6D with or without 24-105 kit lens?

[Jarhead5811]

I currently have a T3i, Tamron 17-50mm f/2.8, 70-200mm f/2.8L and a Sigma 30mm f/1.4. I had been planning on upgrading to a 70D soon but my Wife, who is a stay at home Mom that has (FINALLY!!!) been bitten by the photography bug, has talked me into waiting a little longer for a 6D. Can you believe it?

Of course, my only "dilemma" is that my 70-200mm f/2.8L is my only lens will work on a full frame. So, I was thinking I'd get it bundled with the 24-105mm f/4 L IS USM lens but being my primary motivator in getting a full frame is for low, available light, shots of my very active three little ones, I wonder if I should go for a 2.8 aperture instead. I've even considered just getting a fast prime initially and getting a zoom later but I don't think my Wife would like that. Her hate for the 30mm f/1.4 is only outpaced by the animosity she had for the nifty fifty. I know with my lighting setup it shouldn't matter but she doesn't like to fool with it and, in her defense, it does change the kid's behavior when we use it, usually killing the moment.Any thoughts?

Edit: I should add that the other lens I'm considering is the Tamron 24-70mm f/2.8 Di VC USD. I've been very happy with my Tamron 17-50mm f/2.8 and the 2.8 aperture combined with VC is an exciting idea.

Edit #2: I just realized this should have been in the Lenes subforum.

[Kayaker72]

The general rule of thumb is that you are gaining 2 stops of usable ISO performance with FF over a crop sensor. Since you lose 1 stop going from f/2.8 to f/4.0, purely in terms of light hitting the sensor (ignoring DoF), you should gain at least 1 stop of light going to FF with the 24-105 over a 70D with an f/2.8 lens. My experience is that I can use the 24-105 f/4 in well lit rooms, for example when daylight is pouring in through the windows. I typically shoot indoor night shots at ~f/2-f/2.8 with my 50 f/1.4 (which I much prefer to the 50 f/1.8--but your wife may not like primes from the sounds of things) or the 100 mm L macro. This is with the 5DIII.

Also remember that you will be able to use that AF center point to better focus in lower light. I think that may be a good starting point, if you can quickly AF with the T3i, the f/4 lens will likely be fine, as I said, a 1 stop improvement. But for shots where you T3i is having trouble with AF, you will likely need a f/2.8 (or faster) lens, even on a FF.

EDIT--I thought I'd provide some examples of indoor night time shots:

small-6317 by kayaker72, on Flickr

This was shot at 1/50, f/1.4, ISO 3200 in a room lit with a single 100 W (tungsten equivalent CFL). It would have been ISO 25,600 at f/4 (really stretching the FF) or ISO 12,800 at f/2.8. I do sometimes go to ISO 12,800 on the 5DIII, but prefer lower. There are trade offs the higher ISO you use.


small-2812-2 by kayaker72, on Flickr

This was 1/80, f/2.8, ISO 2000 in a relatively dimly lit living room. f/4 and ISO 4000 would have likely been fine. But if you want 1/160 to better capture motion, f/4 you would have needed ISO 8000, which can be acceptable, but you are approaching the upper limits.

I hope that helps.

[clemmb]

How about a used Canon 28-70 F2.8 L. KEH has several for under $800
Sean purchased one of these from e-bay I think and loves it.

[peety3]

Long story short: I'm amazed at how useful 24-105 is on FF. With 8 L lenses and cameras in three different crop factors here, I now find myself debating what to take for simple stuff, and 24-105 on FF is often a reasonable one-lens solution.

I started with a 1D Mark III and 24-105, and three years later got the 24-70/2.8 (the 24-105 went to my wife's bag, and her kit 28-135 has been on the shelf almost completely since then). Now that we added a 5D Mark III (it's "hers"), I often grab the 5D3 and 24-105 for the simple things.

That said, if the price increase to include the 24-105 is $600, don't get any dreams of selling it for retail (in my opinion). Canon has basically said it's worth $600, so if you want to put it on Craigslist for $775, don't hold your breath.

[Jarhead5811]

After reading all of the reviews, ya'll's advice and just plain mulling it over, I think I'll get the 6D w/24-105 kit. I figure I can get a faster lens later but this will be a cheaper start. Besides, the T3i we currently have does a pretty decent job. Heck, other than auto focus being really slow it does pretty good.

[Kayaker72]

Quick guess is that you'll be pretty happy with the system. One thought would be to include a 40 mm f/2.8 STM or 50 mm f/1.4. As you have f/2.8 from 70-200 mm, that would give you some faster glass at wider focal lengths....

[Jarhead5811]

Yeah, a 50 f/1.4 would be on my short list!

My 70-200 might actually be useful indoors, on occasion. On a crop body it's just too dang long to be of much real use, indoors.

[Jayson]

I think you'll be very happy with the combo. I have a 7d and use my 24-70 at 70 most of the time in our house (3 kids), so I think that you will get a lot of use out of both your 70-200 and the 24-105. Keep in mind the wide end because your Tamron frames like a 28mm indoors. You will have a much better range for stuff now. I would recommend the 40mm pancake, if you didn't want to spend another $100+ on the 50mm. You don't get the low light, but you get a very sharp f2.8 that is relatively wide on a 6D and is surprisingly well built.

Congratulations on your wife approving the upgrade and have fun!

[gschaps]

ISO 6400
1/30 s
24 mm
F 4.0
DxO Optics Pro 8