Comments on: Digital Photography: In Focus

By: Miss. Photo

Miss. Photo — Mon, 21 Dec 2009 06:24:59 +0000

First of all, you need to know that it is absolutely impossible to get perfect focus in digital photography. Even if you can focus perfectly in the camera, you still have to sharpen in post-production.

Second, this shounds like a depth of field problem. Higher apertures (f-stops) have more depth of field. Use the highest aperture that you can.

The apertures are: F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, F22, F32, F45, F64, F90, etc.
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By: MixedMojo

MixedMojo — Mon, 21 Dec 2009 06:22:59 +0000

Perki has the right idea. Your DoF (depth of field) is too shallow. Change your aperture, in either aperture priority or manual exposure modes to f/8-f/11 and your lens will have a DoF long enough to keep objects on the same linear plane in focus. By the way, f/22 is not neccessary for group shots, only when you want both the background and foreground to be in perfect focus. What you want is to still be able to separate your group from the background, for less compositional clutter but still retain a DoF long enough to have focus on one linear plane at a specific distance from the camera. You stop down to f/22 and the background will distract from your subjects and it will look more like a snapshot than a nice group photograph. That's my opinion.
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By: tm

tm — Mon, 21 Dec 2009 06:20:59 +0000

Technically it’s absolutely impossible to get 100% focus. Now I’m not going to go into a long explanation about that, but what I think you mean is that your having depth of field problems.

Stop the lens down. If you want everything in focus put the lens at f/22, and make sure the shutter is above 1/125.

That should solve your problem. If it doesn’t you need to get a new lens…seriously because that ones broke.
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By: foggy_idea

foggy_idea — Mon, 21 Dec 2009 06:18:59 +0000

I believe you’re having some exposure issues, rather than focus… try using a tripod.. use the AV setting and set your camera to f22…. shoot your landscape, and see if you have 100% focus then.

I’d suggest getting the book "Understanding Exposure" by Bryan Peterson. It will explain everything you need to know about exposure and foucs, in easy to understand language.

For your group shots, I’d suggest using a setting somewhere between f11 and f16.. use M mode and adjust the shutter speed til the exposure is correct. Use your flash and see what your results are.
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By: perki88

perki88 — Mon, 21 Dec 2009 06:16:59 +0000

If you are using auto or program stop. You need to go manual or aperture priority for more DOF. Groups try for an f11. A sharpening solution in PS might be a high pass filter overlay of about 3.
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By: Seamless_1

Seamless_1 — Mon, 21 Dec 2009 06:14:59 +0000

Virtually all small format digital cameras require some sharpening in post process and that inlcudes the Canon’s I shoot with, which cost thousands more than the Xti. It’s because the processing done in camera softens the image. A slight amount of sharpening will help with this, since it isn’t a lack of focus, but a lack of local contrast.

Another problem may be that your lens has a backfocus or forward focus problem. Backfocus is the most common, but both can occur. It’s rare with Canon lenses, but it can occur with them just like it can with any other lens. It is much more common with third party lenses like Tamron, Sigma and to some extent Tokina (all of which make some excellent lenses). The only thing that can be done if this is the case is to send it in for service. All of the companies are pretty good about correcting this problem. You can lookup backfocus using google and decide from that if you have a backfocus problem.

The 30D should give you a higher quality image than the XT’s since it’s basically a 20D with some bells and whistles added. Unless you are doing something wrong, it sounds like your focussing system is out of alignment if it’s not a matter of sharpening the image.
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By: HELLO!

HELLO! — Mon, 21 Dec 2009 06:12:59 +0000

a new camera will solve EVERYTHING!>.
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By: Mere_Mortal

Mere_Mortal — Mon, 21 Dec 2009 06:10:59 +0000

Nobody really "gets" digital "100%"; It has kind of been forced on us…like Chinese pet food and $3.45/gallon gasoline.

Make do and carry on if you can.
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By: justme

justme — Mon, 21 Dec 2009 06:08:59 +0000

Most digital cameras have auto-focus. Check your instruction manual or the menu to make sure you have this feature turned on.
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By: proshooter

proshooter — Mon, 21 Dec 2009 06:06:59 +0000

Sounds like a depth of field problem if some parts are sharp and others out of focus
It could be you are becoming more critical of your own work, a good thing.

Try using a smaller aperture.

Lens performance also trends to drop off towards the outer edges.
References :
http://photography.suite101.com/