| Sign in: |
| Members log in here with your user name and password to access the your admin page and other special features. |
|
|
|
|
|| SportsShooter.com: Member Message Board
Apparent Sharpness in an image, viewed on-screen
Michael Myers, Photographer
 |
Miami Beach | FL | USA | Posted: 12:46 AM on 02.17.05 |
->> Maybe it is my imagination, but it seems to me that if I take an image I've shot with my camera, and view it in a reduced size on my computer monitor, it doesn't look as "sharp" as it really is.
As a test, I took two images. One had already been re-sized to 600 pixels wide. When opened in Photoshop, this particular image looked quite sharp, but if I zoomed in at all, it looked "pixelated" as I expected it to. So, I just viewed it at "actual size". That was my reference image.
First, I took a very similar image, opened it in Photoshop, and "zoomed out" until it "looked" about the same size on the screen as my reference photo. By comparison, it "looked" not as sharp. Even when I clicked on "filters > sharpen" it did not look as sharp as my reference photo.
Then, I used Photoshop to reduce the size of the second photo to the same size as my reference photo. After that, I did the "filters > sharpen" function. Now, my second photo looked every bit as sharp as my reference photo.
The bottom line is I'm a bit confused right now. Looking at my images in a "zoomed out" condition, I feel they aren't as sharp as I wish they were, but once I process them (reduce the image size, and maybe sharpen them a bit) they look just fine.
If what I'm noticing here really is true, and viewing images in a reduced size doesn't show them up as sharp as they will appear on a web page, maybe I should be using a different program to view the images? |
|
Zach Honig, Student/Intern, Photographer
 |
Columbia | MO | USA | Posted: 1:19 AM on 02.17.05 |
| ->> In general, I would recommend that you use "unsharp mask" instead of "sharpen". Images in Photoshop that are not viewed at "actual pixels" may look slightly different from the final image. When Photoshop displays an image fitted to the screen or at a certain percentage, it scales the image to that size, without actually resizing the image. |
|
Michael Myers, Photographer
|
Miami Beach | FL | USA | Posted: 1:39 AM on 02.17.05 |
->> First, why do you recommend "unsharp mask" rather than "sharpen"?
Second, do any of the other image viewing programs show what the image will really look like when reduced, if Photoshop doesn't?
........hmm, thanks to an email from Kirt Winter, I now know why the image looks the way it does. Photoshop uses a method that is very fast, but not really representative of what the final image is going to look like when reduced.
What's been botherng me here, is many of the images I shoot just don't "look" sharp when I view the photos I've taken, but when I get done with them and they're posted on the web, or printed in a magazine, they all look just great. I'd really like to know how good they're going to look when I view them on-screen (and at this point, since I've not done any sharpening at all, they just don't have that crisp sharp look that I like to see). |
|
Zach Honig, Student/Intern, Photographer
|
Columbia | MO | USA | Posted: 2:07 AM on 02.17.05 |
| ->> There is no control over sharpness when using "sharpen". Yes, you can "sharpen" and "sharpen more", but try "unsharp mask", you'll have much more control over the sharpness of you images. |
|
Nathan Simpson, Photographer, Student/Intern
|
Santa Barbara | CA | USA | Posted: 3:08 AM on 02.17.05 |
| ->> There are about 10 different ways to sharpen an image that I know of. You can use the not that great standard sharpen settings or the slightly better unsharp mask (normal mode). Or you can go for much more control but more time to. You can duplicate your image layer select other>high pass filter, "zoom in" adjust it so you can kind of see the lines, then blending mode overlay "medium", soft light "softer", hard light "really sharp". You can also adjust the opacity of the layer to control it. Another way is lighten/darken sharpening. Duplicate your image layer twice. Set one to blending mode lighten then the other to darken. Then apply an unsharp mask to both. This way you can control how sharp your highlights and shadows are individually you can adjust the opacity for this one as well. You can also use high pass for lighten/darken sharpening. There are more ways but these are the most common of the of the "high control ways” the other ways like channel sharpening are usually reserved for files that have been interpolated huge amounts. |
|
Ron Holman, Photographer
|
Visalia | CA | USA | Posted: 3:21 AM on 02.17.05 |
->> If you use Unsharp Mask, you'll find three variables: Percentage, Radius, and Threshold.
