Thursday, January 29, 2009

Help for lens shoppers!

If you are looking at getting a new lens, no matter what kind it is you might be overwhelmed by the lens descriptions. Do you need a Canon 75-300mm f/4-5.6 USM IS AF for $600 or will a Canon 100-300 f/5.6-6.7 AF for $130 do? And what will you get if you go for a Sigma 100-300 f/4 EX DG IF HSM for $1065?

Hopefully, if you're lens shopping you have a purpose in mind. Make sure you really think about what it is about your current lens(es) that is making you look for a new lens. What will the new lens be used for the most? Will there be other uses? What kind of lighting situations will it be used in? And are there features you want in a new lens?

Focal length:
This is usually the first part of the lens description followed by "mm" as in the bolded part here:
Canon 75-300mm f/4-5.6 USM IS AF
The smaller the number, the farther away your subject will appear and the more of your surroundings will fit into a shot. "Wide" lenses (10mm to 30mm) are often used for landscapes, "Normal" or "Standard" lenses are 30mm to 50mm and come close to what we see normally with our eyes. For this reason, they are often used for portrait work and as general walk-around lenses. Telephoto lenses are anything 100mm and up. They are used for wildlife, candids, and other situations where you want or need to take photos at a distance.

Zoom Lenses
When you see two numbers like you do above "75-300mm" that means it's a zoom lens. These are the lenses most of us are familiar with. They'll make the subject appear closer or further away as we turn a ring on the lens.

Primes / Fixed Lenses:
If you see just one number, the lens is a "prime", otherwise known as a "fixed" or "standard" lens. These lenses don't "zoom". In order to make the subject appear closer or further away, you'll need to "zoom with your feet", in other words, move yourself closer or further away.

People choose primes because you can usually get better quality and "faster lenses" for much cheaper this way. (We'll discuss "fast" lenses later.) Usually people purchase something like a fast 30mm or 50mm prime for portrait work.

Maximum Aperture:
After the focal length there's usually a "f/" followed by a number or two numbers. The maximum aperture is bolded in the example below:
Canon 75-300mm f/4-5.6 USM IS AF

If you aren't using manual mode yet you can see some of my other articles for the specifics on aperture, but here's the quick and dirty -the lower the numbers after the "f/" the "faster" the lens is. f/4-5.6 is not all that fast, the example lens is fairly average. When you get into f/2.8 or even all the way down to f/1.0 with some specialty primes, those are what are considered "fast".

"Fast" lenses will give you 2 advantages. First, the lower that number, the better low-light performance you'll get. This is really why they are called "fast" -the lower your aperture number, the faster shutter speed you'll be able to achieve, so if you take photos of, say indoor sporting events or dance recitals a fast lens can help you avoid blur due to camera or subject movement.

The side-effect from using really low-numbered apertures like f/2.8 or 1.4 is a really shallow depth of field. So, if you like those photos with really smoothly blurred backgrounds and a sharp subject, those are done with small numbered apertures. This is very nice for portrait work, but when you are shooting indoor sporting events this will mean your focus has to be EXACT in order for you to get a sharp shot. Focus is very important because at these low-valued apertures your depth of field is so shallow.

This usually comes first in the lens description. In the examples above it was Canon, but I included a Sigma lens in the first paragraph of this article as well. Nikon, Olympus, and other camera makers obviously make lenses for their systems as well, but Sigma, Tamron, Tokina, and others are 3rd party lens makers that make lenses for at least Canon and Nikon.

Personally, I consider Canon and Sigma whenever I go to buy a lens. I own both makes of lenses and feel that in some cases Sigma is just as good as Canon, but it does depend on the specific lens you are looking at. I know other photographers who are happy with their Tamron lenses, but I've never found one of quality for my own use. No matter what the make, you'll need to do your homework before buying a lens because quality will differ greatly depending on the lens you are looking at -even with Canon! (...unless you buy all "L" glass.) If you are on a budget, though, 3rd party lenses are worth considering!

