There are 800 factors in making lens selections and they seem to be increasing as time goes on. Personally I am stunned at the wealth of selections we Fuji X system have in such a short time.The G.A.S. in most of us can rationalize why we need all of them or even the "best-est". I probably have more glass than I actually need right this moment but it won't stop me from solving problems I don't actually have with more.
Even if one ends up over investing in overlapping focal lengths for all of the right or wrong reasons it doesn't mean it's fun to carry all that crap around with you. I've tried to develop a habit of buying small-ish camera bags and unpacking them after every outing as opposed to the ever bigger camera bag to fit everything I own. It helps, hell even if I am leaving for a month and make a decision to take way way too much with me I'll take a really small bag as well and make specific decisions for the day.
Buying or choosing what you might want with you, whichever, there are some really basic things to consider.
- Size vs. speed (as in maximum aperture)
- OIS vs speed.
- IQ vs other factors (size being a big one)
- What else do you have in the bag.
Obviously you don't have every choice for every lens but there are quite a few overlapping focal length choices in the X system line-up so it's a good general place to start. Let's take a look at one super common conundrum — the normal zoom. You know, the one that covers all the basics and 80+% of most people's focal length needs. Thank god both go to 55mm (85mm equiv) vs. a crappy not super useful 70mm equiv like on full-grame systems.
Buy/take the big one or the little one? I'm talking about the 18-55mm/2.8-4 vs the 16-66mm/2.8. I don't have the big one and probably never will. Sure it's got a hair more overall IQ better-ness if that's some sort of constraint. For the most part in many situations that won't be material. What about speed? At the short end it's the same so no decision there and if you count the OIS the little guy wins. If you value a small size over everything obviously the little one cleans up. I personally want to keep my camera as small as possible in use no matter how much crap is in my bag.
So the decision points really come down to these questions:
- Why do you need the one stop at best increase in speed?
- Is the incremental IQ bump worth the size and weight penalty?
- The last and possibly most important question is do you really need that extra bit of wide-ness built-in to your zoom?
One Stop Advantage
If the answer to question No. 1 is mostly due to hand-holdability I would say the 18-55mm is the better choice. Much more hand-holdable given any scenario with the OIS. If the answer is because you are constantly seeking higher shutter speeds to freeze fast moving subjects than maybe, just maybe that one more stop could be the answer but I would suggest in today's world if fantastic ISO 800, 1600, maybe even higher this is very narrow range of circumstances where that size and weight are worth the stop gain in real shutter speed, especially when you can have 2 or 3 stops with a prime in those narrow conditions meaning you also need that one stop and zooming a lot.
This is a tough one. I'm not being a smart-ass here but it is even if it's mostly theoretical for 99.9% of situations (hand-holding, moving subjects, etc, etc) as well as actual image use. I would say if this is your only real reason go for the little one or if you are super finicky in all situations grab a prime instead.
This is easy for me. I've never been partial to the 24mm equiv. field of view. I can easily skip it and certainly don't need it on the short end of my normal zoom. I sort of feel the same way about 24mm as most people feel about 28mm. For me and what I take pictures of (even apart from this project) I find 24mm too wide and not wide enough. If that 24mm equiv. is your particular sweet spot that might be enough to tip the balance for you. Then it comes down to how often do you need it in a zoom and what else is in your bag?
What Else Is In The Bag
For me I've got another body (finally). That combined with the fact that I rather jump to 14mm from 18mm solves that last dilemma for me quite nicely. It also solves the IQ and speed and even the super discrete problem's for me as well. I am almost (and in many cases more) as happy with two primes on two bodies instead of a zoom but that's so so dependent on what's in front of your camera. I can live with an 18mm and a 35mm instead of a normal zoom. Sometimes a 35mm and a 56mm. Other times a 14mm and a… You get the idea. Just something to consider in your overall plan. For me having two bodies has always sealed the fate for the pro-zoom as a no-go or me.
Obviously the working conditions for someone else heaven may exist with two bodies with both pro-zooms mounted. I live in 18-55mm land for 90% of what I point my camera at. Most of the time the speed decision for me is for effect and when it is I want something with a much faster aperture than 2.8. For hand-holdability I rather smaller and OIS, especially in the wide department where I value the convenience of micro-adjusting my POV.
More later with additional specifics and maybe even some pixel peeping.
First photo above made with the Fuji XT-1 and 18-55mm XF the rest with the 14mm. Processing via Ligthroom CC with a heavily modified version of VSCO HP-5+