Not able to focus...

[ksong]

Hi proz,
Need some feed back on what I should do.

I recently just sent my D80 for servicing, got it back on Thursday. They did a general checking, clean the CCD and adjusted the press contact (should be for the short cut format button because sometimes it cant work).

For the kit lense, they replaced FPC Unit. Was told that was the problem of the 'F--' issue. Lense fit firmly into the body now and no more 'F--' problem.

Yesterday, I realised that when I try to take a photo of a white wall, or anything that is in one colour (shooting tent blue background cloth too), it cant focus at all. Do you think it normal, should I go back to NSC again? Thanks!

Edit: Edited the Title... to add new 'findings'

[psychobiologist]

Originally Posted by ksong Hi proz, Need some feed back on what I should do. I recently just sent my D80 for servicing, got it back on Thursday. They did a general checking, clean the CCD and adjusted the press contact (should be for the short cut format button because sometimes it cant work). For the kit lense, they replaced FPC Unit. Was told that was the problem of the 'F--' issue. Lense fit firmly into the body now and no more 'F--' problem. Yesterday, I realised that when I try to take a photo of a white wall, or anything that is in one colour (shooting tent blue background cloth too), it cant focus at all. Do you think it normal, should I go back to NSC again? Thanks!

lack of contrast, cannot focus.

there must be some difference in color. try draw a black dot on the paper and then focus

[ksong]

Hi,
Thanks for the reply. I just took this photo of the wall in my room, with light shining in from the window. I used to be able to focus on that, but not any more. I took this using manual focus, which I am still not very good at.

[psychobiologist]

Originally Posted by ksong Hi, Thanks for the reply. I just took this photo of the wall in my room, with light shining in from the window. I used to be able to focus on that, but not any more. I took this using manual focus, which I am still not very good at.

it depends on the light intensity, in dim conditions, like your picture you have shown, it may not focus still.

if you still feel that the camera is unable to focus in such lighting conditions due to a mechanical fault etc, you could probably drop by NSC again.

alternative is to try a fast lens i.e. 50mm f1.8 to see if the focussing is much better

[ksong]

Thanks! I will try to borrow from my friend the lense and try it. Hope I dont have to go back to NSC again.

[Override2Zion]

Originally Posted by ksong Yesterday, I realised that when I try to take a photo of a white wall, or anything that is in one colour (shooting tent blue background cloth too), it cant focus at all. Do you think it normal, should I go back to NSC again? Thanks!

Don't think you'd be able to do that, focusing on a white wall is not a good idea. There might not be enough contrasting details to allow the camera's AF system to perform AF properly. One reason why you might have been able to do that in the past might be because of the intensity of the light, shadows casted on the walls might create sufficient contrast for AF to take place on that wall on a bright day. Try focusing on other stuff under sufficient light. If you're in doubt, no harm paying NSC a visit

[Singer high]

If you are taking photos of anything that is in one colour (eg. sky, clouds) it might be better to use AF-C mode.

[ksong]

Hi,
Thanks for all the reply. I went to office today and asked someone to try it for me and he suggested to go back to NSC. So, now the camera is back there. The technician said they will do a another round of checking on the focusing and also the dark corners on the photos like these below...







Those were taken without any filter or hood, as I was told that filters and hood may cause that to happen. But it still happened. Haiz...

[psychobiologist]

looks a little wierd. but hope it isnt the spot metering/matrix metering that is giving you the pictures

[JacePhoto]

Yeah, when i was using the D80, i also have vignetting problems. But it's always with the lens (18 - 135) and the hood/ filter thats causing the problem.

As for yr 'cant focus' problem, it think its normal. Not all camera can focus on a white wall that well.

[ksong]

erm... can you elaborate more? Cos I had been using spot metering all these while. I am just a beginner... a long way to go. They tested and found this problem... but not sure what mode they using. Thanks!!

[ksong]

Originally Posted by JacePhoto Yeah, when i was using the D80, i also have vignetting problems. But it's always with the lens (18 - 135) and the hood/ filter thats causing the problem. As for yr 'cant focus' problem, it think its normal. Not all camera can focus on a white wall that well.

i tried using my friend's Nikkor 70-210mm 1:4-5.6 D, also having the same problem. Not sure what went wrong. Haiz...

[psychobiologist]

Originally Posted by ksong erm... can you elaborate more? Cos I had been using spot metering all these while. I am just a beginner... a long way to go. They tested and found this problem... but not sure what mode they using. Thanks!!

spot meter will expose the scene based on the lighting/how bright the particular spot you are focussing on in the camera..

matrix metering is an evaluative system that determines how much light average through out the whole scene and captures it..

if you spot meter the wrong areas, i.e. a brighter spot.. the picture can come out under exposed. if you spot meter another wrong area, which is a darker area, the highlights can be over-exposed although the darker area becomes appropriately exposed.. to spot meter accurately.. is to decide for what you want to expose for..

[ksong]

Originally Posted by psychobiologist spot meter will expose the scene based on the lighting/how bright the particular spot you are focussing on in the camera.. matrix metering is an evaluative system that determines how much light average through out the whole scene and captures it.. if you spot meter the wrong areas, i.e. a brighter spot.. the picture can come out under exposed. if you spot meter another wrong area, which is a darker area, the highlights can be over-exposed although the darker area becomes appropriately exposed.. to spot meter accurately.. is to decide for what you want to expose for..

IC, I can understand better now. Thanks a lot. Will try to play with that after the camera come back to me. hopefully soon