What is TTL?

Most manufacturers’ automatic flash systems utilize through the lens (TTL) metering systems. TTL flash works in conjunction with whatever metering pattern you are using in your camera to evaluate the scene. It also receives the subject distance information from the lens and emits a “pre-flash” just before the exposure to judge exactly how much light is needed. The flash uses all of this information to automatically calculate how much power it needs to output to light the scene. Now keep in mind since TTL flash metering works off of your camera’s meter, it can run into the same limitations discussed in this article.

Using Flash in Auto-modes

Now the first major limitation you should know about when using flash in most automatic modes (including Program and Aperture priority; Shutter priority doesn’t count since you are picking the sync speed) is that by default, the camera will sync around 1/60. Some manufacturers will limit your sync speed to the reciprocal of your focal length (ie: at 125mm, your camera would sync at 1/125 sec.). The goal here is to eliminate the risk of blur from camera shake, but it often leaves you with a brightly lit subject and dark background.

Essentially, by picking a higher shutter speed, the camera is relying on whatever light the flash puts out to make the picture. This can be great in a situation where your subject is backlit because the flash will “fill in” and prevent the subject from appearing dark while retaining detail in the background. In dim or low-light situations, this can lead to that dreaded “deer in headlights” direct flash picture with only the subject being brightly illuminated. To prevent this, you can shoot in manual or use the next mode.

The “Slow-Sync” Flash

In automatic modes, most cameras have an option for “slow-sync” flash, or what is sometimes called “night flash.” By selecting slow-sync flash, the camera will sync at the shutter speed it would need without a flash. In situations where you want to capture more of the ambiance of the scene, slow sync is the way to go. The flash burst will usually freeze the subject, but your scene might be a little motion blurred so you might need a tripod depending on the situation. You can sometimes get around this by increasing your ISO or using a wider aperture. Below is an example of a shot with and without the slow sync option.

Left: ISO 500, f/5.6 @1/60 sec. Right: ISO 500, f/5.6 @ 1/20 sec.

Both of the above images were shot in aperture priority. The left is taken with the camera picking its default 1/60 second sync speed. The right is taken with the slow-sync option turned on, bringing the shutter speed to 1/20 of a second. The flash exposure was TTL (we locked the flash value to keep the flash exposure consistent), bounced off the ceiling. The first image is what most auto flash shots look like if your sync speed is high: the subject is lit but the background appears somewhat dark. This is because the higher sync speed is cutting out a lot of the ambient light. The shot on the right is 1 2/3 stops slower, resulting in nearly 4 times more light. This gives a good mix of the ambient light and flash, and looks more natural.

One last thing to keep in mind when using a slow-sync flash, you will often times have to deal with conflicting light sources. Your best bet here is to either use a custom white balance or color correction gel. Custom white balance does an okay job, but is not always perfect. In the shot I took, I used AWB and you can see hints of color casts from both light sources (flash and fluorescent). Gelling the flash is the only way to match the two color temperatures together. This article discusses the different color temperatures of different light sources.

Rear-Curtain Sync

Rear-curtain sync is when the flash pops off at the end of the exposure instead of the beginning. In the auto-modes, rear-curtain sync works like the slow-sync flash mode and allows the camera to utilize sync speeds below 1/60 of a second. Since the flash pops at the end of the exposure, rear-curtain sync is great for conveying a sense of action since it freezes the subject right as the exposure ends. I personally recommend using this mode for any longer exposures. This shot is an example of creating that sense of action.

A demonstration of rear-curtain flash sync. The exposure was 1/5 sec @ f/2.8 The camera was tilted during the exposure while the flash pop “freezes” the water in the fountain at the end.

High-Speed Sync

Most external hot-shoe flashes today support a mode called “High-Speed Sync” (or Auto-FP Mode). Most cameras today offer a sync speed of 1/200 – 1/250 of a second (any faster than that, chances are you’ll see the shutter blade in the shot). This is fine for most controlled situations but limiting in outdoor scenes where you need to shoot faster than 1/250. Without getting too technical, in high-speed sync the flash fires a series of smaller bursts during the exposure instead of one big burst. This allows you to sync at faster shutter speeds but reduces the output of your flash – meaning you need to be fairly close to your subject. (It should be also noted that this feature is generally only available on OEM flashes or 3rd party dedicated TTL flashes. The ability is also camera-dependent as well.) Here is an example of how a fast sync speed is useful outdoors:

High-speed sync/Auto FP flash. Exposure of 1/500 sec @ f/5.6

Now this was shot with a Nikon D50, which actually allows a higher sync speed of 1/500 of a second (this is because it’s an electronic shutter, not a mechanical like most cameras). The flash compensation was dialed down a bit to add a subtle fill. The goal I had in this shot was not to eliminate the shadows, but merely soften them up a bit. Hopefully it will at least give you some ideas.