Percentage- the gas pedal for this filter.
Radius- how far from recognized edges the change is made.
Threshold- determines what areas the filter is applied to.
At our paper we start at 200%, .8 pixel and 4. I have read that values over 1 pixel in radius promises a reduction in detail. Raising the threshold applies the filter to a lesser degree. |
|
Mark Loundy, Photo Editor
|
San Jose | CA | USA | Posted: 3:54 AM on 02.17.05 |
->> Michael, Photoshp is better at drawing images at certain percentages. For example, you might find that an image appears sharper at 50% then is does at 63% It has to do with the math related to thhe screen resolution. This only applies to zooming into an image. The effect goes away when you actually crop it.
If you want to see the true appearance of an image on your screen, crop it and display it at 100%
--Mark |
|
Zach Honig, Student/Intern, Photographer
|
Columbia | MO | USA | Posted: 10:42 AM on 02.17.05 |
->> Ron,
What's the advantage of applying a threshold over lessening the percentage? |
|
Jerry Lai, Photographer, Assistant
|
Evanston | IL | USA | Posted: 11:07 AM on 02.17.05 |
->> Zach -
The percentage sliders tells you HOW MUCH to sharpen.
The threshold slider essentially controls WHERE to sharpen. Adjusting the threshold prevents you from sharpening the whole image... for example, you probably wouldn't want to sharpen the sky or the basketball court or something else uniform like that otherwise it will probably start looking grainy/pixelated. The threshold slider is based on tonal separation. The higher the value, the greater the difference two areas have to be before it gets sharpened. |
|
Zach Honig, Student/Intern, Photographer
|
Columbia | MO | USA | Posted: 11:10 AM on 02.17.05 |
| ->> WOW, I can't believe I never realized that. Thanks a bunch, it makes quite a difference! |
|
Ron Scheffler, Photographer
|
Hamilton (Toronto area) | Ontario | Canada | Posted: 4:31 PM on 02.17.05 |
->> Be careful with the threshold slider. As Jerry suggests, threshold determines which areas in the image to apply the sharpening to. The higher the threshold value, the less areas of a similar color/contrast will be sharpened. So, you can end up with a combination of smooth, unsharpened areas and very sharp grainier areas. To me that doesn't look good... It's personal preference, and I like to keep threshold low (usually at zero) and don't mind the slightly "grainy" look produced by USM. Gives some 'bite' to the image - but again, that's my preference. Really, USM needs to be evaluated for each image and is very much a matter of personal taste. USM variables also need to be evaluated with the final size of the image in mind. This is one of the reasons why USM is often suggested as one of the final image adjustments. No point sharpening an image if it will be reduced in size later (requiring another pass of USM) or worse, if it will be enlarged, the image will have been degraded by the first application USM. For web images, try a high amount and a very low radius (maybe 0.3).
Also, Mark Loundy makes an important point about the percentage at which the image is viewed on screen. Try to avoid the 33.3 and 66.7% settings in PS. 50% is better, or 100% (but that is often larger than the image will actually be printed - unless it's for screen viewing). If it's for web work, then 100% is best. After applying USM and if you view at one of the 'odd' percentages (66.7%), the image will look much noisier than it actually is.
Finally, here's a little trick to try if you have a rather flat looking image that needs a bit of a contrast boost... Use USM, but set the amount to about 10-20%, radius to 50 and threshold to zero... you should see an immediate increase in overall contrast - be careful though, as it can quickly blow out delicate highlight info. Again, play with the sliders to adjust the effect so it is suitable for each image. You can read more about this here: http://www.luminous-landscape.com/tutorials/contrast-enhancement.shtml |
|
Zach Honig, Student/Intern, Photographer
|
Columbia | MO | USA | Posted: 4:52 PM on 02.17.05 |
| ->> Ron, I tried you contrast tip above and WOW! No more "brightness/contrast" for me! |
|
Jeff Kiely, Photographer
|
Tolland | CT | USA | Posted: 5:29 PM on 02.17.05 |
| ->> Zach, check out some of Scott Kelby's photoshop books. If you do a search on the message board you'll find a lot of references to them. They're easy to understand and make sense. |
|
Zach Honig, Student/Intern, Photographer
|
Columbia | MO | USA | Posted: 8:32 PM on 02.17.05 |
->> Thanks Jeff, will do.
