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Old Oct 29, 2010, 2:44 PM   #51
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but a person is allot smaller, so you need to zoom in more. Unlike that train where the path is completely predictable. High speed action can change direction quickly like a small bif's. Vs a high soaring Raptor with a 500mm.

The sony is nice, but there is a reason it is marketed as a mid level camera. Sony does know the limitations of the 1/10 of a sec delay. It is good for predictable and action in confine spaces.

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Yes, I did. The train is not coming faster than any human.
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Old Oct 29, 2010, 2:49 PM   #52
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And you could lose fast that bird even with OVF. Human reaction time isn't that much faster than 1/10 sec
True, but an optical viewfinder will give you a 1/10 second advantage. It may not be much, but I'll take it.
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Old Oct 30, 2010, 1:15 AM   #53
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True, but an optical viewfinder will give you a 1/10 second advantage. It may not be much, but I'll take it.
The only problem is that there is no camera under $5000 that has OVF and can do 10 fps with AF

A55 (according to one test) does 10.7 fps.
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Old Nov 14, 2010, 3:36 AM   #54
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I'm interested in the Sony A55 as a replacement for my ageing Minolta 5D. I am wondering about the autofocus ability. The reviews make the point around its limitations.

Today I shot some simple photos on auto using the minolta continuous shooting and the AF just couldn't keep up, unfortunately. I'm wondering whether the A55 would do a better job?
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Old Nov 14, 2010, 3:37 AM   #55
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I meant to say autofocus in continuous shooting mode
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Old Nov 14, 2010, 4:05 AM   #56
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I guess the 580 is another choice. I suppose I will have to have a look at both in a shop.
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Old Nov 14, 2010, 4:08 AM   #57
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It has been interesting watching the a55 discussion in various forums. It's almost become philosophical. A noob asks, old hands poo-poo it, some support it, arcane references to bif occur. 10fps is mentioned.

Really, the folk this camera is marketed to are regular family type people. They take pictures of kids. they make some short movie clips. once they do 10fps a couple of times, and then realize they have to look at/file somewhere hundreds of photos that are very similar, they'll stop.

personally, a camera with evf doesn't appeal to me. but to a p&s upgrading for better iq, it's really good. he's used to lcd delay. he may even think it's normal. so after pointing out the negative side of the camera design, how about we "let it go"?
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Old Nov 14, 2010, 6:54 AM   #58
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I'm interested in the Sony A55 as a replacement for my ageing Minolta 5D. I am wondering about the autofocus ability. The reviews make the point around its limitations.
I think it's probably a lot better than most people give it credit for. For example, I've seen BIF posts from a user that's owned both the Canon EOS-50D and Sony A55, that says the Sony is much better for tracking.

Now, i've seen posts from users that have higher end Canon gear (for example, the EOS 7D and EOS 1D Mk IV), as well as the A55; and say the A55 is very good, but the higher end Canon gear surpases it for AF (as to be expected).

I've also seen comments from Sony A700 owners (and the A700's AF system is vastly superior to that of your 5D) that also have the A55 , and say that the A55 gives them a much higher percentage of keepers for shooting rapidly moving subjects like birds in flight.

IOW, the A55 is no slouch in that area, although the EVF could take some getting used to.

But, I doubt your 5D's AF tracking ability has anything to do with why your samples are blurry.

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Today I shot some simple photos on auto using the minolta continuous shooting and the AF just couldn't keep up, unfortunately. I'm wondering whether the A55 would do a better job?
First of all, if you're using Auto mode, AFAIK, AF tracking (Continous AF) isn't even enabled.

Now, if you're using Programmed Auto (versus Green Auto), you can set AF to continuous. Note that setting Drive Mode to continuous is *not* the same thing as setting Autofocus to Continuous. They are two separate settings. You can set AF to Continuous (so that it tracks a moving subject while you keep the shutter button pressed half way, taking the photo when you press it the rest of the way down) while stiill using Single Shot Drive mode; and vice-versa (you can set drive mode to Continuous so that it continues to take photos when you hold the shutter button all the way down, but if your AF is not set to Continuous, Focus is locked on the same place it was locked on when you started the burst, and it won't change focus distance with subject movement).

IOW, if you want to take a series of shots of moving subjects, set *both* your Drive Mode and Autofocus mode to continuous. I'd also suggest setting your AF area (yet another setting) to Center Point. Then, when you half press the shutter button, making sure focus is locked on your subject (via a larger Green icon in your Viewfinder that lets you know that Continuous AF is tracking), and press it the rest of the way down (to start taking photos). Frankly, as sharp as the background looks in those images, I suspect you were usiing a focus point that was locking on the background. If you let the camera decide what to focus on, it may find an area with higher contrast that is not your intended subject.

