“Loose fit” at the bayonet as a possible culprit for DBS?

After about 5000 exposures I also experienced the infamous DBS. I’ve got problems mostly with my 70-200/2,8 VR with normal camera batteries as well as with the MB-D10 too but sometimes other lenses were also involved into the problems... My 70-200 had a substantial “play” at the bayonet. I could twist the lens at least 1 mm in the locked position!

The low battery warning could be “cured” either with an exposure or switching the camera off and on again. I cleaned the contacts but I really can not tell if it helped or it was just the “normal laps” between the normal functioning periods and the bad ones… Anyhow I decided to send the camera to the service.

The turn around time was a week and my camera is back now. So far everything is working fine! The service description says that they changed the lens contacts… The interesting thing is that after the service my 70-200 is rock solid in the bayonet! I suppose that they changed the bayonet too even if they were just talking about the electrical contacts… There were some threads about that the 70-200 has a “normal” twist when it is locked into the bayonet… I do think that this “loos fit” can be the culprit of the DBS at least in some cases… Please look up with the “normal twist” when a lens is connected. It is obvious for me that it should not be any "loose connection" at all there… Of course time will tell if my problem is solved or not but the feel of the lens connection is right now and so far no DBS symptoms here…

--
'If you can keep your head when all about you are loosing theirs...' Kipling
Pbase supporter: http://www.pbase.com/ilsmag

I haven't had the DBS, yet anyway. I do have the slop in my mount though and when reading of the DBS issue, wondered if this might be a factor.

are starting to get a handle on it.
That is good.

--
Sam
http://www.samjsternphotography.com

I have the same loose feel at the bayonet mount when my 70-200mm VR is fixed on my D300.

Curiously, there is no sloppy feel when the same lens is mounted on my D200.

hmmmm!

Take a look at the width of the contact pads and then consider just how limited the total amount is that the lens can rock in the mount. After all, the locking pin is only about 1.5mm in diameter. Which means that if the pin in your camera were 1/2mm undersize, which is huge amount in engineerinig terms, the total increase in free play would be only 1/2mm. And it's a sytem that Nikon has been using since 1959.

Chances are that Nikon did nothing to the lock pin on your returned lens. What is more likely is that they put in some stronger springs in the bayonet and that has increased the friction to the point where you just don't notice that the lens iwill still alow that same total amount of movement. In simple turns it feels tighter because you now have tighter springs.

Now, my theory for the cause of this problem is that when the camera is used with a lens that draws a high level of power, there is a component in the camera that fails. As for why cleaning the contacts seems to help the problem, the answer to that is simple. Anytime you increase the resistance in a circuit, you'll also see in increase in the current thru the circuit if the end device on that circuit demands a specific level of total power. Basically, any added resistance in the circuit increases the load on whatever is failing to the point where it fails.

BTW, for anyone experiencing this problem, I would NOT recomend cleaning the contacts. Because it seems to be initially an intermittent issue, I suspect that the failure is due to something being overstressed to the point where it shuts the camera down. Which means that one possible temporary fix would be to just shut the camera down for 5 or 10 minutes. However, after reading many posts about this problem, that intermittent fault generally leads to a total failure of whatever component is going bad. My feeling is that trying to nurse the camera along by cleaning the contacts is the wrong approach to take. For one thing, eventually your warranty will run out. So if you murse it along for a year, you may take your problem camera past the point where it will be repaired under warranty. Second, instead of seeing a flood of cameras coming in with the same issue, Nikon sees them trickling in. Which may prevent from Nikon admitting to a batch of bad components and extending the warranty for this problem. Bottomline, if your having this problem, you will do every D300 owner a favor by NOT cleaning the contacts and pushing the camera to the point where it fails completely and do it as quickly as possible.

BTW, I have been a loyal Nikon user since 1973 but I am getting a bit tired of the problem launches that Nikon seems to be experiencing. I lived with the D70 for 4 years and always had a worry about the BGLOD causing me to suffer not having it if it failed. Which still hasn't happened but that won't ever remove that nagging little voice from my head. Now I have a D300 which has been problem free but have a new nag to worry about. Frankly, I think that Nikon needs to get back to overengineering their cameras like they did my F2, bought it new in 1973 and now in 2008 it still works perfectly.

