Overlapping vs. Complementary lenses

Question

I'd like to know if anyone has any advice or experience they can share about using a pair of zoom lenses that have overlapping focal lengths; or a pair of zoom lenses that have adjacent focal lengths.

I've narrowed down my next big lens purchase to a couple choices, one of which has a focal length range that overlaps a lens I already have and one that has a focal length range that sits next to it. I can compare all their technical attributes through available review sites, but I don't have any experience with the overlapping-vs-complementary question and have read very little about it online.

The overlapping lens neatly encompasses my favorite focal lengths, but I'm concerned that if I buy it I'll use it to the exclusion of my current lens and as a result I'll grow to hate it because it means I leave a great lens in my bag or at home. On the other hand, I fear that if I buy the complementary lens I'll have to change lenses for every other picture. (Obviously there are a lot of pros to each, but its those cons as well as the ones that I don't know about that keep worrying me, so I have a hard time comparing them since I have no experience with this.)

I'd love to know why you chose to go one way or the other, and what you thought after you used the lenses for a while.

Edit 2011-02-10: A couple answers mentioned the common weakness of lenses at the edges of their focal length ranges, which I think is the killer reason to get overlapping lenses. After reading the rest of the answers, though, I see that I wasn't very clear in my question, and I think that using real lenses in my example was a bad idea. Here's my attempt to clarify my question:

Suppose I have a DSLR whose sensor has some unknown crop factor. I currently have a 20-45mm lens, and after trying some other lenses in the 20-200mm range I come to the conclusion that my favorite pictures are all in the 25-70mm range. After investigating lenses I narrow down my choice to two lenses, a 35-85mm lens and a 45-85mm lens. So the lenses in question look like this:

                           1
  2    3    4    6    8    2
  0    0    0    0    0    0mm
==#====.====#====.====#====.==
  +----.----#+
  | current  |
  +----.-----+
     +-.----#----.--+
     | sweet spot   |
     +-.----#----.--+
          +-#----.----#+
          | proposed   |
          +-#----.----#+
             +---.----#+
             |proposed |
             +---.----#+

Clearly there's no do-it-all lens, but one, out of many, of the differences between the two lenses I am choosing from is that one overlaps my current lens and the other one doesn't. I research both proposed lenses, let's call them Lens A and Lens B, and I rank all their attributes, like this:

                       |      Score
Feature       | Weight | Lens A | Lens B
--------------+--------+--------+---------
Max Aperture  |   5    |    5   |    4
Size/Weight   |   4    |    3   |    4
IS/VR/OS      |   2    |    4   |    5
AF speed      |   3    |    4   |    3
Full-time MF  |   4    |    5   |    4
Brand         |   1    |    3   |    5
Sharpness     |   4    |    4   |    4
Flare         |   1    |    3   |    5
CA            |   5    |    4   |    5
Other stuff...|        |        |
Price         |   4    |    1   |    2
Overlapping   |   ?    |    ?   |    ?

Now, I'm asking you to help me answer those three question marks. Is it better or worse to have overlapping ranges, and how important is that. Once I know which option is better, I can give the two lenses their rankings (probably '1' and '5' to indicate they are on opposite ends of the spectrum) and then I can weight the subject based on how important I think that is. Obviously these are somewhat subjective questions, but unlike everything else in the table, there has been very little written about this subject online, that I've found, so I don't have a lot of opinions to draw from. That's where you come in :)

(And please don't overanalyze the table, the numbers are all made up.)

Answer 1

While complementary lenses cover a wider range at a lower cost, you are giving up some flexibility and quality by going that route.

With zoom lenses, the extreme focal lengths on either end are often weaker optically then the center of the range, so with a 18-55mm and a 55-250mm you have covered the 18-250mm range, but you will probably be weak around 18-20mm, 50-60mm, and 240-250mm (just guesses, I haven't actually researched specific lenses).

However, with overlapping lenses, you may have a 10-22, a 15-85, and a 70-200. This way you have covered 10-200mm, and even though the 15-85 may be weak from 15-20, the 10-22 will cover the range quite well. Also, you will need to switch lenses less often, meaning that you will have less issues with sensor dust.

Answer 2

The notion of "complementary" lenses takes for granted that the focal length is the only characteristic that's different between the lenses in question. In reality, that's rarely the case (probably never, really).

To make sensible selections, you need to look at quite a bit more than that, such as speed, size/weight, optical quality (sharpness, aberrations, etc.), durability, and so on. Depending on what kinds of subject matter you shoot (and under what conditions), duplication at or near a given focal length can make a lot of sense.

