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Which File Format Is Best?
Most modern digital cameras give you a choice of file formats when saving your image. It’s very helpful to know the benefits (and disadvantages) of each file format so you can make the best decision on the file format to save your images in.
Why do we need file formats?
A standard photo taken with a 4.3 megapixel camera has 4.3 million little pixels, or pieces of information, that comprise the image. Each of those pieces needs to store a red, green and blue color value so the color of the pixel can be recreated by a computer or printer. Each color value records the strength of that color on a scale from 1 to 256.
This is a lot of information! Each pixel needs three bytes to store the three color values, and there are 4.3 million pixels. 4.3 million times 3 is around 13 million bytes, or 13 Megabytes.
If each image took 13 Megabytes of storage, you’d run out of space pretty quickly on your memory card! So the file formats used to save images compress the image down to a smaller, more manageable, size.
JPEG
The JPEG, or JPG format was invented to help make image sizes more manageable. JPEG is the most popular format used in digital cameras today because it’s a simple and versatile format, and is supported by all image related software.
JPEG works by compressing the image to a much smaller size at the expense of some image quality. Normally you won’t see any difference because the JPEG format looks at the image and removes only the information that it can recreate by looking at adjacent pixels when the image is displayed again.
You can specify the amount of compression with JPEG images. Your camera will usually have a quality setting – low, medium or high. Low quality increases the JPEG compression, and although your images will be smaller, they won’t look at good.
Uncompressed TIFF
TIFF is another file format popular because while it still compresses the image, it does so in a way to ensure that the full image can always be restored. There’s no loss of image quality. It works in the same way as ZIP files on a computer. They are compressed, but you can always get the original file back.
RAW
Images stored in RAW format are exactly what the camera ’sees’. There is no processing done by the camera before the image is saved. This is one of the major advantages of RAW.
Remember when I said above that each color value strength is stored on a scale from 1 to 256? Modern cameras can actually detect more than 256 levels of strength. But since the TIFF and JPEG formats don’t allow more than that number, the camera throws the extra information away. The RAW format saves these extra strength levels resulting in a better image with more contrast levels.
There’s another advantage – the camera doesn’t correct for exposure or white balance before it saves in RAW format. Meaning you have ultimate control in manipulating the image in a paint program – so your image looks exactly how you want it to look.
All these advantages come at a cost. RAW images don’t use any compression so they are large files and take a long time to store and copy. Also, there is no single RAW standard for all cameras, so you usually will need to use your camera manufacturer’s software to read the RAW file.
Which format should I use?
While TIFF and RAW do give you superior images, I personally don’t think the hassle of much larger file sizes are worth it unless you have a really high end camera and need to produce really large prints. Not only do the images take longer to save, but you need to purchase larger (and more expensive) memory cards; a larger hard drive; and more CDs to back up to.
The JPEG format is the most popular – and it’s not hard to see why. It provides a much smaller image size without losing a lot of quality. I recommend using the JPEG format set to high image quality on your own camera.
Large Apertures (f2.8 to f5.6)
Large Apertures, such as f2.8 to f5.6, produce shallow depth-of-field. Basically, this means the area of sharp focus in the picture will be small. This can be useful when you want to isolate the subject of your picture while throwing the background and other distracting elements out of focus. Some useful applications of wide apertures include portraits and wildlife closeups.
Small Apertures (f16 to f32)
Small Apertures, such as f16 to f32, increase depth-of-field which means more elements of a picture, from foreground to background, become sharply focused. This can create a distinct sense of depth to a photograph, drawing the viewer into the picture. It’s no surprise that small apertures are a must for most landscape photographs.
Lens “Sweet Spots” (f8 and f11)
Due to technical aspects of lens optics, the mid-range apertures of f8 and f11 often yield the sharpest images. When neither a large nor a very small aperture is needed, these are good apertures to use to maximize the sharpness your lens can deliver.
ISO Explained!
You are probably familiar with ISO on film used in a film camera. It’s the ’speed’ of the film – higher ISO values mean you can take photos in lower light.
But what about in the digital world?
Surprisingly, there is an ISO setting on your Digital camera. And although there is no longer any film, the ISO setting still plays a vital role.
ISO indicates your digital camera’s sensitivity to light. The higher the number, the less light is needed to take a photo that is bright enough (correctly exposed).
In bright light (like the middle of a sunny day), you’ll normally use ISO 50 or ISO 100. These are the lowest settings and can be used because there is lots of light around.
However, in lower light, your camera needs some help. There are two ways of doing this:
Decrease Shutter Speed
With a slower shutter speed, the camera has more time to ‘take in’ the amount of light it needs. Unfortunately though, the slower the shutter speed, the more chance that your images will turn out blurry.
Increase ISO
Rather than decrease the shutter speed, you can increase the ISO. As I said above, this will increase the sensitivity of the camera which means you can get the same shot with less light entering the camera. Thus the shutter speed can be kept low enough to avoid blurry images.
As increasing the ISO will increase the shutter speed, a high ISO will also help when taking fast moving sports shots. You’ll get clear, crisp shots with no blur.
However, I still recommend you use the lowest ISO possible. Why?
Problems of using a high ISO
Using a higher ISO means the camera has less light to work with. Unfortunately this also means that ‘noise’ is introduced into your camera. Your camera’s highest one or two ISO values will produce a lot of noise in your image, so I suggest avoiding them unless the light is so low that you have no other choice.
Auto ISO
Fortunately most of the time you don’t need to worry about selecting the correct ISO. Most cameras have an “Auto ISO” setting. With Auto ISO, the camera will look at the amount of light in the scene and change the ISO appropriately so that the shutter speed doesn’t get too slow.
ISO Values
If you choose to use a manual ISO, what values should you use?
ISO 50-100. Suitable for bright light (like outdoors on a sunny day.
ISO 200. Great for overcast or cloudy days. However on budget cameras some noise will be seen in your image.
ISO 400 and above. Use for indoor or night shots (even if you use a flash). Also useful to freeze the action in sports shots. These values will produce the most noise.
sir Send me the detial of iso .who can effect on our picture.and whta is the reason on our pic .and when we used the Iso .where used the iso 200.400,800…….. plz sir tell me all detial of ISO.
i m very thanksfullto u
REG
Saqib
@ Saqib: If you are taking the photo in outdoor with ample of light, then select lower ISO like ISO100.
If you are taking the photo in dark place then select higher ISO, like ISO 800 and so on.
*Higher the ISO. higher the noise in the photo.
aBrKci hi great site thx http://peace.com
This is the second time I am stumbling to your photoblog. Love all your photos! Great work. Keep it up.
Dear Sathiyan,
I am amazed to all the pictures you have taken, they are really cool.. I am stumbled by some of the picture you have taken in Magaral since I know it very well, I lived in Arpakkam. Are you from Magaral?
Keep your good work going!
Bests,
Nambi.
@ Nambi: Thanks for dropping in Nambi. I am not from Magaral. But I often go to Magaral to visit my uncle & aunt.
Nice Article Sathiyan.
I normally take many shots in RAW. After seeing it in my computer, i will convert some to jpeg.
There is one more file format becoming popular.
DNG – Digital Negative
Adobe has created it. Many new cameras support DNG format. I think the idea of creating this format is to make things standard. Nikon RAW files have .nef extension and canon RAW files have .cr2, i think.
It has all details as in RAW file. You can use adobe camera raw to open it and do all adjustments as you do with a raw file.
The file size is little less compared with RAW. Adobe has DNG converter.
http://www.adobe.com/products/dng/