The image formats - Photography Course - Lesson 22

This article is part of the online digital photography course.

Before starting photographing it's better to set the format in which our pictures will be saved on the flash card, there are different formats and we choose, depending on our needs.

Personally, I always set the format with the highest image quality, that is the RAW, while if I have to take pictures with friends or family I use the Jpeg format.

Let's see in details the various image formats on my Nikon D90, under the voice "image quality".
  • RAW: This format, as its name suggests, contains all the information captured by the camera sensor, compared to the jpeg allows a greater freedom of movement in post-production without great data loss. This format being not compressed is "heaver" in terms of disk space, for its traits is considered the digital negative, it's not present on all cameras but just on those of medium-high level. Moreover shooting in RAW ensure us at least one or two stops more of dynamic gamma compared to the jpeg images.
  • JPEG: As you can see from the image we have three kind of jpeg, fine, normal and basic, they are three compression levels, the fine is the less compressed and of higher quality one. This is the format normally used to publish pictures on the web, it's a good compromise of quality and size, the better the quality the more space the image will require on the disk and vice versa. After the Photoshop elaboration of the RAW file I usually save the file in Jpeg in my personal photo gallery. Remember that every time you open a jpeg to make some modification, at the moment of the saving it's compressed again, basically it loses quality, hence never delete your RAW files that may be necessary to modify your picture again.
  • RAW+JPEG: The camera save the same picture in both Raw and JPEG, I consider useless this mode because by saving two times the same picture you can shoot less because you fill your memory card at a faster rate. With the modern computers converting a picture from RAW to JPEG is a fast operation that doesn't require a long time anymore.
  • TIFF: It's not present on my camera menu but I'll explain anyway what it is: like in the RAW the image is not compressed, so the quality is equal to the RAW but the TIFF is usually big about the double, Why? The RAW unlike the TIFF is not a universal format. Every manufacturer use its own and not every image elaboration software can open the RAW of all the manufacturers, the TIFF instead is universal, but for the same reason it saves the information in a less efficient way.
Aside the registration formats on the memory card there are also export format, that are those format used to export the image from an image elaboration software after the post production. To us photographers it’s important to know just two export formats:

  • Adobe photoshop export format (.psd): By exporting the photos in this format we save all the settings and the levels applied to the image, this way is possible to modify the parameters at our liking and export the picture in another format. I'll make a practical example: I save my photo on the pc, the file is in RAW format, I open it with Photoshop, I set the lighting, contrast, create levels etc..., at this point I have two options, I can save it directly in JPEG and if I were to rethink about something I must modify again the RAW from the start, or I can save it in .PSD format that allows me to go back on my modifications and export the file in JPEG or other formats.
  • JPEG export format: We have just talked about it, remember that when you load a picture on the web, no matter if on your portfolio or on a forum etc... you should resize it, an image of 4288x2848 pixels will be extremely heavy to load an useless for the web vision where the most you could use is an image of 1200 pixel on the widest side. WARNING when you work on a JPEG and save the work it is compressed again, never re-elaborate a JPEG because it’s compressed at any new save!

Translation by Nina Kozul

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