Moving to Manual

Once you have an understanding of the flash, I think the best way to work with TTL flash is in the manual mode. If you have a basic understanding of how exposure works and how TTL flash works, this gives you the most control over the scene. You have the most control in balancing the ambient light with the flash and can create whatever effect you’re looking for.

Some Final Quick Pointers

Practice makes perfect. The best way to learn flash photography is to practice. The more you use flash, the better you’ll understand it. Digital has made this much easier since you can see your results instantly.

A little diffusion goes a long way. Learning to diffuse the flash can make a big difference. Whether you’re shooting it through an object, or bouncing it off of a wall, it can give you a very different effect. One of my personal recommendations to get started is the cheap Sto-fen Omnibounce cap.

Move the flash off the camera. An off-camera flash cable can be extremely useful in moving the flash off the camera and giving a much different look. If you don’t like cables, you may want to see what wireless options your camera supports. Some manufacturers support wireless triggering from the pop-up flash. Once you get the hang of using the flash, I strongly recommend experimenting with off camera flash.

Good luck and happy flashing!

The SlingShot 200 AW is designed to hold up to a pro-size SLR with a medium zoom lens attached and about 2-4 extra lenses, as well as some other accessories. The main compartment loads from the side so you can swing the bag from your back to your chest and access your equipment.

Like most camera bags today, the divider pads are moveable in order to allow you to customize the bag to your equipment needs. With some minor adjustments to the padding, I have no problem fitting my Nikon D200 with the battery grip attached and about 3-4 lenses or a flash. Rounding out the main compartment are a memory card flap and a built-in microfiber cloth that can be folded over your camera.

I’d recommend putting the two lenses you plan to access the most toward the top of the bag. By doing this, all you have to do is lift up one of the padding flaps to access your gear. Because of the depth of the bag, you can easily stack two small prime lenses and fit them in a single lens compartment.

The SlingShot 200 AW features two main accessory compartments. The first compartment on the front of the bag is great for holding extra batteries, cleaning supplies, or other small accessories. The second compartment sits at the top of the bag and has a decent amount of room. It’s great for holding non-camera related items, but I generally use it for an external flash and all of its accessories.

The bag features a single padded carrying strap that hangs over your right shoulder. There is also a second small strap that clips into the main strap to prevent the bag from sliding around. I would say it distributes the weight much better than a shoulder bag, but not quite as well as a backpack. Even though the SlingShot 200 is comfortable, a fully loaded bag on a full day of shooting may leave you a little sore, but not as bad as a shoulder bag.

If the main compartments don’t quite hold what you need, the bag is fully compatible with the Lowepro SlipLock pouches. There is a holster on the main strap, two on the front part of the bag, and one on the right side. The front SlipLock slot is great for a memory card wallet or a small point-and-shoot case, while the others are perfect for any larger lenses that may not fit into the main compartment (ie: a 70-200mm f/2.8). The only thing I wish they would have included is a spot for a tripod. I have seen several people modify the bags to accommodate one, but it should have been on the bag.

Conclusion

The Lowepro SlingShot 200 AW is the perfect bag for someone who wants to go out shooting with a medium amount of gear. It is by no means a backpack replacement in terms of capacity, but its quick access makes it extremely useful in a lot of situations. I frequently use it in situations where I don’t need everything but want to be able to get at my equipment quickly. If you plan to carry a large zoom lens such as a 70-200mm f/2.8 or 300mm f/4 I would probably recommend looking into the SlingShot 300 AW, which has a little more depth to accommodate such large lenses. If you have a smaller body and maybe 1 or 2 lenses and want a smaller bag, the SlingShot 100 AW might be the best option for you. Overall, I would definitely recommend giving the SlingShot 200 AW a try.

Pros:

• Easy access to your equipment without the stress of a shoulder bag.
• Plenty of expansion slots for Lowepro SlipLock accessory pouches.
• Comfortable shoulder strap with great padding.
• All-Weather Cover for extreme situations.

Cons:

• No access for larger lenses in the bag without adding pouches (or moving to the 300 AW).
• No tripod attachment.
• Sling style design might be a little awkward for some.

If you’re interested, Lowepro has a video demonstration here.

With the metering systems in today’s digital cameras becoming more and more sophisticated, people often wonder if hand-held meters are necessary. This quick tutorial is designed to show why using a hand-held meter would be beneficial.

