Getting a backup camera: 40D, 7D or 5D?

I'm currently shooting with a 40D and I'm actually quite happy with that.
However, I've been doing more and more commission work like low profile weddings, portraits and interior shots that requires me to have some sort of backup body or even a second body to shoot.
Up until now, I've always borrowed a 30D, 400D or 450D (don't like bugging the same guy every time), but since people occasionally pay me now, I've been considering a second body.

Here are my options:
1. Get another (used) 40D.
Pros:
- identical bodies means identical settings and no way to screw up.
- cheap (€350 should get me one).
- same batteries / memory cards etc.
Cons:
- it's kind of an old body...
- everything that ever bugged me about my camera times two

2. Get a new 7D
Pros:
- Much better body (better af/better metering/resolution)
- More settings and buttons!)
- Video (meh)
Cons:
- Don't really need many of the 7D features.
- Expensive.
- Different batteries.

3. Get a bottom of the line body as an emergency backup (400D)
Pros:
- Cheap (€200 or something)
- Not wasting money on features my one body I already have.
Cons:
- Big step down and I'm not used to or comfortable in handling the xxxD/rebel line.
- different batteries / SD cards. (though on the plus side - same as my G9)
- No live view.

4. Get a used 5D (can't really afford a new 5DII without selling my 40D + some lenses which would be useless as I'd still have just one body)
Pros:
- FF body
- Same battery as the 40D (BP-511) / uses CF cards
Cons:
- I have a few EF-S lenses (11-16 / 17-50 / 50-135, so I could only use my primes)
- Older body with often a buttload of shutter actuations on it.
- No live view.


So... I'm stuck on a choice between these two. One the one hand I'd like to add a better body, but I'd lose quite a bit of money on getting new batteries and all that jazz. if I just added a 5D or 40D I'd only need to add one body + battery + cf card, that'd make that particular body about a 100 euros cheaper.

I'm really looking forward to shooting with a 5Dc, but by now they've become really old while still quite expensive (at least twice the price of a used 40D). I could only use a few of my lenses, but between the 28 1.8, 50 1.4 and 100mm macro, I guess I could put a 5D to good use, with the added bonus of some lenses functionally doubling between crop and FF (28mm = wide on FF and normal on crop).
I'm also not against upgrading some lenses like the 17-50 to the 28-75 if I should go for the 5D option.

I'm don't really have a set budget for this, but I'm not looking to waste a lot of money, couldn't really afford more than 1000 - 1500 euros max anyway.
Any advice or comments is really welcome!

Go with what you know. The 40D.

Plus like you said, you can use your crop lenses too.

(But the 5D is a nice option too)

I'd go with the 7D. You'll probably be looking to upgrade sooner or later so might as well do it now.

After writing all of the above down, I've become pretty certain that the choice is only between the 40D and the 5D, screw other options - even though I would LOVE a 7D, I can't justify 4 times the price of a used 40D...
I'm just thorn between using my primes on the 5D + zooms on the 40D or being able to use everything on two bodies. For example, there's not really an equivalent lens like using the 28 1.8 on FF, or being able to use a 50 1.4 as a normal lens.

On the other hand, I could slowly work on shifting my collection to FF and when it's time to finally replace my 40D, go with a 5DII...

Choices choices... Would there be a potentially huge color / contrast / white balance difference when using a 40D vs 5D? For example, if I'd shoot both bodies at 3000K custom WB, with identical lenses (to take that out of the equation)...
Anyone have any experience with that?

I would get the 40D, you already can use it on the fly without having to remember where buttons are(like you would with a newer body). It also streamlines processing because you can do a single batch process instead of 2 for different camera.

And from my experiences all lenses have a different "feel" to them. Some are warmer, some cooler in temperature and they all respond differently. Most modern lenses will be around the same color temperature within a 200K of each other. At work I shoot nikon and we have noticed the colors shift between our new lenses and old up to 800K. I think you will be fine but if you shoot a gray card then you are set and can make them later in post.

Nick

@The Fox, indeed, many of my lenses have slightly different tones... My Tokina's are usually a tad colder (so actually need a slightly warmer WB).
I often use a graycard, but usually only if I'm mixing flash with ambient. Then I usually set a custom WB for preview and get the final touching in the raw processing.

Still not decided between the two, maybe I'll let it depend on whether or not a great deal presents itself in either body.

If you get the 5D, the 40D becomes the backup. Trust me on that one.

For what you shoot the 5d sounds ideal. It'll give you better ISO performance by at least a stop IMO. Lens compatibility could be an issue though. I agree with gonzogolf that if you do get one the 40d will be relegated to a back-up.

I love my 50D but when I upgrade to a 7D or 5D the 50 takes the back seat!

40D and 5D are pretty similar control wise. I'd probably vote for the 7D, but the 5D is a great option, too. I don't think I'd get another 40D - it's better to do things that will give you different looks.

50D interface is very close to that of 40D, but it has the AF micro-adjust feature (can be important for some of your fast lenses).

I'd probably go with option 3 only get a 20D or 30D instead of a 400D. Then you share memory, batteries and general control layout.

Get a refurbished 7D from Canon (trade in an old film body) and use the 40D as backup. That combo works well for us.

gonzogolf wrote in post #11840583
If you get the 5D, the 40D becomes the backup. Trust me on that one.

THIS

I was about to say get a second 40D - a great camera that can be bought for dirt cheap now and makes your life easy
But i looked at you Pics on flikr - you have great landscape shots
the 5D will also serve you well when you do landscape
get the 5Dc and don't look back