do crop sensors really add reach?

[jrista]

This article from Roger Clark, a well-respected scientist and designer of image sensors, might be helpful. It explains and visually demonstrates how pixel density, ISO, noise, and overall light sensitivity relate and work:

http://clarkvision.com/articles/pixel.size.and.iso/

 

[PackLight]

This article from Roger Clark, a well-respected scientist and designer of image sensors, might be helpful. It explains and visually demonstrates how pixel density, ISO, noise, and overall light sensitivity relate and work:

http://clarkvision.com/articles/pixel.size.and.iso/

A couple quotes from your linked author;

"Crop factor and the associated focal length multiplier only affects field of view. They do not affect telephoto reach.

Effective focal ratio is a bogus concept. A cropped sensor does not suddenly multiply the lens focal length with the same f/ratio."

"The bottom line in my opinion: given a focal length limited situation and desire for as much detail as I can get, a camera with small pixels, like the 7D is the what I would choose. Not shown in the test, but given a non focal length limited situation where you can change position to get the subject to fill the sensor, a larger sensor (e.g. full frame) with the most pixels is the what I would choose. But if money were not an object, a compromise pixel size is a good option, if one chooses a high quality sensor like those in pro-series cameras."

Interesting though is his test is on the moon, a rather bland subject. If comparing a good wildlife camera I would think you would want to test with a subject with a bit more color variety and a possibly in the same neighborhood.

 

[gmrza]

Outside of a backup body, why keep the 7D?

For your kids ;-)

OK, my son is 6, and there is no way I would give him the 7D to play with, maybe the 350D (which is still sitting in the cupboard). - Admittedly, when I was 6 my father was occasionally letting me use (what was then) his Zeiss Ikon...

 

[jrista]

This article from Roger Clark, a well-respected scientist and designer of image sensors, might be helpful. It explains and visually demonstrates how pixel density, ISO, noise, and overall light sensitivity relate and work:

http://clarkvision.com/articles/pixel.size.and.iso/

A couple quotes from your linked author;

"Crop factor and the associated focal length multiplier only affects field of view. They do not affect telephoto reach.

Effective focal ratio is a bogus concept. A cropped sensor does not suddenly multiply the lens focal length with the same f/ratio."

"The bottom line in my opinion: given a focal length limited situation and desire for as much detail as I can get, a camera with small pixels, like the 7D is the what I would choose. Not shown in the test, but given a non focal length limited situation where you can change position to get the subject to fill the sensor, a larger sensor (e.g. full frame) with the most pixels is the what I would choose. But if money were not an object, a compromise pixel size is a good option, if one chooses a high quality sensor like those in pro-series cameras."

Interesting though is his test is on the moon, a rather bland subject. If comparing a good wildlife camera I would think you would want to test with a subject with a bit more color variety and a possibly in the same neighborhood.

Well, the nice thing about a bland subject is the fine details, minutia, are easy to find and compare. In a complex scene of a bird or wildlife or even landscapes, it is MUCH more difficult to make an objective comparison. The moon has very distinct, fine features but is otherwise simple...so the details, and the differences in the details that exist, are easier to pick out. Like the fine differences in detail and color that the 7D picked up, but which the 5D II did not.

Assuming money was no object, a 1D X with a 600mm f/4 L II IS and a pair of Mark III TC's is definitely the way to go. I don't think money can currently buy a better set of gear for a nature fan. But money...well...it tends to be THE object most of the time for most people, and objectively, the 7D offers a lot more than people really give it credit for (especially for a nutty nature fan. )

 

[PackLight]

This article from Roger Clark, a well-respected scientist and designer of image sensors, might be helpful. It explains and visually demonstrates how pixel density, ISO, noise, and overall light sensitivity relate and work:

http://clarkvision.com/articles/pixel.size.and.iso/

A couple quotes from your linked author;

"Crop factor and the associated focal length multiplier only affects field of view. They do not affect telephoto reach.

Effective focal ratio is a bogus concept. A cropped sensor does not suddenly multiply the lens focal length with the same f/ratio."

"The bottom line in my opinion: given a focal length limited situation and desire for as much detail as I can get, a camera with small pixels, like the 7D is the what I would choose. Not shown in the test, but given a non focal length limited situation where you can change position to get the subject to fill the sensor, a larger sensor (e.g. full frame) with the most pixels is the what I would choose. But if money were not an object, a compromise pixel size is a good option, if one chooses a high quality sensor like those in pro-series cameras."

