RAW vs. JPEG

What is the difference between the two file types? Well, JPEG (aka Joint Photographic Experts Group) is a is a commonly used method of compression for photographic images. The degree of compression can usually be adjusted, allowing a selectable trade off between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. Hmmm ... "perceptible loss in image quality". Even though there is the word "little" in front of perceptible there is still a loss in image quality. JPEG compression, in my opinion, is a lousy format that throws away the data that you can’t see in order to give you smaller file sizes, but if you don't need high quality images and need a small file size JPEG is definitely for you.

Then what is RAW? A RAW image file contains minimally processed data directly from your camera's image sensor. RAW format is completely loss-less and keeps every piece of data your camera captures (even if you don’t need it). There is one down side though ... RAW format requires a good bit more space on your memory card because it does store every bit of information from your camera's sensor. However, a RAW file isn’t technically an "image file" (in the true since of the word). It has to be converted by special software on your computer and processed in order to be suitable for printing or exporting for other uses. So, why shoot in RAW format? Since RAW format stores every bit of data from your camera's sensor if you screw up a picture it is almost always fixable. Lets say you shoot a picture on a bright sunny day (a once in a lifetime photo) and you don't realize that it was overexposed until you get home and view it on you computer -- if you shot in RAW you could easily adjust the exposure to be properly exposed. So to sum this up, If you are not going to bother processing your photos, RAW is not for you.

So what does all of this mean for your pictures? Well there are pros and cons to shooting both RAW and JPEG images. Many people choose to shoot in JPEG format because it is a universal format which can be taken directly off of the camera and shared via email or published to the Internet. JPEG format also requires less storage space on your camera and computer. RAW, on the other hand, requires some post production work. You will need software to properly edit and export your photos. This software sometimes comes with you camera, and sometimes needs to be purchased. Programs like Aperture (from Apple), Adobe Lightroom, and Adobe Camera RAW in Photoshop are great programs for editing RAW files. I, being a Mac guy, prefer Aperture but I also use Photoshop quite a bit. But even if you view photography as a simple hobby, it is still worth investing in photo-management software like Aperture or Lightroom that make organizing, keywording, searching, and editing your RAW photos as simple as working with JPEGs.

I sure hope this helps you with your decision over the "Great Debate" of RAW vs. JPEG.

Bokeh ... What Is It And How Do You Pronounce It?

I believe that bokeh is best explained in the words of Mike Johnston so please read on.

Bokeh in Pictures

I first learned about "bo-ke" or boke in 1995, from Carl Weese, who learned about it from our mutual friend the oracular and extreme Oren Grad, who holds eight Master's degrees, three Ph.D.s, and an M.D., and who evidently taught himself Japanese so he could read Japanese photo magazines. (Perhaps I exaggerate these facts, but only slightly.) I then commissioned and published three articles about it in the March/April 1997 issue of Photo Techniques back when I was editor — one each by John Kennerdell, who is an American ex-pat living in Bangkok, Oren himself, and Harold Merklinger, a high-ranking research scientist in the Canadian defense establishment. It's one of the few issues of that magazine that sold out. My own contribution was...er, a letter. I decided that people too readily mispronounced "boke," so I added an "h" to the word in our articles, and voilá, "bokeh" was born. A Google search for the word "bokeh" just now resulted in approximately 13,300 hits. Seems the idea's gotten around.

Actually, to be precise, what I had noticed was not just that people mispronounced the word as it was commonly spelled, but that they had a tendency to ridicule it, making lame jokes about it as if it rhymed with "smoke" or "toke" or "joke." Actually, even spelled boke, it is properly pronounced with bo as in bone and ke as in Kenneth, with equal stress on either syllable. It is a Japanese word meaning, roughly, "fuzzy," and it is used to describe old people with cobwebs in their heads among several other things — including the out-of-focus areas of photographs, which, I'm told, might more specifically be referred to as "boke-aji."

One of the curious aspects of the phenomenon for me was that some people then, and some even now, respond to the idea scornfully or even angrily. Is this some sort of insistence on conformity, as if you are supposed to look at certain parts of pictures and not others? I never did know, and I probably never will. (But then, there are a lot of things about my native culture that I will just never understand — for instance, rubber suits as erotic accessories, or why it would occur to anyone to hate black people. What's up with that, anyway? I mean, I certainly know that race hatred exists — I just haven't got the faintest idea why).

