Help ! autofocus problem (not backfocus) ?

mike76 · May 2, 2004

Hi all,

I noticed something with my D70 (kit lense) some of my pictures (let's say 2 over 5) are unsharp. What ever the speed i use, what ever if the subject is moving or not sometimes it guets unsharp lokks like some blur.

I did some test today with my girlfriend, she is not moving at 1/250 4.5 and the photo is a little blur (everywhere in the picture). You don't really notice it at 50 % for example, but at 100 % you see the blur. I took the same picture (same spot) at 1/100 and 4.5 and it's very sharp.
What's wrong ?

Thanks

Terry2 · May 2, 2004

Could be a broad range of things, or could be nothing. You have to post some shots as examples, with the settings that you were using for the shot. Not just the shutter speed and stuff, but also the AF mode, the focus area your using, etc. Without this people could only really guess.

mike76 said:
Hi all,

I noticed something with my D70 (kit lense) some of my pictures
(let's say 2 over 5) are unsharp. What ever the speed i use, what
ever if the subject is moving or not sometimes it guets unsharp
lokks like some blur.
I did some test today with my girlfriend, she is not moving at
1/250 4.5 and the photo is a little blur (everywhere in the
picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Thanks

Kerry Pierce · May 2, 2004

mike76 said:
picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Just guessing, but it sounds like it could be camera shake. Could also be just a misfocus. Make sure you're not in closest subject focus mode. Try as smooth a shutter release as you can and you might want to try changing your focus mode to single, if it's not already there. Might be a stupid question, but are you waiting for the green focus light each shot?

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

mike76 · May 2, 2004

Well when i press the button i hear the bip noise. I'm in Selectiv auto focus. For example I use af-s, my girlfriend is sit, i use the centre bracket and take focus right between the eyes, i heard bip i shoot (1/250 4.5) this one is blur. For the second picture i use the same thing but i set the camera at 1/100 and focus also between the eyes (center bracket too), and this one is not blur. I don't understand...
I don't think it's hand shaking at 1/250, i think it's more like a misfocus.

I don't know how to post picture (they are large 3mo) and you only notice it at 100%.

Kerry Pierce said:
mike76 said:

picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Click to expand...

Just guessing, but it sounds like it could be camera shake. Could
also be just a misfocus. Make sure you're not in closest subject
focus mode. Try as smooth a shutter release as you can and you
might want to try changing your focus mode to single, if it's not
already there. Might be a stupid question, but are you waiting for
the green focus light each shot?

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

Kerry Pierce · May 2, 2004

mike76 said:
I don't think it's hand shaking at 1/250, i think it's more like a
misfocus.

That's what it sounds like to me. But, it is difficult to say with the information I have.

mike76 said:
I don't know how to post picture (they are large 3mo) and you only
notice it at 100%.

Yes. That can be a problem. You need an editor to crop out a section of the photo to demonstrate the problem you see vs one of your images that you like. Then you need to post them somewhere on the web that will allow you to link here, like pbase.

A couple of other questions come to mind. Sharp focus is subjective and means different things to different people. If you only notice it at 100%, perhaps it is just softer than you expected, rather than misfocus. If you don't have an image editor, try bumping up the sharpness settings in the camera to high and see if that solves your problem.

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

mike76 · May 2, 2004

Thanks kerry for your help.

Kerry Pierce said:
A couple of other questions come to mind. Sharp focus is subjective
and means different things to different people. If you only notice
it at 100%, perhaps it is just softer than you expected, rather
than misfocus.

Well, my girlfriend noticed it too, and she really doesn't care about this kind of stuff.

Kerry Pierce said:
If you don't have an image editor, try bumping up
the sharpness settings in the camera to high and see if that solves
your problem.

Well i don't think i need to increase the sharpness because some picture are very sharp and some a little blurry...

I noticed something weird : i was testing the camera, i heard the bip (in the viewfinder everything were ok), but instead of taking the picture i repressed half way another time and the camera focus a little better (i noticed it in the viewfinder...) so tha't mean the 1st picture would be a little blurry, that's why i think the af misses focus...
I can send you the picture if you want 2*3 mo).

