As some of you know, I recently purchased a 5D3 with kit 24-105 IS lens. This kit is replacing my 7D with 17-55 IS lens. I wanted to share my observations in upgrading. I'll also be posting this over on POTN so don't be surprised if you frequent those forums as well. This is not meant to be a scientific review, so don't expect lots of laboratory photo comparisons. Let me walk through each major area of consideration... Body design and Ergonomics As you know, the 5D3 body design borrows heavily from the 7D, making it extremely easy for 7D shooters to feel comfortable with the 5D3. You can be instantly productive with the 5D3 after making a few tweaks (eg. joystick to control focus point selection). Of course all the customization options I was use to with my 7D are also available on the 5D3 so initial setup was quick and painless. What's different is the size and shape of the right hand grip area. It's more pronounced and feels heftier or more solid in my hand even though the two cameras are very similar in weight. The display is significantly larger and brighter on the 5D3 (when both are set to max brightness). It's also the correct aspect ratio for viewing photos so there's no black bar at the top. Here's a quick iPhone photo of the two camera's displays so you can get a sense of the size difference and brightness levels... (both set to max brightness)... The viewfinder is also much bigger and brighter on the 5D3 (even with f4 glass attached vs the faster 2.8 glass on the 7D). The Mode lock button is also a welcome addition for me. The shutter button on the 5D3 requires less effort to fully press than the 7D and as a result is seems much more responsive, although this is probably entirely tactile. When I first started using the 5D3, I took several pictures prematurely by pressing a little too hard to activate focus/metering. Now that I've taken several hundred photos with the 5D3, I find the 7D shutter button unnecessarily stiff and it seems more laggy to me, but again, that could be just the tactile sensation. This obviously means little, but the shutter sound on the 5D3 also sounds more substantial if that's the right word. The 7D shutter sounds light and plastic like in comparison. It's one of those little nuances that you would never notice unless trying both side by side. I really like the two card slots in the 5D3 and the fact that one of them is a SD slot so I can use an Eye-Fi card for JPEGs and a CF card for RAW images. This has proven to be a great way to view images on my iPad screen whenever I want to enjoy some photos while on a trip, do some quick edits and/or share them on Facebook or Zenfolio. I imagine the near real-time untethered viewing on the iPad will also be great for taking product photos (such as my 7D for it's upcoming Craigslist ad) or any studio work so you can see check them on a big screen easier before changing your setup. Lenses On my 7D, my primary go-to lens was the 17-55 f2.8 IS. I also had a EFS 60mm macro, the EFS 10-22, the 35L, and the 70-300L. I will sell all my EFS lenses and be left with the 24-105L f4 IS kit lens, my 35L, and my 70-300L. So far, the 24-105 has been a dream to use. It produces sharp, contrasty, vibrant images on the 5D3... much better images out of the camera than the 7D with 17-55. The build quality of the 24-105 is significantly better than the plastic feeling of the 17-55. The L feels like a $1000 lens. The 17-55 does not. Both lenses use the same 77mm filter size which is convenient and saves me some money. The 35L seems right at home on the 5D3 as well. I haven't noticed the effect of having to move closer to frame a subject the same as I thought I might. It's just transparent since you're doing it by eye and moving your feet. If anything, the 35mm prime on a FF is more versatile than it was on the 7D. The 70-300L with it's 4-5.6 max aperture is going to be just fine on this body with it's amazing ISO capabilities and the things I shoot won't miss the foregone reach of the crop sensor. The jury is still out on whether I will get a 17-40 but so far, I'm happy with the wide-end of the 24-105. So far, I don't miss the f2.8 on my "walk around" lens at all. I rarely want that narrow depth of field and if I do want that, I can usually get a better shot with even narrower depth of field with the 35L. So far, f4 rocks on the 5D3 and taking portraits at 105mm at f4 can result in a nice creamy background. Image quality I've read lots of things about full frame... that it has better dynamic range, less noise, better colour, etc... it all seems to be true The 5D3 with the 24-105L produces much better photos in almost every respect compared to the 7D with 17-55. The RAW images out of the 5D3 are much sharper. I blame the aggressive AA filter in the 7D for the excessive sharpening that's required in post on those files. The 5D3 files require very little sharpening and make the 7D RAW files look like a blurry mess in