fast lens

All posts tagged fast lens


We’ve been talking quite a bit about technique lately, so I thought we might take a break from that and talk a bit more about digital photography in general and what to look for when buying a new camera. This one is aimed more at the beginner to intermediate crowd.

So you’re in the market for a new digital camera? It seems everyone is these days and there are more choices than ever! So how do you choose the one that’s right for you?

The first question you need to ask yourself is what type of shooter are you? Are you looking for something small and compact that you can throw in a purse or a pocket for just general use, or are you looking for a more professional camera with interchangeable lenses?

There are 2 main categories of digital cameras point and shoots and SLRs (Single Lens Reflex). Point and shoots are aimed more at everyday photographers who stay on Automatic settings most of the time and simply want to be able to quickly pull out a tiny camera from their bag and click off a few photos. SLRs are aimed more at the intermediate to advanced crowd that wants the ultimate control over their photos.

Point and Shoot Camera

Point and Shoot Camera (Nikon Coolpix S570)

SLR Camera

SLR Camera (Nikon D90)

In today’s digital camera market the line between these 2 categories is actually becoming rather blurred as new hybrids come out all the time such as the new “Pen” type cameras that have the body of a point and shoot but can use interchangeable lenses like an SLR. Not to mention the fact that a lot of digital cameras can also take HD Video that rivals some video cameras.

Once you have decided what category of camera you’d like to buy there are still a number of different features to consider. The first thing everyone asks when looking at a new camera is “How many megapixels is it?” But, do megapixels really matter, and just what is a megapixel anyway?

When your digital camera takes an image it is made up of millions of very small dots. Each one of these dots is called a pixel. Mega means million, so if you have a digital camera that shoots at 8 megapixels, that means the camera is capable of taking an image made up of 8 million pixels! That’s a lot of dots, so just how many do you actually need, and is more better?

Digital Images are made up of pixels (Photo courtesy of pixelkids.org)

Well as it turns out the importance of megapixels really comes into play only if you are printing your digital images. You see all websites and computer screens display images at a very low resolution. An average image that you see on your computer screen is only made up of a couple hundred thousand pixels.

Wait? only a couple hundred thousand pixels to show an image on a screen? Yes, that’s what I said, so if you’re the type of shooter that mostly displays their images on a digital device such as a computer, tv, ipod, or digital photo frame and doesn’t do a lot of printing of images, then getting a high megapixel camera will most-likely be a waste of money for you!

Even if you’re the type of shooter that prints every image they take you still probably don’t need all of those megapixels. An 8×10 printed image actually only contains about 7.2 million pixels, so even if you’d like to blow up that cute picture you took of your dog to an 8×10 you would still only need an 8 megapixel camera!

Then why is everyone so obsessed with megapixels? It’s just one of those industry numbers that everyone has heard of so they want you to think more megapixels = better images = buy this camera! Now if you’re looking to print larger photos such as 11×14, 16×20 or even posters, than sure go out and buy that 10, 12, or 14 megapixel camera, but if you’re only printing smaller photos or not printing at all and only sharing online then you can save yourself quite a bit of money when buying a new camera.

What else should you look for when buying a new digital camera? One feature that I highly recommend is optical zoom. Be careful not to confuse this with digital zoom. What is optical zoom? Optical zoom means that when using the zoom function to get closer to your subject the lens actually moves and that is what makes the image appear larger.

This is different from digital zoom, which is when the computer in your camera does the zooming in order to make your subject larger. This can cause your photos to be less sharp and will reduce the resolution of the photo.

Some cameras use a combination of both optical and digital zoom to make your subject larger. Try to look for a camera that has just optical zoom or both optical and digital. Stay away from cameras that only have digital zoom. You will get much cleaner and sharper photos from an optically zoomed image.

Digital vs. Optical Zoom (photo courtesy of bobatkins.com)

Another feature you want to look for in your digital camera is how well it will perform in low-light. This is super important because what you consider to be a low-light situation is very different from what your camera considers to be low-light.

