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Author Topic: soft focus or needs post processing????  (Read 8037 times)  bookmark this topic!
aronw
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soft focus or needs post processing????
« on: September 02, 2008, 04:03:45 PM »

I've been trying to improve my photography recently and I've begun to shoot in RAW with my Canon 20D

I have noticed that my pictures just never seem sharp.  I open the RAW images in Aperature and using the zoom or loupe tools, my best only seem "acceptable" not good enough as far as I'm concerned.

I have the EF-S 17-55 f/2.8 IS, the 70-200 f/4L and the 50mm f/1.4, all supposedly good lenses, and it would be odd if all three just happened to be "soft copies"

I've read that the 20D can sometimes have soft focus, and that the consumer bodies are only expected to autofocus on a focal plane "within the depth of field" and I've also read that RAW images MUST be post processed because they don't have sharpness added as a jpg would, but at least in Aperature, I can't get them to what I would call "tack" sharp.

and finally, there is the possibility that I am zooming in too far on the images and my expectations are too high, but I notice that even on 4x6 prints, even ones that I think are acceptable on the screen often look soft printed.

I'm wondering if anyone has some advice or some suggested tests/ideas?

I'm going to try and borrow another body and I'm going to see about comparing the photos taken, but even some general ideas would be a great help!

thanks

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Bob Atkins
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Re: soft focus or needs post processing????
« Reply #1 on: September 02, 2008, 06:30:37 PM »

You might want to take a look at http://www.bobatkins.com/photography/technical/testing_lenses.html. It covers how to test sharpness  and shows some examples. I don't have examples shot with any of your lenses, but I do have samples shot with the 50/1.8 at f1.8 and f5.6. Your 50/1.4 should be similar, though remember the test images on my page were taken with an EOS 40D (10MP) and your EOS 20D would be expected show very slighly lower resolution since it has an 8MP sensor. At f1.8 the 50/1.4 should be a bit sharper, so the two effects may balance each other out.

You could also try using Canon's DPP for RAW conversion to see if that helps. It recognizes the sharpness setting you have when you take the shot and automatically applies it to the RAW conversion (though if course you can change it if you want to).

There are dozens of reasons why an image might not be sharp. Focus problems, lens problems, camera stability problems etc., but if you look through the tests suggested in the article you should be able to sort out what's happening. It''s very unlikely indeed that you have bad examples of all three lenses which are soft or have focus issues.
« Last Edit: September 02, 2008, 06:36:06 PM by Bob Atkins » Logged
aronw
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Re: soft focus or needs post processing????
« Reply #2 on: September 02, 2008, 07:16:14 PM »

I've seen your lens testing - and I've actually done the autofocus test.  It seemed to work alright with perhaps a bit of front focus.

When I clicked on your link though, something caught my eye that I haven't noticed before - the comment about 100% zoom is equal to a 24x36 image - maybe my expectations are too high

I think I will try and do some of the resolution tests and maybe print them off. . .
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Bob Atkins
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Re: soft focus or needs post processing????
« Reply #3 on: September 02, 2008, 08:05:40 PM »

Yes, assuming you have a typical monitor, say 17" diagonal running 1280 x 1024 resolution, a 100% view would represent a section of something  like a 22 x 36" print. With lower monitor resolution, the print would be bigger!

Of course that wouldn't explain soft 4x6 prints. It may be in your RAW conversion. If you apply no sharpening at all, the results may look a little soft. The default sharpening in DPP is 3 (on a scale of 0 to 10) if you have the camera set to it's default state.
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