lenses in flux, help me tie things down

i have a full frame body and a crop body.

UWA

i have a 17-40 as UWA that i want to sell (when i saw the EF-S 10-18)
- i figured that a cheaper lens that's wider, and has IS, what's not to like?
- i only use the UWA once a year during family photos.

but now that changing UWA's is on the table, why not discuss the options?
-16-35 f/4 L IS or EF-S 10-18 IS or Tamron 15-30 2.8 VC

advantage of the two FF lenses, they can be used as stopgap midrange lenses on my crop body. disadvantage is price.

or i could get the cheap EF-S 10-18 and get a real midrange lens.

Mid-zoom

options are

24-70 2.8 VC
24-70 4 L IS
18-35 1.8


i'm super confused.

The 10-18 can only be used on the crop body. I wouldn't limit myself to a lens that can only be used on one of your bodies. If you only use it once a year though then maybe just get the cheapest one you can but if you see yourself using it more in the future put a little more cash behind it and get something that can be used on both bodies.

If you only use the UWA once a year, it doesn't seem worth investing a lot of money in it. And, looking at your gear list, you have a lot of lenses but no mid-range zoom that you can use on your full frame body. So the logical way forward would seem to be the cheaper UWA plus a good mid-range zoom that would work on both bodies. I personally wouldn't consider the 18-35 to be "mid-range" on either body, and in any case you already own a 35 mm prime. Lastly, if you're considering the 24-70 f4, why not also consider the 24-105 f4? It then becomes a question of preference: f2.8 versus reach.

If it were me, I'd go for the cheaper UWA plus either the 24-70 f2.8 or the 24-105 f4.

i think i'm leaning towards the 24-70 f/4 IS + EF-S 10-18

i keep looking at the tamron, but figure that i'm never lucky with electronics.


edit: and then i read about the 24-105 IS STM. and i will put a hold on this purchase until that comes out.

For your consideration:

- Sell your crop body and consider getting the 24-105 (STM or L) and keep it simple with 1 body and lens.
- It's not worth buying a ultra wide lens to use once a year. Just rent a nice one with that money you just saved for that one or two times a year you need it.
- Use saved money on trips or family. Wouldn't that be a better use of money than a lens you use once a year?

i actually use the crop body more than the full frame one.

i sold my 50L to fund the 70D + 35mm f/2 IS. the 18-135 is also nailed to that same body 95% of the time.

i guess i'm thinking:
70D + 35mm f/2 IS
5D3 + 24-105/24-70
is the combo i'd like to bring around, and then i could switch the lenses to get different perspectives.