This is because the human eye can see much better than any camera ever invented. Our eyes have no problem seeing a person perfectly clear in a dimly lit room or even by candle-light.

Your camera on the other hand can sometimes have trouble seeing clearly. Even when it is in what a human might consider a reasonably well-lit room.

Try to take a photo by candlelight and you’re likely to wind up with a blurry mess if your camera doesn’t have the right features! Now of course you could always turn on your flash, but that would ruin the mood wouldn’t it.

What you need to shoot low-light photos is a camera with a very fast lens. When purchasing a point and shoot camera or even a lens for an SLR camera you want to look for one that can open very wide to let the most amount of light in. This is called the aperture of the lens. Being this is an article aimed at beginners I’m not going to get very technical about the aperture here, to learn more about it you can view our previous blog post, A-Mode, Would You Like Your Depth of Field Deep or Shallow.

How do you know if a camera has a fast lens and will perform well in low-light? You need to make sure the camera or lens has a wide aperture. The size of the aperture is measured in f-stops. So it will look something like this “f/4”.

Or it may be written as a range if it’s a zoom lens such as “f/3.5-5.6”. Or possibly it may be written in an abbreviated format such as “1:3.5-8”. Either way, you should  look for a camera whose lens’ smallest number  is f/2.8 or smaller. So if you see a smaller number such as f/1.4 or f/1.8 that would work as well.

Having a camera with a fast lens (wide aperture) will allow you to capture much better images in low-light while other people without a fast lens will have to use their flash to get the same results.

The largest aperture size on this lens is f/3.5 which means it won't perform well in very low-light you want to look for f/2.8 or smaller

To summarize, we have reviewed a few things that you should keep an eye out for when shopping for a new digital camera. Cameras today have all sorts of bells, whistles, and especially features. They come in every size, color, shape, and price. It is not as important who makes your new camera, as it is that it has the particular features that you are looking for.

We were only able to cover a few in this article, as covering them all would require me to write a book, but I hope I’ve given you some things to look out for, and some options to consider.

If you have any questions or would like some further advice on purchasing your new digital camera please feel free to post a comment or get in touch with us.

I’d like to continue our series on exposure modes. I know it’s been a while, I was just waiting for your comments and photos from the last post. It’s ok, I forgive you, I know you were just waiting until we got to the manual exposure modes so your creative juices can flow free 🙂 So we pick up where we left off with Aperture Priority Mode (A).

Aperture Priority Mode is the first semi-manual mode that we’ll discuss. This is the first opportunity for you to have some say on how your camera sets it’s exposure. So let’s get to it. What is Aperture Priority Mode?

Aperture Priority Mode allows you to manually set the aperture on the camera and then have the camera set the shutter speed automatically. As you recall from our previous discussions, aperture, controls the size of the opening of the shutter, or how much light is allowed to hit your film or digital sensor during the time the shutter is open. It is measured in f-stops. So why would you want to set your aperture manually when your camera does a perfectly good job of setting it in P-Mode?

Well, you may recall that aperture not only controls the amount light entering the shutter, but also has the side effect of controlling your….come on, you know this one, depth-of-field! This is an excellent reason to override the camera’s settings and set the aperture yourself. Say your taking a portrait of a beautiful model in a lovely woodland setting…what’s that? No models around you say? No problem, let’s say you’re taking a portrait of your cute as can be 10 year old in a lovely woodland setting. Huh? No woods near you….hmmm ok you’re taking a portrait of your cute as can be 10 year old in a very crowded city park.

This situation is even better, you have all these other people around, and even worse they are in the background of this lovely photo that you are trying to take! What are you to do? You turn to Aperture Priority Mode (A) of course. By manually taking over control of the aperture and using a very large aperture setting of say f/1.8 or f/2.8 you can take that beautiful photo of your cute 10 year old and have all those people in the background become just a blur, so the cuteness of your subject shines right through. Like in the example below:

Bird with shallow depth-of-field

Bird with shallow depth-of-field f/2.8

Ok so my cute 10 year old happens to be a bird 🙂 The point is that this photo has a very shallow depth-of-field and a lovely blurred background because of the large aperture setting of f/2.8 that was used. Working with the camera in Aperture Priority Mode (A) allowed me to manually set the aperture to f/2.8 and ensure that setting is what the camera would use when it took the photo.