Interesting though is his test is on the moon, a rather bland subject. If comparing a good wildlife camera I would think you would want to test with a subject with a bit more color variety and a possibly in the same neighborhood.

Well, the nice thing about a bland subject is the fine details, minutia, are easy to find and compare. In a complex scene of a bird or wildlife or even landscapes, it is MUCH more difficult to make an objective comparison. The moon has very distinct, fine features but is otherwise simple...so the details, and the differences in the details that exist, are easier to pick out. Like the fine differences in detail and color that the 7D picked up, but which the 5D II did not.

Assuming money was no object, a 1D X with a 600mm f/4 L II IS and a pair of Mark III TC's is definitely the way to go. I don't think money can currently buy a better set of gear for a nature fan. But money...well...it tends to be THE object most of the time for most people, and objectively, the 7D offers a lot more than people really give it credit for (especially for a nutty nature fan. )

You did see his degree is in Planetary Science, so no surprise his subject is the Moon.

One of the problems with photographing the Moon is the lack of contrast. For the most part it is a bland flat orb of reflected light. If you are shooting during the early or late phases you can get more shadow for detail. Contrast is one area that the 5D II and 1D IV are much better than the 7D. I have several thousand pictures of the moon on my computer from all three bodies.

I have to discount his comments about loss of color because that has not been my hands on experience.

I don't disagree with his conclusions either. I only say that the margin of IQ between the 7D and the 5D II cropped is very narrow, and not as wide as some believe. From my perspective when talking sensor only, the crop body is only preferred over full frame when you have your longest lens mounted and you have no more focal length.

 

[Loswr]

Assuming money was no object, a 1D X with a 600mm f/4 L II IS and a pair of Mark III TC's is definitely the way to go. I don't think money can currently buy a better set of gear for a nature fan.

"You talkin' to me? You talkin' to me? You talkin' to me? Well, who the hell else are you talkin' to? You talkin' to me? Well, I'm the only one here. Who the f--k do you think you're talkin' to?"

 

[moreorless]

I have a t2I. I've always been very happy with it, but I would like to buy a new camera. Basically so I don't have to switch lenses as much. I shoot pretty much anything. Mainly wildlife, nature scenes, and old buildings. I thought if I'm buying a new camera maybe go for the 5dmrk2. I worry about losing reach on my wildlife pics. Would I really lose reach or can I just crop all the way down to what I would get with my t2I?
As far as lenses go, I have a canon 24-70 2.8, 100-400L, 10-22, and 100 2.8 macro. I think if I go with the 5dmrk2 my 24/70 would be great, but id also have to find an equivalent ultra wide angle. Are the low light capabilities of the 5d2 really worth me adding that camera, keeping in mind I still plan on carrying my t2I on my hikes?

I'd say the main thing you need to consider is which aspct of your photography your looking to improve.

The 5D2 probabley would not help you much for shooting wildlife unless you can get very close where as it would improve IQ for closer subjects and in low light.

If you wanted up improve that aspect perhaps consider the 7D or 1D3 used? you'dnot gain any resolution but would gainy improved AF and FPS.

 

[jrista]

This article from Roger Clark, a well-respected scientist and designer of image sensors, might be helpful. It explains and visually demonstrates how pixel density, ISO, noise, and overall light sensitivity relate and work:

http://clarkvision.com/articles/pixel.size.and.iso/

A couple quotes from your linked author;

"Crop factor and the associated focal length multiplier only affects field of view. They do not affect telephoto reach.

Effective focal ratio is a bogus concept. A cropped sensor does not suddenly multiply the lens focal length with the same f/ratio."

"The bottom line in my opinion: given a focal length limited situation and desire for as much detail as I can get, a camera with small pixels, like the 7D is the what I would choose. Not shown in the test, but given a non focal length limited situation where you can change position to get the subject to fill the sensor, a larger sensor (e.g. full frame) with the most pixels is the what I would choose. But if money were not an object, a compromise pixel size is a good option, if one chooses a high quality sensor like those in pro-series cameras."

Interesting though is his test is on the moon, a rather bland subject. If comparing a good wildlife camera I would think you would want to test with a subject with a bit more color variety and a possibly in the same neighborhood.

Well, the nice thing about a bland subject is the fine details, minutia, are easy to find and compare. In a complex scene of a bird or wildlife or even landscapes, it is MUCH more difficult to make an objective comparison. The moon has very distinct, fine features but is otherwise simple...so the details, and the differences in the details that exist, are easier to pick out. Like the fine differences in detail and color that the 7D picked up, but which the 5D II did not.