Kerry Pierce said:
mike76 said:

I don't think it's hand shaking at 1/250, i think it's more like a
misfocus.

Click to expand...

That's what it sounds like to me. But, it is difficult to say with
the information I have.

Kerry Pierce said:

I don't know how to post picture (they are large 3mo) and you only
notice it at 100%.

Click to expand...

Yes. That can be a problem. You need an editor to crop out a
section of the photo to demonstrate the problem you see vs one of
your images that you like. Then you need to post them somewhere on
the web that will allow you to link here, like pbase.

A couple of other questions come to mind. Sharp focus is subjective
and means different things to different people. If you only notice
it at 100%, perhaps it is just softer than you expected, rather
than misfocus. If you don't have an image editor, try bumping up
the sharpness settings in the camera to high and see if that solves
your problem.

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

Kerry Pierce · May 2, 2004

mike76 said:
Well i don't think i need to increase the sharpness because some
picture are very sharp and some a little blurry...

Based on what you said, I don't think so either.

mike76 said:
I noticed something weird : i was testing the camera, i heard the
bip (in the viewfinder everything were ok), but instead of taking
the picture i repressed half way another time and the camera focus
a little better (i noticed it in the viewfinder...) so tha't mean
the 1st picture would be a little blurry, that's why i think the af
misses focus...

Yes, I think so too. Mine will misfocus at times as well, but it is usually visible in the viewfinder, so I do another half press to fix it. If you're getting a lot of OOF photos, you probably should send it to Nikon for service.

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

mike76 · May 2, 2004

Kerry Pierce said:
Yes, I think so too. Mine will misfocus at times as well, but it
is usually visible in the viewfinder, so I do another half press to
fix it. If you're getting a lot of OOF photos, you probably should
send it to Nikon for service.

Well i think that's what i'm going to do...
Thank you kerry for your help.

Kerry Pierce said:
mike76 said:

Well i don't think i need to increase the sharpness because some
picture are very sharp and some a little blurry...

Click to expand...

Based on what you said, I don't think so either.

Kerry Pierce said:

I noticed something weird : i was testing the camera, i heard the
bip (in the viewfinder everything were ok), but instead of taking
the picture i repressed half way another time and the camera focus
a little better (i noticed it in the viewfinder...) so tha't mean
the 1st picture would be a little blurry, that's why i think the af
misses focus...

Click to expand...

Yes, I think so too. Mine will misfocus at times as well, but it
is usually visible in the viewfinder, so I do another half press to
fix it. If you're getting a lot of OOF photos, you probably should
send it to Nikon for service.

--
my gallery of so-so photos
http://www.pbase.com/kerrypierce/root

sheilsoft · May 2, 2004

Well at an aperture of 4.5 it may just be that the Depth of Focus is too narrow.

Are you taking the shots quite close to the subject, because the closer you are to a subject with a narrow depth of field, small camera movements can make all the difference between staying in focus and not, hence the changes of focus noticed when your press halfway a couple of times.

I would try to get a wider depth of field to play with by adjusting the aperture down to something like F8, which may make the shutter speed too low for hand held, requiring a tripod. Or, because of available light, increase the ISO to 400 or 800 to try to get the better aperture and shutter speed. Moving slightly further back from the subject will also 'stretch' the DOF slightly.

dianec · May 2, 2004

Mike,

What lens and focal length were you using?

Diane

--
http://www.pbase.com/doglover

mike76 · May 2, 2004

I use the 18-70 kit. I took my girlfriend's picture at aperture 4.5 at 1/250 @70mm (i'm sit down to prevent hands shaking) and the picture is blurry.
The same picture 5 sec later @ 1/100 and it's sharp !

I took some ather picture at 60mm or 50mm 1/125 @4.5 some are very sharp and some blurry like a miss focus. (the subject was not moving at all and bright sun).

