Partial metering problem on 400D

[mhc-art]

Hi all,

I hope you can help with something...

I have recently come back from South Africa, having had six weeks of photography During the time there I had a 3 day course with a professional photographer and though he used Nikon he taught me a little about using partial metering (I think it's spot metering on other cameras). Most of my photos were taking by metering from the lightest point of a subject and then locking this exposure by half-pressing the button and then recomposing the picture before taking it. Though I took some photos I was happy with most were not of the sharpness I had hoped for.

On arriving home I read a guide that covered partial metering, it states that 'this exposure/focus lock technique is only possible using the One Shot AF mode' . I think I used the multiple shot mode on the majority of my shots, could this mean that the exposure/focus lock technique would not work as well?...

I have tried to look at my photo information to see whether I had One Shot AF mode on but it does not give me this information.

Any help would be appreciated!... apologies if you don't quite understand the problem, I've tried to explain as best I can!

[Words]

If you view your photos in the DPP program that Canon provide, right-click on a thumbnail or image and select info. About half way down you should see an entry for 'AF Mode'. This will say whether the photo was 'One-Shot AF' or 'AI Servo AF' (which is the mode which tracks the focus on a moving subject).

Half-pressing the shutter button will lock the focus in One-Shot AF, but won't hold the exposure. For that you need to have pressed the first (left) of the two little buttons on the back of the camera (top right as you hold the camera to your face). Once you've fired the first shot of a burst, the camera will reset so I think it's right to say that the technique won't help for any but the first shot taken in succession. After that the camera will sort of the focus and exposure based on where the partial metering and focus point are. At least, I think that's how it works.

Edit: Just checked further and it seems the AF info only shows if you shoot in RAW. My processed JPEGs don't seem to have the AF info displayed.

[mhc-art]

Thank you words!..

Yes that is the process I used to lock the exposure, it's been a while now since I took the photos so I forgot the details..

Looking at my camera yesterday after posting this I realised a mistake I made in my post, I had the One Shot AF confused, I actually did use One Shot AF on my shots so that is not the problem...

I recently upgraded from 400D to 450D, the 450D has Spot metering and also Partial metering, the 400D only has partial metering and it was partial metering that I used. Could the problem of been that I used Partial metering wrongly as I was advised to use it exactly the same way as for spot metering?

[zan]

If you locked the exposure with the * button on the back of the camera, and then recomposed and locked focus with the shutter release button, it's unlikely that you would have made a mistake.

Also, partial metering and exposure lock in themselves (if used as described above) should only have an effect on the exposure of the image, not the sharpness. If you have done everything right, it might be time to look at the lens? Have you checked that it's focussing correctly since you've come back? Also, if the subject moved at all after you'd locked focus, that might have knocked it off...

I'm just guessing, without having seen your photos it's hard to tell what it could be...

zan