Now, I have to admit that I got somewhat obsessed with bokeh after I finally became aware of it. It interested me, in particular, that different lenses render blur in different ways. Even knowing that I take things a bit too far, though, it always seemed strange to me that there are people who don't think it's valid to look at the blurry parts of pictures.

Take this picture by Tony Rowlett, for example. It was made with a Leica Noctilux at a fairly wide aperture. I don't think it's possible to look at this and not get interested in what's going on in the out of focus areas, do you? If you really look at it, there are some pretty amazing abstracted shapes and tones. Does anyone really look at a picture like this and completely ignore all the blurry parts? I doubt it.

The most obvious way bokeh gets into pictures, of course, is simply as background. In Robert Harrington's cruel but beautiful picture here, for instance, most of the area of the picture is occupied by bokeh, even though it has nothing to do with the subject of the picture. The picture might be as good with a plain white or black background. Still, if you just look at the bokeh as it exists, it's hard to deny that the color and brightness of the out of focus parts contribute to the sense of a certain kind of light, and the feeling of the outdoors.

Here's a street shot by the excellent '50s photographer Dan Weiner, who has always been one of my favorites. It shows that motion blur can blend with bokeh in interesting ways. (It also shows just how little sharpness really matters in some pictures.)

Some artists go ahead and use bokeh as an integral part of their subject matter. Kim Kirkpatrick made deft use of it as design, as figuration, and as a way to use color abstractly in a large body of work he made over five or six or so years in the '80s and '90s.

Fear Not

It's true that some photographers seldom or never take pictures in which anything is not sharp. For them, bokeh is not much of an issue when they're working, although it's still pertinent when they're looking at other peoples' pictures. For the rest of us, well, there's nothing to be scared of. It's just another arrow in the creative quiver. ~ Mike Johnston

What Is White Balance

White balance (WB) is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photograph. To get your camera to properly display white, as it was seen in person, you must take into account the "color temperature" of a light source. Color temperature refers to the relative warmth or coolness of the white light. Our eyes are quite good at judging what is white under different light sources, however, digital cameras often have difficulty in judging this using the auto white balance setting (AWB). Improperly set WB can create unsightly color casts which are unrealistic. To adjust white balance in traditional film photography required using different cast removing filters, which had to be attached to the lens, for each lighting condition. Digital cameras do not require these filters. Understanding WB can help you avoid color casts that are created by you camera's AWB which will help you improve your photos under a wide range of lighting conditions.

To understand WB requires understanding a little bit about color temperature. Color temperature describes the spectrum of light which is radiated from a "blackbody" with that surface temperature. A "blackbody" is an object which absorbs incident light, neither reflecting it or allowing it to pass through. In simpler terms, think of a piece of metal being heated up. You can heat that metal to become "red hot" and for even higher temperatures it can be heated to be "white hot". In the same instance, "blackbodies" at differing temperatures also have varying color temperatures of "white light". Click here to view a chart of color temperatures of some common light sources.

If you shoot in RAW file format-
RAW is the best, by far, solution to getting the proper white balance. RAW, unlike other file formats, allow you to set the white balance after the photo has been taken using photo editing software.

If you shoot in JPEG or TIFF format-
Most digital cameras, now-a-days, contain a variety of preset white balances. These presets are a good place to start if you have a DSLR camera and work quite well if you are using a point and shoot that has no further adjustments. The best way to set white balance, however, is to use a "18% gray card" and set that as a custom white balance setting. Please refer to your owners manual to see how to set a custom white balance for your camera.

Of course this is just the simplified version of White Balance so to find out more and in more detail please try searching the internet for White Balance. There are many good resources in print and on the internet.

Manual Mode

So you have mastered Aperture Priority mode, Shutter Priority mode, and you know how to properly select your ISO for the lighting ... Well, now you are ready to step into the world of full Manual mode!