Now those of you have been reading carefully, might think I’ve made a mistake about something. You might even think I’ve completely lost it, because it seems I’ve made that mistake in more than one place. You may be thinking, “dingus over here doesn’t know that 2.8 is a small number..he keeps saying that f/2.8 is a large aperture, how can that be??!!” Let me assure you it is no mistake, and it is something that does take getting used to.

You can think of it like fractions, 1/2 is bigger than 1/10 even though 10 is a larger number. It turns out that aperture numbers work the same way. The larger the f-stop value the smaller the aperture size. You can see an example of this below:

Aperture sizes and depth-of-field (Courtesy of http://howtotakepics.blogspot.com/2009/03/basics-terms-of-dslr-photography.html)

Aperture sizes and depth-of-field (Courtesy of http://howtotakepics.blogspot.com/2009/03/basics-terms-of-dslr-photography.html)

The diagram above clearly illustrates that the larger the aperture, the smaller the f-stop number. You can also see that the larger the aperture, the more shallow your depth-of-field becomes. This is why photographers love to get lenses with the largest aperture possible. Since a larger aperture lets more light in, this allows you to use a faster shutter-speed when shooting in low-light (remember reciprocity from our previous discussion). For those of you that own DSLR cameras, you may have noticed that the lens that is included has an aperture range of approx. f/3.5 – f/5.6. This means that the largest aperture that can be set is f/3.5 and as you “rack-out” your zoom the largest aperture your lens can achieve is only f/5.6. By the way, to rack-out, means to zoom your lens out to the maximum focal length.

This is why camera companies can afford to include these lenses in the kit with your camera. As you can see they do not have a particularly large aperture. Or as we say in the industry, they are not very “fast” lenses. A lens that has a larger aperture compared to another lens is referred to as “faster”. The faster a lens is, the larger the aperture setting that can be used, and also the more expensive it is! You will find that most people who shoot with the lens that came with their camera always feel they cannot get great photos in low-light situations. This is because as we’ve seen before the kit lens is usually not very fast, or the camera companies wouldn’t be able to afford to give it away. It is not uncommon for a photographer to buy a faster lens, either an f/2.8 or f/1.4 after shooting with the kit lens for a while.

We’ve learned before that when shooting portraits a large aperture is usually used to achieve a nice shallow depth-of-field. So what if we’re shooting landscapes? Well for that we want just the opposite, we want to use a very small aperture like f/16 or f/22 (remember small aperture, large f-stop). This will give us a very large depth-of-field or high degree of sharpness throughout the photo. This is exactly what we want for landscapes. Picture a beautiful mountain scene with water, hills, trees, in a photo like this we want to make sure that everything in the scene from the water in front to the mountains in the distance are nice and sharp. How do we do this? With a small aperture of course!  Take a look at the example below:

Reservoir, large depth-of-field, f/16

Reservoir, large depth-of-field, f/16

Wow, look at that, not only is everything in the photo nice and sharp because of the small aperture we used, but the content of the photo actually matches what I was describing, how unusual 🙂 By the way when we want to refer to an area in the photo which stretches on as far as the eye can see past the horizon, such as the one above, we refer to that point as infinity. So for a photo like this you would actually set your focus to infinity when taking the shot.

Now that you have a new creative tool under your belt, go out and start shooting! Don’t be afraid to experiment with your aperture settings. Try out what we talked about above, or mix it up a bit. Sometimes using an unconventional aperture setting can create some very interesting results. Shooting in Aperture Priority Mode (A) really opens up a whole new world of creative possibilities. I actually find that I shoot in Aperture Priority Mode about 90% of the time. And don’t forget that the camera still sets the shutter speed automatically, so the camera still ensures that you get a nice even exposure. That is until next time when we discuss Shutter Priority Mode (S).

Until then, please feel free to comment, ask questions, and absolutely send or post some results!