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Automatic focusing with telephoto lens
Jul 22, 2012 11:25:58 #
When I use my 300mm lens the autofocusing has trouble focusing. It goes in and out and won't focus unless I drop down my focal length. What am I doing wrong. We are going to Africa and I'm thinking about buying a 80 - 400mm lens but I am worried that I will have even more trouble with autofocus.
Jul 22, 2012 11:33:32 #
Jul 23, 2012 06:54:46 #
If you are using a Nikon body it may be that the contrast is not significant enough for the camera to grab at that lenght. Try shifting your lens a bit (side-to-side, up-down) to grab a noticible contrast.
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Jul 23, 2012 08:20:30 #
If it does that AND makes a tiny grinding noise, send it back or send it in for repair. My Nikon did that and Nikon replaced it. New lens is great.
Jul 23, 2012 08:29:36 #
gonate
Loc: sacramento,calif
BboH wrote:
If you are using a Nikon body it may be that the contrast is not significant enough for the camera to grab at that lenght. Try shifting your lens a bit (side-to-side, up-down) to grab a noticible contrast.
It's a big question with so little info, more info needed.
Jul 23, 2012 14:49:15 #
You are short on light when you go to the longer zoom. AS you come back to the shorter zoom your diaphram sets in more light and you have enough for the lens to focus. I have a Tamron 28-300 that does the same thing. I just gave up on automatic and go to manual focus. With the limiteddepth of field at the long lengths focusing is not to hard. - Dave
Jul 23, 2012 18:54:04 #
shealinda4 wrote:
When I use my 300mm lens the autofocusing has trouble focusing. It goes in and out and won't focus unless I drop down my focal length. What am I doing wrong. We are going to Africa and I'm thinking about buying a 80 - 400mm lens but I am worried that I will have even more trouble with autofocus.
I frequently have the same situation with my 55-300mm zoom lens.(Nikon lens). I'll drop to about 200mm, auto focus, then go up to 300mm and it will autofocus. I think it something to do with contrast, as was pointed out by someone else.
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Jul 23, 2012 22:27:41 #
gonate
Loc: sacramento,calif
kschwegl wrote:
quote=shealinda4 When I use my 300mm lens the aut... (show quote)
My 70 to 200 mm will do that when it has to much to focus on, It refuses to focus .or it dont know what to focus on.
Jul 23, 2012 23:49:42 #
The Nikon 80-400 is a superb lens with one main drawback. It has no silent wave auto focus motor. This means it is incredibly slow to focus and can't handle really fast action. Also, it will not autofocus at all with some Nikons. If you are not shooting fast action it is an incredible lens.
Also, there are rumors online that it will soon be replaced. It is Nikon's oldest VR lens.
Also, there are rumors online that it will soon be replaced. It is Nikon's oldest VR lens.
Jul 24, 2012 20:27:42 #
I have a Nikon D7000 and the lens is a Nikon AF-SVR 70-300mm f4.5-5.7.
Jul 24, 2012 20:35:48 #
When you say contrast do you mean in color? Also, do you mean that you move where you are standing or side to side and up and down before you take the shot?
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Jul 24, 2012 20:51:25 #
With longer focal length there is a loss of light that cause the autofocus to miss the contrast lines it uses to autofocus. Sometimes increasing the Iso setting will help. The amount of light in f2.8 lens is why they focus faster and better then say f5.0 lens
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