The short...
You will need to use what you learned about shutter speed, and what you learned about aperture settings and how they affect DOF (depth of field). You will also need to learn how to read and use the light meter that is built into your camera to select the proper ISO, shutter speed, and aperture.

The long...

Shutter

The shutter is the hole that allows light to enter your camera. If it is held open for a long time lots of light gets through the hole - if it is held open for a short amount of time less light gets through the hole. We discussed this, in depth, in the Shutter Priority mode blog entry. Basically, having a fast shutter speed will allow you to freeze fast action such as sporting events, splashing water, racing, and so forth. There is, however, a drawback to using a fast shutter speed. The faster the shutter speed the less light enters the camera. Conversely, you might want to use a slow shutter speed to compensate for low light situations because the longer the shutter is held open the more light enters the camera. Unfortunately, there is also a drawback to using a short shutter speed. The slow shutter speed is more likely to cause motion blur if you or the subject move while the shutter is open.

In Auto Mode, Program Mode, and Aperture Mode the camera decides what shutter speed is needed. Sometimes the result is what and sometimes it is not because the camera does not know if you want to freeze fast motion or capture a low light portrait. The only thing the camera knows is whether the correct amount of light is entering the camera to produce a proper exposure. However, with the camera in Manual Mode you control the shutter speed to get the shot you want.

Aperture
Although the aperture does open and close which affects the amount of light entering the camera, the main purpose of the aperture is to control the depth of field. Again, the larger the aperture is open the more light gets in and the smaller the the aperture the less light enters. Also the larger the aperture opening the shallower the DOF and the smaller the aperture opening the deeper the depth of field is. To read more about the setting the aperture read the Aperture Priority Mode blog entry.

In Auto Mode, Program Mode, and Shutter Priority Mode the camera decides the aperture setting. The camera only knows how to get a properly exposed photo so with the camera in Manual Mode you can control the aperture setting.

ISO
In Auto Mode ISO is automatically selected for you, but in Aperture, Shutter, and Manual Modes you must select the ISO setting of your camera. ISO is what sets the sensitivity to light of your camera. The higher the ISO the more sensitive the camera is to light which in turn allows you to shoot pictures in lower light situations. To read more see the ISO blog entry.

So to sum it all up Manual Mode puts you in complete control of your camera from the shutter speed to the aperture setting to the ISO setting you get to choose how your picture turns out. My only suggestion is if you have not yet tried out Aperture Priority Mode and Shutter Priority Mode you should try those out first to get a feel for setting the aperture or the shutter. Again this is an advanced mode and you should learn how to properly use the features of you camera before using this setting to produce pictures. This is not what I consider a "safe" setting. Please practice with this setting before using it to take important pictures. Other than that go out and give Manual mode a try!

Shutter Priority Mode

So you've tried Program Mode and Aperture Mode, now you are wondering what Shutter Priority Mode is good for. Well, you are in luck! Because that is what this weeks post is all about. Just in case you don't know this is part three in a four part discussion on advanced camera modes. Alright, lets get started.

Shutter Priority mode will allow you to set the speed of your shutter. So what's the difference between adjusting the aperture and adjusting the shutter? Well the aperture and the shutter do essentially the same function ... they both control or regulate the amount of light reaching the sensor or film when you take a picture. However, the aperture and shutter controls affect a photo in very different ways. The aperture, as we know, adjusts the depth of field while the shutter speed makes a picture sharp or blurry depending on the length of time the shutter is open.

To select the Shutter Priority mode turn the command dial to either "S" or "Tv (meaning "time value")" depending on your model of camera. If your camera does not have a command dial you may be able to select Shutter Priority mode by entering the on camera menu. By selecting this option you will be choosing the shutter speed and the camera will automatically adjust the aperture to properly expose your photo.

So why would you want to adjust the shutter speed? Well, the main reason most people adjust shutter speed is to stop or to show action. A high shutter speed of 1/1000 of a second or higher will stop action and allow you to get a great clear shot of the action. Just remember that as you increase shutter speed you may have to increase your ISO to get a properly exposed photo. Alternately a slow shutter speed of 1/30 of a second or slower will allow the action to blur so that you can show action or movement. Because nothing says "That was really flying by!" like some motion blur. So go out and stop some action using Shutter Priority mode.

