This question already has an answer here:

I'm new to cameras with interchangeable lenses.

I'm looking at a 18-200mm zoom lens or a 55-210mm zoom lens.

I already have an 18-55mm lens.

Is it fair to say that an 18-55mm lens, combined with a 55-210mm zoom lens, will give me the same "zoom range" as the 18-200mm lens? (Ignore the fact that the first is 210mm, and assume it's a 55-200 for the same of this question).

To get the zoom % you would take 200/55 = 3.63 X Zoom 200/18 = 11.11 X Zoom

The first has a lower zoom ratio, but that's only because the lowest field of view is 55mm which would be the exact same field of view at the highest zoom of my 18-55mm. Meaning it picks up where the 18-55 left off.

So, an 18-55mm and a 55-200mm would provide the exact same field of view and zooming options than a single 18-200mm lens. The only difference is having to swap between the lenses.

Based on what I understand I believe this to be the case. Am I spot on? Is there anything else I should be considering or be aware of?

Both lenses are Sony and will be fitted on my new a6000.

marked as duplicate by Michael C, MikeW, mattdm, Paul Cezanne, AJ Henderson Apr 14 '14 at 14:12

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • Your assumption looks about right. – Yao Bo Lu Apr 13 '14 at 21:00
  • @MichaelClark I see this more as a preliminary question to that one - until you know that the angles of view are equivalent from the two combinations, you don't even know to start thinking about the advantages of one combination over the other. – Philip Kendall Apr 14 '14 at 7:31

In terms of which angles of view the lens(es) will allow you to select, you're correct: the combination of an 18-55 lens and a 55-200 lens will let you choose from exactly the same angles of view as a single 18-200 lens.

However, I think you are missing a couple of important points, both of which are well covered in this answer: you'll get better image quality and a better maximum aperture with the 18-55 / 55-200 combination than you will with the 18-200. On the other hand, you'll be carrying around two lenses and having to change them - at which point, it's a personal decision as to which matters more for you.

The other minor point I'd pull up is that "zoom ratio" isn't really a useful concept for interchangeable lenses; as I think you've realised, it's a concept which makes sense only for lenses which start at similar focal lengths. As such, it's vaguely useful for most compact cameras, which tend to start somewhere in the 20-28mm (equivalent) range, but pretty much worthless for comparing most interchangeable lenses. See this question for more details if you want to.

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