Camera Meters (Reflected)

Most of today’s camera meters give you three options of evaluating the scene (Matrix/Evaluative, Center-Weighted Average and Spot). Anyone who has played around with these metering types will find that even though they provide pretty good results, they can easily be fooled. The reason an in-camera meter can easily be fooled is it reads reflected light and is designed to “see” everything as a neutral gray. This works well if you have an even amount of light, dark and middle tones in the scene but not so great if there is a bias towards bright or dark tones. This is easy to overcome once you familiarize yourself with how your camera reacts in situations – but frustrating none the less.

Hand-Held Meters (Incident)

The biggest benefit of a hand-held meter is the ability to read incident light. What this means is the meter reads the light falling on the subject instead of what is reflecting back to the camera. This means you’ll get the same reading regardless of what color or range of tones the scene contains.

Sometimes you can’t walk over to your subject for an incident reading so most hand-held meters also allow you to read reflected light as well, including spot metering. Some of the more sophisticated meters will allow you to take multiple readings and average those values, which is great for complex scenes.

Reflected vs. Incident Metering

Below is a perfect example of the benefit of a hand-held meter. This scene was shot with two 100w modeling lights, both placed 45 degrees from the subject, bounced into umbrellas. The first image was shot with the Matrix Metering function, the second with the Sekonic L-358 Light Meter.

Left: Nikon D200 Matrix Metering / Right: Sekonic L-358 Incident Metering

You’ll notice there’s about a two-stop difference between the scenes! The problem here is the reflected meter sees our white background as a middle gray. The result is an under-exposed picture. The opposite would have happened if we had shot the same subject on a black background: an over-exposed picture. Since the hand-held meter is measuring the light falling on the subject, it ignores the tone of the background.

Alternatives

If a light-meter isn’t in your budget, a cheap alternative would be a gray card. Since your subject meters off of a neutral gray, you would place the gray card in front of your subject, fill the scene with the card, then take your reading. This should result in a neutral reading with your highlights and shadows falling where they should be.

Hopefully this gives you an idea of the benefits of both types of metering. Good luck shooting!

People often get frustrated when they take a picture and the color does not represent what they saw. A prime example is when you take a picture indoors that has a strong yellow/orange cast. Or perhaps when you take a picture of a gorgeous orange sunset but the photo comes out with a blue tint. Understanding what white balance is and how to use it can help you in any of these situations.

What is White Balance?

To put it simply, white balance tells the camera exactly what the color temperature of white is in degrees kelvin (K). Going back to 35mm days, most film was rated at “daylight,” which is about 5200-5500K. If you shot under a lighting condition other than daylight, then you would need to get a correction filter (unless of course you bought tungsten film). White balance eliminates the need for these filters by being able to tell your camera’s sensor what the white point is. The common color temperatures in photography range from about 3200K (orange) to 7500K (blue).

What About Auto White Balance?

Auto white balance (AWB) does a pretty good job in a lot of cases and continues to improve considerably with each new generation of digital cameras. The biggest problem with AWB is it can easily be fooled and overcompensate for a particular light source. This leaves you with an image that might be close to what you want but not perfect. The best way to describe the difference between AWB and preset WB: AWB gets you in the ballpark while preset WB puts you on the pitcher’s mound.

How Preset White Balance Works

The way a preset WB works is it adds the opposite color to make the light source appear white. This table breaks down the type of light source, its color temperature, what that light source will look like compared to daylight, and what color is added when using that WB.

*Fluorescent light tends to vary based on the type of bulb being used. Most fluorescent light does not fall into the traditional photo color temperature range as it has a strong green cast. Certain daylight or warm balance fluorescent lights fall around 4000-4500K.

Using Preset White Balance to Add Warmth

A common practice for scenic shots is to shoot the WB slightly warmer than the actual light you are in. For example: When I’m outdoors, I often times use the cloudy WB over the daylight WB to add a little extra warmth to the image. There are some situations where you intentionally have to shoot the image at a warmer WB to have the light reflect what you saw. Below is the same image with three different WB settings: the first daylight, the second cloudy, and the third shade.

Daylight WB

Cloudy WB

Shade WB

I really like all three images, but the second is much more representative of what I actually saw. The first one is a little too cool while the third is much too warm. Now in certain situations, you might want to have a warmer or cooler look so hopefully these three shots illustrate that in some shots the right WB setting is the one that you want personally.

If you’ve read the DSLR Buying Guide, you’ll remember I said the “RAW vs JPEG” question could take up an entire article. Well, here it is! This article is a basic overview of the main differences as well as the pros and cons of each file format.

