MtnMan Loc: ID

The 18-55 is 52 mm.

Not sure about the 55-200. You need to look on it. My 55-300 is 58mm.

Look on the bottom of the lens near the camera. It should be in the white lettering the last number after a Greek "phi" symbol.

Regards,
Larry Leach\

Greg Loc: Maryland

52mm

Paw Paw Bill Loc: d

The bigger the glass on the front of your lens, the more light it lets in. Also the bigger the glass the higher the price. The bigger the glass the bigger the filter must be to cover it.

If you can not afford a $12,000 low light 500mm focal length telephoto, then you may purchase a smaller sized medium light 500mm focal lenght with smaller glass and smaller filter for $3,000. Even lower you can get an even smaller glass in a $1,000 telephoto that has a 500mm focal length and smaller filters. But, you will be able to take good pictures only in bright light. The sharpness and contrast is also better (usually) with the bigger lens.

If you watch football, you will see photographers on the sidelines with BIG telephoto lenses that are good for LOW light and have hugh front glass. These lenses can run over a hundred thousand dollars. To help on filter size and cost, they have the ability to place a smaller filter inside the lens near the smaller camera end.

Paw Paw Bill Loc: d

The same holds for any focal length lens. The lower the f/stop (bigger aperture), the bigger the lens diameter, the more light passes through the lens and the bigger the filter required to cover the objective glass(first glass at the front of the lens) and also accompanied by a higher price and quality of photo (usually) that can be taken.

I have said 'usually' a couple of times, because under bright light conditions and smaller f/stops some of the less expensive lenses can perform virtually as well as the high priced ones. But, ONLY UNDER CERTAIN CIRCUMSTANCES>

sbesaw Loc: Boston

As short true story. I was coming into my house through the garage I stupidly had not properly closed my Domke shoulder bag. Next thing i heard was a crash and the sound of broken glass. I almost threw up. A lens, I usually cary three, had slide out and fallen 3+feet to a cement floor. It landed on the front element. As I examined it the breakage was to the glass filter. I went to Hunt's Photo where they examined it and tested it and found it to be operating perfectly. The filter took the hit. Now this was a Nikon 24-70mm 2.8 leas which goes for about $ 1,800. If I only had one filter and it was on another lens it would have been a very costly mistake.

I am not suggesting that everyone needs a filter for every lens i am only pointing out that it is a risk/reward kind of thing. If you happen to have expensive glass then a filter is perhaps a good investment. It also means less chance of dust on the lens very time you swap the filter. If it's a good lens and finances allow I would say it's a good idea to put one on every lens. If finances dictate otherwise then you keep one on your priciest lenses.

Paw Paw Bill Loc: d

By the way, none (ok, maybe an exception or two) of the photographers on the sidelines own those hundred thousand plus lenses. Sports Illustrated owns a couple and the staff photographers get to use them at the games.

The rest are owned by corporations that will rent them to a photographer for the game. The photographer is also required to pay an insurance fee for the time he has the lens. It can run a few thousand for the rent and insurance for one game. Each is hoping to get the golden photograph that can be sold for 5 to 10 thousand.

Paw Paw Bill Loc: d

As a side note, two years ago I saw 4 photographers with 20 to 40 thousand dollar lenses on the sidelines in one small area just past the bench. A lineback recieved a pass and was headed in thier general direction. They were taking all the shots that they could get.

Just as the player reached the group, he went out of bounds into the photographers. Now, one of the photogs still had his eye in the viewfinder. I don't know why...all he could see by then was an out of focus red blotch that was the center of the runner's jersey. My thought was "if all you can see is the light on the engine of the freight train, then it's time to get off the track!"

