Posts Published in December 2009

Why Higher ISO Leads to Larger File Sizes

Something you may have noticed when adjusting your camera’s ISO setting is that as you increase ISO, the number of remaining shots you have decreases. This is because the size of each photograph increases with ISO, and thus less of them can be stored in the available space of your memory card.

So why does the file size increase as you increase ISO? The answer has to do with image noise and file compression. First we’ll discuss the noise element.

Image Noise

You probably know already that a higher ISO number leads to more noise in the resulting image. This is because digital cameras achieve the same behavior of “more sensitive film” by amplifying the image signal the camera receives when it captures a photograph. This amplification also amplifies the noise that exists in every image regardless of ISO, and therefore higher ISOs have highly amplified noise.

To demonstrate, I captured the following photograph at both ISO 100 and ISO 3200:

Here’s a side by side comparison of crops from the two images:

The noise should be pretty obvious. The RAW file of the ISO100 version is 10.2MB in size, while the ISO3200 version is 14.7MB. In this case, the higher ISO leads to a 44% larger file.

An interesting property of digital cameras is that there is more noise in darker regions of photographs than brighter regions. The opposite is true for film. This means that the file size difference discussed here will be far less when shooting with more light, such as when you’re photographing outdoors.

As an example, here is another scene that I photographed first at ISO100, and then at ISO3200:

Though there is still a significant amount of noise in the image, the ISO100 photo has a 15.8MB file size, while the ISO3200 photo is 16.7MB. This means that for this outdoors shot, the higher ISO only caused a 5.7% increase in file size. There’s other factors that will cause this percentage to fluctuate, such as the complexity of the scene, but in general the percentage should be less when photographing with more light.

File Compression

Now that we’ve shown the increased image noise that comes with higher ISO numbers, we’ll discuss why this causes the file size to increase.

Regardless of whether you’re shooting RAW or JPEG, it’s likely your photographs are stored in a compressed format. While some cameras allow you to choose whether and how files are compressed, RAW images (i.e. Canon’s CR2 format) are usually compressed using a lossless algorithm, meaning the exact original data can be reconstructed from the compressed data. On the other hand, JPEG is lossy, so the more you work with JPEG files, the less data you’ll have as the compression throws out more and more data.

Here is a sequence of images from Wikipedia showing lossy compression (with PNGs):

The image on the right is the most compressed, and therefore has the least information. There is no way to recover the original detail from the compressed image to reconstruct the original (on the left), since the information was thrown out in order to save space when compressing the file.

The reason noise increases file sizes is because image compression relies on repetition, or patterns. In images with less noise, there are more areas of consistent patterns (i.e. the clear blue sky) that can be compressed. On the other hand, when noise is introduced, these adjacent areas that could have been grouped together and compressed must be split and stored separately, since the noise introduces randomness that cannot be compressed.

Here are four different 100×100 JPEG squares, saved with the same image quality:

On the left is a square with solid blue, which affords maximum compression and therefore the smallest file size. The second square has two shades of blue, alternating by row, while the third square alternates by column. Due to the way the JPEG format compresses images, the second square can be compressed more efficiently than the third, even though both contain exactly the same number of pixels of each shade. Finally, the last square has artificial noise added in using Photoshop. This noise introduces randomness, which results in the least compression and the largest file size.

Now, for a super simplified example of compression, consider the following “photo” with 3 “pixels”:

Since all three pixels are the same, instead of storing the data for all three, one possible way I could “compress” the photo would be to store the color information once and just remember that the entire range of pixels is that color. (i.e. Pixel 1-3 = Blue)

Now, lets say some “noise” is introduced, which changes the image to the following:

Now I can’t specify a single range and a single color, since the sequence has been interrupted. The best I could do might be to say (Pixel 1 & 3 = Blue, Pixel 2 = Yellow), which obviously takes more information to represent.

This isn’t exactly how image compression works, but hopefully you get the point that randomness interferes with compression.

Conclusion

In this post we showed that increasing ISO causes increased noise, which in turn causes larger file sizes due to inefficient file compression. Many of you more advanced photographers might have known some (or all) of this already, but hopefully it was illuminating for some of you.

Photographer Cries Wolf? Contest-Winning Shot Allegedly Staged

Spanish photographer José Luis Rodriguez recently received the prestigious winning title as the Veolia Environment Wildlife photographer of the year, along with £10,000 (about $20,000 $16,000) in prize money for his image, Storybook Wolf.  The photograph depicts a rare, Iberian wolf hopping a fence to enter a corral where the photographer had placed meat to attract the animal.

