alliebess Loc: suburban Philadelphia

I shoot library events and, since the building is well lighted and I prefer that to harsh flash, I turn off my flash. Sometimes the focus is sharp, sometimes not. I shoot with a Kodak Z740 which I really like. Any ideas or suggestions as to why the auto focus is not always accurate?

Frank T Loc: New York, NY

Hard to say without seeing the photos.
Could be user error, camera movement or least likely, a defect in the camera.

alliebess Loc: suburban Philadelphia

If it helps, flash photos are always in focus. Photos shot outdoors, no problem with auto focus, unless camera tells me I need to use flash and I've turned it off.

mtnredhed Loc: The part of NorCal that doesn't move

Can you look at the shutter speeds used by the "out of focus" pictures? Should be in the EXIF data. I put that in quotes since I think what you're seeing is camera movement not out of focus.

steve40 Loc: Asheville/Canton, NC, USA

Many things can affect auto focus. Since most auto focus is based on contrast differences, a lack of contrasting tones can throw the auto focus off. Trying to focus on an area of solid color, can cause auto focus not to work properly. Any movement in the subject, can cause the auto focus not to work properly.
Strong reflections can! cause errors in the system. Trying to focus on several objects of differing distances, within the auto focus area, which extends beyond the little square in the center of your screen. Will cause the auto focus not to work, or select objects to focus on, other than those you wanted. Slight movement when doing macros after focusing, will through the auto focus off, this is good reason to use a tripod when doing serious macro work.

As you can see, auto focus is not perfect. Although it works 99% of the time, when used properly. It also brings your error percentage down, to think about what you are trying to focus on, when you press that shutter. If there are no good contrasting tones, focus on the edges. Use a tripod more often, and turn the auto focus off, you will get a lot better images as a result. Why do you think! you see most of the pros using a tripod; there's a reason - quality images.
I am not talking about the run and gun photojournalist, but the professional portrait, landscape, and still life photographers. But to wind this up, these are a few! reasons why your auto focus might fail at times. And sometimes it may just be broke. :)

BboH Loc: s of 2/21, Ellicott City, MD

Are you shooting with a low number F stop? If so, the wide aperture will tend to have in focus only the object, other objects to the side on the same plane and some objects close in front in focus. All else will be a bit blurry

George Kravis

Sounds like you have a depth of field problem, so in order to be able to set a smaller aperture, you'll need to go to a higher ISO. Also you might not be setting your focus point and your metering field to good advantage. I use center weighted in a situation like that. I aim the focus point on the subject, depress the shutter half way to hold it, recompose and take the picture.

les_stockton Loc: Eastern Oklahoma

Without having enough information about how your auto focus is set up, I can offer several ideas that might make focusing off.

Focusing is based on contrasting of objects. If you are in low light, sometimes certain surfaces don't offer the right contrast for the focusing mechanism to work right. I have photographed shiny objects in good light that wouldn't focus right because the light reflecting off the object confused the camera. So it works in low light, but also in good light, depending on what you are focusing on.

Another possibility is that if you have multiple focus points, and you focusing set to use all, rather than just one, then the computer has to pick something to focus on, which might not be the same object that you would pick. That would cause focusing to be off.

penguinpete

Can you afford the inflexibility of tripod mounting? That with shutter delay would eliminate camera movement as a probable cause. I have 2 of these Z740s, in addition to my Canon dSLR, and I always thought the design suffered from not having provision for a remote release, so I built a remote release frame (out of LEGOs) and I no longer have to use shutter delay. PM me if you want to see the remote release frame.

-- Pete

Weddingguy Loc: British Columbia - Canada

There is no such thing as an auto focus system that is "always accurate", but 95% of the time it is operator error. Using any auto focus is an acquired skill. Canon has an on-line video that explains the auto focus system and how to use it properly. I realize you are shooting Kodak, but the information would apply.

PNagy Loc: Missouri City, Texas

Possible problems:

1. some parts of the library are darker than others, causing the camera to set a very slow shutter speed, like 1/50 sec. This would tend to blur from the slightest motion.

2. Your metering style might be set to spot. A tiny spot then might be in a a kind of focus that is not appropriate for the rest of the picture. Set the metering to one that covers at least a big part of the centre of the screen.

3. Your focus style might be set on spot. This will cause the same problem as above. Spot focus works great in specialized situations, such as trying to zero in on a small animal surrounded by thick vegetation. Change the focus to default one, which should focus on enough of the room to give you a good exposure.

4. If all else fails try shooting in full auto. Few cameras will fail to give a good exposure in that mode with a flash.

marcomarks Loc: Ft. Myers, FL

Being that you're not using flash, likely your shutter speed in auto mode is becoming slower to where handheld shooting can cause blur.

Try putting a very thin single sheet of toilet paper across the flash and attach it with Scotch tape. That will take off the harshness but still provide added light to let shutter speed come back up. Personally, I bought a cheap $3.50 hot-shoe-mounted translucent diffuser on eBay that stands in front of the built-in flash when I want a little fill without bring out the big guns.

If you have adjustable ISO also boost it up to at least 400, even when using flash. My dSLR has very low noise at higher ISOs so I can use ISO 800 indoors and ISO 400 outdoors with no noise. Flash output is also less to achieve the correct exposure with higher ISO, reducing flash output and potential harshness.

Outdoor Party, ISO 400, onboard flash, diffuser

bawlmer Loc: Baltimore, MD

Just a guess, but even my Sony A55 has trouble focusing in what may appear to be sufficient light, but to the camera is actually LOW light. I don't think there's anything wrong with the camera. If possible, bump up the ISO and see if there's an improvement, assuming you can adjust the ISO. Otherwise, I would go with the flash. If you don't like the harsh look of flash, as Marco said above, put a napkin or tissue over it when you use it to diffuse it a bit. It gives you a softer flash and is more evenly distributed. :)

Wabbit Loc: Arizona Desert

Hey Doc ..... how about posting the picture .....

alliebess Loc: suburban Philadelphia

Thanks everyone for the suggestions. I did check the shutter speed and ISO on some of the problem pictures and you all were correct - too slow a shutter speed and too low ISO. So shall have to play around with the camera some more and see what happens. I do have a tripod, but for much of what I shoot it would not be practical to use.