do crop sensors really add reach?

[houston1852]

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?

[Axilrod]

Yes you'll lose some reach, as your 100-400mm on your T2i is giving you a very long field of view.  To duplicate the view you get at 400mm on your T2i you would need a 640mm lens.  If you're shooting wildlife it may be worth keeping, or upgrading to a 7D instead.  Your 10-22 has the wide end covered pretty much.  Yes the low-light capabilities of the 5D are an advantage, but how much wildlife are you going to be shooting at night?

[Mt Spokane Photography]

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 sell the 10-22 and replace it with the 16-35mm L if you get a 5D MK II. 
I keep my 7D for the longer reach, but its not a huge benefit.  My 7D and 100mmL is a benefit for macro shots wince I get all 18mp on the cropped image.
Personally, if I had to make a choice, the 7D would go and the 5D MK II / MK III would stay. 
Another possibility for you is a used 1D MK III.  It is better all around, but no super wide lens for aps-H.

[jrista]

It depends on how you define "reach". Technically speaking, when only factoring in the crop factor, the answer is "No, a cropped sensor like APS-C does not necessarily increase reach." Using a cropped sensor will definitely reduce your angle of view relative to a full-frame camera, as you are cropping the outer edges of the relative frame.

When it comes to discussing reach, what is more important is pixel density, or to be explicit pixel density in the context of a narrower angle of view. I'll get to the specifics in a moment. In most cases, APS-C sensors do have smaller pixels than full frame sensors. As such, historically, it has indeed been true that APS-C type cameras offer greater reach than FF, but with the advent of high density full frame sensors like the D800 and even more so Canon's 46.1mp prototypes that are supposedly out in the field, this is no longer guaranteed to be true.

An ideal comparison of FF to APS-C from a reach standpoint would be to compare the 18mp 1D X and the 18mp 7D. Both cameras have the same number of pixels, and the same image size output. The 7D truly has "greater reach" not only because it has a narrower angle of view, but specifically because it has much smaller pixels. The 1D X has 6.95 micron pixels, while the 7D has 4.3 micron pixels. For the exact same image area, in a photo taken with the exact same lens, the 7D will produce more detail. If the 7D also had 6.95 micron pixels, despite it's narrower angle of view it is not actually extending your reach. The 7D would produce 3208x2144 pixel images that contained the exact same detail as a 1D X image cropped to the same dimensions.

From a pixel-size standpoint, the 7D has about a 60% "reach" advantage over the 1D X, and a 45% reach advantage over the 5D III. If we compare the D800 with the 7D, the 7D's reach advantage shrinks to a mere 7%.

[dlleno]

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?

The short answer is yes, as a practical matter the t2i will provide a meaningfully superior image compared to a 5D2 image that has been cropped to the same FOV -- when the ISO is relatively low, the lighting is good, and the image properly exposed, etc.  This is because in this situation the t4i "puts more pixels on the image".   I mentioned all those disclaimers because  - as the available light decreases and ISO goes up, there will be some point where the cropped 5D2 image will be better (even though the final result may not be worthy of a large print)

It escapes me who provided the comparison on this forum (hats off to whomever that was), but it has been established with reasonable credibility that the 7D (which uses the same 18MP sensor as t2i) provides  "just noticeably better IQ" (my interpretation) compared to a 5D3 image cropped to the same FOV -- in optimum lighting conditions where the 7D shines.  So -- given the small IQ improvement of  the 5D3 over the 5D2 (see http://the-digital-picture.com/Reviews/Canon-EOS-5D-Mark-III-DSLR-Camera-Review.aspx) I would say yes you can expect photos from the T2i to be better than those of the 5D2 cropped to the same FOV -- again where the lighting is good, the image is properly exposed and you are shooting at 400 ISO for example.

My observation, however, is that adding the 5D2 to your bag would be more about adding new capabilities to your arsenal, not about loosing reach.  They are different cameras optimized for different situations.   As the above review shows, the 5D2 can provide significant IQ improvement over the 18mp crop (7D/T2i) esp in high iso situations and if  you CAN move in closer. Especially if the light is poor, then 5D2 is a no brainer advantage. 

Bottom line is that the combination of the two bodies will allow you to optimize IQ in many more situations, avoiding the use of the t2i when it is disadvantaged, and reaching for it when the situation calls for it. In well lit distance-constrained situations where you can't get closer, reach for the t4i.  As ISO increases, though, the 5D2 will start to become more attractive, and especially when you are NOT distance constrained (say, old buildings in low light)  it will produce better IQ than the t2i.

[Basti187]

I currently own a T2i as well and do lots of wildlife shooting, so I did quite a lot of research, my advise don't get a 5dm2 as the autofocus is just shitty, no improvement over the t2i, so depending on your budget i'd say go for a 5d mark iii, or IF you don't mind waiting another half a year or longer wait for the 7d mark ii to be released. Another option would be to get a 7D, but it has the same sensor as the t2i which wouldn't be much of an improvement than the obvious AF and FPS.

[jthomson]

I currently use a T1i which has  15.1 MP sensor.  the 5D3 has approximately 47% more pixels so I would only be giving up small amount of reach but would add several stops of ISO.  I find I am more limited by noise at ISO  1600 on my T1i  than by the  reach.

