So I’ve stumbled onto a chance to trade my now redundant 24-70 f/2.8L for a 16-35 II. The reviews and a look at the Flickr group for it are promising. Any insight out there?
I need some room to run, and maybe I can spark an idea or two on the way.
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380 euros for a print →
…But I’m tempted. If I capture one image in my life on par with this, I’ll be pleased.
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A few photography basics (Part 4)
If you haven’t read the first three parts I’d suggest that first so we’re on the same page. Now we’ll consider shutter speed.
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Similarly to the previous parts of this, if you change shutter speed you’ll have change aperture or sensitivity (or both) to get the exposure right. The point of changing shutter speed is to either freeze movement of the subject or blur it. I shot all of these at ISO 100:
This one is pretty self-explanatory. For these I held the ISO constant and changed the aperture, but I could have done the opposite just as easily. I was a little surprised by how fast a shutter you need to capture things which don’t appear to move very quickly, but that is my experience.
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Part 5 will cover a few real-world things and tie all of this together.
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A few photography basics (Part 3)
Part one was the basics, part two had the effect of changing aperture, and part three here will be brief and demonstrate the effect of changing sensitivity.
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Similarly to film, the more sensitive the sensor setting, the worse the image will look.
High sensitivity (ISO 100, f/2.8, 1/15 sec, same image from before)
Low sensitivity (ISO 6400, f/2.8, 1/1000 sec)
Changing the sensitivity changes the amount of light the sensor needs to form an image. Accordingly a change in ISO requires a change to aperture or shutter speed (or both) to get the exposure right.
Many modern DSLRs can get good images at high ISO settings and there is also software for further noise reduction, but generally you want to use the lowest setting you can.
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The next part will cover shutter speed.
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A few photography basics (Part 2)
So now we have a subject, light reflecting from it, a lens with its aperture, and a camera with its shutter and sensor. From here I’ll show you how these all interact. Don’t worry about following along with your camera the first time though, the ideas are the same but the buttons will be different across brands.
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First of all aperture, shutter speed and sensitivity (ISO setting) all interact. Lets start with ISO: The basic thing is that (at any given ISO setting) too much light landing on the sensor will produce an image that is over-exposed (all white) and too little light will produce an underexposed image. With a digital camera we can easily change any of the factors to get an exposure right.
In practicality it is a matter of setting one of the three to achieve a result and then striking a balance between the other two to get the exposure right. You can do this all yourself in manual mode, some of it in the assisted modes, or you can use the automatic modes. I prefer the assisted modes and I’ll show why a bit later once we have a few pieces in place.
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Let’s start with a simple scene consisting of an open hardcover book lying flat on a table, a light above it and a camera, where they’re all fixed in place.
Further, these were all shot at 70mm with the sensor set to ISO 100. This first image was taken at f/2.8.
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Large aperture (Linked because this theme doesn’t play nice with larger images)
F/2.8 is a smaller aperture than f/1.8 like we talked about earlier but in practical terms it is still very large. You can see in this image that only some of the text on the page is in focus. At f/1.8 a smaller slice of the page would be in focus, and with Canon’s 50mm f/1.2 lens it might be as little as a line or two in focus. The amount of the image that is in focus is called the depth of field, and it can be changed to artistic effect.
Now in this scene, we’ll change aperture value and hold the ISO value for the sensor. If we didn’t change the shutter speed then as the aperture gets smaller (and lets in less light) the image would get darker and darker. The image above was taken at f/2.8 and a shutter speed of 1/15th of a second. This one below was taken at f/8 and 0.5 sec, and you can see how more of the text is in focus.
Finally at f/22 and 4 seconds the entire image is reasonably in focus. It isn’t perfect due to an incandescent light source and the fact that my ersatz tripod wasn’t as rigid as it should be. Notice between the three images the black blob on the left side of the image. It is on the lens on the surface facing the body. I would regret it otherwise but it makes a point here.
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To recap: The larger the aperture, the less of the image is in focus. When changing aperture you must change shutter speed or sensitivity (or both) to get proper exposure.
The next part will be the effect that sensor setting has on your image.
