D50 - Focus help please?

PaulBoy

PaulBoy

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After posting this over in Photo Sharing it was mentioned that the focus seemed to be a bit off on at least one of the shots - I checked the settings for focus on my D50 and find I have the following settings ...
Autofocus: AF-A (further choices of AF-C and AF-S)
Autofocus Area: Closest Subject (further choices of Single Area & Dynamic Area)
When shooting at Slimbridge I was using Speed Priority as I was using my Sigma 100-300mm f4 for the first time (usually on a monopod) & wanted to make sure the beast of a lens wasn't shaking too much! - Typically I was getting this sort of Exif Data:
1/500th sec
f16
300mm
ISO was set to Auto but on this shot is shows 1600 (in fact all images appear to have defaulted to this - on checking the ISO setting it was on 1600 despite the fact that I would never have set it to this? Would setting ISO to Auto have done this?)
I find the focusing side of the D50 a bit of a grey area & it isn't explained well in the manual or in the D50 "Field Guide" either - any help greatly appreciated ... Paul (y)
 
Joe T said:
AF-S is for stationery subjects. AF-C is for moving subjects.
I wouldnt think that the AUTO setting would give ISO 1600. Anyway, I would set it to ISO 200 and change it when you need to.
HTH
Click to expand...
Joe - Thank you - I knew what they meant I just don't know what to use? AF-A means the camera decides whether the subject is static or moving which seemed to be the sensible choice (?)
I'm still unclear about what to set the focus on - Single Area / Dynamic Area / Closest Subject (?) - Again I understand what they mean I'm just unsure about which is best (?)
As to the ISO - I set it to "Auto" so that in poor light I would still be able to get a shot when if set to 200 this would not be possible (other than with a really slow speed or something unusable)
I have never set the ISO to 1600 - Can't work out how that happened (?)
Thanks again ... Paul (y)
 
Joe T said:
AF-S is for stationery subjects. AF-C is for moving subjects.
Click to expand...

Well kind of....

(Not sure which a/f module is in the D50 I know it's different from the D70 etc but most Nikons work like this...)

AF-S is for stationary OR uniformly moving subjects that are in motion when focus is achieved. That's predictive autofocus - the camera says "hang on, that's moving in this direction at this speed" and attempts to predict where it will be when the shutter fires.

AF-C is for erratically moving subjects or ones that start to move after focus is achieved.

AF-A automatically switches from one to another (I'm not sure how and I no longer have a D50 to test this on).

Personally even on relatively fast moving subjects I use AF-S and refocus a fraction of a second before firing (I track it then release, focus and shoot in one motion). With AF-C and all area focus you have to watch out when tracking birds because the bottom focus point can lock onto the ground as they swoop.

I never use auto ISO because of the risk of it doing something stupid and choosing ISO 1600. There's something fancy on the D200 where you can set a minimum shutter speed and let the camera choose iSO to match that which would be more use.

Personally I'd have been at F4 in aperture priority (or more likely manual), AF-S and ISO set to give me a shutter speed around 1/200s or faster.
 
Jonathon - thanks for your informative post which was very helpful ... Paul (y)
 
I wouldn't use auto ISO for the very reason you've described. It will boost the iso to keep a shutter speed that you set when you turn a-iso on.

As for focus mode...

I use AF-c for moving stuff, what you need to remember is that this is a release priority mode. i.e. the camera will take the shot even if focus hasn't locked, although it will try and lock focus inbetween you pressing the release and the shutter opening.

Af-s is a focus priority mode. It won't let the shutter release until the camera has locked focus.

Dynamic, single area and closest subject should be available in both s and c modes....

Dynamic....you chose the focus area, but if the subject moves or is moving when you halfpress the shutter it will use the other focus areas to keep the subject in focus, however, it doesn't update the viewfinder display to show this is what it's doing.

Single area....locks and keeps the focus on that area with no guessing.

Closest subject just locks onto whatever is closest under any of the focus brackets.

AF-c and Dynamic area is what I use for moving stuff

Af-s and single area is what I use for landscape, either that or manual.


HTH?
 
Gandhi - yes helpful in so much as it clears up the ISO side but I'm still not sure what combination of Autofocus type & Autofocus area is best although it appears you should adjust both depending on what you are photographing (?) - keep the help coming ... Paul (y)
 
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