Assuming money was no object, a 1D X with a 600mm f/4 L II IS and a pair of Mark III TC's is definitely the way to go. I don't think money can currently buy a better set of gear for a nature fan. But money...well...it tends to be THE object most of the time for most people, and objectively, the 7D offers a lot more than people really give it credit for (especially for a nutty nature fan. )

You did see his degree is in Planetary Science, so no surprise his subject is the Moon.

One of the problems with photographing the Moon is the lack of contrast. For the most part it is a bland flat orb of reflected light. If you are shooting during the early or late phases you can get more shadow for detail. Contrast is one area that the 5D II and 1D IV are much better than the 7D. I have several thousand pictures of the moon on my computer from all three bodies.

I have to discount his comments about loss of color because that has not been my hands on experience.

I don't disagree with his conclusions either. I only say that the margin of IQ between the 7D and the 5D II cropped is very narrow, and not as wide as some believe. From my perspective when talking sensor only, the crop body is only preferred over full frame when you have your longest lens mounted and you have no more focal length.

Well, there are subjective feelings about IQ, and objective comparisons of IQ. Your "feelings" about the 5D II and 1D IV's contrast, at least at the moment, are just that. I was trying to add some objective evidence to the conversation with my link to Roger's article, and I think his evidence speaks for itself.

Regarding moon photography, I too am a moon aficionado. I photograph it all the time with my 7D. Out-of-camera "contrast" is actually something highly dependent on which "camera settings" or "camera profile" you use in your RAW editor. It is also something that is very easy to tweak post-process without any loss of detail. Contrast is certainly not a problem with the 7D, either with neutral white balance, or with enhanced color. All of the following photos, exposed VERY far to the right (so the moon was almost a white disc), looked extremely flat and drab "strait out of camera", appearing to lack any detail at all. I import with the Canon Neutral Camera Profile. With a neutral white balance, bit of exposure tweaking, clarity, vibrance/sat (for the color enhanced versions) and some curves adjustments:

http://500px.com/photo/13321795 (B&W)
http://500px.com/photo/13321799 (Color)

http://500px.com/photo/13008253 (B&W)
http://500px.com/photo/12964733 (Color)

http://500px.com/photo/13008271 (B&W)
http://500px.com/photo/13008277 (Color)

I'd advocate that much the same information is present in each camera, regardless of whether it is a 5D II, 1D IV, or 7D. Despite higher full-well capacity in the 5D and 1D, there is little difference in actual dynamic range between all three cameras. All three are also 14-bit cameras, so there is little difference in the quantization output. The 5D II and 1D IV probably have a higher gain (more electrons per output level), but all that serves to do is mitigate some of the potential benefits of a higher full well capacity (such as greater ADC bit depth without the need to quantize fractional electrons...the other benefit would be S/N). A higher S/N, which leads to a lower per-pixel noise, for the 5D II and 1D IV is mitigated when a 7D image is normalized to the same size. In terms of pixels on subject in a focal-length limited scenario, the 7D actually captures the most total overall light since the moon covers more total pixel in it's frame relative to the 5D or 1D frames.

I would offer, for the benefit of the OP, that the 7D is essentially synonymous with the T2i (from a "reach" or "pixels on subject" standpoint), as they both use the same sensor.

 

[PackLight]

Out-of-camera "contrast" is actually something highly dependent on which "camera settings" or "camera profile" you use in your RAW editor. It is also something that is very easy to tweak post-process without any loss of detail. Contrast is certainly not a problem with the 7D, either with neutral white balance, or with enhanced color. All of the following photos, exposed VERY far to the right (so the moon was almost a white disc), looked extremely flat and drab "strait out of camera", appearing to lack any detail at all. I import with the Canon Neutral Camera Profile. With a neutral white balance, bit of exposure tweaking, clarity, vibrance/sat (for the color enhanced versions) and some curves adjustments:

I think that is one of the points. The 7D has allot of headroom to be "tweaked".
So a person with far less PP skill than you wouldn't necessarily see the same results out of his 7D would he?

Still, my opinions are based on actually owning all three bodies and actually using them in the field taking wildlife pictures. The 7D gets taken because of its AF system over the 5D II, if I owned a 5D III and its AF system was as good as they say I would take it over the 7D. Right now I take my 1D IV over the 7D and and 5D II. We can read the so called "experts" opinions but in the end, it is the pictures I take that provide the final proof for me. So yes, my opinions are just that opinions of the 3 bodies based on the 80,000 pictures they have put on my computer in the last 3 1/2 years. Some of us prefer to find out for ourselves what is best.