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A few photography basics (Part 1)
I’ve talked with a few people about this and this is it condensed somewhat. My background is Canon, although the principles hold across the brands.
I’ll start with the parts in the process and what they do, then I’ll describe how they work together. There is some depth here, but with a grasp of the basics you’ll be able to make educated choices about what you buy and the images you get with your new purchase.
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So the whole idea is to record an image. That means capturing the light reflected from your subject. That light goes through a lens, through the shutter while it is open and then it lands on the sensor/film.
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The shutter plays a significant part in what you capture. Most modern cameras can offer shutter speeds (how long it is open) as short as 1/8000 of a second, and as long as 30 seconds. The limit on the short end is moving the parts that quickly, and the limit on the long end is a design choice based on the real-world conditions.
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The lens takes the light that reaches it from the subject and focusses it onto the sensor. It also has an aperture, which is a hole that can open or close to admit more or less light to the sensor. Two characteristics of a lens tell you what it can do, those are the focal length and the maximum aperture.
Canon’s popular 50mm f/1.8 for example: This lens has a fixed focal length, and it is such that an average car will fill the frame when photographed from about 10 feet back. The figure f/1.8 means that its maximum aperture is its focal length divided by 1.8, or about 28mm. Its minimum aperture is f/22, or about 2.2mm. So there is a hole through the lens that can vary between the two extremes.
The next step in lenses is zoom lenses, they have a range of focal lengths. Canon’s 24-70mm f/2.8 is a simple enough example, at 24mm it has a wider view than the 50mm above, and at 70mm it has a narrower view. However at any zoom setting the aperture is a maximum of f/2.8.
Last thing on lenses (for now) is the example of the Canon 70-300mm f/4-5.6. It obviously zooms in further than the previous lenses, but the maximum aperture varies between f/4 at 70mm and f/5.6 at 300mm. This is characteristic of a more affordable lens, a constant aperture across a zoom range is usually only found in the spendy lenses.
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The last part in the process is the sensor. The backstory on them is that 35mm film was popular before digital photography happened, so that is the size the designers went with for the sensor. A camera body with a sensor that size is called full frame for that reason. Realizing that they could make cameras with small, cheaper sensors, designers created crop(ped) sensor bodies. More on that later, I’ll deal with full-frame for now (and I have up til this point.)
The sensor records the light landing on it so the camera can save it as an image. The megapixel figure in the specifications refers to how many individual elements the sensor has to record the different colors in the image. Yes, you can get more but that is often money better spent elsewhere. The sensor in a Canon t4i - their current entry-level SLR - has nearly three times the resolution of an HDTV. So, don’t sneer at a 10MP body, that is a lot.
The other thing about sensors is their sensitivity to light. This is measured in ISO values, and they are arbitrary. Most common SLRs for sale now have sensitivity from 100 somethings to 12800 somethings or more. The biggest thing that a better camera gets you is better images at higher sensitivity.
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So that is the players in getting light from your subject to your sensor. Why not take a break and come back for part 2? I’ll get into how they fit together.
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A brief look at shutter speed to capture moving objects. I shot these with my 70-200mm f/2.8 IS II handheld. Note that at about 1/60 sec the static parts of the image are tolerably sharp, and it is only at 1/400 that the spinner is halfway steady. It was two hundred or so revolutions per minute, and another click faster (in Tv) might have been informative. Perhaps I’ll reshoot it tomorrow from sticks and see how it looks.
Anyway, food for thought for capturing moving subjects. A living subject might be sitting still, but eyes move terribly quickly so by all means try a faster shutter than you might think necessary.
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View high resolution
I have a habit of going with first impressions rather than looking at something new in any detail; That I took so long to appreciate this should be evidence of that fact.
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View high resolution
I like this one. It isn’t a technical masterpiece, but it looks good. It had more dynamic range, but I upped the shadows some to sanitize some identifiable information; I roll in that manner.
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A significant motive for starting a tumblr was to better interact with the people who maintain some really swell ones. Jennybird29 is one, and I like this as much as its aesthetic as for what I can learn from it as an amateur photographer. (To whit: There is a place and a time for an enormous aperture, no sense buying any less, and yet still a place to stop it right down!)
(via jennybird29)
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