JPEG

If you’ve taken a digital picture, you are probably familiar with a JPEG. It is pretty much the “standard” file format for most digital imaging. Even if you shoot a RAW image, once you’ve processed the image you’ll probably convert it to a JPEG.

Perhaps the biggest advantage of shooting JPEG is the varying image quality and size compressions. If your only plans for the photos were to post them to the web or play them back in a video slideshow, you would probably be fine shooting at a lower image quality. Or perhaps you never print larger than a 4×6 print. In that case, you’d probably be better off with a medium image size. The main advantage here is if you don’t need the higher image quality, you can get more images on your storage card.

The biggest drawback to a JPEG file is that it’s what’s known as a “lossy format.” Essentially, this means if you start doing a lot of image manipulation and re-saving over the original file, you will eventually start to see a degradation in quality. Also, you lose some information when you try to “fix” certain things. Here’s an example:

Photoshop Autolevels: Before and After

The image on the left is the original. Notice that it is slightly underexposed and has somewhat of a blue cast to it. The main thing to look at on the histogram is that even though it doesn’t extend all the way to the right into the highlight region, the levels are even.

The image on the right is after using the “Auto-levels” function in Photoshop. The image looks much better and the histogram extends through the entire input range, but you’ll notice it almost looks like it’s been brushed over by a rake. The portions where there are white lines are sections of the image where there is no data, or the program is “making it up.” Now this won’t really affect you in smaller prints or applications for the web, but this can be problematic when trying to make large prints.

RAW

A RAW image is the unprocessed data from your camera’s sensor. RAW images are generally uncompressed or have very little compression. Every manufacturer has its own proprietary RAW file format (.nef, .cr2, .orf, etc.) that generally encrypts some file information (more on that later).

The biggest advantage to shooting RAW is you have much more control of your camera settings including white balance, saturation, hue, contrast and sharpening after you’ve shot the image. With most RAW editors, you never make these changes to your original image. Generally the changes you make are applied to the original image as a “develop” setting once you export the image to a JPEG or TIFF. If you aren’t happy with the changes you’ve made, you can always go back to the original data.

Also, since a RAW image is not usually set to a particular color space yet, you are able to pull out or recover more information from lost shadows or highlights. Here’s an example similar to what we did with the JPEG:

RAW Processing: Before and After

Once again, the left image is the original. I intentionally shot it underexposed and forgot to change the white balance to match the light setting I was in. The right image is after making some adjustments in Lightroom to the exposure, brightness, contrast and saturation. The result is what I wanted the picture to look like, had I shot it properly to begin with. The important thing to note here is that the histogram is not “raked” at all. This has a lot to do with the fact that I’m working with a 12-bit uncompressed file versus an 8-bit compressed file (JPEG).

The biggest drawback to shooting RAW is file size. You can expect to get about half as many RAW images on a card compared with JPEG images (it will be even less if you are shooting something like 14-bit uncompressed). Because you are working with larger files, you also need more memory to edit the files.

The other drawback to RAW files is you have to edit them before you can really do anything with the file. To open and edit/convert RAW files, you need a specific software program to do so. Most manufacturers provide a RAW converter with their cameras, but these often provide only very basic controls. The biggest advantage to using the OEM’s RAW converter is it’s able to read encrypted metadata that third-party converters don’t have access to, including your camera’s settings for color, noise reduction, sharpening and other image processing parameters. Third-party RAW convertors generally give you more control overall but aren’t able to read your camera settings and provide their own “default” conversion. This can be frustrating for first-time users, but once you develop your own workflow, you can create your own develop settings or ones that mimic the manufacturer’s settings.

What about shooting RAW + JPEG?

Most DSLRs today give you the option to shoot both a RAW and JPEG image simultaneously. This can be useful for first time RAW shooters so they at least have a “backup” file in case they decide they don’t want to go through the process. It can also give you a good reference if you are trying to set up your third-party processing software to match the color parameters of your camera. Personally, I wouldn’t recommend doing this on a regular basis since it takes up a considerable amount of space. The other thing to keep in mind is if you shoot a RAW image and simply want to retain the camera processing settings the way you shot the image, all you have to do is run it through the OEM’s RAW converter. By converting the files this way, you’d produce the same result as a camera-processed JPEG.

Conclusion

Both RAW and JPEG images provide benefits. You can get a lot more images per card with JPEGs, but you end up with more compressed data for post-processing. A RAW image does give you more data to work with but takes up a lot more space and requires more work to get the final result. Either way, both formats have their equal place in digital photography.