Lens Tutorial

[jtimmons]

I want to take the plunge into DSLR photography soon, but I have one major problem. I don't know what lenses to buy. I need someone to point me to, or give me a tutorial on lens sizes and what all of the numbers mean. Do I have this right

Macro Photography - Under 25mm Lense

Everyday Photography 25-80mm lense

Long Zoom Photography 75 - 300 mm lense

Moon shots, etc. 500-1000mm lense


Thanks for the help!

 

[We-Luv-Disney]

These look good except the macro range. Macro lens are usually anywhere from 50mm to 180mm. Other than that this list looks good.

 

[ukcatfan]

With most DSLRs, you also have to consider a crop (magnification) factor. It means that a lens is actually working at a different range than the description. Most are around a 1.5x - 1.6x factor, but some are as high as 2.0x. The 25mm might not be wide enough for you. Most digital designed zoom lenses for the wide end start at 18mm, which ends up being around 27-28mm after the crop factor is considered. A 25mm becomes around 38-40mm, which is actually not even as wide as some p&s cameras.

I am not sure on the moon shot lens. That one might get expensive to get the desired results. If you are really in to doing this, then you might want to consider a telescope and telescope mount.

Kevin

 

[jann1033]

http://www.usa.canon.com/consumer/controller?act=ProductCatIndexAct&fcategoryid=150
lots of stuff on this page to click on...tamron also has some good info on their eurpoean page but i can't seem to find it right now

 

[MarkBarbieri]

I want to take the plunge into DSLR photography soon, but I have one major problem. I don't know what lenses to buy. I need someone to point me to, or give me a tutorial on lens sizes and what all of the numbers mean. Do I have this right

Macro Photography - Under 25mm Lense

Everyday Photography 25-80mm lense

Long Zoom Photography 75 - 300 mm lense

Moon shots, etc. 500-1000mm lense


Thanks for the help!

The focal length (number of mm) of a lens tells you how much it magnifies the subject. Smaller numbers mean less magnification. Another way of looking at it is that lenses with shorter focal lengths (smaller numbers) show a wider field of view.

So a lens with a focal length of 25mm or less would show you a wide field of view. It really has nothing to do with being a macro lens. A macro lens is just a lens that allows you to focus very closely. That ability is typically used to take pictures of small things.

As ukcatfan stated, you also need to consider the sensor size (aka crop factor) of the camera that you will use the lens on. A camera with a smaller sensor size will use a smaller portion of the image generated by the lens. That means that the field of view will be even smaller. It's very much like having a longer focal length.

To get an idea of what you would see for a particular focal length aimed at something a particular distance away, try the dimensional field of view calculator on this page: http://www.tawbaware.com/maxlyons/calc.htm#fov_calculator. For the focal length multiplier, use 1.6 for a Canon DSLR or 1.5 for a Nikon. That will be correct for all but their very expensive camera bodies. For a 35mm film camera, use 1.0.

Another major factor to consider when looking at a lens is the aperture (f-stop). Generally only the smallest f-stop is specified. So if you see a lens listed as 17-40mm f/4.0, the smallest f-stop is f/4.0. Smaller numbers mean a wider lens opening (aka aperture). That means that you can use a faster shutter speed. It also means that less of your picture will be in focus. That's useful for isolating your subject and making the background blurry and less distracting.

If you see a lens with multiple f-stop numbers (f/3.5-f/5.6) that usually means that the smaller number is the minimum f-stop when the lens is zoomed out to its widest view and the larger number is the minimum f-stop when it is zoomed in to the its narrowest view.

There are other factors to consider when buying a lens, including compatibility with your camera body (don't a Nikon lens for a Canon body), size, weight, image stabilization, and optical quality.

