Last installment we covered the basic operation of our camera in ‘P’ aka ‘idiot mode’. Now we’re going to get really adventurous and move that mode dial from ‘P’ to ‘A’. ‘A’ stands for 'Aperture', or 'Aperture Value', or more commonly, ‘Aperture Control’. If you recall, the lens aperture is the size of the opening in the lens diaphragm, which in turn controls how much light strikes the sensor. I would argue that of all the non-P modes, this is by far the most important to understand.
Aperture Control means just that... when we turn the mode dial to ‘A’, the camera will be expecting us to tell it what aperture to use for the next photo. And why would we want to control, or choose the aperture? Because the aperture that the camera uses can have HUGE effects on the image, especially at the extremes (wide open, like f/2.8, f/4.0, or, stopped down, like f/11, f/22). If you control the aperture, the camera will select a shutter speed to match that will, given enough light, provide a proper overall exposure.
The size of the aperture controls what is called ‘depth of field’, or, in simpler terms, it controls what will be in focus in the image, and, conversely, what will be out of focus. Easier to understand by seeing some images.
Here is a portrait of my niece. This is an excellent example of an image shot in ‘A’ mode with the lens aperture wide open. You would call this ‘shallow depth of field’. What is in focus here? Basically, the eyes and everything that is in the same plane as the eyes. The tip of her nose is slightly out of focus, the ears are considerably out of focus, and of course the forest background has receded into a wonderful melange of shades of green. This image, in a nutshell, is why you want to be able to force that aperture as wide open as you can for portraits like this.
Since we all love cats, here’s a similar cat portrait. You can possibly make the argument that the nose should be in focus as well. However, in any portrait, human or animal, we must get the eyes in focus first and foremost. This image was taken at an aperture of f/2.0. Probably closing down another f stop, to 2.8, would have brought the nose into better focus.
You’ve all seen those great sports photos shot in ‘A’ mode. You can shoot ‘wide open’ to isolate a subject from a crowd. Here’s a NYC Marathon shot that shows this:
Or, to isolate a subject from a confusing background.
Obviously, ‘A’ mode works best at the extremes. We’ve seen now what happens when we use Aperture Control to force the lens aperture wide open. Would we ever want to force it to its ‘stopped down’ limit? Of course. If we want to make sure that everything in our image is sharp from front to back, we will choose an aperture like f/11 or f/16.
Here’s a classic example of an interesting old wooden fence. We want this fence to be in focus from top to botttom. So we’re going to pick a ‘small’ aperture, like f/11.
Here’s another, taken at a farm in the Schoharie Valley region of the Catskill Mountains, (that I hope still exists), of an array of pumpkins.
Note that these images are both acceptably sharp front to back.
Obviously, things are not quite this simple. Going back to the ‘honey’ example, if we are in a romantic candle-lit restaurant with our honey, we can probably do a nice portrait in ‘A’ mode with the lens wide open. Want to get the honey with the chef in the kitchen behind, both nice and sharp? Sure you can ‘stop down’ the lens in ‘A’ mode, but there might not be enough light to pull it off (to give you a fast enough shutter speed that will still result in a sharp photo without blurring from camera shake).
There are further interesting and scientific ways to use Aperture Control... use your favorite search engine to find ‘hyperfocal distance’ or use this link as a start.
September 8, 2011 6:50 AM - Open Thread
There is an urgent need, both for our city and our country, for some level-headed scholar to write a revisionist, balanced history of Robert Moses and his works. I call the need “urgent” because we still suffer from the intellectual legacy of the political hit-piece written by Robert Caro. The agenda behind this book is spelled out in its subtitle: “Robert Moses and the Fall of New York”.
At the time that this book was written, it certainly did appear that New York had not only declined, but that it had indeed fallen into the abyss. The city’s intellectual and political establishment refused to take responsibility for any of it. To read the editorials of the New York Times on the topic is to witness a search for other forces to blame: the federal government, racist suburbanites, the rise of the automobile nation, etc. Robert Caro, however, found the ultimate bogeyman in Robert Moses. Here was a guy who had already fallen from power, had an aloof, imperious public persona and was the driving force behind many of the factors they were blaming the city’s decline on: highways, urban renewal projects, etc.
I believe that Caro’s book will not stand the test of time, nor does it deserve to. The book is a hit piece with an agenda. Some of it is just silly: a whole chapter on his private relationship with his never-do-well brother. More telling, however, are the substantive chapters, some of which have morphed into myths. Let’s take a look at one the most significant: the construction of the Gowanus Expressway, which he covers in pages 520 to 525. I urge all to re-read this section.
To begin with, he writes of the project as an ill-conceived one that had only downsides, especially the damage to the fabric of that part of Sunset Park. Never once does he mention the over-riding need for this expressway, namely, that prior to its construction the only way for trucks to enter Brooklyn was through Manhattan and the East River Bridges. This chokepoint added to the cost of distributing goods to Brooklyn, in addition to creating more congestion and pollution in Manhattan. Indeed, not only does Caro not mention this upside, he actually views the improved access as a downside. Here is the exact quote from the book:
“With Moses’ road and tunnel making Sunset Park more accessible to trucks, industries requiring truck traffic –including two large new plants, one a division of Bethlehem Steel, the other a division of American machine and Foundry –moved onto Sunset park’s waterfront, already crowded with industrial activity”.
