resizing vs cropping

[boxer82003]

whats the difference between the two

i guess what im getting at is when i resize an image from 3072x2078

to 1024x768 my picture tends to look less sharp if i crop it then resize it will it bit better whats the best way to make a photo smaller keeping the image quality

[robertwgross]

First, let's get our terminology straight.

If you start from an image with pixel size of 3072x2078, what kind of camera are you using? Hint: common sizes for Canon EOS digital cameras are 3072x2048 or 3152x2068.

If you start from 3072x2048, then you can resample downward to 1024x683. That is taking every third pixel in length and every third pixel in width. That reduces the digital file size by a factor of nine.

If you start from 3072x2048, then you can change the DPI setting from 180 to be 300 or anything else. This effectively changes the dimensions of a print.

If you change out of a TIF (uncompressed image file) to JPEG (compressed image file) then you probably get to choose the factor for compression, which is the same as setting the JPEG quality factor. The more you compress it, the smaller the image file will be. Of course, little by little, you are destroying the image quality.

Now, what are you trying to do?

---Bob Gross---

[boxer82003]

sorry its 3072x2048

i m trying to get the best 4x6and 5x7 prints but also my online photo gallery pics dont look so great after i make them 1024x768

[Scottes]

What program?

Though written for Photoshop, this list of tutorials (http://photography-on-the.net/forum/showthread.php?t=34606) may help with any program, especially the one on Cropping.

[evilenglishman]

whats the difference between the two



cropping is when you select an area of your image and then 'crop' the area so you are only left with part of the original.

resizing is when you take an image and make it bigger or smaller.

[boxer82003]

som from what you guys are saying there is no point really taking a picture in such a high setting if i only print a 4x6 or 5x7 i would be better a a lower resoloution and there would be less resizing =more of an original ?

[robertwgross]

Sometimes you shoot a scene and the lens on your camera is too wide. You get the scene with a very small subject in the center. You can cut that center part out and use it as the whole image. That would be cropping. In that case, you need all of the maximum resolution you can get to begin with, because the finished/cropped image may be only 10% of that.

---Bob Gross---

[ejwebb]

i m trying to get the best 4x6and 5x7 prints but also my online photo gallery pics dont look so great after i make them 1024x768

This is a normal result of downsizing an image as it takes on a softer appearance (someone else may be able to give you the reason why this happens - has to do with eliminating some of the image detail). Sharpening techniques such as applying an unsharp mask to the image is necessary to restore the apparent sharpness of the image. More or less sharpening may be needed depending on the subject matter and the amount of downsizing. The amount of compression applied in your JPEG images for the web also affect the appearance.

Be carefull with sharpening as it can add its own negative characteristics to the image such as increased noise or halos around the edges of subjects. Normally, prints require and can handle more sharpening than images on the web without adverse effect.

i would be better a a lower resoloution

I think you should always shoot in the best quality available unless you have other factors (memory issues, addtional processing when using RAW, etc.) preventing you from doing so. You should capture the best image possible and process for your prints. What if you decide you need an 8X10?

That being said, you should pay attention to your composition when taking the photos to reduce the amount of unnecessary cropping later to get the image you want. Remember to fill the frame with your subject and if it does'nt add to the image leave it out. Just because cropping is easy doesn't mean its the best way to go.

Hope this helps!

[Hellashot]

I have a digital rebel and usually shoot in the largest size. Depending on what I'm shooting, it might be better not to fill the image with my subject so that I can do a 1x1 crop to fit on a 4x6 or 5x7 without having to reduce/alter the image.

I took a quick group photo and ended up with a lot of extra in the image (didnt plan it), and the group ened up fitting perfectly in a 5"x7" crop.

Hellashot

[ejwebb]

Good point Hellashot! I usually try to anticpate a little extra on the long side of the photo so that it can be cropped to 5X7 or 8X10 dimensions.