To Monte 12345,

Of course I do not know the right answer for the problem but the service hasn´t changed any electrical cicuits in my camera. Anyhow if I would have the problem again I do not have to worry about the warranty thing... My 70-200 fits tight now but the funny thing is that all my other lenses had a tight fit before this service too... Why just the 70-200 was loose...???
--
'If you can keep your head when all about you are loosing theirs...' Kipling
Pbase supporter: http://www.pbase.com/ilsmag

I am doubtful....My camera was retruned from service with 70-200 repaired and D300 checked and cleaned and was no snugger a fit, possibly even less snug, in that it rotates on and latches more smoothly.

Without word from Nikon on any culprit unfortunately..this is just grasping at straws.

John

And it's pretty obvious. If only the 70-200 was "loose" on your camera before the repair and all your other lenses were "tight", then the only logical conclusion is that your 70-200 had a defective mount. But then, you didn't say a thing about sending your lens in along with your camera. Which leads me to conclude that you only sent in the camera.

So, why would stronger springs tighten the lens up? Simple, they provide enough friction to overcome the effect of the increased leverage that a lens as large as the 70-200 can provide. To put it simply, stronger springs give you a snug enough fit that you just don't notice the free play because more force is required to move the lens than you would normally apply to a lens that is locked in place.

Hopefully Nikon actually did an effective repair on your camera. However, I do have to wonder about that if they didn't replace any electonic components. My huch is that they have something in the power circuit that is failing when it's exposed to a heavy curent drow for an extended period of time. Unfortunately, if you sent your camera in while the problem was still at the intermittent stage, they may not have been able to duplicate the problem and basically did nothing to your camera. In which case you'll probably see this problem again. In which case I would suggest taht you flog the camera until it's totally dead without any glimmer of recovery and then send it in with a note letting them know that you are NOT happy.

However, I have seen some a couple of posts that this probem may be caused by a bug in the battery sensing software. If that is the cause, it would be a problem that could be fixed with a firmware update. Not sure if I beleive that because Nikon could avoid a lot of bad publicity with a firmare update, which has not happened. But, just to cover all the bases, how about posting the A and B versions of the firmware that is installed in your camera so we can compare notes.

Laci55 said:

The low battery warning could be “cured” either with an exposure or
switching the camera off and on again. I cleaned the contacts but I
really can not tell if it helped or it was just the “normal laps”
between the normal functioning periods and the bad ones… Anyhow I
decided to send the camera to the service.

Click to expand...

See my recent post on the low battery indication. I am waiting for it to return from Nikon but your problem sounds similar to what I experienced using my 70-300 VR and 18-135.

http://forums.dpreview.com/forums/read.asp?forum=1039&message=28259269

To Monte12345. Thank you for your explanation. Yes, you have right. I sent just the camera body to the service. Your theory about the stronger springs could be right but why would a lot of 70-200 have a better or worse tolerances as far as the bayonet connection concerned? (Lot of people is talking about that their 70-200 has not so firm connection to the camera than the other lenses…) Thank you for your suggestion too! Yes, if I would have trouble again I will follow your advice. My firmware version are: A: 1.02 B: 1.00.
Thanks to you and to every one who is contributed to this thread!

--
'If you can keep your head when all about you are loosing theirs...' Kipling
Pbase supporter: http://www.pbase.com/ilsmag

johnrg said:

Without word from Nikon on any culprit unfortunately..this is just
grasping at straws.

Click to expand...

And many like to do just that! lol

Laci55 said:

(...) but why would a lot of 70-200 have a
better or worse tolerances as far as the bayonet connection
concerned? (Lot of people is talking about that their 70-200 has not
so firm connection to the camera than the other lenses…)

Click to expand...

Like Monty12345 said: it is not that the 70-200 has a bajonet that is significantly worse than other lenses. It's just that, given the weight and size of the 70-200 the amount of torque that the bajonet has to cope with is so large that play becomes noticeable.

Other big lenses probably have the same issue (80-400, 300/2.8 etc) but those lenses are not as popular as the 70-200.

Further on, if the problem is indeed power related, those other big lenses might not have the power consumption of the 70-200 because they're not AF-S VR lenses (both AF-S AND VR require a good amount of juice flowing through the contacts). The 80-200 is big and heavy, sure, but most versions are not AF-S and none is VR so it doesn't consume enough power to trigger the problem.

