D300 won't AF, needs +5 EV compensation to produce decent image

I recently picked up a used D300 body and a used 18-200 VRII lens to use with it. When the body arrived, I checked basic functionality using my old Tamron 18-200 AF (non-VR) lens, and the autofocus seemed to be functional. Today, the used Nikkor 18-200 VRII arrived, and now the D300 appears to have no AF functionality at all. The seller reports no known issues with it in this area, and there are other areas of wonkiness apparent as well; auto ISO produces images that are multiple stops underexposed. Compensating with a +5 exposure compensation produces an acceptable result, but that much should not be needed outside of unusual situations.

 

I have already tried restoring the factory defaults for all settings, updating the firmware to the latest version (from 1.10 to 1.11) and carefully checking the position of all switches on the body and lenses; nothing is set in a manner that ought to cause AF to be nonfunctional, but that's the major issue - with the need for EV overcompensation second.

 

I'm leaning toward a diagnosis of "Body needs professional attention", but given that such devices often have Known Quirks which can be dealt with less extravagantly, I'm hoping that people with more experience will be able to point me at the necessary magic if it exists.

One addendum: In the interim, I had tried a different Nikkor 18-200 of questionable state of functionality, and nothing on it appeared to work at all. I can't think of a way that briefly mounting a nonfunctional lens on the D300 might have bollixed its works, but people more familiar with the internal tech might.

Have you also checked and cleaned all the contacts on the lens and camera body?

Did you already try a new or different battery, and/ or charger ?

Some chargers seemed to have a problem not charging propperly, while indicating a fully charged battery

Old batteries can be reported by the camera as being fully charged, but just do not Always deliver the required power..

( i have experienced both in the past with my former D300...)

 

Lastly : Check the switch on the right side of the mount ( looking from the front of the camera) ), and move it a few times in all 3 positions …?

I too would check the basics first:

• Clean the electronic contacts around the lens mount, on both the body and the lenses
  
• Make sure that all AF/MF switches are switched to AF, again on both the body and on the lenses
  

How does it look through the viewfinder? Is it dark?

 

What happens when AF doesn't work? Do the AF indicators in the viewfinder flash, or does it just give one indicator and refuse to focus?

 

I'm wondering if the stop down lever on either the body or the lens is damaged. This would cause the lens to remain fully closed, which of course would probably result in underexposure. The AF module also PROBABLY wouldn't be able to function(I don't know specs offhand for the D300, but even the most sensitive AF sensors in an array will only work to f/11 or so, and I seem to recall that the best one-center-on the D300 is only good to f/8).

Possible a bad lens?

The view through the finder is bright until the stop-down button is pushed, and then the results are as one would expect, so the body's lever for stop-down is working, but that says nothing about the lens' aperture servo, which appears not to be engaging. Also, I hear nothing from the VR widgetry - which is supposed to be quiet enough that I shouldn't, really. The AF results are the same whether I choose Continuous AF © or Single-Servo AF (S) on the selector next to the lens. Both lenses are in AF-capable switch positions on the lens itself. I have switched the positions multiple times, and the fact that they both work flawlessly on the D60 body seems to rule out a problem forward of the bayonet.

 

I found out some more info from the seller; he had used this body exclusively with older F-mount non-DX (full-format) lenses, and the problems could have been present from day one without his noticing. That seems to indicate a problem in the CPU contacts, maybe a complete disconnect. He was just compensating, and didn't realize that the meter was much farther off than it ought to be. The contacts on the body look good. I'm now suspecting that I just didn't notice the AF/VR/Aperture-control problems when I mounted the Tamron for a couple of minutes initially. All that I really verified was that the shutter worked - and if the metering issue is what I suspect, that the aperture is diving to its smallest level on every shot without the aperture servo setting the required opening, then the fact that the first test shots were in bright daylight would not have shown it.

 

The CPU lens contacts on the body appear clean and pristine with a strong magnifier, in at least as good condition if not better than those on the D60.