Imagine that!! This highway brought two new large manufacturing plants to Brooklyn!! What a disaster!! Would that we had such a disaster today.
The other notable thing about Caro’s “reporting” on this project is his discussion of the choice of Third Ave as the location for the highway. He spends pages decrying what was lost by putting the highway on this avenue – one that had long had an elevated train running over it. He spends one paragraph discussing the simple question: what alternative locations were there? Again, let’s quote directly from his book on this topic:
“Residents of Sunset Park had pleaded with Moses to build the road along Second Avenue instead of Third. After it was built, and they saw what had been done to their neighborhood, they knew their suggestion had been correct. “That was an industrial area anyway. Building it over there wouldn’t have changed anything in the area at all,” Cathy Cadorine said.”
There you have Caro’s thorough research into the topic: a quote from a neighborhood ”activist”. Had Caro spent a minute analyzing the matter, he might have addressed the following real issues concerning Second Ave:
a) Second Ave ENDS at 40th Street!!! Was Moses supposed to run the highway over the waterfront from 39th Street to 17th Street, destroying the piers and maritime activity there?!?!?!!?!?
b) Brooklyn’s premier industrial complex, Bush Terminal, runs right smack up to Second Ave. Would it have been better if he tore down these loft buildings, the source of thousands of jobs?
c) It would have been more expensive to locate the highway on Second Ave, and the budget for this project was tight. The budget for this project was so tight that Moses REUSED the pillars of the Third Ave El to support the new highway. This savings would not have been realized if the highway was located on Second Ave. More importantly, the eminent domain and demolition costs for the Bush Terminal buildings would have been far higher than the tenements along Third. These buildings take up a whole city block, rather than the 20 x 100 lot that a tenement usually stands on. Finally, it would have been an enormous expense to run the highway over the waterfront from 39th Street to 17th Street.
I ask folks to read Caro’s book, and determine if there is any analysis of alternatives such as that just presented. I assert that you will find precious little, as befits a hit piece.
I stated at the beginning of this article that there is an urgent need for a balanced, revisionist history of Moses and his times. I state this not so much for the benefit of Moses’ reputation. Rather, it is because of the intellectual legacy left by Caro’s book. It has been 50 years since Moses left the scene, and since that time we have lost the capacity to both think, and act, in a big way. We are still living off the infrastructure he built, and have done little to advance it. I’d rather hear someone propose something new and big, rather than listening to another drone going on about all of Moses’ mistakes. Learn from his mistakes, and let’s move on.
Lower East Side Ecology Center, Friends of Carroll Park and Council Member Brad Lander are hosting an e-Waste Recycling Event, 10am-4pm, October 1, Smith Street between President/Union Streets. (check flyer for list of accepted items)
Lower East Side Ecology Center, Park Slope Armory, Council Member Brad Lander and Assembly Member Jim Brennan are hosting an e-Waste Recycling Event, 10am-4pm, October 15, at the Park Slope Armory, 8th Avenue between 14th/15th Streets. (check flyer for list of accepted items)
Lower East Side Ecology Center, Park Slope Civic Council and Council Member Brad Lander are hosting an e-Waste Recycling Event, 10am-4pm, October 16, in front of the John Jay Educational Campus, 7th Avenue between 4th/5th Streets. (check flyer for list of accepted items)
Lower East Side Ecology Center, PS 29, PS 29 PTA, Cobble Hill Association and Council Member Brad Lander are hosting an e-Waste Recycling Event, 10am-4pm, October 23, in the PS 29 school yard, Baltic Street between Clinton/Henry Streets. (check flyer for list of accepted items)
September 7, 2011 7:11 AM - Open Thread
What would Life In Brooklyn be without photos of Brooklyn?
Today we take it for granted that a simple rather inexpensive pocket camera will produce well exposed well focused images without much effort on our part. Japanese engineers have over the past few decades mounted a concerted effort to turn cameras from a difficult-to-use object that required considerable practice and training, into a mass market device that everybody has and everybody uses without much effort. They have succeeded brilliantly. (It remains to be seen how smartphones will impact the market).
When I first became interested in photography, as a boy in the 1960s, there was a lot to learn. First, you had to measure the light with a light meter. Then you had transfer the shutter speed and aperture settings to the camera from the meter. Finally, if the subject was still around (haha), you had to focus the camera. And after tripping the shutter release you had to wind the film to the next frame.
In the 1960s, manufacturers figured out how to get the light meter into the camera and have it measure the light through the lens. The 1970s brought exposure automation (no need to manually transfer meter settings). The 1980s brought electronics and metering improvements and especially, auto-focus. In the 1990s it all came together in easy to use cameras (but you still couldn’t put them in your shirt pocket). And of course the digital juggernaut, combined with these usability improvements, has brought us to where we are today. Simple, inexpensive, pocketable cameras that will give us excellent photographs 90% of the time (it’s the 10% I want to talk about).