However, rival photographers along with a wolf expert allege that the shot was set up, suggesting that the wolf would not naturally jump over the fence, but would be more likely to squeeze through the openings.  Additionally, they allege that Rodriguez may have used a captive, tame wolf from a zoological park near Madrid, and trained the animal to hop the fence until he got the shot.

The contest prohibits use of a captive animal unless specified in the description, and the judges noted they would give preference to photos of natural wild animals.

The description that ran with photographer Rodriguez’s image explain the painstaking efforts he made to get the shot, baiting the wolf with meat, camping out and anticipating its entry into the corral.

Now, the photographer not only has prize money and the winning title at stake, but now his reputation as a photographer is on the line as judges decide the image authenticity during the next few weeks. However, the Guardian quotes contest judge Rosamund Kidman Cox, who said,

But until one bit of evidence can be verified I don’t think it’s possible to accuse the photographer of cheating. […] It’s not 100%.

(via The Guardian)


Image credit: Storybook Wolf by José Luis Rodriguez

NASA Showing Some Serious Nikon Love

Nikon announced today that NASA has placed an order of 11 D3s full-frame DSLRs and 7 Nikkor 14-24mm f/2.8 lenses. The bodies each retail for about $5,000 while the lenses cost about $1,800 apiece, so NASA spent about $67,600 on this gear purchase. NASA’s budget is currently over $17 billion, so they spent roughly .0004% of their annual budget on this camera gear.

The unmodified equipment will be sent up to the International Space Station (ISS) to document the various activities that go on inside.

If you’re wondering why they purchased 4 fewer lenses than camera bodies, it’s because the ISS already has over 35 lenses on board for photography both inside the space station and out in space.

Nikon has a relatively long history with NASA, first providing the agency with Nikon Photomic FTN cameras for the Apollo 15 mission in 1971, two years after NASA first photographed the moon with specially modified Hasselblad cameras.

There are all sorts of reasons being suggested on the web for why NASA chooses Nikon gear over Canon gear in the DSLR era, but it would be interesting to hear the exact reasons straight from the horses mouth.

(via The Imaging Resource)

Photos of the New Samsung Pseudo-DSLR System

Samsung is releasing a new hybrid digital camera system sometime in early January of next year called the NX Series. The idea is that the new series would combine the advantages of DSLR and point-and-shoot cameras. Before we go into some details, here are a couple photographs of the actual camera that were posted to dpreview’s forums.

The camera has the form of a DSLR, but uses an electronic viewfinder, allowing them to remove the traditional mirror system in DSLRs to make the camera smaller and lighter (and probably virtually silent). Though it has the portability of point-and-shoot cameras, it still offers a DSLR-style sensor for higher quality images, and an interchangeable lens system.

The decreased distance between the lens and sensor allows the system to use lens designs that traditional SLR/DSLR cameras could not support (similar to the crop sensor lenses of Canon/Nikon). Here are a couple photographs of the 30mm f/2.0 “pancake” lens that were posted to the k-rumors forums.

If that’s not a “compact” lens, I don’t know what is.

Though DSLR enthusiasts might not be too enthusiastic about the electronic viewfinder, the portability is something that will likely be a hit among people who would like to do DSLR style photography but don’t want to lug around bulky equipment. The company estimates that the hybrid digital camera market will have a 20% market share by 2012.

What are your thoughts regarding the NX Series?

(via Photo Rumors)


Image credits: Camera body images from dpreview, lens images from k-rumors.

Two Largest Photographs in the World

It’s quite a coincidence, but two of the largest images in the world were both announced recently. These images were created by taking thousands of individual high-resolution photographs and stitching them together to create gigantic panoramas.

Dresden – 26 gigapixels

The first, and the largest image in the world currently in terms of megapixels, is a panorama of Desden, Germany. It boasts a whopping 26 gigapixels:

desden

It was created using 1,665 individual 21.4 Megapixel photographs taken with a Canon 5D Mk II and a 400mm lens. A robot was used to shoot the photographs, and spent 172 minutes capturing the images. The 102 gigabytes of RAW data that resulted took 48GB of memory, 16 processors, and 94 hours to convert.

The photo was taken on the roof of the building “Haus der Presse” and starts at the left side with the Ostragehege. You can see the Congress Center and the Maritim Hotel rightwards. In the center is the city of Dresden with the famous Semperoper (back view), the castle and the Church of Our Lady. In the background is the television tower and you can identify outlines of the Saxon Switzerland. In the right part you can see the south of Dresden.

Prague – 18 gigapixels

This second image has less gigapixels than the previous one, but is a 360-degree panorama, meaning you can look in every direction:

prague

Hundreds of shots were taken over a few hours, and weeks were spent stitching the image. It was created by Jeffrey Martin the founder of 360cities.