I was going to wait for the  7DII but maybe the 5D3 would be a viable upgrade.
I'm mostly into bird photography so  how does the AF system of the 5D3 compare to that of the current 7D for birding?

[neuroanatomist]

I've compared 5DII cropped to APS-C framing to 7D, and found the IQ to be a wash. With minimal processing, the 7D had more sharpness/detail, and the cropped 5DII had less noise.  Noise can be traded for sharpness, of course. The main difference is that the 7D is 18 MP while the cropped 5DII is 8 MP - fine for web and small prints, less desirable for large prints.

Still - I'd not recommend the 5DII for birds/wildlife due to the AF.  The 5DIII is a different story.

An APS-C sensor vs. FF is sometimes called a 'perfect teleconverter'. But that's theory - generic APS-C vs. generic FF.  I have directly compared my 7D with 100-400mm to my 1D X with a 1.4xIII behind the same lens, and at ISO 100, there's no real IQ difference, while at ISO 3200 the 1D X with TC is clearly better.

[tnargs]

How is a 5D mk2 going to meet your need to not switch lenses as much?

[Kernuak]

I've compared 5DII cropped to APS-C framing to 7D, and found the IQ to be a wash. With minimal processing, the 7D had more sharpness/detail, and the cropped 5DII had less noise.  Noise can be traded for sharpness, of course. The main difference is that the 7D is 18 MP while the cropped 5DII is 8 MP - fine for web and small prints, less desirable for large prints.

Still - I'd not recommend the 5DII for birds/wildlife due to the AF.  The 5DIII is a different story.

An APS-C sensor vs. FF is sometimes called a 'perfect teleconverter'. But that's theory - generic APS-C vs. generic FF.  I have directly compared my 7D with 100-400mm to my 1D X with a 1.4xIII behind the same lens, and at ISO 100, there's no real IQ difference, while at ISO 3200 the 1D X with TC is clearly better.

I didn't make any direct scientific comparisons between the 7D and 5D MkIII last week, but looking at the wildlife images I took on the first day, the 5D MkIII was noticeably better, probably as much due to the AF capabilities as the low light. It was so much better, that the 7D barely came out of the bag again, it just came out for some closer (or rather cropped view) macros shots of a dragonfly's head and some wood ants. I'm planning on doing a full review of the MkIII, now that I've finally had a chance to use it properly in the field, instead of just test shots of things that aren't part of my real world photography. I've done brief blog posts before, but I want to spend more time on it now. I got over the problem of reach by using a 2x extender when needed instead of a 1.4x and the image quality was just as good as the 7D with the 1.4x, with the ability to push the ISO higher (I went to ISO 5000, with cleaner images and higher shutterspeeds than the 7D at ISO 1600). The MkII would be less of a difference though, mainly because of the poor AF in comparison, but also, I wouldn't push the ISO quite as high as the MkIII. IQ-wise at lower ISO, it should be a match for the MkIII, if you can focus quick enough.

[houston1852]

How is a 5D mk2 going to meet your need to not switch lenses as much?

I am really appreciating all the replies on this.  I'm gradually starting to understand, but it's gonna take me reading these posts a few more times before I fully get a grasp on it!  As for not switching lenses as much, I just meant I plan on carrying 2 cameras with me.  Most likely keeping my 400 on one, and 24/70 on the other.

[dlleno]

I just think the motivation to carry two bodies is more about broadening the toolset to optimize more situations-- so your best bet is to understand where the two bodies excel and where they are weak.   If it were (just) about the convinience of lens changing, then you could pick up a refurb t2i for less than the 5D2 and achieve your goal.  In any case, as a way of trying to simply some of the comparisons,  consider:

1.  a crop body focuses the image on a smaller sensor (hence the term). Here you get the full number of pixels "on the image" but at an IQ disadvantage in some situations (due to, among other things, higher pixel density) where the larger sensor will produce better results

2. cropping the FF image to match the "reach" of the crop body could be considered starting with "better" pixels but throwing some of them away to match the field of view of the crop body.  Hence Neuro's results showing a wash between the cropped 5D2 (about an 8 mp image) and the uncroped 7D at 18mp (nice information thanks Neuro).  Accepting these data, one can only imagine how much better the uncropped 5D2 image can be compared to the 7D esp in those situations that favor the FF

[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.

[jrista]

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).

[CharlieB]

So the basic question -

Is the FF with some crop applied, as good, the same, or better than a 1.6 crop body shooting whole sensor.....

I think you'll find that a 5Dmk2 cropped, will be much better than your T2i.  Not tested the same, but just having a feel for cropping with my own 5Dmk2.

Having said that - Profeel.com has 5Dmk2 for $1750 - not totally bad price.  And they have the 7D for $1229 - which I just got from them.  Both are "with shipping".  They shipped my 7d the same day.

I plan on using the  7D as my crop body - mostly for the focusing and FPS, not so much for the reach.  I chose it because it control layout closely matches the 5Dmk2 and because the battery is the same (and I'd have two chargers the same, to charge up a pair of batteries at once).  Maybe less than spectacular reasons...  but it will work for me.  I didn't really want to bank on the any replacement having a totally different control layout.  It matters to me that things are almost fluidly integrated, no thought to use one or the other.