He got run over straight head on. The other three did nothing to prevent him hitting the ground. They all simultaneously grabbed for the LENSE. That was their immediate concern and I don't blame them.

gizzy.whicker Loc: Cumberland Co., Illinois

Not a problem. I'll get me a one of them there hundred thousand dollar lens and duct tape it to the front of my brand spanking new Canon PowerShot SX40 HS that'll digitally zoom out to 3,360mm all by itself and what with the hundred thousand dollar lens duct taped to the front of it, why, I'll be able to get a good shot of a Chicago Bears fumble while I'm sitting on a fishing dock in New-Awlens dipping crawdads into a galvanized bucket. Dead ringer.

lluon

Why does the size change with the different lenses? The 2 I now have are the same.
Larger aperture the smaller smaller f number .f number is the quotient of focal length divides by diameter of the opening
(pupil or iris)lets say 50mm lens with maximum aperture f/1.8
would be 1.8=50/28.If manufacturer wants to make faster lens
(smaller f number)with the same focal length,say f/1.2=50/42.
Now we see that in order to make the lens faster the diameter of pupil has to increase from 28mm to 42mm and the filter size will relatively change to fit the pupil.
I hope this will answer your question (my English is not very good)

gizzy.whicker Loc: Cumberland Co., Illinois

Very well spoken, lluon, except that I didn't hardly understand every word you didn't say!:wink:

Armadillo Loc: Ventura, CA

You have made some very good points, and don't fret about your English, you have done very well so far.

Lets look at a few things in a little different way.
The Focal length of the lens is the measurement from the "Objective Lens Element" to the photo "Sensitive Device" inside the camera.
The "Objective Lens Element" is that circular glass element that faces the scene to be photographed.
The pupil or iris can relate to the Aperture opening inside the camera. (Aperture settings used to be located on the barrel of the lens, but in modern digital cameras the aperture has been placed inside the camera body and is controlled by settings in the camera.) Some what like the Human Eye and Brain function when we look at a scene.

There is another part to the /F-Stop value of a lens. The internal construction of the lens. Fixed lenses may have as few as 5 lens elements in 1 group. A zoom lens may have as many as 8 elements and 3 groups designed to control specific errors in glass lenses. The more lens elements and groups within a lens assembly the less light is transferred to the photo sensitivity device.

The only way to compensate for this loss of light is to manufacture the same lens with a larger Objective Lens; the larger the diameter of the Objective Lens the more available light to the photo sensitive device.

There is one more part to the /F-Stop value of a lens, magnification. For optical discussion magnification (zoom, fixed telephoto, telescope, or microscope) is in fact an optical illusion. The focal length of a specific lens restricts the angle of view in a scene. If you select a 55mm lens you get a wide angle of view (landscape). If you select a 300mm lens you might have a 4.5 degree angle of view. Because the 300mm lens restricts the angle of view down to 4.5 degrees the scene looks like it has been magnified (an optical illusion). When increasing the focal length of a lens you restrict the available amount of light to the sensor. To compensate for this loss the lens needs a larger Objective lens. this is why telescopes have from 4-inch to 16-inch objective lenses, to gather as much starlight as possible.

johnr9999 Loc: Carlton, OR

Tripod?

Audwulf Loc: Golden State

This is why I like the Cokin filter system. My lenses span from 52mm to 67 mm. The "A size filters are the ones I use. Three adapters, one holder, and I can slide any of my filters in without screwing them in and out. I leave UV filter in all of the lenses all of the time, and screw the adapter ring into them. I have filters for landscapes, portraits, weddings, sports and special effects (about a hundred). They're made from photo resin, and very cost effective. The filter styles are circular and square. The holder lets you stack up to three square filters. Look into the system, you might like it.

Armadillo Loc: Ventura, CA

Always use a tripod!

gizzy.whicker Loc: Cumberland Co., Illinois

Good Grief, Armadillo, I haven't had to read that much technical stuff since one of my first two ex-wives thrust a pre-nup in front of me and demanded "sign it" which I did and is the reason why now I can't afford one of those high-powered DSLR XPJT OLUH TTLP cameras with an articulating lens cap.