Just for example, I have an 85, a 100, a 28-135, and a 70-210 all in (or at least covering) the "short telephoto" range. Despite the near duplication, I use each of these lenses on a regular basis, and see no conflict between them at all:

1. The 85 is an f/1.4, two full stops faster than any of the others -- and with care, it produces truly gorgeous portraits. At the same time (especially wide open) it tends toward flare and low contrast.
2. The 100 is an f/2.8 macro, which is certainly useful in quite a few situations where none of the others would work at all. It's extremely sharp, but the focusing is really slow (I usually focus it manually).
3. The 70-210 is also an f/2.8. It's great for sports and wildlife, but weighs about as much as all the others put together, and it's not the sharpest lens around by any means (especially close up).
4. The 28-135 obviously covers the widest range of focal lengths, but it's also the slowest, so it's the least flexible in terms of depth of field. Like most relatively wide-range zooms, it's also fairly flare-prone.

I guess I could settle on one lens for the range -- if I could find a 28-210 f/1.4 that focused to 1:1, with adjustable contrast, essentially instant focusing, no distortion, and was less than six inches long and weighed less than a pound.

Until I can find that, though, I think having multiple lenses at (or close to) the same focal length can be quite useful. You're looking at a different range, but you still need to look at a lot more than just the focal lengths to figure out which makes sense for you.

Answer 3

Well, its better if you have a little overlapping focal lengths between your lenses. That way you can reduce the hassle of changing lenses every time your subject distance changes. I know it doesn't take much to swap lenses on the fly, but again you can wait to change the lens but the subject might not always.

For example, lets say you have 10-22mm and 70-300mm. Now you need a lens in between theirs length range. You can get 24-70mm to complement your existing one, but surely 24-105 gives you slight better flexibility on the longer end and 15-85mm gives you flexibility on both ends. Another positive thing is, while traveling if you want to go lightweight, you can pick anyone of the lenses having most versatile range without thinking much of missing a certain focal length.

I was in the same dilemma few months back. I was using 18-55mm and wanted to get 55-250mm which compliments the kit lens. But when I consulted a few fellow photographers, they all said complementary lenses are effective but not handy. So, I've decided to get 70-300mm and then upgrade my kit lens to 24-105. This overlaps about 35mm, but it also gives me equal flexibility.

I might suggest, if you can take a look back at all the pictures you've shot in past. Determine what were the focal lengths you used the most and get decided for prime lenses. Primes are usually sharper, in some cases cheaper and comparatively faster.

Again, choices of lenses mostly depends on what you shoot, what lenses you currently have and what you're planning to shoot in future. If you can mention these, I'm sure you'll get much more precise answers than mine.

Answer 4

There are some legitimate reasons to want overlapping ranges. One of the reasons you buy a zoom lens in the first place is to reduce the number of lenses (and lens changes) you need to cover a zoom range. Even if you've got a 50 prime in your bag, for instance, it's a whole lot more convenient to take a quick shot with your zoom at 50mm if you've already got a 18-55 or 24-70 or something like that mounted on your camera, and the same idea goes for overlapping zooms -- it's really convenient to be able to cover wide-to-normal and normal-to-tele in a pair of lenses because either let you grab a shot in the middle of that range, and it doesn't mean that you'll necessarily be using one at the expense of the other.

In some cases, you may also have a zoom that's less sharp at one or both ends of its range, and this is also a great reason to overlap that part of the range with another lens (and hopefully, to upgrade the lens at some point).

As far as being afraid that you're going to like one of your existing lenses less when you buy a new one, I wouldn't worry too much about that. After all, if your new lens ends up really being better than your old lens, then you've made a worthwhile upgrade. Maybe you end up being able to sell that old lens and upgrade another part of your range. If your old lens stands the test of time, though, you'll keep going back to it. Don't be surprised to "rediscover" a lens at some point, too (ie, "I'd forgotten how much fun it is to shoot with a 50 prime...").

Answer 5

If those (17-55mm and 24-70mm) are the lenses under consideration and you have a 10-22mm, I'd go for the 24-70mm just to increase your versatility. There will be a "hole" in you arsenal, but not a huge one. All three lenses would be nice, but we're not talking about $39.99 bottle bottoms here, are we? (Both are f/2.8 constant-aperture lenses.)

Ideally, you'd like to have a bit of overlap, but an (eventual, maybe?) combination of 10-22mm, 24-70mm and 80-200mm will leave you with darned few pictures you can't take. The two shorter ones will make a reasonable, manageable walkin'-around kit that will get you everything but long shots. If you need something that looks like it was shot at 23mm, you can shoot at 22 and crop. (Same thing if you absolutely need the framing of a 76mm lens -- shoot at 70 and crop.) You won't be losing enough to really care about.

Answer 6

In my bag I've got the Tokina 11 - 16 and Canon EFS 17 - 85 for my 450D. My 17-85 is mediocre at 17mm, giving me lots of wavy distortion - no good for straight lined things like buildings. It doesn't really improve will somewhere around 24mm. My Tokina however is wonderful at 16mm. If I had my time and money over again, I might have pursued the Tokina 12 - 24 in order to get better images (or at least simpler distortion - ie easier to correct). Hope this helps with an example. And as a few others have said, you don't need to change lenses so often.