Would I benefit from going full frame?

[bycostello]

why do you think u need FF? 

[insanitybeard]

my 17-40 on full frame is inferior to the EF-S 10-22 on crop.

My experience too. Is that what others have found, or did I have a bad copy or didn't spend enough time with the setup?

The main problem with the 17-40 on full frame is at the wide end with wide apertures (f4 up to f8), the extreme corner resolution is poor until well stopped down (Check out the Photozone test). Using it on a crop camera masks this issue. The 10-22 has much less barrel distortion as well. Having said that, on a crop camera, the 17-40 delivers very good results because it's main weaknesses on full frame are disregarded.

[elflord]

2. I am aware that if I move to FF, I will have to trade my EF-S lenses for FF equivalents. My lenses will hold their value and I can get the 24-105 and 17-40 without losing any money (cannot afford the 24-70 II). But while the 24-105 is very good lens, I am not so sure about the 17-40. I didn't like the copy I owned (and I used it on a 5DII as well). And, I cannot afford the 16-35 II. Additionally, if I use f/4 after moving to FF- what do I gain over using f/2.8 in APS-C?

That's a good question. You gain about a stop, so if you're going to put f/4 glass on it, you're not going to gain very much as far as low light shooting is concerned.

If you're shooting indoors a lot, you'll be better served by faster glass (e.g. the 50mm f/1.4) and a dedicated flash unit that you can bounce (e.g. 430EX or 580 EX) than a full frame with no flash and f/4 glass. This option will also not cost you nearly as much.

If you do go full frame, look into the original 24-70 or the Tamron or Sigma 24-70 for your standard zoom.

[elflord]

Now, $2,300 isn't out of the question, but that is for old technology. If I want the 6D and the new 24-70 L lens the cost of entry rises to about $3,500.

But, that is for a single lens kit. To take full advantage of the full-frame I would want to invest in other lenses, such as the 24 2.8 IS prime and probably the 135 f2 prime. After all, what is the point of the full frame if you can't take advantage of its perceived shallower depth of field?

Entry level would be more like the 6D and  the Tamron (or if you're open to older glass but not body, the original 24-70)

Then the 50mm f/1.4 as your "shallow dof prime"

But even without the prime, having something that behaves like an APS-C 15-45mm f/1.8 lens is pretty handy.

So there are plenty of benefits to FF, but you're right that there are plenty of costs too. In the above example you'd have a fairly limited selection of glass (standard prime + standard zoom)

[sdsr]

Earlier this year I moved to a Canon 5DII (I also bought a Rebel t3i as back-up) from a Pentax K-5 (which supposedly has a better sensor than the 7D) after renting 5DII + 24-105 and doing some direct comparisons.  If you can do the same, I would recommend it, as we all have different needs/uses and standards; the differences that matter to me may not matter to you.

Among other differences that matter to me, the FF is much better at capturing busy detail (e.g. leaves on trees), cropping is better, shallow depth of focus is more easily obtained, and most important of all, images in low light (typically outdoors; I like cities at night) look far superior.  On the other hand, there are situations where the differences are minimal to non-existent (simple subjects in bright light that are fairly close, for instance).  The failures of the 5DII's autofocus are lost on me as I hardly ever want to shoot something that moves fast.

As others have pointed out, f/4 on FF is at least as good as f/2.8 on crop in low light, so you can imagine just how much benefit you can get with faster lenses on FF - I'm often amazed at how low the ISO can get in relatively low light with even f/2.8 (let alone f/1.4).  Throw in effective IS and the situation only improves (there are situations where a slow lens with IS yields better results than faster lens without IS).

As for the poor corner performance of the 17-40, all I can say is that I almost never take a photo where something in a corner should be in focus (the reverse, in fact), so I don't care.  It's certainly true that the huge barrel distortion of the 24-105 at 24 will look worse on FF, but if you have software that fixes that sort of thing (I use DxO, which does so automatically) it doesn't matter.  As for complaints about these two lenses cf the two EF-S lenses you have, perhaps I've been lucky with my two or unlucky with the 17-55 I rented (I've not tried the 10-20), but I much prefer the results I get on my 5DII with the 24-105 than I did with the 17-55 on my Rebel, which was at its best on close objects. (I also think that people around here exaggerate the differences among good lenses, but that's another matter....)

