Pistnbroke Loc: UK

I just bought a D800 with large back focus issue ( about +40)for about $280 . It takes about 30 min to fix and re align. You need a small cross head screwdriver and a 1/16 or 1.5mm allen key.
Remove the rubber pad from the bottom ..it will go back fine. Stick it on a window so it does not pick up dust.
Remove 7 screws holding the bottom ,Not the 4 near the boss the other 4 (different lengths) and the three around and inside the battery door. The bottom plate will just lift off real easy. Beware the yellow battery retaining latch, if it comes off you will have a pig of a job to get it and the spring back.
If the chassis is cracked it will be on the LHS (viewed from back) at the front of the camera where it bends down . Mine was not cracked so the frame must have been bent.
If the frame is cracked then stabilize the crack with some epoxy but turn the camera the right way up while it sets as if you get any dripping inside you is buggered.
On the front edge of the camera you will see a cutout and also in the circuit board. down inside at 45 degrees are two shiny hex head screws. These are the adjusters for the focus module.
Take a lens that you know the fine focus setting for ,preferably 70mm + .I used a 24-85 which I know needs +2 and I used it at 85mm . Set the backfocus in the menu to +2 or whatever your lens needs.
If you are backfocusing turn each of the adjusters clockwise .I suggest two turns to start with. Then re fit the bottom or you cannot get the battery to stay in ..you only need a couple of screws to hold the base plate and check the back focus with an angled chart in the normal way.
The focus point should be on the scale .use small movements of the adjuster clock or anti clock to get it to zero. You can use any lens from any Nikon provided you know the fine focus adjust figure .the figure is the same when fitted to any camera.
Job done refit the back and don't use the threaded boss again. 30 min if you don't loose the latch spring.
Will try and get some photos tomorrow as I have to re glue the main grip rubber and its best with the base plate off.

turp77 Loc: Connecticut, Plainfield

Great post. Thanks

CO

You're saying that the focus point should be on the scale. What scale are you talking about? I'm not doubting that it works. I'm just not sure which scale you're referring to.

Pistnbroke Loc: UK

When you have moved the module about 2 turns you fit a lens with known FFA .set the fine focus adjust to the known value for that lens on the menu and then re test . The scale is the scale on the chart you use to check the focus adjust..you could use a ruler tilted at about 40 degrees. No good using a wide lens you need something 70-200mm, If you are in the UK you can send your D800 and I will do it for you.

Grahame Loc: Fiji

How did the AF accuracy of the outer upper, outer lower, outer left and outer right focus points compare to the centre focus point after your testing?

mflowe Loc: Port Deposit, MD

Glad you got it fixed. I read your thread yesterday and didn't respond because it was out of my realm of knowledge. A little ingenuity goes a long way.

Pistnbroke Loc: UK

I did a shot of a test chart and it looked good. But as I only shoot at F8 I am not too worried. I turned a pile of scrap into something I can trade in for twice what I paid for it so not too bothered. Of course every impact damaged camera will be different but if you own it and it wont work then its worth a go if you have the manual dexterity.

Nicholas DeSciose

Send a Camera to Nikon there’s too many things wrong with it to try to fix it Yourself, they may offer you a refurbished one for a reasonable price