Aperture Priority Mode

This is part two in a four part discussion on advanced camera modes.  We will continue to discuss other modes in later posts but this post will deal with aperture priority ... so now its time to get brave and rotate that dial away from the Auto setting and learn how to use the Aperture Priority (A or Av) setting.   

Lets start off with the basics.  Aperture Priority mode lets you select the size of the camera's aperture.  The aperture is the opening that controls how much light reaches the sensor or film at the moment of exposure.  Unfortunately, for most of us, aperture settings are quite hard to understand.  Contrary to what would make sense, the smaller the aperture number the larger the aperture is open and the larger the aperture number the smaller the aperture is open.  There is a reason for this backward looking numbering.   The lens aperture is usually specified as an ƒ number, the ratio of the focal length to effective aperture diameter.  The term "one ƒ-stop" refers to a factor of √2, which is approximately 1.41, change in ƒ-number which in turn corresponds to a factor of 2 change in light intensity.  Wow! Was that way too much mathematical information?  I think so!  So here is the deal … The larger the aperture is open the more light is let through the shutter so you can take pictures in lower light situations.  Unfortunately, and sometimes fortunately, the larger the aperture is open the shorter the depth of field is.  I have supplied some pictures to demonstrate this.

As you may be able to tell, the picture to the left has been shot using a larger aperture opening (ƒ/5 to be exact) and the picture to the right has been shot using a small aperture opening (ƒ/32 to be exact).  Notice how the depth of field changes the smaller you go with the aperture setting.

So what does all of this mean to you?  Well it means that you can set your camera to Aperture Priority mode set your aperture opening and take pictures.  This is a fairly safe way to take pictures, because the camera is still doing half of the work by selecting the correct shutter speed for the ƒ-stop selected.  The best way to get used to using Aperture Priority mode is to experiment with it on a day when you don't need to worry about taking great pictures.  Practice taking pictures with different aperture settings and see how they turn out.  It wont take you too long to figure out how to make the aperture work for you.

Program Mode

Is your DSLR stuck in Auto Mode? Would you like to be able to get more out or your camera? We all know that command dial on the top of our cameras ... most of them have all those great automatic modes like landscape, portrait, sports, and so on. But what are those modes that are just letters? Things like P, S, A, and M or maybe P, Tv, Av, and M ... These are the advanced modes of Program, Shutter Priority, Aperture Priority, and Manual. This is part one of a four part post dealing with the advanced shooting modes on DSLR cameras and the modes that exist on some advanced compact cameras. This particular post will deal with the Program Mode and in other posts to come will deal with the other modes. So lets get started!

Program Mode - If you have only used Auto Mode on your camera, Program Mode is a good place to start. On most cameras Program Mode is selected by moving the Mode or Command Dial to the (P) setting. A lot like Auto Mode, Program Mode still selects the appropriate aperture and shutter speed, so you have no worries about not having a correctly exposed picture. So why use this setting? Well, when using Program Mode, your camera will now unlock some settings that you previously had no control over. These settings vary depending on the camera make and model you own. Some of these settings may be the ability to change the ISO (discussed in a previous blog entry), to change the white balance (which will be discussed in a later blog entry), be able to shoot continuous and self timer modes (the ability to shoot fast bursts of pictures and to be able to push the shutter release button and run to get in the picture), and be able to use exposure compensation (this allows you to adjust the exposure up and down to achieve the proper exposure).

The main advantage to using Program Mode is that it is great for easily getting a great photograph without having to think too hard about settings. But you will now gain some control over advanced settings in your camera. So now go out and give it a try and be sure to check in next week to find out about Aperture Priority Mode.

What Is ISO And How Does It Affect My Pictures

The International Organization for Standardization or "ISO" defines both an arithmetic scale and logarithmic scale for measuring color-negative film speed. Although, in digital camera systems there is an arbitrary relationship between exposure and sensor data values which can be achieved by setting the signal gain of the sensor. So what does that mean for you? Well, ISO is the measurement of the speed of film or how sensitive it is to light. A low ISO film is not very sensitive to light and the higher the ISO rating the more sensitive to light the film is but there is a trade off. The higher you go with the ISO rating the larger the film grain which means that more grain will be seen in the final product. When using a film camera, it is typical to shoot with a low ISO film (ISO 100 or ISO 200) for photography in normal daylight or for portraiture in a properly lit studio (due to the lack of visible grain in the finished product). ISO 400 film is typically used in lower light situations, such as, well lit indoor pictures. ISO 800 and ISO 1600 films are available for photography in very low light situations.