So, assuming that you DO need a large and heavy VR (afaik all vr's are af-s, right?) among all other conditions to experience DBS, the law of numbers come into play: the 70-200VR is likely by far the most popular lens in that segment that qualifies, making it seem like a 70-200VR problem.
--
Cheers,
Bart

The longer the pry bar, the more leverage you have to overcome resistance. That 70-200 f2.8 is a pretty large lever, in lens terms. So, it's not too surprizing that any weakness in the springs in the bayonet mount will be most apparent with this lens. It's also heavy enough that if someone were to try and support both camera and lens by the body alone, the springs at the top of the lens mount will probably be completely compressed and an observant person may notice that the lens is actually pulled away from the mount at the top. Basiclly, it's a lens that requires that the lens always be supported, either by the left hand or by a tripod. Otherwise, the lens will probalby be slightly cocked in the mount and cause a slight difference in sharpness from top to bottom.

You don't even have the issue yourselves, yet you're urging someone else who does to push their camera to component failure rather than clean their freaking contacts???

That is very bad advice that sounds not a little bit sadistic to me, when a simple workaround is available that takes works most all of the time, takes very little effort and costs next to nothing.

Furthermore, if this issue were simply about spring pressure in the bayonet mount, it would have been easily remedied many months ago.

Ivan J. Eberle

Unless something has changed, if you introduce resistance into a constant voltage circuit things don't demand more "power" and get it. E = IR tells us that because E (battery voltage) didn't change, current (I) actually goes down when R (resistance) goes up.
--
Best regards, Johnny

monte12345 said:

Take a look at the width of the contact pads and then consider just
how limited the total amount is that the lens can rock in the mount.
After all, the locking pin is only about 1.5mm in diameter. Which
means that if the pin in your camera were 1/2mm undersize, which is
huge amount in engineerinig terms, the total increase in free play
would be only 1/2mm. And it's a sytem that Nikon has been using
since 1959.

Chances are that Nikon did nothing to the lock pin on your returned
lens. What is more likely is that they put in some stronger springs
in the bayonet and that has increased the friction to the point where
you just don't notice that the lens iwill still alow that same total
amount of movement. In simple turns it feels tighter because you now
have tighter springs.

Now, my theory for the cause of this problem is that when the camera
is used with a lens that draws a high level of power, there is a
component in the camera that fails. As for why cleaning the contacts
seems to help the problem, the answer to that is simple. Anytime you
increase the resistance in a circuit, you'll also see in increase in
the current thru the circuit if the end device on that circuit
demands a specific level of total power. Basically, any added
resistance in the circuit increases the load on whatever is failing
to the point where it fails.

Click to expand...

According to your theory all power lines on poles around the world should self destruct as the infinitively high resistance would cause a huge current flow.

Nice theory unfortunately it is flawed.

Increasing resistance in any circuit DECREASES current flow.

Take an AA battery and connect a 10,000 Ohm resistor between the contacts

Asuming the battery delivers 1.5V the current will be

I = E/ R

I Current
E Voltage
R Resstance

in this case 1.5 / 10,0000 = 0.00015 Amps

Do the same thing with more resistance, say 20,000 Ohms and the result is

1.5 / 20,0000 = 0.000075 Amps, HALF the current flow

Doubling the Resistance results in HALF the current flow.

Clean ALL the contacts and move on IS the correct solution.

See this post on D3 forum

http://forums.dpreview.com/forums/read.asp?forum=1021&message=28261046

You cannot have a lens mount with zero play else you would find it near impossible to change lenses.

monte12345 said:

BTW, for anyone experiencing this problem, I would NOT recomend
cleaning the contacts. Because it seems to be initially an
intermittent issue, I suspect that the failure is due to something
being overstressed to the point where it shuts the camera down.
Which means that one possible temporary fix would be to just shut the
camera down for 5 or 10 minutes. However, after reading many posts
about this problem, that intermittent fault generally leads to a
total failure of whatever component is going bad. My feeling is that
trying to nurse the camera along by cleaning the contacts is the
wrong approach to take. For one thing, eventually your warranty will
run out. So if you murse it along for a year, you may take your
problem camera past the point where it will be repaired under
warranty. Second, instead of seeing a flood of cameras coming in
with the same issue, Nikon sees them trickling in. Which may prevent
from Nikon admitting to a batch of bad components and extending the
warranty for this problem. Bottomline, if your having this problem,
you will do every D300 owner a favor by NOT cleaning the contacts and
pushing the camera to the point where it fails completely and do it
as quickly as possible.

