D800 with MF lenses

Discussion in 'Nikon' started by shiang_wang|1, Jul 10, 2012.

  1. I received D800 recently and have been testing it with several lenses that I have. AF lenses are working fine, two of my manual lenses have problems, specially 28mm AIS f/2. At the center focus point, the live view and the focus indicator are in sync. At the left and right most focus points, live view and focus indicator do not agree with each other. After I focus in live view, and turn the live view off, the focus indicator in the viewfinder says it is not in focus when it is actually in focus.
    I wonder if anyone has experienced similar issue on manual lens. The other MF lens I have tested is Voigtlander 58mm. On this one, left and right focus point have the same issue, but it is too far off (focus indicator shows circle and an arrow). Suggestions?
     
  2. Which is your method?
    • When you use Live View, do you accurately focus in -exactly- the same area where the right and left AF points are?
    • Are you focusing on a flat surface, using Live View, and then checking the "focus indicator" for the right and left AF points?
    Maybe another?
     
  3. Shiang - I have my D800E at Nikon UK for the third time because of another issue with manual focus lenses - that they all focus beyond infinity. I would be curious to know how your MF lenses work when you look at infinity in Live View with the lens wide open. Have you checked for that yet by any chance?
     
  4. How are you getting the focus point to the right and left parts of the frame Shiang? If you're swinging the camera, then that's where the discrepency is coming from. As you swing the lens left, right, up or down the plane of focus swivels with the camera, so something that was in focus at the centre of the frame will be out of focus if swung to an edge of the frame. This effect gets more and more noticeable as the coverage angle of the lens increases. Plus you have to consider the added (or subtracted) effect of any curvature of field of the lens.
     
  5. First of all, thank you for taking time to reply.
    On my original post, I meant to say the problem on Voigtlander 58mm is not as bad as 28mm. Elliot, on 20mm AFD, the left and right focus point do show a little off, but it is within my tolerance level. I wouldn't worry about it. I am not a pixel peeper, the off focus problem on 28mm is so predominant that I can see it in the viewfinder.
    Jose, my test method is set the camera on a sturdy tripod with 2 seconds timer to confirm what I see in the Live View is what I get in the picture. Aperture is set to the brightest. My target is a book standing a table, the distance is roughly 1-2 meters. I did not move the book, I simply rotated the camera on the tripod so its right/center/left focus point is on the book.
    James I don't have problem with infinite focus. From Live View and the picture, they all look fine.
    Rodeo, your explanation makes sense. But I do re-focus after I change the focus point, the focus indicator (or confirmation) should have been reliable.
    I am thinking about sending it in along with the 28mm for repair, with so many AF left focus issues going on and some don't get fixed the first time. I don't know, maybe I should wait.
     
  6. My target is a book standing a table, the distance is roughly 1-2 meters. I did not move the book, I simply rotated the camera on the tripod so its right/center/left focus point is on the book.​
    If I understand it correctly, the problem is the one Rodeo mentions... when you rotate the camera the plane of focus fall behind the subject. So it should be clearly out of focus.
    If your lens has a field curvature issue, it will probably minimize the focus error. But the method is still wrong.
    I do re-focus after I change the focus point, the focus indicator (or confirmation) should have been reliable.​
    Do you perform the same focus procedure as with the center AF point? The correct procedure is as follows;
    1. Rotate your camera to center the left/right AF point in your subject,
    2. Open Live View to accurately focus over this very same area
    3. Leave Live View
    4. Check if the AF system refocus over this point, or if it stays quiet (the RF aid LED lights).
    If it is OK, the camera is fine. If not, I`d say depending on the error magnitude, it could be right or not.
    Important; although I haven`t tested it on a D800, you should take into consideration that the Electronic Rangefinder Aid system use to work within a margin. It could be that the focus plane is not -exactly- at the point where the LED light "pops". You can test it by yourself;
    1. Set the focus mode to manual (camera or lens)
    2. Set the lens to the minimum focus distance (0.25mts.) and carefully start to move the focus barrel until the RF aid LED lights.
    3. Take a photo
    4. Now, set the lens to infinity, and carefully move the focus barrel until the RF aid LED pops again.
    5. Take another photo.
    Compare them at your photo editor, and take your own conclusions.
     
  7. Jose, I performed the AF test on 20mm AFD just as you described. On left and right focus, it shifts a little when I auto-focus, on the center it is dead on. I can live with it since I don't use 20mm very often, if I do, I can use Live View.
    28mm happens to be the lenses that I use frequently. No matter where I start adjusting focus barrel from, infiinity or the nearest, the pictures look very blur. I have used this lens on F100 for a while, never notice this issue, at least from the hi-res images I scanned myself.
    I found this old thread http://www.photo.net/nikon-camera-forum/00Kt1U and realize it is not an unique problem to me.
     
  8. AF points on the F100 are not that spreaded as with MultiCam 3500. I wonder if the design of "older" wide angle lenses make the things difficult to the current, farthest AF points.
    Check this thread, where a MF 20mm and a 17-55AFS are compared. The prime is simply useless with the RF aid. If it were AF, results could probably be the same. Not with the AFS zoom, at the same setting.
     

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