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There seems to be a preference for to have the

  • 18 mm - 55 mm
  • 55 mm - 250 mm

lenses, but no mention of why they're better than a single 18-200mm. Could someone please explain why the two separate are better than the one combined, and if anyone has quantified this difference?

(I'm curious about Canon in particular.)

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5 Answers 5

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  1. Image quality. The wider the range of focal lengths on one lens, the more design compromises are made and the more correction must be applied to deal with things like geometric distortion, chromatic aberration, and light fall off in the corners.

  2. Aperture. Even though the EF-S 18-200mm f/3.5-5.6 has the same maximum aperture of f/5.6 as the EF-S 55-250mm f/4-5.6 IS II at each lenses respective maximum focal length, the 18-200 is slower for most of the range they share in common. The 18-200 is at f/4 by 28mm, f/4.5 at 45mm, f/5 at 55mm, and f/5.6 from 80mm on up. The 55-250, on the other hand, doesn't reach f/4.5 until 74mm, f/5 until 96mm, and f/5.6 until 154mm.

  3. Price. Depending on where you buy, the kit with the EF-S 18-55mm f/3.5-5.6 IS II rarely costs much more than the body only for the cameras it is offered with. I have seen occasions, usually during camera+lens rebate promotions where the kit was actually cheaper than the body only! The current difference at amazon.com for a T4i body is $16 less than the kit. So the 18-55 costs very little. The EF-S 55-250mm f/4-5.6 IS II goes for about $300 in U.S. stores, but you can get it from amazon.com for $174. The EF-S 18-200mm f/3.5-5.6 IS sells for around $700 in the stores and $569 on amazon.com. The 18-55 & 55-250 will run you around $190 more than a T4i body. That's $379 cheaper than the 18-200. The Sigma Sigma 18-250mm f/3.5-6.3 DC OS HSM IF is even slower than the Canon 18-200, costs $349 and performs about the same or worse than the Canon 18-200.

The-Digital-Picture reviews the EF-S 18-200mm f/3.5-5.6 IS lens here, the Sigma 18-250mm f/3.5-6.3 DC OS HSM here, and the EF-S 55-250mm f/4-5.6 IS II here.

DxO Mark has all the quantification you could want of theses three lenses.

Here's a screen grab comparing the Canon 18-200, Canon 55-250, and Sigma 18-250. The charts show sharpness at maximum focal length and aperture of each lens. Green is sharper, yellow is in between, and red is less sharp.

Screen grab

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    \$\begingroup\$ So you really do pay substantially more for a lesser product if you go with the 18-200mm than the two lenses 18-55mm and 55-250mm \$\endgroup\$ May 3, 2013 at 8:45
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    \$\begingroup\$ Unless the portability of only one lens is the most important feature to you. \$\endgroup\$
    – Michael C
    May 3, 2013 at 9:37
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A smaller zoom range means fewer compromises in the optical design and usually better quality. It's better to have a boat and a car and use them where appropriate than to have some sort of boatcar that doesn't do either job as well.

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    \$\begingroup\$ BUT BUT BOATCAR! \$\endgroup\$ May 3, 2013 at 9:03
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    \$\begingroup\$ And so a new term enters the discipline of photography. "Dude, that lens is a total boatcar, why did you buy it?!". Not to be confused with bokeh, of course. \$\endgroup\$ Jun 24, 2014 at 10:56
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Although the two answers are correct, I would like to chime in with a slightly different opinion. Note that I am not a professional by any means.

I used to have the two kit lenses for my Sony Alpha 55 (18-55 and 55-200), but switched to a new configuration where I have a 18-250 and a couple of nice, sharp primes (a 35/1.8 and a 105/3.2 macro).

I have probably lost a bit of sharpness by switching from the two zooms to the new one, but I really am much more comfortable with this set-up. I now have a lens that covers a wide focal range to get the work done for small prints, the web, and family snapshots. It lets me switch from a moderate wide angle to a nice zoom — got that squirrel stealing a nut to my daughter while I was photographing the view of a lake.

When I see something more worthwhile, that I would probably want to enlarge and print, I use the primes, which perform much better than the two kit zooms ever could.

If you'd like a bit of humor on this theme, read John's Shermann take on "18-300 is bad".

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  • \$\begingroup\$ Love the John Sherman article... the same as I love my GPL. \$\endgroup\$
    – Tetsujin
    Oct 16, 2017 at 6:31
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Go with the kit. As what others have mentioned, you compromise image quality and aperture openings for a superzoom.

However, I use one (an 18-250) for travel purposes. It can get the job done, but don't expect good image quality no matter what the price of the lens.

Plus I usually find these superzooms to be more expensive than 2 kit lenses (say a $350 superzoom, a 55-250 cost as low as $160 and an 18-55 costs $140, plus its way cheaper if bought as kit)

Lastly, kit lenses (individually) aren't as heavy than the superzooms, so you won't feel like your camera's weight is centered at the front.

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You have two choices, the first is a normal 55-18 lens, which is usually used for general use (depending on the brand and price, it has different quality) and the second is a 250-55 telephoto lens, although it is in the range of telephoto lenses with zooming power. It's average, but you need to know which lens you need for what kind of photography and in what genre, and these two groups of lenses have their own problems, as the previous user above explained well, image distortion and color and lighting. And the clarity and distortion varies according to the focal range of the lenses, the brand and price of the lenses is definitely effective in solving the problems mentioned above, you should know what style and genre to get a separate lens for according to your needs. ........................................ If you mean the combination of these two lenses to use them simultaneously in a box or kit so that it can cover the range from 18 to 250 for you, you should be able to get a super sensitive kit along with lenses with completely accurate diopters and no Reduce the amount of light in the corners, do not have distortion in the stretching of the side images, do not have distortion, do not have a white light diffusion mode and create a color spectrum on the sides of the images, perform geometric correction for straight vertical and horizontal lines, and do not have the ability to reduce input light. And install it, which is probably very difficult and expensive.

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