Gigapixel Dresden (via PhotographyBLOG)
Prague TV Tower (via TechCrunch)

Nikon Releases Interesting Survey Results

nikonlogo100pxNikon recently conducted a survey called “Picture Yourself”, and released some interesting findings today, a lot of which reveals things about the way people view themselves. The survey was conducted using random telephone dialing, and sampled 1000 Americans 18 and older.

If only we had thought of some of these questions for our weekly polls… Maybe we’ll use a few in the future.

Anyhow, here were some interesting findings:

  • 25% would choose to retake a family photo if they could turn back time
  • 92% of adults had at least one photograph taken of them so far this year
  • 79% believe they look better in person than in photographs (do you?)
    98102794_39ef3eae1f
  • 26% chose weight as the feature they dislike the most in photos
  • Men have an average of 73 photos taken of them, while women have only 38

Are there any other questions you wish Nikon had included in the survey? Let us know, and we’ll conduct “research” with PetaPixel polls!

(via The Imaging Resource)


Image credit: Mirrored self-misidentification by eqqman

Photosimile: An Office Machine for Product Photography

photosimile

At CES 2010 next year, photography automation company Ortery will unveil the Photosimile 5000, a device that they claim is the “next generation imaging device for the office.” Essentially it’s like a copier, except for stock/product photography. You can simply walk up to the machine, place what you’d like to photograph inside, adjust a few settings on the parameter, and walk away with a professional looking product photograph. The computer-operated system automatically adjusts lighting to remove shadows, and takes care of handling white balance.

This isn’t exactly news for photographers, but it’s interesting to see the landscape of what’s out there and what’s to come.

(via The Imaging Resource)

Ho Ho Ho! A Lensbaby Christmas Giveaway!

Update: This giveaway has ended. The winner was randomly selected and announced here.


Hello all you awesome readers out there! To celebrate this Christmas season, we’re going to be giving away a Lensbaby Composer lens + a Creative Aperture Kit (a $280 value).

composer

To enter, all you need to do is answer the following question:

What’s the first item on your wishlist for Santa?

There are two ways to send your answer to us, and if you use both ways you will receive two entries in this contest:

  1. Leave your response as a comment (on this PetaPixel.com post)
  2. Tweet your response, and include the following link to this post anywhere in the tweet: http://j.mp/ppchstms

    If the link appears in your tweet, then the elf Santa loaned us will automatically find it and count it as an entry. If you don’t include the link, then the elf won’t be able to find it and it won’t be counted.

We’ll be picking a winner randomly on Christmas morning – December 25th, 2009. Good luck!



A big thanks to our sponsor Lensbaby for providing the prizes for this giveaway!

FlickrPoet Transforms Poems into Photographs

flickrpoetlogoFlickrPoet is a neat little web-app built by Thomas Sturm that turns text into photographs using Flickr’s API. Though the concept is extremely simple and only somewhat novel, the results can be quite beautiful.

Feed it some poetry, song lyrics, or even random text, and watch the photographs begin to fade into existence. Here’s a screenshot made with the help of the quick brown fox (not a poem, I know).

flickrpoetscreen

The only change I would suggest to Sturm would be to provide permanent links to result pages so people can share their “FlickrPoems” with one another.

If you find any text that returns interesting results, please share it with us in the comments!

FlickrPoet

A Digital Dog Tag for Your Lost Camera

youmusthavefound

Recovering your camera after losing it is one of those things that most people don’t really think about until the situation actually arises. If you were to lose your camera today, would anyone be able to return it to you?

Andrew McDonald‘s solution is to always keep his email address in a photograph that never leaves his camera.

Anyways-Can-you-email

In fact, he keeps a whole series of photographs that help him “speak” to the stranger (or thief) that found his camera.

It’s a pretty clever idea, since someone who finds a camera is bound to look through the photographs stored on the memory card. You don’t even need to take a fancy photograph – a simple hand-written note should suffice:

IMG_5107

The reason you should save your contact information as a photo on the memory card rather than as a text file is because the text file won’t show up when viewing the photographs using the camera. Even if the person who finds your camera is tech-savvy enough to browse through the card using a computer, they might not see a text-file intended for them no matter what you title the file.

A problem with this simple approach is that simple altruism isn’t enough of an incentive for some people to return the camera rather than to keep it or sell it. Thus, the following “digital dog tag” might have a higher chance of success:

IMG_5106

Notice how the prize is completely ambiguous. This might be a good way to get the finder to email or call you so you have some tangible link to your camera. What you choose to offer them as a “prize” is up to you. How much is your camera worth to you?

For the rest of Andrew McDonald hilarious set of images, check out the following link:

A Pictoral Guide to Avoiding Camera Loss