 

[mabas9395]

If you are just jumping into the DSLR world, its a pretty good idea to take the lens that comes with the camera and use it for a while to help you decide what lens to get next. For example, my Canon XT came with an 18-55mm f/3.5-5.6 (or something like that). One of the first things I realized is that I needed a faster lens for low light conditions so I got the 50mm f/1.8. Then I realized I needed something a little longer for general purposes so I got the 28-135mm IS. But then I realized that my flash pictures really stunk so I got the 430ex flash. Then I realized that I liked my low light lens but it was too wide for some things so I got the 85mm f/1.8. Now I'm thinking that the 18mm end of the kit lens is too wide so I'm considering an ultra wide angle like the 10-20mm, but I also know that when spring sports start up again I'm going to need something longer, so maybe a 70-200 f/2.8 with a 1.4 teleconverter is what I'll need. But then I'll start to think that the 200 isn't long enough and I'll start to look at the 300 or 400 or even the 500mm Bigma. But all of those lenses really need a good sturdy support so I'll have to get a tripod. But then I won't want to carry the tripod everywhere so I'll have to get a monopod. And then my bag won't be big enough for everything so I'll need a new one of those. And after using some nicer lenses for a while, I'll start to think that my 28-135 is a little soft so maybe I should replace it with something sharper, like a 24-70mm L. But then I'll realize that I didn't get as good of a tripod as I should have in the first place so I'll have to upgrade that. And then I'll realize that I need a ........

Bottom line is that there are plenty of choices. It might save you a buck or two if you wait until you see what your first lens CAN'T do for you and then go from there.

 

[boBQuincy]

This very well written essay should help with selecting lenses to suit the type of image you wish to produce:

http://www.luminous-landscape.com/columns/composition-3.shtml

As you will see, it's more (a *lot* more) than just macro, everyday, long, etc. As somoene else mentioned, you might be best off starting with the kit 18-55 and getting used to the camera before deciding what other lenses suit your style of photography.
Or you can just go and spend a bunch on lenses like most of the rest of us! Hey, it's FUN!

 

[handicap18]

I want to take the plunge into DSLR photography soon, but I have one major problem. I don't know what lenses to buy. I need someone to point me to, or give me a tutorial on lens sizes and what all of the numbers mean. Do I have this right

Macro Photography - Under 25mm Lense

Everyday Photography 25-80mm lense

Long Zoom Photography 75 - 300 mm lense

Moon shots, etc. 500-1000mm lense


Thanks for the help!

As someone else stated, start with the kit lenses, they are not very expensive and are generally pretty good to get you going. Your list while a good starting point will become much different as you start looking into it more and then getting into the actual photography itself.

Macro lenses range from about 24mm to about 300mm depending on the lens, prime or zoom. Many macro photographers will use primes lens macro's like a 60mm, 90mm, 105mm, or 180mm. They are also generally a f/2.8 lens and will focus to a 1:1 ratio (life size). Many zoom lenses that have macro features will focus to a 1:2 or 1:4 ratio (1/2 life size or 1/4 life size).

The everyday zoom lens on a dSLR will range between 18mm and 200mm. Kit lenses are 18-55, others will use 18-70, 18-125 or 135, 18-200, 24-80, 24-105 among others. Telephoto zoom are pretty much right on at 70-300, also 70-200 and other higher end ones are longer and more expensive.

I also don't know if I would classify a moon shot. I use my 70-300mm lens then will crop it tighter. Lenses 500mm and above can get very expensive (and heavy).

Once you get past the focal lengths we can get more into the f/stops and how that effect performance.

Good luck with your search and keep asking questions. Thats how we all learn.

 

[jann1033]

This very well written essay should help with selecting lenses to suit the type of image you wish to produce:

http://www.luminous-landscape.com/columns/composition-3.shtml

As you will see, it's more (a *lot* more) than just macro, everyday, long, etc. As somoene else mentioned, you might be best off starting with the kit 18-55 and getting used to the camera before deciding what other lenses suit your style of photography.
Or you can just go and spend a bunch on lenses like most of the rest of us! Hey, it's FUN!

truly an excellent article bobq... thanks for the link....are the rest in the series freebies or on a dvd or something? only bad thing is it made me want a nice wide angle lens ...will this insanity ever stop

 

[boBQuincy]

truly an excellent article bobq... thanks for the link....are the rest in the series freebies or on a dvd or something? only bad thing is it made me want a nice wide angle lens ...will this insanity ever stop

Most of Alain Briot's essays are available for free. The book is at Amazon for about $25 so I will probably buy it (or drop less-than-subtle hints to DW for my upcoming birthday). Alain is a rare individual who can write about photography as well as practice it.

I really wanted a wide angle lens so I finally got Canon's 10-22, a really nice lens! Since it wouldn't fit my 10D I had to get a 30D to go with it. Makes perfectly good sense to me!
Now I need to use the camera and lens more often to make them worthwhile, so I need to go back to WDW soon. Why do most people have trouble understanding all this?