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Niet dat ik hier een oorlog wil starten want ik heb zelf een D80 en hou ervan als van een baby, maar bij mijn onderzoek of ik al dan niet een backfocus probleem had, reageerde er iemand als volgt, het komt van deze persoon : http://www.flickr.com/photos/maiasuvi/ , toch niet de minste, en heeft zelf dus de volgende ervaring:
Actually, in the professional portraiture forums I'm on, this has come up frequently with the Nikons in the D80 class (D200, D80, Fuji S5). The autofocus mechanism isn't backfocusing so much as it is not finding the correct contrast point within your af area and so guesses - wrongly in all too frequent cases.
It's not something that most D80 owners will notice since they rarely shoot wide open or even close. But for portraiture, I tend to shoot at F/1.4 nearly all the time, and this becomes a serious problem.
With my 50mm, I had a 50-50 chance that the camera would get a full body subject (e.g., distance) shot in focus using the center focal point. Using the outer focal points, which are weaker single axis sensors, yielded a horrific less than 25% success ratio. With the 24mm, I gave up on any distance shots at all - more than 5 feet from the subject and it would focus on anything but my subject (it was actually quite impressive how it never found my subject's contrast points).
I did my tests - putting my standing subjects near and far from high contrast areas, using tripod and remote to eliminate shake (which wouldn't be a case anyway because part of the picture IS in focus), Using the AF modes, changing lenses, testing portrait vs landscape abilities (putting the subject paralell or perpendicular to the af sensors), etc.
Honest, even at F8 my camera couldn't consistently hit focus on the side of a barn. It was ridiculous. Especially considering the D50 was flawless.
Since a) the problem isn't a consistent backfocus or a consistent front focus error (rather, it's just the camera failing to find the contrast point of your subject), and because the problem tends to be stronger on some cameras than others, it looks like this is a quality control issue. Friends who had the same problem with their D200 and I both documented the problems and tried to get the cameras fixed. But we were refused service because they could not find an error in the camera (e.g., they are not acknowledging a quality control issues).
So no, I don't think it is the lens and I don't think it is backfocusing/front focusing that is the problem. And your focus test is fine - the front of the word should be a little out of focus in the front - that's how cameras work. The issues appears to be more about the single axis sensors not being capable of consistently finding a contrast point of your subject. Put them even a bit of distance from the camera and it is going to start finding other more interesting objects to lock focus onto.
In keeping with this, low light also affects focus because that dims the contrast points - so the camera goes for the lighter areas.
I personally could find no justification to upgrade to the D200 since it has the same AF system. So I've sold my D80 now and have bought a Canon outfit. Nikon service lost my trust and confidence over these quality issues (my 50mm 1.4 purple fringed so strongly that my subjects were glowing purple).
Heeft er hier iemand anders een objectieve mening over ervaring mee? Liefst geen canon-nikon propaganda...
Actually, in the professional portraiture forums I'm on, this has come up frequently with the Nikons in the D80 class (D200, D80, Fuji S5). The autofocus mechanism isn't backfocusing so much as it is not finding the correct contrast point within your af area and so guesses - wrongly in all too frequent cases.
It's not something that most D80 owners will notice since they rarely shoot wide open or even close. But for portraiture, I tend to shoot at F/1.4 nearly all the time, and this becomes a serious problem.
With my 50mm, I had a 50-50 chance that the camera would get a full body subject (e.g., distance) shot in focus using the center focal point. Using the outer focal points, which are weaker single axis sensors, yielded a horrific less than 25% success ratio. With the 24mm, I gave up on any distance shots at all - more than 5 feet from the subject and it would focus on anything but my subject (it was actually quite impressive how it never found my subject's contrast points).
I did my tests - putting my standing subjects near and far from high contrast areas, using tripod and remote to eliminate shake (which wouldn't be a case anyway because part of the picture IS in focus), Using the AF modes, changing lenses, testing portrait vs landscape abilities (putting the subject paralell or perpendicular to the af sensors), etc.
Honest, even at F8 my camera couldn't consistently hit focus on the side of a barn. It was ridiculous. Especially considering the D50 was flawless.
Since a) the problem isn't a consistent backfocus or a consistent front focus error (rather, it's just the camera failing to find the contrast point of your subject), and because the problem tends to be stronger on some cameras than others, it looks like this is a quality control issue. Friends who had the same problem with their D200 and I both documented the problems and tried to get the cameras fixed. But we were refused service because they could not find an error in the camera (e.g., they are not acknowledging a quality control issues).
So no, I don't think it is the lens and I don't think it is backfocusing/front focusing that is the problem. And your focus test is fine - the front of the word should be a little out of focus in the front - that's how cameras work. The issues appears to be more about the single axis sensors not being capable of consistently finding a contrast point of your subject. Put them even a bit of distance from the camera and it is going to start finding other more interesting objects to lock focus onto.
In keeping with this, low light also affects focus because that dims the contrast points - so the camera goes for the lighter areas.
I personally could find no justification to upgrade to the D200 since it has the same AF system. So I've sold my D80 now and have bought a Canon outfit. Nikon service lost my trust and confidence over these quality issues (my 50mm 1.4 purple fringed so strongly that my subjects were glowing purple).
Heeft er hier iemand anders een objectieve mening over ervaring mee? Liefst geen canon-nikon propaganda...
Anderzijds in halfduister gaat 'm een muur met behangpapier en een motiefke zonder probleem en zonder hulplicht locken 
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