Eagle BIFs and URGENT AF-S question to birders/tele shooters/trouble shooters!

Started Jan 30, 2013 | Discussions thread
windsprite
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The problem
In reply to windsprite, Jan 30, 2013

Sorry to make this a very long story, but I have little time, so I'm in panicked problem-solving mode and want to include as many details as possible:

I bought the 300/4 second hand a few years ago, and for over a year, I used it happily on fast-moving subjects (as I wrote in my post above, I own two whippets -- race dogs -- with whom my husband and I sometimes do competitive distance frisbee).  Last fall, the AF-S motor died.  A few weeks ago I was invited on this year's eagle-shooting trip, so I rushed the lens to the Nikon service center in nearby Sapporo, and they replaced the motor.  I was too busy to test it outdoors right away, but shots around the house (between 2 and 10 meters) and out my window showed the focus was just about perfect, like before.  Awesome.

Then yesterday I took it out on our deck and tried shooting some objects around my house (I have a cough and fever right now and can't venture out into the wilderness to test this thing).  I live right in the city, so my subjects were urban junk like TV antennae, electrical poles and insulators, crows, airplanes, etc.

Well, I've noticed that the motor is incredibly jittery when shooting at distant subjects, say more than 20 meters, and no matter what I do, I can't seem to get a sharp picture.  I can see through the OVF that the focus is dancing all over the place, but it's mostly the WRONG place.  It makes a stuttery dit-dit-dit clacking noise, and it's busy to the point where I'm afraid it's going to wear out the motor again in no time.  Again, this dancing and clacking does NOT happen indoors, at distances of around 2-10 meters, even in light so ridiculously low that I can barely see through the OVF and definitely can't hold the lens steady enough for the required shutter speed.  The focus is also spot on in these conditions, even with a telecon attached.

I've tried every setting I can imagine, to no avail.  I thought maybe it was my technique or the weird subjects I've been shooting, but get this:  I go indoors and shoot the same outdoor subject through our dirty triple-pane glass windows, and the focus stabilizes, and everything is fine.  Accurate AF, and no clack-clack dit-dit.

I'm using NO filters on the lens.  My batteries (EN-EL3s) are new and fully charged.  The green focus lamp lights up even though the subject is obviously out of focus.

My preferred setting is AF-C, using the AF-ON button.  AF-S reduces the jitter, but the accuracy doesn't seem much better, and anyway, it's a no-go for eagle BIFs.  Single point (my default) or 9-point AF makes no difference.  I normally have the a4 focus tracking with lock-on set to "short," but changing it to "long" doesn't help.  AF-C is on release priority, and I'd prefer not to change that for fast-paced action photos.

I have the problem with and without the teleconverter.  It happens on the D700 and also a second-hand D300 that I bought the other day.  The position of the focus limiter switch makes no difference.  I've only tried center point so far, because that's what I usually use for action.

It is a little chilly outdoors, but only around freezing (it's probably going to be at least -20 below where I'm going next week).  I will stand inside my house and fire off five or six photos of an object through my glass door at 5-6 fps, and almost all will be in focus.  Then I will stay in the same position, swing the door out of my way, and shoot at the same object, and I'll be lucky if one of the frames is even "sort of" in focus.  The difference is obvious even on the back LCD, without zooming in.  Even my husband, who is not particularly into photography, will actually laugh at how bad the images are!  Then I'll close the door, shoot through the glass, and everything will be OK again.  I could be wrong, but I don't think it can be a temperature-related problem, because I'm standing indoors, and it doesn't seem like there would be enough time for the system to expand/contract.

Since the focus is OK through the windows, I have a hard time believing it's a problem with my technique or settings.  I'm also guessing that fine-tuning the AF would do no good?

That's about all the info I can think of.  This might turn out not to be a problem with the real-life photos I intend to take, but it's making me very nervous.  I would be very happy to learn that I am making some stupid mistake and everything will be fine if I correct it, but for the life of me I can't figure out what it might be.

Has anybody heard of anything like this?!

Am I going to have to take a dirty window from my house on my trip or put a cheap and nasty filter on my lens?!

One last thing that occurs to me is, when I took the lens to the service center a few weeks ago, they cleaned my D700 sensor and updated the firmware (I was on the original FW).  Is anybody aware of any FW  changes that might cause problems?

I called Nikon today, and they have no ideas at all what the problem could be, but they said that if I sent in the lens and one of the bodies, they would check it out and kindly lend me their 300/4 display model if they saw a problem with the lens.  However, even if I send everything in tomorrow (Thursday), I won't have the body and lens back until Monday, and I leave on Tuesday.  And what if they *don't* see a problem?!

I have around 14 hours to figure this out before I have to send or take the lens to Nikon.  I will try and post my test samples a little later, but for now I hope the action shots in the post above will at least reassure you that I'm fairly experienced with telephoto lenses.

Thanks in advance for any help offered!

Julie

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