 

[LetTheRightLensIn]

I have a t2I. I've always been very happy with it, but I would like to buy a new camera. Basically so I don't have to switch lenses as much. I shoot pretty much anything. Mainly wildlife, nature scenes, and old buildings. I thought if I'm buying a new camera maybe go for the 5dmrk2. I worry about losing reach on my wildlife pics. Would I really lose reach or can I just crop all the way down to what I would get with my t2I?
As far as lenses go, I have a canon 24-70 2.8, 100-400L, 10-22, and 100 2.8 macro. I think if I go with the 5dmrk2 my 24/70 would be great, but id also have to find an equivalent ultra wide angle. Are the low light capabilities of the 5d2 really worth me adding that camera, keeping in mind I still plan on carrying my t2I on my hikes?

Usually but not because of the crop per se but just because they usually have a denser sensor than the same FF models of any given era. The key is to have a higher density of photosites per area.

 

[LetTheRightLensIn]

I have done the comparison as well. Comparing the 7d to the 5d II image cropped to match, the amount of improvement you gain with the 7d is marginal. If you have no PP skills it is non existent as the 5d II will be better. To make the 7d file marginally better requires more processing than the 5d II. The difference is not enough to matter.

The difference that does matter is the AF system of the 7D and the high frame rate which makes it a better wildlife camera.

This really depends on the ISO setting. At lower ISO settings (sub ISO 1600), I would say the 7D generally wins. It has noise, but the greater number of pixels on subject will usually more than make up for that fact. Noise becomes sub-detail, making it a lot easier to remove (i.e. moderate noise removal tends to have zero effect on actual useful detail). It is only when you get into super ISO 1600 settings that the 5D II would consistently win because of its lower noise. Anything at or beyond ISO 3200 is pretty much dead territory for the 7D...it just doesn't hold up well unless you have a lot of light, in which case you can usually opt for alternative solutions to getting light onto the sensor in trade for a lower ISO setting.

Also, don't forget with a 5D II, you'll have to crop any photo taken with the same lens by about 45% to match the 7D. Assuming you put as many pixels on subject as possible, a 45% crop on the 5D II (leaving 55% of the image remaining) will definitely increase the effects of noise. Now visible noise is also depends on what tonal range it exists in. If you are taking photos of higher key scenes, then cropping the 5D II is probably find. If you are taking photos if lower key scenes, or scenes where smooth gradients are primarily 18% gray tone or less, then noise could very well be a bigger problem on a cropped 5D II than on an uncropped 7D...assuming you get as many pixels on subject as possible (i.e. fill the frame with your subject.)

I would agree that the AF system on the 5D II is very wanting. I would actually pick up a 6D over a 5D II these days if I wanted a cheap FF body (assuming one wasn't willing to convert to Nikon for the D600).

I was talking about cropping the 5D II to match the 7D. When compared the two I was using lower ISO settings. The 7D is just marginally better, not substantially. To get it better you have to do more post processing to bring it out than you do the 5D II. So if you are shooting JPEG in camera I would say the 7D is not going to be better at all.

I have had these discussions in the past, until it finally got to the point that I compared. The logic is that the higher pixel density is going to trump substantially the lower pixel density of the 5D II. The logic makes sense, but in real terms it isn't the case. Do keep in mind, I did say "marginally better" I didn't say the 7D's would be worse.

The 7D is the better wildlife camera. I am not sure the T2i would be, you have to weigh out the AF system and frame rate as well. You can have all the pixels in the world, if the camera can't track a BIF will it make a good birding camera?

I posted a series of test files a while back that would definitely disagree with that assertion and so did Romy (liquidstone). 7D has a real advantage for reach (and it's even a trace less noisy per sensor area than the 5D2 although not than the 5D3/1DX).

I can try to dig up the files ago, I may have posted them on this site in the past, definitely in other forums, too.

 

[weixing]

Hi,
Since crop sensor use only the central region of the image circle where the lens perform the best, its should produce sharper image when using an EF lens. So theoretically, when there is enough light, a crop camera with EF 300mm F2.8 will give better IQ (mainly sharper image) compare to a full frame camera with a EF 400mm F2.8 (both will have similar FoV), right?

Have a nice day.