I did another test last night : i took my computer keybord : i used the center focus area and shot the letter H at 70 mm @4.5 1/100 well the H was blurry and the Y was sharp....glurp !!! 2 shots over 5 were blurry, the 3 others shot were very sharp...

dianec said:
Mike,

What lens and focal length were you using?

Diane

--
http://www.pbase.com/doglover

sheilsoft · May 3, 2004

Trust me... it's your depth of field!

That keyboard shot just proves it. Your lens is only doing what it's designed to do at f4.5. If you want more to be in focus you'll have to step down that aperture. It's just because you are indoors using available light that the camera is selecting the wide aperture. Use a tripod or up the ISO.

mike76 · May 3, 2004

I'm going to do some test with aperture set around 7-8 to see if it change something..

sheilsoft said:
Trust me... it's your depth of field!

That keyboard shot just proves it. Your lens is only doing what
it's designed to do at f4.5. If you want more to be in focus you'll
have to step down that aperture. It's just because you are indoors
using available light that the camera is selecting the wide
aperture. Use a tripod or up the ISO.

Andy Warren · May 3, 2004

Mike

I have a very similar problem, only my problem lies at the wide angle end with the 18 - 70. At 70 mm my images are invariably sharp, at 18 mm I seem to have the same problem you have.

I can set the camera/lens up on a tripod say 3 ft from a subject with ample contrast/detail for normal focusing, initial pressing of the shutter releasea focuses the lens and the green light comes on. However a further pressing of the shutter release engages the auto focus again but the lens focuses on a slightly diferent distance from before. Very inconsistent and in my opinion obviously not at all accurate.

From your last posting the problem you raise with the computer key board shot indicates a similar situation to mine but at different focal lengths?

I have spent several hours today trying to establish what where the problem lies, I am now becoming convinced that my camera body has the dreaded 'back focus' syndrome as well as inconsistent auto focus.
Maybe the two go together?

I have taken a number of shots at 18 mm - 24 mm at varying distances, first with auto focus and then by manually focussing slightly closer than the point indicated by the auto focus. Virtually all of these manually adjusted shots are sharp or sharper than the auto focus equivalents. Boy was I p* when I discovered this.

I phoned Nikon Australia this afternoon and they suggest sending the kit back for investigation along with any samples highlighting the problem. I asked if they were getting many returns of this nature and they indicated that they had had a number of returns for various reasons, focusing was one of them?

Sorry to put a dampener on your situation, maybe your problem IS back focus related???

I just hope it can be rectified!

Andy Warren

mike76 · May 3, 2004

Thanks Andy for your answer, well i called my shop dealer today and guess what, the guy told me some camera came back for focus issue....He's going to call nikon and keep me in touch.

Andy Warren said:
Mike

I have a very similar problem, only my problem lies at the wide
angle end with the 18 - 70. At 70 mm my images are invariably
sharp, at 18 mm I seem to have the same problem you have.

I can set the camera/lens up on a tripod say 3 ft from a subject
with ample contrast/detail for normal focusing, initial pressing of
the shutter releasea focuses the lens and the green light comes on.
However a further pressing of the shutter release engages the auto
focus again but the lens focuses on a slightly diferent distance
from before. Very inconsistent and in my opinion obviously not at
all accurate.

From your last posting the problem you raise with the computer key
board shot indicates a similar situation to mine but at different
focal lengths?

I have spent several hours today trying to establish what where
the problem lies, I am now becoming convinced that my camera body
has the dreaded 'back focus' syndrome as well as inconsistent auto
focus.
Maybe the two go together?

I have taken a number of shots at 18 mm - 24 mm at varying
distances, first with auto focus and then by manually focussing
slightly closer than the point indicated by the auto focus.
Virtually all of these manually adjusted shots are sharp or sharper
than the auto focus equivalents. Boy was I p* when I discovered
this.

I phoned Nikon Australia this afternoon and they suggest sending
the kit back for investigation along with any samples highlighting
the problem. I asked if they were getting many returns of this
nature and they indicated that they had had a number of returns for
various reasons, focusing was one of them?

Sorry to put a dampener on your situation, maybe your problem IS
back focus related???

I just hope it can be rectified!