I’ve been interested in doing a simple series on digital photography ever since a few younger acquaintances have gotten more interested in photography and have ‘upgraded’ from p&s (point and shoot) cameras to DSLRs (Digital Single Lens Reflex cameras(1)–see footnote at end). However, if you don’t have a DSLR, keep reading: Most cameras today have what is called a ‘mode dial’ and even the ones that don’t offer some of these options within menus.
Unfortunately we can’t do inline images here so I’ll be linking to photos describing what I am discussing. Here’s a photo of a typical ‘Mode Dial’. Some others have little drawings of mountains, flowers, and all kinds of things, but what we’re interested in is the three main ones that will appear on just about every camera with a Mode Dial.
They are P (Program Mode), A (Aperture Mode), T (Time Mode), and, on more sophisticated cameras B (Bulb Mode).
My acquaintances have said, I know what P mode is, but what are these other modes, how do I use them, and why should I bother to learn what they do? The answer is that while P Mode (aka idiot mode) will get you good results most of the time, there are other times when you will want to exert some manual control over certain camera functions to make your photography better.
We will be examining when, why, and how to use these other modes in this series.
First, let’s discuss how an image is placed on a light collecting medium (for this series I will refer to it as a sensor, as in digital, but all this also applies to film).
There is an optimal amount of light for any given photograph that will give us a pleasing picture, that is, not too light, not too dark, and with good detail in both the shadows and highlights. This amount of light is determined by three factors.
-First, the sensitivity to light of the sensor itself. That is expressed in ISO, as in ISO 100, ISO 400, etc. The higher the number, the more sensitive to light the sensor is (there is more to it than that, but let’s keep it simple here).
-Second, the amount of time the shutter stays open, which is expressed in fractions of a second. 1/125, 1/60, etc. Of course, the amount of time the shutter stays open has other implications. For example, if the shutter is open too long, the photo will be blurry since your hands will shake. Most people cannot hand hold a camera and expect a sharp photo at shutter speeds less than 1/60 of a second (again, many caveats). Note that the shutter speed doubles or halves at each setting (1/250 second being half the time of 1/125 second).
-Third, the aperture size. The aperture is the hole in the lens diaphragm that lets light through to the sensor. When a lens is ‘wide open’ it will obviously let much more light in than when it is ‘stopped down’. Apertures also have numbers: f/2.8, f/4, f/5.6 etc. The higher the number the less light is let through to the sensor. It is not quite as obvious as shutter speed but these numbers also function in the same way: Going up or down the scale doubles or halves the amount of light striking the sensor with each f stop. (i.e., f/2.8 allows double the light to the sensor as f4.0).
So, obviously, if we are sitting in a nice romantic restaurant with our honey, we will be looking at a high ISO, a low shutter speed, and a large aperture. Conversely, if we’re at the beach on a sunny day looking to capture our honey in a bathing suit, we’ll be thinking low ISO, high shutter speed, small aperture.
So why worry if the camera will figure this out? Because the optical properties of the lens change depending on aperture, as will our photos. And there are times when you may want to use a slow shutter speed, not a fast one, or vice versa. We can use these different modes (Aperture Mode and Time Mode) to exploit these properties, exercise more creative control over our images, and ultimately increasing the percentage of photos that we find pleasing.
Back to my acquaintances with their cameras set on ‘P’ mode. P, as in Program. In ‘P’ mode, the camera will select both an aperture, and a shutter speed. A sort of middle of the road aperture and shutter speed. You don’t have to think about it, which is why we also refer to it as ‘idiot mode’. Most of the time, it works and works well. It’s what I keep my own cameras set to when I am walking around. It’s knowing when to turn that Mode dial off ‘P’ Mode that we’ll address in the next installment.
(1). SLR stands for Single Lens Reflex. A SLR contains some form of pentaprism that allows the light coming in through the lens to be directed through the viewfinder. This is significant because it allows you to see exactly what the lens sees (an early example of WYSIWYG thinking). All SLRs allow you to affix different lenses, so whether you shoot with a super wide angle lens, or a super telephoto lens, you will at all times see an accurate portrayal of your subject.
September 6, 2011 7:08 AM - Open Thread
Back to Work....
Yesterday evening, I registered lifeinbklyn.com and pointed it here.
I did this both to help people with spelling/memory problems, as well as to keep someone else in the future from registering a name so similar to hours.
In the first few days of the site, it was mentioned that it would be a more logical name of our site, since bklyn is a more common abbreviation than bkln. There is no technical reason why would could not promote that as the primary name. It is not a question that I have any strong feelings on.
The only downside from switching names is that people who are logged in under one URL would have to re-log in if they enter the other.
September 2, 2011 7:50 AM - Open Thread
September 1, 2011 7:11 AM - Open Thread