I'm also seeing motion blur in those images. That part has nothing to do with Autofocus. It's because your shutter speeds were to slow to freeze movement. ;-)

Shoot in Av (Aperture Priority) mode with the Aperture opened up some (smaller f/stop numbers) and set your ISO speed higher. Each time you double your ISO speed, the camera can use shutter speeds twice as fast. . So, set the ISO speed higher manually until your shutter speeds become fast enough to freeze movement. I'd aim for shutter speeds faster than 1/500 second; and you may need to use ISO 800 to get there with a dimmer (typical consumer grade) lens that only has a widest available aperture of f/5.6 when zoomed in much. When you half press your shutter speed while aiming at your subjects, you can see the shutter speed being used in your viewfinder. Note that if you're using a Polarizer on the lens, then you will lose around 2 stops of light (only about 1/4 the light gets through), which could require very high ISO speeds to freeze movement (it's a good idea to remove that type of filter if faster shutter speeds are needed).

Also, for better responses, it's a good idea to post samples that have the EXIF information included. That way, members can tell camera settings used (aperture, focal length, ISO speed, shutter speed, focus mode, etc.). This information is embedded in a header that is part of your images and can be read by many EXIF viewers and editors. One of my favorite readers that includes more maker notes information is PhotoME. See this thread for more details on EXIF readers:

http://forums.steves-digicams.com/ne...mage-data.html

The EXIF is stripped out of the samples you posted, so we can't tell the camera settings being used.

Now, that can happen for several reasons...

The editor you used to downsize the image may have stripped it out. For example, if you use "Save for Web" usiing Photoshop, it's going to remove it. Use Save as instead.

Or, if your image size (either dimensions in pixels or file size in bytes) exceeds the maximum size allowed by the forums software here for attachments, then the forums software is going to strip it out (it will attempt to resize and recompress the images and strips out the EXIF at the same tme).

Images being attached to posts should be downsized so that they are no larger than 1024 pixels on their longest side, with a file size that is no larger than 253.9KB (260,000 bytes).

If you open the downsized images on your hard drive that you attached using something like the free PhotoME and see EXIF information, then the forums software stripped it out (because you exceeded the maximum sizes allowed here). When you attach an image to a post here, you'll see those max allowed sizes shown at the time you're browsing for them on your hard drive using the forum's attachment manager. For a JPEG image, you'll want to keep the file size at no larger than 253.9KB (260,000 bytes) and make sure the longest side is no larger than 1024 bytes.

One tool you can use to resize your images is the free Irfanview (see http://www.irfanview.com to download it).

With this software, after you open an image, select "Image>Resize/Resample" and make the width around 800 pixels wide for posting. Leave the Preserve Aspect Ratio box checked. After you click OK, use the "File>Save As" menu choice and give it a new filename (since you don't want to overwrite your original). I'd set the Quality slider you see come up at around 80% to keep the file size within limits, making sure the box to preserve EXIF is checked (and it is by default unless you change it).

That way (attached images still contain the EXIF), members can see what settings were being used and better diagnose any issues.

But, my guess (since I can't tell what settings were being used), is that you had more than one issue going on. IOW, you may not have been using a focus point that was locked on your subjects, you may not have been using continuous AF, and you were using shutter speeds too slow to freeze rapid movement because ISO speed was set too low for the aperture (your f/stop setting) you were using in that lighting (since I'm seeing blur from subject movement, and that has nothing to do with Autofocus).
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Old Nov 14, 2010, 7:31 AM   #59
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Shorter Answer...

You don't need a new camera for shots like those. The biggest issue I see is that you've got blur from subject movement, and that has nothing to do with Autofocus (your shutter speeds were too slow to freeze movement).

If all of what I said above is difficult to understand, just switch the mode dial to Sports mode (the icon that looks like a runner) and use it that way. Half press the shutter button to make sure you've got a good lock (green icon in viewfinder), then press it the rest of the way down to start taking photos. The camera will set AF mode to continuous, drive mode to continuous, and favor aperture settings (your f/stop) to let in more light so that shutter speeds are faster. If your shutter speeds are not faster than 1/500 second (which you can see in your viewfinder) increase ISO speed until they are fast enough and/or remove any filters you have on it causing significant light loss (like a Polarizer will do).
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Old Nov 14, 2010, 2:13 PM   #60
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Thanks. I am going to read those comments a couple of times to make sure I get them right on board. Appreciate the schooling a bunch.
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