Andy Warren

Andy Warren · May 3, 2004

Mike

I just did the same test as you did with the key board.

And surprise surprise! It seems that its the 18 - 70 lens that is the problem

as I did the same test with my other AF D nikkors (24/50/28-105/70-300) and they all performed faultlessly, auto focused on the mark and sharp.

The 18 - 70 was inconsistent and only sharp when I manually focused slightly short of the auto point!

I will talk with Nikon tomorrow with a view of returning the lens for testing and hopeful replacement or repair.

Andy

mike76 said:
Thanks Andy for your answer, well i called my shop dealer today and
guess what, the guy told me some camera came back for focus
issue....He's going to call nikon and keep me in touch.

mike76 · May 3, 2004

thx andy, i bring the camera to my shop and there re going to see (someone have had the same problem).

I read in an earlier post that it could be the lense (18-70 kit), well we'll see in a few weeks. I keep you in touch.

Andy Warren said:
I just did the same test as you did with the key board.

And surprise surprise! It seems that its the 18 - 70 lens that is
the problem
as I did the same test with my other AF D nikkors
(24/50/28-105/70-300) and they all performed faultlessly, auto
focused on the mark and sharp.

The 18 - 70 was inconsistent and only sharp when I manually focused
slightly short of the auto point!

I will talk with Nikon tomorrow with a view of returning the lens
for testing and hopeful replacement or repair.

Andy

mike76 said:

Thanks Andy for your answer, well i called my shop dealer today and
guess what, the guy told me some camera came back for focus
issue....He's going to call nikon and keep me in touch.

Click to expand...

ed cheong · May 3, 2004

This happened to newcomers like you and me.
I solved it yesterday. Wasted half hour.
This is the probem.

You have put the camera to select a focus on one of the other areas other than center. Change that back to center.

Then make SURE you lock it by moving the manual switch from * to L.

See your manual. It is there.

mike76 said:
Hi all,

I noticed something with my D70 (kit lense) some of my pictures
(let's say 2 over 5) are unsharp. What ever the speed i use, what
ever if the subject is moving or not sometimes it guets unsharp
lokks like some blur.
I did some test today with my girlfriend, she is not moving at
1/250 4.5 and the photo is a little blur (everywhere in the
picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Thanks

mike76 · May 3, 2004

Ed, all my shots were made with the center focus. I even lock it !

ed cheong said:
You have put the camera to select a focus on one of the other areas
other than center. Change that back to center.

Then make SURE you lock it by moving the manual switch from * to L.

See your manual. It is there.

mike76 said:

Hi all,

I noticed something with my D70 (kit lense) some of my pictures
(let's say 2 over 5) are unsharp. What ever the speed i use, what
ever if the subject is moving or not sometimes it guets unsharp
lokks like some blur.
I did some test today with my girlfriend, she is not moving at
1/250 4.5 and the photo is a little blur (everywhere in the
picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Thanks

Click to expand...

mocca · May 3, 2004

In couple of my pictures on my D70 (returned due to backfocus problem which is not what cause this problem), I had similar problem. I'm not sure if it is the same problem as your or not but in my case, the left side of the picture is blur (very obvious) while the right side is very sharp )both sides are on the same plane and I was taking pictures of buldings). I and my friends who did the shooting with me that day ruled out the DOF or focus problem. It looks like the lens was the culprit. Anyway, it might worth your time to try another lens on your D70 and see if that solve your problem or not.

Mocca

mike76 said:
Hi all,

I noticed something with my D70 (kit lense) some of my pictures
(let's say 2 over 5) are unsharp. What ever the speed i use, what
ever if the subject is moving or not sometimes it guets unsharp
lokks like some blur.
I did some test today with my girlfriend, she is not moving at
1/250 4.5 and the photo is a little blur (everywhere in the
picture). You don't really notice it at 50 % for example, but at
100 % you see the blur. I took the same picture (same spot) at
1/100 and 4.5 and it's very sharp.
What's wrong ?

Thanks

Help ! autofocus problem (not backfocus) ?

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