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Old Feb 21, 2005, 11:03 AM   #11
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To get rid of the softness created by the AA filter, Canon recommends applying USM in PS with the following settings as a starting point:

Amount = 300%
Radius = 0.3 pixels
Treshold = 0

I usually take my image in RAW and set the sharpening to standard (or lower) before creating the jpeg then apply the above USM to each print. The result is really nice IMO. The only time I don't apply sharpening in PS is when I want the photo to remain soft (i.e., to soften a persons complexion).

I think that the best result would probably be when USM is applied with a jpeg made with sharpening turned off (i.e.,only do sharpening in PS to avoidsharpening twiceon the route to make the final jpeg), but I haven't been able to see a difference.

Read from page 24 on in the following pdf, which has some great info (wish there was a similar pdf made specifically for the 20D):

http://www.photoworkshop.com/canon/EOS_Digital.pdf



I hope this helps!



Bob
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Old Feb 21, 2005, 11:22 AM   #12
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eric s wrote:
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I didn't think (I'm a bit ignorant here) that a good quality filter (B&W, for example) did anything but block IR frequences. You're suggesting that they block light in the visible spectrum. I didn't think that was true... but don't honestly know.
I agree. From everything that I have read or heard, when you use a good quality UV filter (B&W, Canon or top line Hoya) there is so little difference in image quality that only the most picky professional could even see it.

Being aUV filter isn't the problem. The issue is with putting a poor quality piece of glass in front of an expensive element. I use a Canon filter for my 20-70L and can't see any differences in imagescreated with it removed. Hmmm ... maybe a good test is in orderusing a tripod with mirror lock-up on a day with nothing better to do :-).



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Old Feb 21, 2005, 4:32 PM   #13
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It would be interesting to see your results. My bet is that Canon doesn't make its filters, I bet they buy them from Hoya or B&W and rebrand them. Just a guess (they don't make their extention tubes, for example.)

Those USM numbers are interesting. I find that 200,.6,0 works well. I'll have to try those numbers too. My numbers do produce halos, but also produce sharp images (so I fix the halo with masks or selections and I'm good to go.)

Eric
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Old Feb 21, 2005, 6:05 PM   #14
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Yup, I also would guess that Canon do not make their own filters. But they seem to be a decent quality product. I looked all over for a filter test/review site, but couldn't find one ... so I based my selection based on comments on various forums that I visit. So far I can't find anything wrong with the Canon brand (rebrand) ... who knows, maybe it's the same as some other cheapo brand :G

For USM it would also be interesting to test if it is better to shoot RAW and produce the jpeg with sharpening "off" then use USM in PS. By the way, I have a copy of Filter Magic which also gives nice results and can even correct for some motion blur.

I wonder if the AA filter is the same strength for the 20D as the for the cameras that the pdf file (and recommended USM starting point) was based on. If it's not as strong, then the amount of sharpening to get the same result should be less.

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Old Feb 21, 2005, 8:25 PM   #15
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For USM it would also be interesting to test if it is better to shoot RAW and produce the jpeg with sharpening "off" then use USM in PS. By the way, I have a copy of Filter Magic which also gives nice results and can even correct for some motion blur.
I'm not sure what you're asking. If you're asking if the sharpening in the RAW converter is better than USM.. that is an interesting question. There are many aspects to sharpening and workflow. The a mount of sharpening is dependent on the output. Large prints can take more sharpening than smaller prints. And the web usually requires less than that (i.e. it shows sharpening well and can show over sharpening very easily.)

This leads me to think that sharpening during conversion is not a great idea. But its also working on the pixels at a time when USM can't (during the conversion to the internal memory format of the software converting it.) At least, it might be. Or maybe its just applying some version of USM with preset values. I don't know.

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Old Feb 21, 2005, 8:33 PM   #16
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I guess I'm wondering if by sharpening twice it creates more sharpening artifacts. If this is the case it may be better to turn sharpening off when creating the jpeg from RAWthen only sharpen once using USM, as the final enhancement, in PS.

Edit:

Just did a test:

1. Created a jpeg from RAW with sharpness=average then applied USM in PS as per my earlier post

2. Created the same jpeg from RAW with sharpness=off then applied USM in PS as per the earlier post

The image was a picture of one of my girls, where one of her eyes was very sharp. Zooming in on her eye (100%) in PS showed that method 2 gave an image with a very slight improvement in detail. For example the lines in the iris of her eye were more clearly defined. I didn't notice any jaggies or halos for either image.

The difference is so small that I don't think it would be noticeable at a lower resolution, so I'm not going to bother posting it.
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Old Feb 21, 2005, 8:54 PM   #17
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Hey Bob,

I took your advice on paramenter 1 and upped the sharpness, contrast and saturation.

In the end, I backed off the contrast and saturation and just left the sharpness up one notch.

The zero sharpness gives the image a filmy effect, but notching up the sharpness even by one gives it more a digital look. Not sure which I like better.

Strange.

-- Terry


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Old Feb 21, 2005, 9:07 PM   #18
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Hi Terry,

I've found that if you want to shoot jpegs and not do any post processing (assuming the white balance and exposure is ok) then setting the sharpness to medium (one notch up from the middle) is a nice compromise. Sometimes it's a bit too much ... sometimes too little.

If you shoot RAW it doesn't matter what you set sharpness, saturation or contrast to since you can change them to whatever you want when you convert from RAW to jpeg. If you're not handling a lot of images and aren't concerned about storage space or transfer rate you could try RAW+jpeg, and use the jpegs produced from the camera like you do now ... but have the ability to create a new jpeg from RAW if you'd like.

RAW is like a digital negative, while making adjustments to a jpegseems to be like messing with a scanfrom a print (my simplistic view).



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