BTW, I have been a loyal Nikon user since 1973 but I am getting a bit
tired of the problem launches that Nikon seems to be experiencing. I
lived with the D70 for 4 years and always had a worry about the BGLOD
causing me to suffer not having it if it failed. Which still hasn't
happened but that won't ever remove that nagging little voice from my
head. Now I have a D300 which has been problem free but have a new
nag to worry about. Frankly, I think that Nikon needs to get back to
overengineering their cameras like they did my F2, bought it new in
1973 and now in 2008 it still works perfectly.

Click to expand...

--
Inspector Kluso

Bascially, if you suspect a weak link in a chain, it's much better to test that chain to it's full rated capacity than ignore it and hope that it doesn't break when you need it the most.

Common symptoms for DBS.

1) It starts out as an intermittent issue that is temporarily fixed by turning the camera off and then on again. Re-seating the lens also seems to help but I suspect that is most likly due to most users turning their camera off when mounting a lens. so, it's quite possible that it's the act of turning the camera off that temorarily clears the problem. However, rotating the lens against the contacts for the lens will act to provide some friction cleaning so this may end up being a combination of both actions. Cleaning the lens contacts seems to provide a temporary fix but in the posts that I have read it only extends the period between the first intital problem and total failure. In general, total failure seems to occur somewhere between 4000 and 7000 picutres, with 5000 pics being given as the most common threshold.

2) It seems to happen most often with cameras that are used with either the 70-200mm f2.8 VR or the 200-400mm f4 VR. Both large an heavy lenses which probably require and additional amount of current in order to move the focusing elements and the elements that provide the VR. Simple logic would dictate that these moving elements are considerably more massive than the same type of elements in a lens like the 18-55mm VR. BTW, simple Newtonian Physics dictates that Force = Mass x Acceleration. And Power = Force expressed over an interval of Time. So, simple Physics dictates that moving a heavier object at the same rate as a lighter object will require more power. So, these two lenses are probably the two lenses in common usage that draw the most current from the D300. However, in this thread I now see that there is also one 70-300 VR involved in this issue so this problem is not totally limited to the usage of these two lenses.

My conclusion is that this problem has an electronic cause. Most likely due to something overheating to the point where the circuit shuts down. My personal hunch is that it's related to current draw instead of an over voltage failure. Most lectronic components exposed to excess viltage levels fail immediately. Over current failures cam sometimes cause a circuit to overheat without a total burnout. Which is what seems to be happening here. Unfortunately, overheating an electronic circuit usually weakens it and at some point it will fail completely.

As for my advice being "sadistic", it's not, it's simple self interest. I want this problem acknowledged and corrected. It's also based on a pretty fundemental aspect of Engineering. Something that Nikon should have done, or didn't do throughly enough. That is Test To Failure. It's the basic principle used in order to determine the Mean Time Before Failure. Thomas Edison used these tests when he was discovering how to make a light bulb that would last long enough for a viable commercial product. So, it's nothing new. Unfortunately, it now seems that we are the testers. So, while it may seem sadistic, it is in our best interest that we push Nikon into acknowledging the problem as quickly as possible and come up with a permanent solution.

Of course Nikon could do something that would probably help nip this problem in the bud. That is come clean and publish just how many cameras have failed due to this issue and specifically state the cause and their plan of action. Which they haven't done at this point. One big negative about the internet is that it can act like an amplifier for an issue like this and blow the whole problem up to immense proportions when it is in fact a rare occurance.

I have a condition where sometimes I feel like I'm going to faint and the feeling goes away in about a minute. A doctor told me that this condition can be caused by and probably in my case IS caused by the brain incorrectly determining that my blood pressure is too low and trying to make adjustments that cause a drop in blood pressure to compensate. This results in an abnormal decrease in blood supply to the brain which causes the feeling that I'm about to faint.

