making a case for that crop body camera

[AlanF]

My passion is wildlife photography and my prime lens is the 100-400 4.5-5.6 L IS.  I often have to do a significant amount of cropping even at 400mm in order to get useable images.  The more I crop the more I have to contend with noise.

My two bodies are a 7D and a 5D Mark iii.  Each has its advantages and I use both of them a lot.  The 7D obviously gives me meaningfully greater reach.  But, for me, it produces noisier images than the Mark iii.  So much so that I generally shoot with considerably lower ISO on the 7D than on the Mark iii.  The 7D also has a much slower, and for me, considerably less accurate autofocus than the Mark iii.  I get far more blurry and useless photos with my 7D.

I've wound up using the 7D only at times where I really need the extra reach, where the lighting is bright, and where I'm not too worried about objects in motion.  For all other shoots it's my Mark iii.

+1. Exactly my experience. And, in practice the higher IQ and lower noise of the 5D III more than makes up for the loss of crop factor.

[chauncey]

Most of the time, it puts less

Oh really...take a picture of a ruler with the same lens on each camera then crop out a 1" segment of the ruler...you will have more pixels with the crop camera.

[FatDaddyJones]

Crop body = 1.6x extra reach. Talking about the 7D, you also get 8fps. That's just awesome. After buying the 5D Mark III, I was planning on selling my 7D and EF-S lenses, but I decided against it. Other than the first two reasons listed, the main reason I couldn't part with it was my EF-S 17-55. I love that lens so much that I had to keep a body to use it with.

[neuroanatomist]

Other than the first two reasons listed, the main reason I couldn't part with it was my EF-S 17-55. I love that lens so much that I had to keep a body to use it with.

I hear this a lot.  In case you didn't know, the FF equivalent of the EF-S 17-55mm f/2.8 is a hypothetical 27-88mm f/4.5 lens (adjusted for AoV and DoF for same framing), so the 24-105mm f/4L kit lens is longer, wider, faster, still has IS, and will deliver sharper images on FF than the 17-55 on APS-C.  The better ISO performance of FF (>1.5 stops from 7D to 5DIII) more than makes for the loss of a stop of shutter speed.  The only thing you're theoretically giving up is the high-precision center AF point...and since the center point of the 5DIII is reportedly more accurate than the center point of the 7D, and the 5DIII has overall superior AF, it's not much of a sacrifice.

My advice: sell the 17-55 (I did), and probably the 7D, too.

[Mt Spokane Photography]

Good used 7D's often sell for well under $1000, so they are a bargain.  Some lenses perform better on APS-C, but some do better on FF. 
Like Neuro, my 7D no longer got any use when I bought my 1D MK IV.  Eventually due to problems with my wrists, I bought a 1D MK III, it is far better overall than my 7D was, but the 7D did work very well with my 100mmL.
I'd certainly recommend a good used 7d.

[Plamen]

Most of the time, it puts less

Oh really...take a picture of a ruler with the same lens on each camera then crop out a 1" segment of the ruler...you will have more pixels with the crop camera.

Most of the time, you do not use the same lens (same FL) to shoot the same object.

[FatDaddyJones]

Yes, I realize the FF equivalency. This is getting off topic from the OP's original post, but I've read numerous times online that the 17-55 is sharper. I don't have a 24-105 to compare it to. However, I've never been disappointed with the performance of the 17-55. Coupled with the extra reach (my 70-300 for instance becomes a 112-480mm and faster frame rate... and no, I can't afford the 1DX's 14fps) it was enough to convince me to keep my 7D as a second camera. I now shoot with both, and they make a great combo. The similar interface and body style makes switching between the two a seamless experience.

Bottom line is that if you can't take a good picture with a crop camera, then you can't take a good picture with a full frame camera either. As far as equipment goes, they're both excellent.

[Plamen]

Crop body = 1.6x extra reach. Talking about the 7D, you also get 8fps. That's just awesome. After buying the 5D Mark III, I was planning on selling my 7D and EF-S lenses, but I decided against it. Other than the first two reasons listed, the main reason I couldn't part with it was my EF-S 17-55. I love that lens so much that I had to keep a body to use it with.

The 17-55 is a great lens, indeed, I used for several years. But ... the 24-105 on FF is even better, and not much different in weight and price.

[Plamen]

Yes, I realize the FF equivalency. This is getting off topic from the OP's original post, but I've read numerous times online that the 17-55 is sharper. I don't have a 24-105 to compare it to.

I do. The 17-55 is sharper on the same crop body. What is even more amazing that it compares well to the 24-105 even at f/2.8 (and the 24-105 at f/4).

But the 17-55 on crop is softer than the 24-105 on FF. Not a huge difference, but it is easy to see. I have one  comparison on my site, and of course, there is also TDP, PZ, etc.

[neuroanatomist]

Yes, I realize the FF equivalency. This is getting off topic from the OP's original post, but I've read numerous times online that the 17-55 is sharper. I don't have a 24-105 to compare it to.

I do. The 17-55 is sharper on the same crop body. What is even more amazing that it compares well to the 24-105 even at f/2.8 (and the 24-105 at f/4).

But the 17-55 on crop is softer than the 24-105 on FF. Not a huge difference, but it is easy to see. I have one  comparison on my site, and of course, there is also TDP, PZ, etc.

I also had both, and Plamen is absolutely correct.  That's why I sold my 17-55.

[FatDaddyJones]

Neuro, what do you use as a standard zoom on your 7D? Or do you use a standard zoom on the 7D now?

[neuroanatomist]

Neuro, what do you use as a standard zoom on your 7D? Or do you use a standard zoom on the 7D now?

I would probably use the 16-35 II...if I needed a standard zoom for the 7D.  But since I don't use the 7D at all anymore, it's a moot point. 

[pdirestajr]

Even if I had a 5DIII & a 1DX, I'd take the 7D to work because I can fire Speedlites off camera without any other equipment. I also don't need to even use a tripod cause the built-in viewfinder level features allows me to frame my shots easily. It's a simple and quick setup with minimal gear.

I'm shooting toys that are then masked out from the background and dropped onto packaging, sell-sheets, instruction manuals, web sites, etc. In this case, I really don't think the sensor size matters at all. If anything, the smaller sensor probably helps me with a little more DOF.

This camera is the right too for my job.

[Plamen]

If anything, the smaller sensor probably helps me with a little more DOF.

Smaller sensors do not have more DOF. You get the same DOF with equivalent settings; and if you push it too far, you get a very soft image due to diffraction anyway.

Not that I disagree that the 7D can be better for what you are doing.

[pdirestajr]

If anything, the smaller sensor probably helps me with a little more DOF.

Smaller sensors do not have more DOF. You get the same DOF with equivalent settings; and if you push it too far, you get a very soft image due to diffraction anyway.

Not that I disagree that the 7D can be better for what you are doing.

I haven't done a test, but wouldn't I have a shallower DOF if I used my 5DII with my 100mm macro with the same framing- ie: I'd have to be significantly closer with the 5D?

I always thought focus distance was part of the factor in DOF. Again, I'm not a lab tester of this stuff, I was only assuming another benefit to the amazing APS-C sensor