Posts Tagged ‘jpeg’

A Higher Quality Setting in Photoshop Sometimes Reduces JPEG Quality

While looking into the new compression service JPEGmini yesterday, the following statement caught my eye in an interview they did with Megapixel:

[...] sometimes you increase the quality setting in Photoshop and the actual quality of the image is reduced…

I had never heard of that before, so I decided to dig a little deeper.
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JPEGmini Magically Makes Your JPEGs Up to 5x Smaller

JPEGmini is a new image compression service that can magically reduce the file size of your JPEG photos by up to 5 times without any visible loss in quality. ICVT, the Israeli company behind the service, explains how the technology works in an interview with Megapixel:

Our technology analyzes each specific photo, and determines the maximum amount of compression that can be applied to the photo without creating any visual artifacts. In this way, the system compresses each photo to the maximum extent possible without hurting the perceived quality of the photo.

You can test out the technology on your own photos through the service’s website.
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Example Showing the Benefit of RAW’s Higher Dynamic Range

One of huge benefits of shooting in RAW is that RAW files usually have considerably more dynamic range than a JPG. This means that details in the shadows and highlights of an image that would otherwise be lost if shooting JPG are stored in the RAW file, and able to be recovered if needed during post-processing. Reddit user Jake Kelly shot the photo on the left of his friends in a dark movie theater, severely underexposing the image but avoiding hand-shake with a shutter speed of 1/60. A quick adjustment in Lightroom helped him recover a ton of detail that definitely wouldn’t be possible had he been shooting in JPG (try taking the JPG on the left and getting the result on the right).

For a more in-depth look at this topic, you should read the “Dynamic Range & Exposure Compensation” section of the RAW tutorial over on Cambridge in Colour.

(via Reddit)


Image credits: Photographs by Jake Kelly and used with permission

Google Wants to Speed Up the Web by Killing the JPEG

Google unveiled a new image format today called WebP that it hopes will make the web faster by cutting files sizes of images without affecting quality. According to a blog post they published earlier today, photos and images account for 65% of the bytes transmitted by websites. In their tests done using 1 million randomly selected images from the web, re-encoding images as WebP resulted in an average file size reduction of 39%. Here’s a gallery with image and file size comparisons.
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Saving JPEG Photos Hundreds of Times

Most of you probably know that JPEG is lossy compression method, meaning compression permanently throws out data and detail. Luckily, a typical compression can save 10 times the space of an uncompressed image without sacrificing much noticeable quality. However, if the image is repeatedly compressed and saved, artifacts introduced during compression become more and more obvious.

Reddit member Grundle decided to see what repeated compression looks like by saving the same image over itself 500 times at high quality (10/12 in Photoshop). He then combined the images into the following video:

10 months ago another Reddit member elezeta did the same experiment, compressing a JPEG 600 times:

I think it’s pretty clear why you should always work with RAW files if you care about the quality and longevity of your work. Every time you save those JPEG photographs, you lose a little piece of awesomeness.

Shadow of a Tennis Ball

Here’s a photograph I randomly snapped on a tennis court a few days ago:

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It was taken with my Sony DSC-P200, a 7.2 megapixel point-and-shoot camera released back in 2005. Compared to my Canon 40D, the image quality is much less contrasty, and much duller. One of the things I like to do to quickly and easily improve photos from the P200 is to process the JPEGs in Adobe Camera Raw as though they were RAW files (though it’s less flexible compared to if you shot a RAW file).

In Adobe Bridge, you can right click the photograph and click “Open in Camera Raw…”, or press Ctrl+R.

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This allows you to use the sliders and tools provided by ACR rather than processing the JPEG in Photoshop.

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For this particular photograph, I made the following edits:

White Balance and Exposure : Unchanged. I liked the warm look of the photo, and the exposure looked fine.
Recovery: +50. Certain areas of the photograph were clipped due to the harsh sunlight. By sliding recovery upwards I can get some of the detail back in those areas (like the glow on the side of the tennis ball).
Fill Light: +20. I wanted to boost some of the shadow areas to make the difference between shadow and highlight less pronounced. Moving recovery and fill light up helps to even out this difference. Careful though… too much of either will make your photograph look either murky or strange.
Blacks: +10. Look at the photograph. There doesn’t seem to be any black, and everything’s gray. Increase the black point to where the darkest of those gray pixels become black.
Contrast: +70. We lost a lot of contrast when evening out the shadows and highlights via the recovery and fill light sliders. Get this contrast back with the contrast slider (or the tone curve section for more control).
Clarity: +30. For photographs with a murkiness due to near-direct sunlight, I’ve found that increasing clarity helps to improve the look of certain areas, like the hairs of the tennis ball.
Vibrance and Saturation: Unchanged. I could have dropped one of them to make the colors more natural, but I liked how it looks a little over-saturated.

Here’s the final condition of these main sliders:

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I also did sharpening amount +80 and lens vignetting -50.

Here’s the final result of fiddling with 7 sliders total in ACR (hover over it to compare it to the untouched image):

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Using Adobe Camera Raw (or Lightroom/Aperture) to post-process your JPGs is a really quick and easy way to give them an extra boost.

If you have any questions, comments, or suggestions, please leave a comment!

See you all next Monday, when we post an interview with Otto Kitchens.

Happy shooting!

MIOPS: Smartphone Controllable High Speed Camera Trigger

MIOPS is a new smartphone-controlled camera trigger that combines all of the features photographers want in a high-speed camera trigger into one convenient device.

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