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Photo

Digital Cameras And Focus


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#1 Rimmer

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Posted 04 April 2006 - 08:03 PM

I'm in the process of learning how to use Paintshop Pro to manipulate digital images and was reading a tutorial (and can't find the link dammit!) about applying unsharp masking to an image. The process is pretty simple and can provide some dramitic improvements. e.g.

Original: Posted Image

After Masking: Posted Image

The tutorial seemed to be implying that if your digital camera produced slightly unfocussed images then that was GOOD because you could maintain more control over the final images and still achieve the sharp focus effect using unsharp masking (USM).

In another article here http://www.photocritic.org/articles/usm.php
(my emphasis)

Digital cameras and USM

If you feel that you are photo-savvy enough to use the USM tool on a regular basis, you should have a close look at your digital camera. Usually, there will be a setting in a menu somewhere that says "sharpness" or "sharpen". You'll want to turn this down as much as it'll go. Why? All consumer / prosumer digital cameras sharpen the images in-camera. Why? Because the average consumer only sees the pictures that come out of their camera, and if those images are soft, they will run to the manufacturer and complain, out of ignorance. Sad, but true.

Professional cameras (Canon EOS D30, D60, Nikon D100 and the higher-end models) don't compensate as much, and also offer the option to turn the sharpening off altogether. This is A Good Thing, because it leaves the photographer with full control. And photographers are control freaks (especially anally-retentive perfectionist photographers), so that's sweet.


Can someone explain to me what's happening here? Why don't the cameras take a properly focussed image in the first place? and why would you want to apply USM yourself rather than have the camera do it for you? In other words what benefit is this extra level of control?
:thumbsup:

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#2 stevealmighty

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Posted 05 April 2006 - 10:28 AM

Ok, lemme see if I can explain this. The Unsharp Mask (USM) actually originates from the old film days. It was called something else (can't remember what though :thumbsup: ). It was used to make an out of focus image more infocus (or by todays standards "sharper"). They would take a negative and duplicate it, then lay it on top of the original negative, but a touch out of alignment (for lack of a better term) so that the final print from the 2 negatives would appear to be more in focus than the original single negative.

It's not that todays cameras are taking bad, soft, fuzzy or out of focus pictures. It's that the digital image itself is made up of pixels. Pixels are shaped like stop signs (octagon shapes). Now, put 4 of them together and you have a gap in the middle. That gap is reffered to as interpolation. The camera actually has to "guess" what information (colors) are supposed to be there. If it doesn't do a good job, then your image may appear "soft" or "fuzzy". Most camera's will apply a "sharpen" filter to an image when it's captured wich will help to offset the soft appearance of the image. You can also NOT have the camera sharpen the images, and do it yourself for more control in whatever software you use to edit/manipulate your images. This whole paragraph stands true for all cameras, professional or not.

I want to say that USM works by adding contrast to the overall image, specially the interpolation and outlines/high contrast areas, which helps to add texture to an image. Don't quote me on that though, as I've only had like 6 hours training on photography/digital photography :flowers:

I'm not sure about Paint shop pro, but with Photoshop (all versions), using USM will make your image considerably larger when you save it, as compared to not using USM and then saving it. Try saving an image and note the size when saved as a jpg, then apply USM and save it again seeing if there's a difference.

Most typically, I don't like USM when I'm not going to print an image. On the flipside, I NEVER print an image without applying USM to it first. More often than not, when you apply USM to an image, it may appear grainy or have "choppy" edges if it's to strong (to high a setting) and then saved. You might want to check to see if PSP has a standard "Sharpen" filter or "Sharpen More" filter, and try them out. Also, try printing a small image, then apply a stong (not to strong) USM filter to the same image and print again and see if you notice a difference. I've found that (remember I use photoshop to print) when I apply USM to an image before I print it, if it looks like it's way to harsh a filter on my monitor, then it usually makes for a nice print.

Did this help you at all? Or did I just confuse the crap outta ya?

More importantly, did this answer your question(s)?

Lemme know!

Edited by stevealmighty, 05 April 2006 - 11:48 AM.