Michael, Sorry for taking over your thread, I hope all of your questions were answered. |
|
Tony Gieske, Photographer, Photo Editor
|
North Hollywood | CA | USA | Posted: 9:42 PM on 02.17.05 |
->> Maybe this is OT, but it's about sharpening, and it's for BreezeBrowser users. When I look at my images in BB, they are lovely and sharp with dynamics just so.
But when I pick 'em up in PS, they get slightly grundgy and the dynamics go to hell.
Does any one know a setting that would duplicate whatever it is BB is doing with the images?
BB forums are closemouthed about this. |
|
Gary Gardiner, Photographer
|
Westerville | OH | USA | Posted: 11:09 PM on 02.17.05 |
->> Michael,
Please re-read Mark Loundy's post.
You're problem has nothing to do with sharpening. It has to do with screen interpolation.
Viewing images in Photoshop in any magnification that is not divisible by 25% forces the software to interpolate pixels to properly represent the image. Any other setting, such as 16.7%, 33% or 67%, force dropped pixels and interpolation to show the image on screen.
Test this by opening an image at 100%. Use ctrl/- to step down from 100% through the default resolutions. You'll see the "sharpness" appears skewed at anything other than 75%, 50% and 25%.
It's nothing to do with unsharpen mask. It's a screen image and screen image is not the way to measure proper unsharpen masking. |
|
Michael Myers, Photographer
|
Miami Beach | FL | USA | Posted: 9:09 AM on 02.18.05 |
->> Thanks for all the additional information, as I think I learned a lot from reading what you have all been typing here.
Gary, I know it's not a "fair comparison", but I'm used to looking at an envelope full of 36 prints of my images (in film days) and nowadays I'm used to taking the card of my images and reviewing them on the PC monitor. With my Canon S330, just about all the images look crystal clear, nice and sharp, with vibrant colors... really pretty. However, when I look at the images right out of my D2h, or my D70, not only do they seem relatively lifeless (none of that vibrant color) but they also look quite un-sharp, making me feel that I never got the type of images I was after. I've learned that this isn't really the case, as after I start working with them in Photoshop, I end up with the type of images I wanted, sharp, colorful, and so on. So, I then send the (un-edited) images off to the magazine, along with a note that the images will look better once they've been "photoshopped".
I ran into this at a temple I was shooting near Madurai, India. I took one set of images with my Canon S330, and another set with my D70. When the people there looked over what I had done, the images in the review screen of the S330 "looked" so much nicer than those from my D70. I'm pretty sure that this is because the Canon manipulates the images to make great looking snapshots, and the Nikon is giving me the "real" image, un-manipulated, which I can always make look like the Canon images should I want to (in Photoshop).
What I'd really like right now, is a quick way to review the images I've taken on my computer screen, in some kind of program that's going to show them at their best. If I did my part right taking them, I'd like to see crisp, razor-sharp images, with lots of color. I guess what I'm saying, is I'd like to see them looking as they do when I use the S330 Elph.... ....and before anyone suggests it, I know I can change the settings on the Nikon to boost the sharpness and the contrast and get images that look the way I'm describing, but I also know that when the images reach the editor at the magazine, they won't want me to have done any of that stuff.... they just want the "real" images, and they can/will add whatever they need to make the pictures look their best.
So, do I view my images in Explorer (which usually makes them look nice), Photoshop (doesn't show what the final image will look like unless I really reduce the image size and add sharpness), Nikon View (looks good), or ?????
Maybe it's a stupid thing to ask for, and maybe it's not really possible because of the way computers work, but I'd like to preview what I've done, and have the preview images represent what I'll be able to do later on when I work on the image a little (add sharpness). I'd also like to be able to preview the images with Photoshop's "shadow/highlight" tool automatically applied to the preview. I usually expose my images for the main subject, and some parts of the image can get quite dark. I know from past experience that there's still lots of detail in those dark areas, but I never get to see it until I actually work on the image in Photoshop.... but that's another story. |
|
Return to --> Message Board Main Index
|