So my brain is constantly monitoring blood pressure like the D300 is constantly monitoring the condition of its battery. And I feel that there's a glitch in the firmware that causes the camera to determine that a perfectly good battery with a full or nearly full charge is faulty or has very little power remaining --- so the camera makes an unnecessary adjustment and shuts down. This camera has taken monitoring of its battery to new levels of refinement, even reporting how far the battery is along in its expected useful life. When you add complication to something there's a greater liklihood that something will go wrong -- this is a true statement. And I'll bet that this new system has its flaws --- that they could be worked out --- and that if the system could revert back to a simpler system that only showed you how many bars you had on a display but didn't go into all the complex checking on condition, etc. and shutting the camera down that this DBS would not exist. The similarity is that my brain is erroneously reporting that my blood pressure is high when in fact it is fine and the D300's brain is reporting that the battery is bad or has a low charge when in fact it is fine.

I have just started to experience the DBS on my D200. I first noticed it a few weeks ago while on hloidays, it only happened a couple of times when using my 70-200. At the time I thought the lens was little looser than I remebered. This past week while shooting again with the same combo I started to get the DBS more and more. I found that if I twisted the 70-200 slighty or pushed up slightly on the lens the low battery indicator would go away.

Camera and lens will be going into Nikon when I get home in a week.

monte12345 said:

Take a look at the width of the contact pads and then consider just
how limited the total amount is that the lens can rock in the mount.
After all, the locking pin is only about 1.5mm in diameter. Which
means that if the pin in your camera were 1/2mm undersize, which is
huge amount in engineerinig terms, the total increase in free play
would be only 1/2mm. And it's a sytem that Nikon has been using
since 1959.

Chances are that Nikon did nothing to the lock pin on your returned
lens. What is more likely is that they put in some stronger springs
in the bayonet and that has increased the friction to the point where
you just don't notice that the lens iwill still alow that same total
amount of movement. In simple turns it feels tighter because you now
have tighter springs.

Now, my theory for the cause of this problem is that when the camera
is used with a lens that draws a high level of power, there is a
component in the camera that fails. As for why cleaning the contacts
seems to help the problem, the answer to that is simple. Anytime you
increase the resistance in a circuit, you'll also see in increase in
the current thru the circuit if the end device on that circuit
demands a specific level of total power. Basically, any added
resistance in the circuit increases the load on whatever is failing
to the point where it fails.

BTW, for anyone experiencing this problem, I would NOT recomend
cleaning the contacts. Because it seems to be initially an
intermittent issue, I suspect that the failure is due to something
being overstressed to the point where it shuts the camera down.
Which means that one possible temporary fix would be to just shut the
camera down for 5 or 10 minutes. However, after reading many posts
about this problem, that intermittent fault generally leads to a
total failure of whatever component is going bad. My feeling is that
trying to nurse the camera along by cleaning the contacts is the
wrong approach to take. For one thing, eventually your warranty will
run out. So if you murse it along for a year, you may take your
problem camera past the point where it will be repaired under
warranty. Second, instead of seeing a flood of cameras coming in
with the same issue, Nikon sees them trickling in. Which may prevent
from Nikon admitting to a batch of bad components and extending the
warranty for this problem. Bottomline, if your having this problem,
you will do every D300 owner a favor by NOT cleaning the contacts and
pushing the camera to the point where it fails completely and do it
as quickly as possible.

BTW, I have been a loyal Nikon user since 1973 but I am getting a bit
tired of the problem launches that Nikon seems to be experiencing. I
lived with the D70 for 4 years and always had a worry about the BGLOD
causing me to suffer not having it if it failed. Which still hasn't
happened but that won't ever remove that nagging little voice from my
head. Now I have a D300 which has been problem free but have a new
nag to worry about. Frankly, I think that Nikon needs to get back to
overengineering their cameras like they did my F2, bought it new in
1973 and now in 2008 it still works perfectly.

Click to expand...

I can't figure out why you sit and worry about the problems others are experiencing when it has not happened to you. You should be thankful. Do you worry about the transmission on your car failing as well because other owners with the same cars have failed. Your logic makes no sense. I think i am gong to start worrying about the oxygen sensor on my Honda failing because i know this guy who knows this guy whose oxygen sensor failed!!!