War produces veterans, wounded both physically and mentally. They have sacrificed for us.....and it is now our job to help these veterans, as they have already helped us in ways we will never know, in ways that we cannot fathom, and in ways that we take granted every day.
Posted Image

#3 Rimmer

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Posted 05 April 2006 - 09:58 PM

Did this help you at all? Or did I just confuse the crap outta ya?


Well kind of...
Firstly thanks very much for trying to explain complex visual concepts to the photographically challenged like myself. If I understand you correctly you're saying you take your photos without sharpening done by the camera. The images you view on the computer screen look best without USM applied and images you print look best with USM applied.

Would that imply that your camera takes images that appear acceptably sharp without further 'sharpening'? Again the impression I got from other sites was if you turned off the cameras' sharpening the images would be noticably 'soft' or out of focus - enough for many people to "complain to the manufacturer". But then again I believe many photographers like a soft focus look to their images is this a personal preference on your part?

using USM will make your image considerably larger when you save it

Good point about that, I didn't check those image sizes before but here's what they are:
Original image downloaded from tutorial site = 16KB, same image with USM applied and saved as a flat jpg = 132KB. I have no problem with a 132KB image but if I started with an image of 1MB say does that mean it's going to be 8MB with USM applied? That I would have a problem with!

I should point out I don't own a digital camera but I'm seriously considering getting something having seen the amazing effects PaintShop/Photoshop are capable of. But there are mysteries/considerations to digital photography that I'm only slowly becoming aware of such as this onboard sharpening process.

You might want to check to see if PSP has a standard "Sharpen" filter or "Sharpen More" filter, and try them out.

Yes PSP has those functions but the effect is constant across the image, it will emphasise the blemishes in someones skin as much as it emphasises the line of the profile, it doesn't give the image "punch" the way USM seems to. But more experimentation needed. :thumbsup:

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#4 stevealmighty

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Posted 06 April 2006 - 07:02 AM

Firstly thanks very much for trying to explain complex visual concepts to the photographically challenged like myself. If I understand you correctly you're saying you take your photos without sharpening done by the camera.


Not a problem explaining anything to you (or anyone)!

Yes, I take my pictures without using the cameras feature (option). This way, I control the amount that the final image is sharpened. Now, with that said, I do it for a living, and get paid to monkey with pictures all day long, so I have the time to play with each individual picture I take. For my little point and shoot camera that I have at home, I have that set to "low" sharpening of an image when it takes it. This way I can just email it some place, or if needed, I can apply a sharpening filter to it later if needed (using a low sharpening filter helps the images a tiny bit, but still leaves room for me to make adjustments).

The images you view on the computer screen look best without USM applied and images you print look best with USM applied.


When using PS, this is true. However, if an image is very soft (as in slighlty out of focus), it may help it look better on screen if it's hit with USM. I'm not really familiar with PSP, but with PS you can adjust the options within the USM filter making it weaker or stronger before applying it to your filter. I'll include 2 pix at the end of this, one with USM and one w/o USM. I think that you'll see the difference.

Would that imply that your camera takes images that appear acceptably sharp without further 'sharpening'? Again the impression I got from other sites was if you turned off the cameras' sharpening the images would be noticably 'soft' or out of focus - enough for many people to "complain to the manufacturer". But then again I believe many photographers like a soft focus look to their images is this a personal preference on your part?


Yes and no. I've seen some cameras overdo it on the sharpening, and seen others not do enough. I've also seen cameras that took beautiful shots that looked marvelous without using the camera's sharpening option. What some of these people are complaining about could possibly be because the bought an off-name brand of camera that was really cheap. While digital photography is pretty much like shared technology (meaning that most camera's are pretty much the same, no one has any truly "unique" properties that set it above the competition), it stands true that you get what you pay for. If you buy a 1mp camera for $50, you can expect crappy photos. I think that the most of this is how the camera deals with interpolation, and how the program that they use can deal with interpolation. Photoshop can deal with interpolation good. Windows paint (the standard one).......not so good. Having the sharpening option on in the camera is ok, and (unless it's set to "high" or "max") shouldn't do any damage to your photo.