 

I suspect that this guy had a body that was faulty from day one, and never snapped. If I had to take an initial guess, I'd be looking for the ribbon cable from the contacts to the body's circuit board to be improperly plugged in, pinched, or damaged. It's apparent that the electronic functions in the lenses are not being driven from the body at all. Ribbon cables are infamous sources of Issues; the electronics themselves tend to be pretty bulletproof, though there are always exceptions.

 

Eh, if I can find a repair manual, I may attempt surgery on this myself. I've fiddled with things at least as delicate and painstaking in the past. If it's just an unplugged cable, that's easy to correct.

I found the repair manual online. The most obvious probable suspect is a bad solder joint to the lens contact ribbon cable, causing all of the powered lens functions to be down. But looking at the degree of disassembly required and the general "you really need to have done this before" nature of certain parts of it, I'm going to haul it to a trusted repair shop tomorrow.

It is merely me, of course, but I would prefer to return and get refund over repair. A used D300 doesn’t worth that much while repair is expensive; repair technician labor cost is high. Hopefully it is not too late to get a refund. Edited July 15, 2018 by ShunCheung

Confirmed: No voltage across the connections for the lens anywhere, and at least two of them should have been at battery voltage with respect to at least one other with the camera switched on. There are several possible causes, but my electronics instincts still point me to the ribbon cable and/or the solder joints to the points on it just above the lens mount. We'll see what the tech says when I haul it over to the repair shop.

It is merely me, of course, but I would prefer to return and get refund over repair. A used D300 doesn’t worth that much while repair is expensive; repair technician labor cost is high. Hopefully it is not too late to get a refund.

 

Agreed with this. If the camera was bought from a shop with any sort of guarantee or warranty, I'd take it back for exchange or refund.

 

My first D300(from KEH) had issues with randomly showing "ERR" and locking up. I called, explained the problem, and got a replacement that worked perfectly.

How Much did you pay for it?

It was bought from an individual on eBay, and I suspect that he bought it in Central America; the owner's manual was in Spanish, though the camera's data screens are all in English. It was just under $150, enough below market price that if I can get it fixed for under a hundred, I'm OK on overall cost. The seller has a good rep otherwise, and he appears to be someone who stepped up to the D300 from one of the mid-70s pre-AF bodies and stayed with his old collection of lenses. (Not gonna say this is a bad idea, because I don't know what or how he shoots, and apparently it worked for him well enough; the shutter count is over 50K.) I'm firmly in the DX camp, though, and the lack of automation is a no-go for me. Yes, from one standpoint, it would be "easier" to return the body and look for a different one, but if the bird in the hand can be taught to fly economically, I don't have to go though all the rigamarole and hassle of shipping and shopping. (Though at the moment, the local big used camera place has a D300 is semi-decent shape for about $225.)

It was bought from an individual on eBay, and I suspect that he bought it in Central America; the owner's manual was in Spanish, though the camera's data screens are all in English. It was just under $150, enough below market price that if I can get it fixed for under a hundred, I'm OK on overall cost. The seller has a good rep otherwise, and he appears to be someone who stepped up to the D300 from one of the mid-70s pre-AF bodies and stayed with his old collection of lenses. (Not gonna say this is a bad idea, because I don't know what or how he shoots, and apparently it worked for him well enough; the shutter count is over 50K.) I'm firmly in the DX camp, though, and the lack of automation is a no-go for me. Yes, from one standpoint, it would be "easier" to return the body and look for a different one, but if the bird in the hand can be taught to fly economically, I don't have to go though all the rigamarole and hassle of shipping and shopping. (Though at the moment, the local big used camera place has a D300 is semi-decent shape for about $225.)

Several things to consider:

How was the camera described? Was it sold "as is"? Of not, did seller indicate that it functions normally? If it's supposed to work properly then ... (1) You may return and ask for a full refund for reason of "Not as described". eBay will definitely support your claim. Or (2) If the defect is acceptable to you, communicate with seller for a partial refund if you would rather save the trouble of returning it. (3) Call eBay Customer support to ask for suggested options and how to proceed (1 (866) 540-3229). Good luck.

 

I still have a D300 and a D300s and both function well with any lens.

I seem to remember there is/was the ability to add internal exp. comp. that is NOT reset by 'restore to factory' settings??