So, I would suggest you rent or borrow a 5DII/24-105 combination (or 70-200 f/4IS, for that matter) and compare it with your 7D + EF-S lenses (and compare the rented/borrowed lens(es) on both).  You may reach completely different conclusions from mine.... 

[dtaylor]

I have an APS-C setup with the 7D and 10-22 and 17-55 2.8. I have considered moving to FF with the recent reduction in prices of the 5DII and the 6D being announced, but here's the dilemma:
1. I am quite happy with the IQ of the 7D up to ISO 1600, but the noise above that is bad. So indoor photography without flash suffers. That is the main reason for my FF considerations.
2. I am aware that if I move to FF, I will have to trade my EF-S lenses for FF equivalents. My lenses will hold their value and I can get the 24-105 and 17-40 without losing any money (cannot afford the 24-70 II). But while the 24-105 is very good lens, I am not so sure about the 17-40. I didn't like the copy I owned (and I used it on a 5DII as well). And, I cannot afford the 16-35 II. Additionally, if I use f/4 after moving to FF- what do I gain over using f/2.8 in APS-C?
3. I did like using the 5DII for the short time I had it and the images were very nice, especially since I almost exclusively use the center AF point, but I do use the high-speed mode a lot on my 7D and I will certainly miss it (and again, cannot afford the 5DIII).

* The stop difference between your 17-55 and its FF replacement(s) is most of the difference in high ISO between the 7D and 5D2. The 5D3 is better still, but you've ruled that out for now on price. Nobody knows what the 6D will be like, though I imagine it will be comparable to the 5D3.

* You say noise above 1600 is bad. Use Canon's DPP for high ISO shots along with a 3rd party NR plugin. With that combination I find ISO 3200 noise is difficult to detect in an 8x10 print.

* Finally, for the price and hassle of moving, why not just add a fast prime?

If you could afford the 5D3 I would say go for it. But my guess is you will miss the speed and AF of the 7D vs. the 6D. Add a fast prime and optimize your high ISO workflow.

[RLPhoto]

i am not sure why people complaining about not being able to push iso over 2000 with 7d.  as for me, it is still usable up to 6400.  i do not have my 7d here, but i do bring my 30d with me when traveling to work (keep learning after working hours) and this following picture was taken with max iso of 30d (straight out of camera, just re-size with ACDSee as you can tell from exif).  i choose to use my 7d and 5d iii for events; therefore, i always leave them home.

what i am trying to say here is to choose your angle of shooting and shift your exposure to the right... do not shoot low key with high iso on any crop body...  you can see noise even with FF when shooting low key with 400 iso...

note:  i do not have macro lens, but this is should same kinda shot... "bright background"

just a thought...

I got usable files up to 3200, 6400 was for High-speed B&W's in my use of the 7D. 12,800 was just mush.

Infact, all my graduations shots on my website were from my 7D @ 1600 - 3200 ISO. Perfectly fine.

[ishdakuteb]

I got usable files up to 3200, 6400 was for High-speed B&W's in my use of the 7D. 12,800 was just mush.
Infact, all my graduations shots on my website were from my 7D @ 1600 - 3200 ISO. Perfectly fine.

i used my 7d to take a candid shot on bridesmaids with 12,800 one time only (just an experiment, right in the church).  after that, i have said to my self, i will only use it when there is no other choice

this is one of my 6400 iso that i helped my friend to shoot for his client's wedding.  snapped this when seeing this gent. sitting by himself and wanted to try something different to see how it looked like.  no noise reduction applied on this image...

[sagittariansrock]

Firstly, >1600 ISO images from 7D aren't bad, and I am sure in the hands of competent photographers are perfectly usable- however, that I feel is the one weakness of that excellent camera.
Secondly, when you think of all the extra light there is to be had if you go FF (I know FF users can also think the same of going MF!) and all the shallow DoF that you can use creatively, that is one big incentive.
I haven't ruled out 5DIII, in fact that is what I am going to save up for now- thanks to the general advice I got in this thread and elsewhere. I do think I'd miss the fps of the 7D if I go with 5DII/6D.
But this is very good advice:

If you're shooting indoors a lot, you'll be better served by faster glass

* Finally, for the price and hassle of moving, why not just add a fast prime?

I think I'd benefit from f/1.4 glass as well- it will counter my high ISO problem as well as provide the shallow DoF when I do go FF. But I think a 24mm or 35mm will suit me better indoors. 50mm on a crop is too long. I used to have the 1.4, but ended up selling it and just kept the 50 1.8.