The Alphabet Soup:
After the basic lens description ("Canon 75-300mm f/4-5.6") comes a bunch of letters. I'll try to define as many as I can here:
  • AF -AutoFocus
  • EF or EF-S -"EF" means it'll fit any Canon camera wether it's full frame or a crop sensor. These lenses are required if you have a full frame camera (a Canon 1D or 5D). "EF-S" lenses fit only crop sensor cameras. These include Canon's Rebel lineup (XT, XTi, XSi, XS), and the 10D, 20D, 30D, 40D, and 50D's. The "EF-S" lenses are usually a little cheaper, but if you decide to move to a 1D or 5D someday, you won't be able to use them on your full frame camera.
  • HSM -Sigma's version of "USM", it's an autofocus mechanism that's faster, focuses better than non-HSM in low light, and it's quieter than non-HSM lenses as well.
  • IF -Internal Focus, these lenses will not have rotating front elements and they won't change length while you are focusing. This is a good thing for macro photography where if the lens moves while you focus there's a risk of the front of the lens hitting your subject as you focus.
  • IS -"Image Stabalized", this means the lens will compensate for some movement as you take photos. This helps in low-light situations when camera shake often ruins photos. It's not magic, but it'll help give you a stop or two advantage depending on the lens. Some lenses have dual IS motors so you can turn on just vertical IS or both vertical and horizontal compensation. The ability to turn off horizontal compensation is nice for automotive photography since it can help keep panned shot sharp.
  • "L" -If you see an "L" tacked on to the end of a lens description like "Canon 70-200mm f/2.8L" it designates the lens as one of Canon's pro line lenses. If it's a telephoto, it'll be white like you see on the sidelines of many sporting events. If it's a wide-angle lens it'll just have a red ring that designates it as an "L", but either way "L" lenses are generally of excellent quality, but are also very expensive.
  • Macro -These lenses will focus closer than non-macro lenses. True macro lenses will give you 1:1 size ratios although some "macro" lenses won't do 1:1, so if you really want to get into macros, make sure you verify whether the lens you're looking at will do 1:1.
  • MF -Manual Focus
  • OS -"Optically Stabalized", Sigma's equivilent of the "IS" designation for Canon lenses
  • Rotating front element: One thing to watch out for on cheaper lenses is a front element that rotates. This will make it difficult to use a circular polarizer filter on the lens.
  • USM -"Ultra Sonic Motor", this is an autofocus mechanism made by Canon that's fast, focuses better than non-USM in low light, and it's quieter than non-USM lenses as well.
  • VR -"Vibration Reduction", Nikon's designation for image stabalized lenses
More Nikon lens definitions:

More Sigma lens definitions:

Lens Test Data:
The final step in lens shopping is to look at comparisons between similar lenses. Google searches may result in many test shots, searches on Flickr can show you samples of what others have done with the lens, and these are really good things to do, but the best way to compare lenses is to look at the sites below:

Tuesday, January 27, 2009

Photos to learn from: Day 223 - O Brother

Day 223 - O Brother
Originally uploaded by Aaron Courter
The poses for both children are perfect here. As a "big sister" to a "little brother" this really conveys what I felt many times in childhood -annoyance at my little brother!

The lighting is suberb. Just like the flower photo, there's enough definition with shadow to show contours, but no sharp shadow lines -they are all very soft and not distracting.

The background is simple. The low perspective helps with that. It also lets us connect with the girl better. Generally, shooting at eye-level with your subject will help your photos a lot.

The wide-angle gives a lot of depth to the photo and the fact that the line from the corner of the 2 walls divides the children adds to the photo in a subtle way as well.

...I'm not usually a big fan of "kid" photos because most people just try to capture their kids as they are, but this one is creative and really strikes me (personally) emotionally with memories of my own childhood. Thinking of capturing an emotion in addition to a photo will bring your work to the next level and make it more interesting to a general audience.

Photos to learn from: A cala copout

A cala copout
Originally uploaded by ejbSF
This is a simple flower shot, but what makes it exceptional in my mind is the fact that most of us would never think to let such so much of the flower fall outside the frame like the photographer has done here.

The reason that cropping the flower is okay here is that the flower isn't so much the subject as is shape. -It's almost an abstract. That gentle S-curve that's accentuated by the plain and contrasting black background is what makes this shot -and (IMO) is what the shot is about.

The lighting is also superb. There are shadows to show 3-dimensional shape, but they are very soft -there are no sharp lines where they begin or end. It's all very subtle and perfect.

Exercise: Take a simple subject like a flower, a fork, a shoe -whatever you have lying around and take at least 50 shots of it from different angles. Aspire to 50, and push yourself. You'll be surprised how creative you can be if you push yourself!

...feel free to post photos that you find to be exceptional on Flickr here for us all to see & we can discuss what makes them great and the lessons we can take from them. Explore is a great place to go to find inspirational photos.

