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07-15-2009, 04:17 PM   #1
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zoom question

hey im new here and i was wondering when you zoom in on the picture in photoshop is it streching the picture or showing the actual size?

07-15-2009, 04:36 PM   #2
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In photoshop, anything past 100% (Actual size) is zooming past the normal viewing size of the picture. I don't think of it as stretching the picture, more like it's dropping into the picture to see more of the detail. This also expands the size of each pixel to make them more visable.


I've been neglectful.

Welcome to the forums. There's no other place I know of for anything related to Pentax photography, with more helpful and informative people than anywhere else.
07-15-2009, 07:24 PM   #3
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Thanks I have asked around and no one has given me an answer they just skate around the question and then say oh I'm not familiar with Pentax Cameras. I have a K110d and seem to be having a really hard time keeping the focus sharp, am not sure if it is the camera or operator error...hand shaking ect.
Thanks
07-15-2009, 08:35 PM   #4
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Actual size?

QuoteOriginally posted by jrsavs Quote
Thanks I have asked around and no one has given me an answer they just skate around the question and then say oh I'm not familiar with Pentax Cameras. I have a K110d and seem to be having a really hard time keeping the focus sharp, am not sure if it is the camera or operator error...hand shaking ect.
Thanks
You may not be getting an answer to your Photoshop question because, when viewing an image on the computer, the term "actual size" doesn't really mean much. An image from a 6MP camera, such as the K110D, is about 2,000 x 3,000 pixels. Not many people have a monitor with that kind of resolution, so most of the time, PS has to shrink the image to fit on the screen. At 100 percent, the image pixels have a more or less 1:1 relationship to the screen pixels. That's about as close as you are going to come to a definition of "actual size".

At that resolution, the image will not fit on the screen, obviously. At larger magnifications, PS will use multiple screen pixels to display each image pixel.

As for focus sharpness, is the blur due to camera motion, subject motion or focus? If its subject motion, then the subject will be blurred but the background is sharp. Camera motion usually shows up as more or less parallel streaks, in the direction of the camera motion, affecting both the foreground and background. Out of focus is a general softening of the part of the picture that you think should be sharp, but without the telltale signs of camera or subject motion.

Both camera and subject motion can be the resuilt of too slow a shutter speed. In film days, the rule of thumb was that you should not attempt to handhold a camera at a shutter speed slower than the reciprocal of the focal length. For example, with a 50mm lens, don't handhold at speeds slower than 1/50 second. For APS-C digital cameras, the rule is the reciprocal of the focal length x 1.5. So, a 50mm lens shouldn't be handheld at slower than 1/75 second.

With autofocus cameras, sometimes the camera is focusing properly, but not on the part of the picture that you think should be in focus. It is actually quite rare for an entire image to be at the critical focus point. Usually, there are some things in the foreground, some a little farther away, and some in the background.

Another thing to consider is that most lenses have a "sweet spot" in terms of their aperture for sharpness. Most lenses are sharpest when stopped down part way, say to f/5.6 or f/8. Wider than that, or smaller than that and sharpness drops off. On some lenses, the dropoff is quite noticeable.

Depth of field plays a role in perceived sharpness as well. This is the area in front of and behind the point of critical focus, in which items still show acceptable sharpness. The smaller the aperture, the greater the depth of field. On any lens, wide open gives the least depth of field. Stopped down as far as the lens will go gives the most depth.

An example of two might help us help you diagnose your focus problems.

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