 

[PackLight]

I have done the comparison as well. Comparing the 7d to the 5d II image cropped to match, the amount of improvement you gain with the 7d is marginal. If you have no PP skills it is non existent as the 5d II will be better. To make the 7d file marginally better requires more processing than the 5d II. The difference is not enough to matter.

The difference that does matter is the AF system of the 7D and the high frame rate which makes it a better wildlife camera.

This really depends on the ISO setting. At lower ISO settings (sub ISO 1600), I would say the 7D generally wins. It has noise, but the greater number of pixels on subject will usually more than make up for that fact. Noise becomes sub-detail, making it a lot easier to remove (i.e. moderate noise removal tends to have zero effect on actual useful detail). It is only when you get into super ISO 1600 settings that the 5D II would consistently win because of its lower noise. Anything at or beyond ISO 3200 is pretty much dead territory for the 7D...it just doesn't hold up well unless you have a lot of light, in which case you can usually opt for alternative solutions to getting light onto the sensor in trade for a lower ISO setting.

Also, don't forget with a 5D II, you'll have to crop any photo taken with the same lens by about 45% to match the 7D. Assuming you put as many pixels on subject as possible, a 45% crop on the 5D II (leaving 55% of the image remaining) will definitely increase the effects of noise. Now visible noise is also depends on what tonal range it exists in. If you are taking photos of higher key scenes, then cropping the 5D II is probably find. If you are taking photos if lower key scenes, or scenes where smooth gradients are primarily 18% gray tone or less, then noise could very well be a bigger problem on a cropped 5D II than on an uncropped 7D...assuming you get as many pixels on subject as possible (i.e. fill the frame with your subject.)

I would agree that the AF system on the 5D II is very wanting. I would actually pick up a 6D over a 5D II these days if I wanted a cheap FF body (assuming one wasn't willing to convert to Nikon for the D600).

I was talking about cropping the 5D II to match the 7D. When compared the two I was using lower ISO settings. The 7D is just marginally better, not substantially. To get it better you have to do more post processing to bring it out than you do the 5D II. So if you are shooting JPEG in camera I would say the 7D is not going to be better at all.

I have had these discussions in the past, until it finally got to the point that I compared. The logic is that the higher pixel density is going to trump substantially the lower pixel density of the 5D II. The logic makes sense, but in real terms it isn't the case. Do keep in mind, I did say "marginally better" I didn't say the 7D's would be worse.

The 7D is the better wildlife camera. I am not sure the T2i would be, you have to weigh out the AF system and frame rate as well. You can have all the pixels in the world, if the camera can't track a BIF will it make a good birding camera?

I posted a series of test files a while back that would definitely disagree with that assertion and so did Romy (liquidstone). 7D has a real advantage for reach (and it's even a trace less noisy per sensor area than the 5D2 although not than the 5D3/1DX).

I can try to dig up the files ago, I may have posted them on this site in the past, definitely in other forums, too.

LOL, ok I will dig up all my test pictures that I have taken. Then we can debate how much your "real" advantage is compared to what I consider a "marginal" advantage. There is the chance that what I consider "marginal" may even be better than what you consider a "real" advantage.

But in the end, the answer to this question is that the 7D trumps the OP's original camera he has and the 5D II for wildlife. The reason is the AF system and the frame rate. Any other benefit isn't as substantial as that one.

 

[PackLight]

Hi,
Since crop sensor use only the central region of the image circle where the lens perform the best, its should produce sharper image when using an EF lens. So theoretically, when there is enough light, a crop camera with EF 300mm F2.8 will give better IQ (mainly sharper image) compare to a full frame camera with a EF 400mm F2.8 (both will have similar FoV), right?

Have a nice day.

It would actually be closer to the 500mm with FF. 1.6 x 300mm would be 480mm.

I think if you did side by side examples you would prefer the FF. I know I do. You could test the 85mm vs the 135mm, I have seen where people have done this test and the FF comes out on top.

 

[jrista]

Out-of-camera "contrast" is actually something highly dependent on which "camera settings" or "camera profile" you use in your RAW editor. It is also something that is very easy to tweak post-process without any loss of detail. Contrast is certainly not a problem with the 7D, either with neutral white balance, or with enhanced color. All of the following photos, exposed VERY far to the right (so the moon was almost a white disc), looked extremely flat and drab "strait out of camera", appearing to lack any detail at all. I import with the Canon Neutral Camera Profile. With a neutral white balance, bit of exposure tweaking, clarity, vibrance/sat (for the color enhanced versions) and some curves adjustments:

I think that is one of the points. The 7D has allot of headroom to be "tweaked".
So a person with far less PP skill than you wouldn't necessarily see the same results out of his 7D would he?

