Posts Tagged ‘exposure’

A Great Graphic for Understanding How ISO, Aperture, and Shutter Speed Work

Check out this awesome exposure triangle graphic found in this Exposure Guide tutorial on the fundamentals of exposure:

When these three elements are combined, they represent a given exposure value (EV) for a given setting. Any change in any one of the three elements will have a measurable and specific impact on how the remaining two elements react to expose the film frame or image sensor and how the image ultimately looks. For example, if you increase the f-stop, you decrease the size of the lens’ diaphragm thus reducing the amount of light hitting the image sensor, but also increasing the DOF (depth of field) in the final image. Reducing the shutter speed affects how motion is captured, in that this can cause the background or subject to become blurry. However, reducing shutter speed (keeping the shutter open longer) also increases the amount of light hitting the image sensor, so everything is brighter. Increasing the ISO, allows for shooting in lower light situations, but you increase the amount of digital noise inherent in the photo. It is impossible to make an independent change in one of the elements and not obtain an opposite effect in how the other elements affect the image, and ultimately change the EV.

If you’re just starting out in photography, do yourself a favor and work through the Photography Basics page over on Exposure Guide. It’s a fantastic resource.

Exposure – ISO, Aperture and Shutter Speed Explained [Exposure Guide via Reddit]

Apple to Use Face Detection for Exposure Metering and Snappy Autofocus

Apple camera patent for face detection exposure metering

Face detection has become the snapshot photographer’s invaluable assistant in ensuring tack-sharp faces, but soon it’ll be able to add two more job responsibilities to its resume: exposure metering and speedier autofocus. Two patents recently awarded to Apple show that future iOS cameras (perhaps the next iPhone?) will have standard camera features that rely much more on face detection technology. The first patent, titled “Dynamic exposure metering based on face detection“, allows the camera to automatically select faces as the primary target for metering. In more difficult situations — group shots or people standing in front of a crowd, for example — the camera will use factors such as “head proximity” to select the primary subject.
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FilterCalc: An Android App for Calculating the Exposure Offsets of Filters

Still shoot film? Use filters when you shoot? FilterCalc is a new Android app that’s designed to help non-TTL photographers figure out proper exposure when using filters.

This base ISO exposure calculator comes with preloaded database of almost 500 filters. By selecting the actual ISO value and filter type, the app computes base ISO to be used with the light meter resulting in proper exposure.

FilterCalc can compute ISO compensation in increments of 1/3, 1/2, 2/3 and full stop EV. You can select compensation values by stops, by filter factor, by preloaded filter brand/type, or add your own custom data.

The app is free and can be downloaded over on Google Play.

FilterCalc [Google Play]

Scream Activated Photo Booth Featured on the NBC Today Show

After a tour of the blogosphere last month, photographer Billy Hunt‘s scream activated photo booth the Screamotron3000 caught the attention of the folks over at NBC Today. This past Sunday Hunt went on national television to share the joy of scream photography.
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Use Your Hand as a Makeshift Gray Card for Estimating Exposure

Peter West Carey of DPS has a neat trick for always having a gray card “at hand”: he suggests using your hand as a gray card when you don’t have a card handy. You’ll need to start with an actual gray card for “calibration”:

In a nice even light, using spot metering and manual exposure mode, point your camera at the gray card. Set your ISO so it is not on Auto and maybe to 800, the number isn’t too important. Now adjust aperture and shutter speed until the camera metering is at zero, meaning it is not over or underexposed according to the camera. Next place your hand (I suggest your left hand) where the card was, with your fingers together. Ensure the center metering spot is completely covered by your hand.

What does the camera’s meter read now? Mine says the settings I had for the gray card are 2/3rds of a stop too dark for my hand. [...] This means whenever I point the spot metering at my hand, and my hand is in the light hitting my subject, I just have to adjust my settings until my camera thinks the exposure is 2/3rds of a stop too dark and I am set!

So basically, since the color and tone of your palms don’t change very much, you can use the difference between your hand and 18% gray for snap exposure judgements while shooting.

How To Always Keep A Gray Card At Hand [DPS]


Image credit: Hand by mnsc

Apple Patents Multi-Point Exposure/Focus Selection for the iPhone

A new patent application by Apple is showing off some of the technology we may be finding in the next generation camera. The application, which you can read in its entirety here, mentions a few new features, among them the ability to select multiple focus points, allowing the the phone to take over and adjust the aperture, exposure and even post-process to get the best possible picture for those points.

A few other notable features mentioned in the patent include motion tracking for focus, automatic sharpening of key areas, and the possibility of a dedicated image processor (instead of the image processing hardware built into the A5 chip?). Of course we can’t be sure that these advances will make their way into the next iPhone or that they’ll see the light of day at all, but just the fact that Apple is taking this much of an interest in improving an already good smartphone camera seems to bode well for the phoneotographers among us.

(via Photography Bay)

An 8-Bit Explanation of the Three Basic Components of Exposure

Matthew Gore of Light & Matter created this beginner-friendly video tutorial on the three basic elements of exposure: aperture, shutter speed, and ISO. It’s explained with easy to understand illustrations and examples, and features graphics and sounds that are reminiscent of old 8-bit video games. You can also find a text-based version of the tutorial here.

The Three Basics of Photography (via Xatakafoto)

A Man Can’t Live on Image Credit Alone

So, from time to time, I receive requests to use my images for various purposes — like on a blog or a pamphlet or a calendar or the side of a zeppelin or for a urinal cake. Typically, if they are nice and they’re not going to be making a load of cash off where they’d like to use my image then I’ll let them use it as long as they give me credit. I’m especially generous with environmental interests and non-profits and ice cream manufacturers offering vouchers for all-you-can-eat tours.

But then there are the chumps (and chumpettes) who will be making a substantial amount of money off of the use of my image and I send them packing unless they pony up a fair amount of money. The latest version of this repetitive saga really got caught all up in my craw and so I felt the need to write a bit about it.
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A Simple Explanation of F-Stop Numbers

Even if you have a good command of using f-stop numbers and properly exposing photographs, you might not understand the math behind why f-stop numbers are what they are. Here’s a simple (albeit math-filled) explanation by Dylan Bennett of what f-stop is, including a simple trick you can use to memorize the f-stop scale.

Overlay an Inverted Layer Onto a Photo to Brighten Underexposed Areas

Adam Dachis over at Lifehacker offers a simple method for correcting underexposed photo with any image editor that supports layers, inversion, and Overlay blending mode. Simply create a duplicate later, invert it, set the blending mode to Overlay, and then adjust the opacity to suit your taste. While it’s certainly not a pro photography trick — other techniques including adjusting the curves and levels may be better — it’s a quick and easy tip that may be good to know.

Fix Your Photo’s Exposure Problems in Seconds With This Simple Trick [Lifehacker]