"Here's the secret that governs film speed: Doubling the ISO number of the film doubles its sensitivity to light. So ISO 200 film needs half the light to take the same picture as ISO 100 film. ISO 400 film needs a quarter of the light that ISO 100 needs. In other words, you could capture a low-light scene with a shutter speed of 1/15 second with ISO 100 film, or 1/60 second with ISO 400. That's an incredibly powerful capability that means the difference between getting a blurry mess and a sharp photo." ~ Dave Johnson

Who cares, right? ... I mean we are dealing with a digital camera world. You can't put film in a DSLR! No, but we are able to adjust the ISO of our digital cameras. Which means that by controlling the ISO adjustment on our digital camera we are mimicking loading different speed film into our cameras.


My digital camera shoots at ISO 3200 so I will just set it to that and shoot away. Well, that statement is not necessarily right. There is a down side to shooting at high ISO settings on a digital camera. The big one is that the higher you go with the ISO setting the more "noise" will be visible on the picture. You should always shoot at the lowest possible ISO setting at all times. In most normal conditions, stick with the cameras lowest ISO setting, since that will provide you with a picture with the least amount of digital noise. But when you notice the camera recommending a very low shutter speed (less than about 1/30 of a second for handheld shots) it is time to raise the ISO. Just remember that when you are done shooting at the higher ISO speed to lower it back down so your camera is ready for the next time you use it. To reiterate, do not be afraid to use a higher ISO setting just remember that the higher you go the more noise you are going to see on the picture.

The Difference Between A Full Frame Sensor And An APS-C "Crop" Sensor DSLR Camera

What exactly is a crop sensor camera? Well, a full frame 35mm camera (film or digital) takes a picture that is around 36mm x 24mm in size. When digital sensors were first introduced it was not possible to make a digital sensor that large in any quantity. The ones that could be made were so expensive that no one would have been able to afford a camera that used one. Camera makers decided to make a smaller sensor that was around 15mm x 22.5mm which just happened to be close to the image size of the (short-lived) APS film format. The reason that we call them "crop" is because if you take a full frame image and crop the center 15mm x 22.5mm out of it you get an imager the size or the "crop" sensor.

So what does all of this technical mumbo-jumbo mean for the average photographer? Not a whole lot! For the average user a "crop" sensor camera will provide you with just as high quality pictures as a full format camera, just put your kit lens on it and enjoy shooting pictures. For people that want to learn more read on. Other than the obvious difference in image size the only other difference between the two sensors is the angle of view. Because the APS-C sensor is smaller is has a smaller angle of view than the full frame sensor has. This smaller angle of view creates a something called a "digital multiplier". The digital multiplier is 1.6x for Canon EOS DSLR cameras and 1.5x for Nikon, Pentax, and Sony DSLR cameras. This digital multiplier can work in you favor or it can work against you if you don't understand it. So all this to tell you that if you need a wide angle lens of around 16mm on a full frame camera you will need around a 10mm lens on an APS-C sensor camera to achieve that same wide angle. However, if you need a zoom of around 450mm you only need to buy a 300mm lens for the APS-C sensor camera. So to put it simply...

For Canon EOS cameras:

• APS-C sensor focal length to equal field of view of full frame focal length you multiply by 1.6
• Full frame focal length to equal field of view for APS-C sensor you divide by 1.6
  

For Nikon, Pentax, and Sony cameras:

• APS-C sensor focal length to equal field of view of full frame focal length you multiply by 1.5
  
• Full frame focal length to equal field of view for APS-C sensor you divide by 1.5

Also note that the aperture stays constant because there is no digital multiplier for lens speed. To find out more information on this topic including more technical data than you can throw a stick at please visit www.bobatkins.com.