metering question

K

knocker

Suspended / Banned
Messages
470
Name
Barry
Edit My Images
No
i seem to be having problems focusing on moving animals, would i be better using spot metering rather than evaluative metering ? i can't seem to get good focus on the ferrets face, could it be the auto focus getting confused ? would higher shutter speeds help ?

ferret.jpg
 
Choosing spot or evaluative metering will have no effect what so ever on your focussing.

If you are having focussing difficulties it may be worth increasing the depth of field by decreasing your aperture to maybe f5.6. You shot this at f2.8 and 1/640 sec so decreasing the aperture to f5.6 would drop your shutter speed to 1/160 unless you upped the ISO.
 
What focus mode were you using and how many AF points?
 
I use centre point AF for wild life stuff. Gives you a better chance of getting the head/eyes in focus:thumbs: For non static subjects you'll need a shutter speed over 200 or so but a lot depends on the lens, iso, lighting conditions etc.
 
Not convinced that camera shake is not evident in your pic.

Can you provide details:-
Lens
Aperture
Shutter speed
 
Hi Try focusing manualy. For the exposure. If the light is constent. Calaulate correct exposure from test shot. Do not rely on camera to do it all. Best of luck vetonbike
 
If the subject is moving, then A1servo would constantly focus on the moving subject.
 
lens is a 70-200 siggy f2.8
aperture f2.8
shutter 1/640
single shot

i think there may be a touch of shake now i look at it, it was taken hand held and the siggy is a weighty lens, i'll have another go with a higher shutter speed and then with a larger aperture and see what happens, i can always get the tripod out ;) i love this forum, so much help and advice :clap:
 
knocker said:
lens is a 70-200 siggy f2.8
aperture f2.8
shutter 1/640
single shot

i think there may be a touch of shake now i look at it, it was taken hand held and the siggy is a weighty lens, i'll have another go with a higher shutter speed and then with a larger aperture and see what happens, i can always get the tripod out ;) i love this forum, so much help and advice :clap:
Click to expand...

By larger aperture I assume you mean a "larger aperture number".
A larger aperture would be f2, or f1.8 etc and the aperture diameter would be larger. This would give less Depth of Field -not what you want in this situation.
A smaller aperture such as f5.6 will give a smaller diameter aperture and more Depth of Field. :)
 
bloody smelly things
Click to expand...

thats probably what the ferrets think of us too :lol::lol::D


oops, yes i did mean to say a higher aperture number, something around 5.6 as suggested
 
exif said:
# Exposure Time (1 / Shutter Speed) = 1/640 second = 0.00156 second
# Lens F-Number/F-Stop = 28/10 = F2.8
# Exposure Program = action program (high-speed program, fast shutter speed) (6)
# ISO Speed Ratings = 400
# Exif Version = 0221
# Original Date/Time = 2009:02:08 16:00:12
# Digitization Date/Time = 2009:02:08 16:00:12
# Components Configuration = 0x01,0x02,0x03,0x00 / YCbCr
# Shutter Speed Value (APEX) = 614400/65536
Shutter Speed (Exposure Time) = 1/663.98 second
# Aperture Value (APEX) = 196608/65536
Aperture = F2.83
# Exposure Bias (EV) = 0/1 = 0
# Metering Mode = pattern / multi-segment (5)
# Flash = Flash did not fire, compulsory flash mode
# Focal Length = 114/1 mm = 114 mm
Click to expand...

I agree with EdBray, I dont think exposure mode is relevant to focus issues. Although it will change the exposure settings which may have an impact - ie longer shutter speed etc

It looks to me as if the focal plane is behind the ferrets ear and the depth of field is narrow as one would expect at f/2.8.

I notice that exif says 'Action Program', so you're using an auto mode? Try instead using Aperture priority and shooting to get the depth of field you want, or use Shutter priority and experiment to find a speed that captures stuff OK.

Was the ferret moving? how fast? Could you have misfocussed?

As an olympus user I dont know the set up on canon in terms of will it shoot before it gets focus? I know I can set it so that it takes the pic when I press the button - regardless of whether it thinks it has a focus point or not. Nor do I know if the auto settings on the 40D would override that behaviour.

ISO is 400 which I think is another auto setting (lots of canon shots seem to be iso 400 for no good reason, so I assume that its a default of some sort)
 
try f4 or 5 to give you more depth of field

Iso 400 is in the middle of the range not much noise but still v sensitive ;)
 
I'd try a few manual focus shots to see how you get on and not at the lens widest aperture.
If there has been camera shake it may have caused the autofocus to select a focal point you did not intend and therefore the part you wanted sharp is not so. In that case your high shutter speed would do nothing to help.
 
If you were shooting in Sports mode that would explain why the AF might not be doing a good job. This mode uses AF-Servo with all the AF points active and you need to have the centre point over your subject when you first engage AF. The camera should then track the subject around the frame using all the points (as long as the shutter is half pressed) but can and will prefer something with better contrast.

Come out of sports mode and you'll be able to select a single AF point which you should then keep over the part of the subject you want in focus.

When you were shooting did you aim and shoot or aim, track and shoot? AF servo works best when you give it some time to track first, even just a quarter of a second.
 
thanks for the advice, i have a lot to think about there :) time for some experimentation i think :thumbs:
 
You must log in or register to reply here.
Back
Top