Friday, January 23, 2009

How I learned manual mode

Here's a secret for all of you who are frustrated trying to learn manual mode. took me at least 3 REAL tries (in addition to numerous half-hearted attempts) before I learned how to use manual mode. Know how I finally did it? I tackled it one piece at a time. I limited my reading to what the numbers meant for aperture and shutter speed and with the aim that all I cared about was how the different aperture settings would effect my photos, and what shutter speeds would be fast enough so I didn't need a tripod. And I wrote down short notes to help me when I had my camera in hand:

small numbers = shallow depth of field = more light
large numbers = deep depth of field = less light

Shutter Speed:
60mm or less = minimum of 1/60th
over 60mm = 1/lens (100mm = 1/100, 500mm - 1/500, etc)

That's it -that note and your camera's manual are all you need for your first outing. Put your camera on Aperture Priority mode, go outside during the day when there's a lot of light, and practice on anything you can find. Aperture Priority mode is great -all you do is set the aperture you want, the camera will find the shutter speed to match it, so as long as the shutter speed is fast enough (according to the note above), you're fine -shoot away! If the shutter speed is not fast enough, increase your ISO.

With time you'll get a feel for how aperture effects your photos, how your shutter speed changes when you change the aperture, and how ISO effects your settings as well. It's a great, slow way to learn.

When you're comfortable with aperture, explore other people's photos and find things to experiment with as far as shutter speed goes -there's light painting, silky/milky waterfall effects, ghost effects, etc that involve shutter speed. The more you experiment, the more you'll learn.

This slow way of learning by doing worked much better than reading and studying for me because there's just so much to learn at the beginning. You can read and understand 10 pages of material, but when you pick up the camera it all seems to blur while you try to figure out which of those numbers are what setting, and which buttons and dials effect what. Learning one thing at a time, slowly, worked much better for me. If you're frustrated trying to learn manual mode and feeling overwhelmed, this way of learning may work better for you as well.

Tuesday, January 6, 2009

Manual Mode Cheat Sheet

Exposure & your light meter:
* Exposure means how bright or dark your photo is.
* "Correct" exposure means that the photo came out as dark or light as you intended.
* The light meter on your camera will show you your exposure.
* The light meter on your camera looks like this:
* "0" on your light meter usually gives you a "correct exposure".
* Exposing for positive numbers like "+1", "+1.5", "+2", etc will make the photo BRIGHTER.
* Exposing for negative numbers like "-1", "-1.5", "-2", etc will make the photo DARKER.

* Aperture adjusts how large of an opening your lens makes to let light in.
* Low numbers like f/4 = larger opening = more light = a more shallow depth of field
* High numbers like f/20 = smaller opening = less light = a deeper depth of field
* Depth of field means how much of the photo is in focus. See examples below:

Shallow depth of field:
42 Profile
(click for larger version)

Deep depth of field:
Sedona Tree
(click for larger version)

Shutter Speed:
* "500" in the viewfinder means a shutter speed of 1/500
* Shutter speeds of 1/60th or less can't usually be handheld, put your camera on a tripod
* For telephoto lenses, even faster shutter speeds are needed to handhold the camera, a rule of thumb is for a 100mm lens you need 1/100 or faster, 300mm = 1/300 or faster, 500mm = 1/500 or faster, etc.
* 1/6 or 1/8 is good for blurring waterfalls
* 1/125 can be used for panned shots of cars
* 1/500 will stop most action
* The slower your shutter speed, the more light you get.
* The faster your shutter speed, the less light you get.

* ISO determines how fast your image is recorded
* ISO 100 will record light the slowest (less light)
* ISO 800 will record light 8x faster than ISO 100 (more light)
* Higher ISO's will result in more noise or "graininess" in your image.

Each setting effects the rest. Once you find settings that give you a "correct" exposure ("0" on your exposure meter), you can change your settings to find a more "creatively correct" exposure.

If you change the aperture from f/4 to f/5.6 you'd be SUBTRACTING light by 1 stop. You could ADD back a stop of light by increasing the ISO from 100 to 200, or by choosing a slower shutter speed like 1/30 instead of 1/60.

A great way of seeing how aperture and shutter speed relate to one another is to play with this camera simulator for awhile. And note that ISO relates to aperture and shutter speed in the same way.

...but don't worry too much about calculating the exposure like the examples above. Eventually you'll want to know how to do it, but for now you can just change the settings, watch the exposure meter, and aim for "0" (or whatever gives you the brightness you want, but "0" is a good place to start if you're unsure -it'll at least get you close and you can adjust from there).

Feel free to print this or copy and paste parts of it to keep in your camera bag as a quick reference. I kept a cheat sheet like this with me for at least 6 months after learning to shoot in manual mode.