comparison. Here's a quick comparison of the unadjusted RAW files in Aperture for both pieces of kit (ISO 400, f8, 1/200) 5D3: 7D: The high ISO performance is better than 3 stops in my opinion. That is, the images at 25600 from the 5D3 look better than the ISO 3200 images from the 7D. Now that's not necessarily all because of less noise, but the detail and colour that's retained at high ISO's on the 5D3. In addition, the noise in high ISO images from the 5D3 is much more pleasing to the eye so you can tolerate more of it, AND it cleans up without loosing sharpness much easier in post than the 7D. Below are a couple of pictures of my unlit fireplace... there's a floor lamp off frame to the left but that's really the only light source. It's DARK in there! To capture this photo, I set both camera's to Auto ISO, used Av mode to set them both wide open (f4 and f2.8 respectively) and let the camera do the rest. This is not a scientific test... but a good real world "I want to take a hand-held photo of this dark object"... here's what they both produced... (unadjusted other than exporting the RAW to a JPEG to Zenfolio for hosting) 5D3 (24-105 IS @ 75mm, f4, 1/50th, 25600 ISO) 7D (17-55 IS @ 43mm, f2.8, 1/10th, 3200 ISO) 7D (17-55 IS @ 44mm, f2.8, 1/40th, 12800 ISO) Now, the 7D image at 3200 ISO is fuzzier, and that's no doubt due to pushing this exposure to the limits where the IS wasn't able to cope with camera shake. While it's not a fair comparison of image quality, but it is a fair comparison of how well each piece of kit is able to capture a subject like this on Auto ISO. However, as someone suggested, I've added a shot from the 7D at 12,800 (it hadn't occurred to me to turn on ISO expansion!). As you can see, the 7D fares much better here, especially at web image sizes. 100% crops of the fireplace shots are posted below. For kicks, here's the same picture taken on my iPhone... perhaps giving you a sense for how dark this is (or how good the camera in the iPhone really is) iPhone: Here are some more high ISO shots to look at from the 5D3... 5D3 with 35L (f2, 1/80, ISO 20,000) 5D3 with 24-105 at 105 (f4, 1/30, ISO 25,600) 5D3 with 35L (f2, 1/60, ISO 25,600) Auto focus I thought the auto-focus in the 7D was very good... much better than my first T1i DSLR. But the 5D3 is unbelievably good. In that dark shot of the fireplace, the 5D3 could focus anywhere in the frame... on the log set and even on the nearly black wall at the back, while the 7D on the other hand, could only get focus on the textured bottom or the bottom edge of the log set. My keeper rate of shots taken at dimly lit restaurants and bars (usually using the 35L) has improved significantly. Anecdotally, I would guess it's gone from 50% to around 95%. I don't normally shoot a lot of moving subjects with AI Servo, but I was completely amazed that just by turning this on and pointing the camera at some birds, I was able to get a ton of keepers just from fooling around. Both of these have been cropped so the birds are not in the center of the frame as they were in the original... Dynamic Range Upon import, the RAW images on the 5D3 don't appear to have any added dynamic range over the 7D. I tried taking some shots today into the sun with some high dynamic range and sure enough, the images, apart from my previous observations initially yielded very similar dynamic range. Similar content was blown out on the high end and buried in shadows on the low end. However, where the 5D3 seems to pull away, is when you start to try and recover content from the shadows. It's remarkable, how much you can pull up the shadows on the 5D3 almost creating a single image HDR without noise. The 7D RAW files have significantly less room to play with here. Here's a side by side in Aperture of the same ISO 100 shot from both kits with bright sun backlighting putting the porch area in dark shade. When you lift the shadows significantly as I've done here, you can see lots of noise and loss of information above the mail box on the right (7D) compared to the still fairly usable image on the left (5D3). Interestingly, both had limited information in the blown highlights. The overall contrast and colour in the 5D3 image is much better even after recovering the shadows and highlights. Click for a larger size... Here's an example of how you can pull the shadows to create an effect similar to HDR... Or you can use it more subtly... for example, in this image, the shadows under the arch were completely dark when I first loaded this image into Aperture... Conclusion: The price of a 5D3 kit is extraordinary but selling my EFS lenses and 7D will finance a good chunk of it. The upgrade has been everything I expected and much more. I get better pictures with lest post processing. I'm still learning the camera and how to get the most out of it both at the point of capture and in post. It's an absolutely stunning tool and I'm really glad I made the leap.