sometimes) but its generally more reliable than just using continual focus with an outer point...

    the bigger point, though, is that I want to use continual with an outer point, I still can, and if I want single shot AF, I can just press the button until I am in focus, let off and recompose then shoot. Its a way to get both continual focus and single focus kinda at the same time without having to look out of the viewfinder.

    As far as why the 15 cross points are all centered? I have no clue, but it stinks. Shun pointed out above, though, that its a problem in lots of FX style cameras, so maybe its a technical thing.

    Last point: I am sure the D700 will get a firmware update eventually, and I betcha it includes 'AF performance' adjustments, just like the D3 firmware did. That may help, if the improvements made to the D3 arent already built in.
     
  17. Robert,
    Thanks for your concepts. I may try them and see whether I like the concept of continuous with single point AF with the
    other button. Makes a lot of sense to me. Will have to retrain my fingers, but that should be the easy part.

    My images off of the D700 for people in motion are clearly superior to my D200, but for studio shooting it works with a
    thorn in the side.

    I love the image quality though.

    Regards, Steven
     
  18. Very helpful thread... and like Robert suggested I've disabled focus on the shutter and only use the AF-on button to focus.

    However I've noticed one really irritating problem shooting this way. After taking a picture - the image appears on the monitor for 4 seconds - if you're still looking through the view finder - and want to use the AF-on button to re-focus before taking another shot - you can - and it will focus - but you CAN'T move the focus points using the multi-wheel - because the monitor is still previewing the image (you'll just move to another image in preview/play mode). A nuisance when you want to quickly switch between horizontal and vertical composition - focus, move your focus point and shoot again (within a second or two). Can the image preview be disabled altogether? A pity the AF-on button doesn't kill the monitor just like the shutter button does. Maybe a firmware suggestion? Thoughts or suggestions appreciated....

    Regards,

    Tony
     
  19. Ignore me... after searching every option in the Shooting Menu and Custom Settings Menu - there it was right in front of me under the Playback Menu.... sigh. Image review is now set to off.

    Would still be nice if pressing the AF-on or AE-L/AF-L buttons killed the image review as well.

    Tony
     
  20. Very useful thread.
    As I generally use old manual lenses I have not though a great deal about AF on the D700 which I have had since Dec 08, and have been very pleased with it. Having just found an old AF Nikkor 35-70 2.8 (not D) and looked more at AF I tried the offcentre testing outlined in this thread and found the following - neither the type of AF whether 9, 21, 51 or 51 3D nor the continuous or single seemed to make any difference:
    Outside the centre core of + sensors a plain vertical object - I used the edge of a door or some rectangular tiling (with camera horizontal) was not picked up by the AF, neither shutter 1/2 pressed nor AF rear button seemed to make any difference. The moment there was some complexity in the focus object, handle - lock - defect on tile then the focus was very quick and precise. Rotation of camera results in the focus starting to work after about 45 degrees ie when the the focus object line is nearer horizontal than vertical.
    Within the central zone no such issues.
    An interesting limitation to factor in when planning shots, perhaps that is why I like old manual lenses.
    Having resolutely avoided zooms in most situations I have found since buying the D700 that my current favourite is the 35-105 3.5/4.5 twist and push/pull focus/zoom with a secondary close focus adjustment for those tight facial shots.
     
  21. Steven, I completely agree with you. I am disappointed with the autofocus in the D700. I've just purchased this camera two days ago as an upgrade to my D300 and I have issues with the autofocus. It hunts forever. This never happened to my D300. Last Saturday I got my camera, and today—monday, two days after— I tried to returned it. Unfortunately the manager wasn't there, and they wanted to charge me a restocking fee of 10% after spending almost 2800 with insurance. I'll go tomorrow morning and return to cam. hope that I don't get charged that much. But after all even if it means loosing almost 300 bucks (which I'll be very very sorry after) I'll better wait and save the money for the D3S, hoping that one doesn't have the same autofocus issue. Otherwise I loved the quality of the pictures and the high ISO mode of the D700.
     
  22. What did you end up doing about the autofocus issue? Did you find a way to work around it?
     
  23. ShunCheung

    ShunCheung Administrator

    The D300 and D700 have identical AF systems, but since the D700's sensor area is much larger, those same 51 AF points do not cover the edges of the frame nearly as well. When you use the camera in the vertical portrait orientation, there is no cross-type AF points in the top 1/3 of the frame. That may be the problem you are experiencing.
     

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