Still, my opinions are based on actually owning all three bodies and actually using them in the field taking wildlife pictures. The 7D gets taken because of its AF system over the 5D II, if I owned a 5D III and its AF system was as good as they say I would take it over the 7D. Right now I take my 1D IV over the 7D and and 5D II. We can read the so called "experts" opinions but in the end, it is the pictures I take that provide the final proof for me. So yes, my opinions are just that opinions of the 3 bodies based on the 80,000 pictures they have put on my computer in the last 3 1/2 years. Some of us prefer to find out for ourselves what is best.

Again, I was just trying to add some objectivity to the discussion. Personally, I'd still take the 1D IV as well. "Overall", it is the better camera, no way around that. I totally agree that there are other factors to consider, and the 1D IV brings a lot of additional factors to the table (including a pretty incredible AF system that includes f/8 AF, meaning it has the potential to use 2x TC's on f/4 lenses, which could offer a whole additional level of "reach" beyond what the 7D can.)

I just think the 7D gets a really bad rap when it is not really deserving of it, and I try to provide concrete evidence to the contrary whenever I can.

 

[weixing]

Hi,

Hi,
Since crop sensor use only the central region of the image circle where the lens perform the best, its should produce sharper image when using an EF lens. So theoretically, when there is enough light, a crop camera with EF 300mm F2.8 will give better IQ (mainly sharper image) compare to a full frame camera with a EF 400mm F2.8 (both will have similar FoV), right?

Have a nice day.

It would actually be closer to the 500mm with FF. 1.6 x 300mm would be 480mm.

I think if you did side by side examples you would prefer the FF. I know I do. You could test the 85mm vs the 135mm, I have seen where people have done this test and the FF comes out on top.

Hmm... I just wondering: will image shoot with a crop sensor resolve more details than a full frame camera using the same lens at the same distance?? Meaning will I see details on image shooting with a crop sensor that didn't appear on image shoot with full frame sensor using the same lens at the same distance?

I'm very interested in this as I'm currently thinking of whether to get a full frame or not for birding. Currently, I'm using EF 400mm F5.6L with 60D. The problem I had with 60D are basically noise (I confess I'm obsess with noise, so I seldom shoot above ISO 1600... ) and AF at dim light... miss quite a few opportunity at some rare birds when they appear at time when light is low, so I think getting a 6D (when it become available) might improve on this (I can't afford any of the > 400mm lens) and I like the idea of have a GPS coordinate tag with my image... ;D Also, I can keep my 60D as a backup camera since most of the accessories can be share.

Have a nice day.

 

[epsiloneri]

Just adding my moon comparisons of 7D vs. 5D2+TC1.4x to the thread.

 

[TexPhoto]

Is the crop 7D going to have more reach? Yes of course. But of course you can just crop the FF image for more reach also.

is the 7D going to yield more pixels vs. the cropped 5D/ yes of Course

Is it going to yield more detail? Depends if the lens is sharp enough. And the 100-400 is not known for sharpness at 400. So maybe not.

On my 400mm f2.8 IS I, my 7D has way more reach and detail than my 5D II (now III)

 

[LetTheRightLensIn]

LOL, ok I will dig up all my test pictures that I have taken. Then we can debate how much your "real" advantage is compared to what I consider a "marginal" advantage. There is the chance that what I consider "marginal" may even be better than what you consider a "real" advantage.

But in the end, the answer to this question is that the 7D trumps the OP's original camera he has and the 5D II for wildlife. The reason is the AF system and the frame rate. Any other benefit isn't as substantial as that one.

make sure to click as much as needed to get to the full original image size

You don't think the top and bottom (7D) show noticeably more detail captured than the 5D2/5D3 (center)?
And look at Romy/liquidstone's various tests....

And the thing is, if you say the 7D has no reach advantage over a 5D2 then you must also agree that usage of TCs is always a waste....

 

[sandymandy]

Of course there is more detail because the dollar is bigger in the photo. If you use a microscope there will be TONS of more detail...
get what i mean? Such test photos only make sense when the final output is the same.

7D just gives u more detail in aka you dont have to move closer to the subject to get the field of view you want. 80mm lens on 5D and 50mm lens on 7D should give equal results. But not EXACTLY cuz the bokeh will also look different etc.