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Old Jul 1, 2004, 3:54 PM   #1
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Hi

i've taken few pictures with my A1, and they became not sharp enough.

i don't know why.

is there any possible reason??


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Old Jul 1, 2004, 4:54 PM   #2
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There are lots of possible reasons. Were you shooting in Portrait mode? Aperature Priority? Using the flex focus point, etc, etc. Giving us no information, other than the pictures aren't sharp, will generate very few guesses.
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Old Jul 1, 2004, 5:04 PM   #3
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the dial button was in "P" position, auto single focus, using flash.


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Old Jul 1, 2004, 5:18 PM   #4
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You may want to post some examples (unaltered originals) for users to look at. It's difficult to see what you are talking about, based on one small image.

If you can post some unaltered images on a web site somewhere, then we can look at the EXIF information in the image header (to see things like focal length, aperture, shutter speed). This will give us a better idea of what may be going wrong with your photos.

In the one example above, the focus point appears to be on the top of the woman's head in the foreground. Depending on the focal length, aperture, and distance to subject, you could just be seeing a Depth of Field limitation for the settings selected (making objects further away, or closer to the camera than the focus point, appear to be blurred).

Without more (and larger examples), with EXIF information, it's difficult to guess what could be wrong. There are anumber of things can cause images thatdonot appear to be sharp (inaccurate focus, depth of field limitation from aperture/focal length settings used, motion blur due to a slow shutter speed, user perception of sharpness due to in camera sharpening settings used, etc.).

If you don't have a place to post the images, you may want to open a 30 day free trial account at http://www.pbase.com

They will allow 10MB of space for a trial account (enough for a few sample images).
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Old Jul 2, 2004, 1:51 PM   #5
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I agree with Jim...especially if you are shooting in strict Program mode. The camera will assume the aperature you want when you might have wanted more depth of field to insure sharp results of all subjects. You can adjust this easily in Program mode by changing the aperature using the Program Shift feature. (It's explained in the manual which wheel will change aperature).
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Old Jul 3, 2004, 6:03 AM   #6
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hi

how can i know before i shoot that the aperture size isn't fine?

where can i upload the pics so u can get the exiff info?

do u want me to create a screen-shot of it?


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Old Jul 3, 2004, 9:09 AM   #7
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biot wrote:
Quote:
hi

how can i know before i shoot that the aperture size isn't fine?

where can i upload the pics so u can get the exiff info?

do u want me to create a screen-shot of it?

Let's make sure that's what it is first. However, my gut feeling isthis is most likely what you are seeing (Depth of Field limitation). Based on your one sample, it does appear that your focus point is sharp, yet the people in the background are not. So, your perception of the images not being sharp, is most likely a Depth ofField issue.

The EXIF is already embedded in the image file header. You don't have to do anything for us to be able to see it. Most image editing software can read this information.

If you create a trial account at http://www.pbase.com , we would not need to download the photos to see the EXIF, since it pbase.com will automatically read this data from the image file, and display it underneath uploaded photos.

If you upload images somewhere else, then we can download the photos to see the data using many image editing software packages.

I don't even own your camera model, but I can already tell you that the camera is probably shooting "wide open" (largest aperture) indoors, unless you change the aperture from what the camera is selecting by default. This is because thelargest aperture (represented by the smallest F/Stop number), allows more light through to the sensor. Most manufacturers will go this route with the autoexposure algorithms, to try and make sure that shutter speeds are faster in low light. I doubt that the A1 is an exception. However, the wider the aperture setting, thesmaller your depth of field.

Depth of Field is the amount of the photo in focus, as you get closer to, or further away from your focus point. Have you ever looked at a professional portrait, where the subject's face is in focus, yet the background is very blurry? This is done deliberately, by choosing a larger aperture (small F/Stop number), combined with more focal length (amount of zoom used), and staying close to the subject.

In fact, consumer (non DSLR) cameras are often criticized for having TOO MUCH Depth of Field (too much of a photo in focus). A Shallow Depth of Field (less of a photo in focus) is very desirable for some types of photos, since the background can be a distraction. Blurring the background allows the subject to stand out more.

Anyway, the camera's autoexposure is unable to read minds (sorry, technology hasn't advanced quite that far yet), so it doesn't know that you'd prefer more, instead of less Depth of Field for any given photo you are taking.

So, the autoexposure algorithms are typically designed to set cameras to a larger aperture (less depth of field) in lower light, since this allows more light through theto sensor (or film in a film camera), allowing faster shutter speeds to help prevent motion blur from camera shake or subject movement. However, this does limit your Depth of Field.

Depth of Field is based on Aperture, Focus Distance, and Focal Length (amount of zoom used).

I have no way of knowing what the settings were for your sample photo, without viewing the EXIF. However, lets look at an example based on some typical settings, using a handy online Depth of Field calculator.

Your camera model's lens has an actual (not 35mm equivalent) focal length of 7.2mm - 50.8mm. This gives it a 35mm equivalent focal range of approximately 28mm-200mm.

Load this Depth of Field Calculator and selectyour camera model.Then select50.8mm (maximum zoom for your camera) as the focal length, F/3.4 as the Aperture, and4 feet as your distance to subject.

http://dfleming.ameranet.com/dofjs.html

Note that the Depth of Field using these settings is VERY shallow. In this example, only objects from around 3.95 feet to 4.05 feet would beacceptably sharp.

Now, change the focal length to 7.2mm, leaving the other values the same.

Note that your Depth of Field increased dramatically. Now, with a focus distance of 4 feet, everything from about 2.46 feet to 10.8 feet would be acceptably sharp.

Now,select a smaller aperture, like F8 , leaving your focus distance at 4 feet, and your focal length at 7.2mm (full wide angle). Note that your Depth of Field then increases dramatically again. Now, everything from 2.8 Feet to Infinity (as far as the camera can see), should be acceptably sharp.

Experiment with this Calculator, and you'll get a better idea how these parameters (Aperture, Subject Distance and Focal Length), impact the amount of a photo that is in focus.

Once you have a better understanding of how a camera works, you'll be able to better determine when you need to change your settings to get the desired affect.

For typical indoor photos (family around a dinner table, etc.) -- not portraits; you typically want to stay at as close to full wide angle as possible, not getting too close to your subjects. This increases Depth of Field so that more of your photo is in focus. If this is not sufficient, then you can change the aperture.

If you have time, upload a few photos to pbase.com, and we'll take a look to see if that's what the problem is (Depth of Field), or if some other issue is causing your photos not to appear sharp.

Hopefully, my explanation above was not too complicated. If it was, let us know what you don't understand, and I'll try to explain it in simpler terms.
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