I should point out I don't own a digital camera but I'm seriously considering getting something having seen the amazing effects PaintShop/Photoshop are capable of. But there are mysteries/considerations to digital photography that I'm only slowly becoming aware of such as this onboard sharpening process.


If you have any other questions, let me know and I'll try to help! If you would like some advice when you buy a digital camera, let me know and I'll share some "things to look for" and some "things to look out for".

This image has no unsharp mask applied to it.
Posted Image

This image does have USM applied to it.
Posted Image

Look at the antenna on the hummer in both pictures. See the difference? Also, look at the UAV in the top left, the grass and the outlines in general. See how the edges aren't quite "right"? They're not straight, and look slightly pixelated. Now, if I printed both images, the one with USM would look better. But, IMHO, I think that the one without USM looks better on a monitor. Keep in mind that I've adjusted the USM in the lower picture so that it makes the grass and trees stand out more, but see what it did to the "finer" details (like the blemish you mentioned earlier).

Hope this helps!

Edited by stevealmighty, 06 April 2006 - 07:05 AM.

War produces veterans, wounded both physically and mentally. They have sacrificed for us.....and it is now our job to help these veterans, as they have already helped us in ways we will never know, in ways that we cannot fathom, and in ways that we take granted every day.
Posted Image

#5 Rimmer

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Posted 16 April 2006 - 11:25 PM

I've been playing some more, with layered masks this time - kind of a manual USM - with some very good results (and some not so good). The best I can do for now with your pic is this:

Posted Image

This one I'm happier with. Please click the thumbnails to see the full size image.
(Photo posted by ~*Kristy*~ in this thread http://www.bleepingcomputer.com/forums/topic49136.html)
Original:
Posted Image

Modified:
Posted Image

The flower pic was done with a couple of high-pass edge filters applied with soft and hard lights at different opacities and then an adjustment layer for saturation and lightness applied- loads of fun!
:thumbsup:

Edited by Rimmer, 17 April 2006 - 07:13 PM.


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#6 stevealmighty

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Posted 20 April 2006 - 03:15 PM

Using layer masks is good, it'll keep things from getting "fake" looking, or to sharp from using a USM.

another method, and maybe a little easier, is to use a lasso or selection tool to select just the things you want to sharpen. This gives you more control over what you sharpen, and allows you to sharpen one thing more than another thing on the same image.

Great work BTW! Keep it up :thumbsup:
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#7 boopme

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Posted 21 April 2006 - 01:32 PM

Is it me or do other users find a longer delay with digi cams over conventional in (what's the word here) snap time? It seems to me ,especially with a moving target you have to click ahead of time . Did I make my self clear?

OOOPs Sorry ,maybe I should've started new topic.

Edited by boopme, 21 April 2006 - 01:33 PM.

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#8 stevealmighty

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Posted 22 April 2006 - 07:40 PM

Is it me or do other users find a longer delay with digi cams over conventional in (what's the word here) snap time? It seems to me ,especially with a moving target you have to click ahead of time . Did I make my self clear?

OOOPs Sorry ,maybe I should've started new topic.



There is a delay. Even in some of the "more expensive" camera's. It's cheaper to manufacture them that way. I believe (might be wrong though, but it's what I've been told) that it's got something to do with the size of the cmos sensor and the camera's overall ability (speed) to process the information. They're now starting to get away from the delay and moving more towards an instant "snap" when you press the shutter button.

A quick "fix" to this is to either plan in advance like you said, or to say "I'll take a picture on the count of 3, ready 1, 2, 3! Now, press the button on 2 and it'll snap the photo on 3! :thumbsup:
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#9 boopme

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Posted 22 April 2006 - 08:33 PM

It's good to know they working on it. It was tough. I was trying to shoot some breaking( board and brick) and Kendo (sword) at my school. Well you can't give it a count. I anticipated a fee strikes but it was so hard to get all the ones I wanted. Good thing I also had the camcorder going. Thanks for your response. I was starting to think I was loosing it. :thumbsup:
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