Back when I had a Canon 30D, I was struggling to find the right normal lens. The optically-excellent Sigma 30 was not autofocusing reliably, and the Canon 28/1.8 paled optically by comparison, so I began to consider whether it would be better to buy a Canon 35mm f/1.4L lens or spend a bit more to replace the 30D with a 5D and 50mm f/1.4. The 50mm f/1.4 lens costs roughly $800 less than the 35L and gives similar field-of-view coverage on a 5D to what the 35L provides on a 30D. I was thinking that $800 would go a long way towards making up the price difference between a 30D and a 5D.
I ended up buying the 5D, and right away it felt as though I had made the right choice. Every lens I owned at the time seemed to get significantly sharper when mounted on the 5D rather than the 30D. Thus, when Dave Chow (user name "chowy") in the DPR forums asked for advice about the same decision I had just made, I recommended he sell the 30D to buy a 5D. Like me. Dave was very happy with the performance of the 5D after he made the move. Unlike me, Dave had much of the best glass Canon had to offer prior to changing bodies. With the 5D and 30D in hand, he presented in the forums the following series of comparisons. All images shown below were taken by Dave Chow. Thanks again to Dave for letting me share these here.
First up: Canon 5D and 50mm f/1.4 versus Canon 30D and 35mm f/1.4L. These two systems provide a similar field of view, with the 5D system being slightly wider. The 30D system provides about the same depth of field with the 35L at f/1.4 as the 5D does with the 50 at f/2.2. Here is the test scene with the two systems at those settings (Click image for intended viewing size):
I can't tell much difference between them. The 35L bokeh is a touch more appealing (less of a hard edge), but that's a subtle distinction. Let's pixel peep. Here they are at 100% (Click image for intended viewing size):
The 35L is damn impressive wide open, isn't it? Still, I believe the edge in resolution goes to the 5D system here, particularly when the two images are compared at the same output size (30D image upres'd or 5D image downres'd). If right about now you are thinking that I should be comparing these two camera systems at the same f-number rather than at the same DOF, or the same focal length rather than the same field of view, then you are bringing up a topic that I have chosen not to address in this article.
Next pair: Canon 5D and 135L versus Canon 30D and 85/1.2L. Once again, these two systems provide a similar field of view. The 30D system provides about the same depth of field with the 85L at f/1.2 as the 5D does with the 135L at f/2. Here is the background for the test scene:
Here they are with the subject close and the background nearly completely blurred (Click image for intended viewing size):
In this comparison, the 30D system has rendered a slightly more pleasing background blur. Dave shared a second comparison set for these two systems in the original thread, but I am omitting that one from this article because I believe the outcome with regards to bokeh was affected by backfocus on the part of the 30D system. Although I cannot provide the 100% crops for these images, a number of reviews have established that the 135L is sharper at f/2 than is the 85L (either version) at f/1.2.
Finally, we have the standard zoom shootout: Canon 5D and 24-105/4L IS versus Canon 30D and 17-55/2.8 IS. Once again, these two systems provide a similar field of view with the 5D system covering a somewhat wider as well as moderately longer field of view. In this particular comparison, the 30D system was used at 55mm with the 5D system at roughly 90mm to provide a similar field of view. Each lens was shot at maximum aperture, which gives the 5D system a slightly more shallow DOF. Click the image for the intended viewing size.
In this case, the 5D image has more bite, producing nicer colors with greater contrast, though Dave pointed out that the 30D had +1/3 stop higher exposure compared with the 5D system. The 24-105 has also done a slightly better job here with the bokeh, though the slightly different DOF is a confounder. At any rate. neither of these lenses is going to win any awards for bokeh.
Here's what I learned from these comparisons:
1) The 5D system and 30D system in these comparisons produce very similar images, and the cost of the two systems is comparable. The 5D, 50/1.4, 135L, and 24-105L would cost a combined $4000 on Amazon right now. The 30D, 35L, 85L, and 17-55 would set you back $4600.
2) Based on these limited data, the 5D&50/1.4 and 5D&135L combos may do a slightly less good job handling out-of-focus regions when compared with the 1.6x crop system equivalents.
3) Lens testing is a bitch. Okay, so I already knew this, but it bears repeating.
Other points to consider:
1) Current crop offerings do a lot that the 5D can't do.
2) The 5D is probably due for an update soon. I expect that the 5D replacement + 50/1.4 + 135L will likely cost about the same as a 40D + 35L + 85 L though.
3) The 5D combos can go shallower (and faster) than the crop equivalents. Not shown above, for example, was the 5D&50/1.4 at f/1.4, because the 30D and 35L can't produce a photo with DOF that shallow.
4) The 50/1.2L yields nicer bokeh than the 50/1.4, so if the slight bokeh edge to the 30D/35L combo in the above comparison was troubling, the 50L is always an option for the 5D user.
5) The 5D combos, in general, capture slightly more detail than 1.6x crop systems with equivalent settings.
6) Petteri's site has a nice wide zoom shootout between Canon full frame and crop systems.
Originally published on the old Serious Compacts blog. Older comments can be found here: http://seriouscompacts.blogspot.com/...e-vs-crop.html