Photo Tips: Shoot­ing RAW

Howler Magazine - - Contents - By Gre­gory Basco

Begin­ning pho­tog­ra­phers may hear a lot about the RAW im­age for­mat. Pro­fes­sion­als shoot RAW. Should you? The most com­mon im­age for­mat out there is JPEG. If you're a hob­by­ist and want to pro­duce pic­tures ready to print and share, get out there and shoot in JPEG. Just be­cause you don't shoot RAW doesn't mean you can't take good pho­tos.

But if you're look­ing to take your na­ture pho­tog­ra­phy to the next level, RAW is for you. Why? JPEG files don't make use of the vast ma­jor­ity of in­for­ma­tion modern dig­i­tal cam­eras are ca­pa­ble of cap­tur­ing. RAW files do, and that trans­lates ul­ti­mately into more con­trol over im­age op­ti­miza­tion and high­erqual­ity large prints.

Here's how it works. Each pixel on your cam­era's sen­sor con­sists of three color chan­nels — red, green, and blue. JPEGs are 8 bit files, mean­ing 8 bits of binary in­for­ma­tion (1s or 0s) are pos­si­ble for each color chan­nel. Rais­ing 2 to the 8th power (for each chan­nel, ei­ther a 1 or a 0 is pos­si­ble 8 times) gives 256 pos­si­ble com­bi­na­tions for each color chan­nel. Since there are three col­ors, we take 256 to the 3rd power (red, green, and blue), which yields a to­tal of around 16.7 mil­lion pos­si­ble color val­ues in a JPEG im­age. Sounds pretty good, right?

But now let's look at RAW files. Most cam­eras these days cap­ture RAW files with 12 bits. Us­ing the same math as above, we have 12 pos­si­ble binary out­comes for each color chan­nel. So, 2 to the 12th power is 4,096. If we take those 4,096 pos­si­ble tonal­i­ties for each color chan­nel and look at all of the pos­si­ble color val­ues for the three color chan­nels com­bined, we can take 4,096 to the 3rd power. This yields over 68 bil­lion color pos­si­bil­i­ties. So, a RAW file has over 4,000 times as much po­ten­tial color value in­for­ma­tion as a JPEG file. Put an­other way, if you shoot JPEG, you're only us­ing about 2.5 per­cent of the pos­si­ble color in­for­ma­tion your cam­era is ca­pa­ble of record­ing!

In ad­di­tion, JPEG files are com­pressed in a lossy fash­ion, which means some of the rel­a­tively lim­ited in­for­ma­tion cap­tured in the first place is thrown away to keep file size smaller. So, on top of the fact that JPEG files start with less in­for­ma­tion than RAW files, some of that in­for­ma­tion is then dis­carded dur­ing the com­pres­sion process. RAW files also are com­pressed, but use loss­less math­e­mat­i­cal al­go­rithms so no im­age data are thrown away.

Most pros want to be in con­trol of how their images look when they go on the web, for fine art print­ing, or for a mag­a­zine or cof­fee ta­ble book. RAW files take ad­van­tage of your cam­era's so­phis­ti­cated im­age cap­ture ca­pa­bil­i­ties and al­low you to stay in con­trol of op­ti­miz­ing your com­puter images. You can even shoot RAW with many smart­phones on the mar­ket today!

I used a long ex­po­sure and two flash­lights to pho­to­graph a high­land swamp at night on Cerro de la Muerte high in the Tala­manca Moun­tain Range. Long ex­po­sures pro­duce noise, and shoot­ing in RAW al­lowed me to re­duce the noise in the com­puter.

Land­scape shots are chal­leng­ing be­cause of the dif­fer­ence in bright­ness be­tween sky and fore­ground. Be­sides us­ing a grad­u­ated fil­ter to en­sure the best ex­po­sure pos­si­ble for this photo of the Poás Vol­cano, shoot­ing in RAW meant I could lighten shadow ar­eas where nec­es­sary with­out de­grad­ing my im­age.

I loved the dreamy back­ground in this im­age of a tiger heron in Tor­tuguero Na­tional Park. JPEG files are sus­cep­ti­ble to pos­ter­i­za­tion in pho­tos like this be­cause the lack of color in­for­ma­tion can re­sult in abrupt tran­si­tions through­out a smooth back­ground. RAW helps keep things clean.

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