400D/50D AF comparison

Hi all, I've been absent from the forum for a long time. I've been using a much abused 400D for a the last 5 years and it's on the point of dying permanently. I have the oppertunity to buy an almost new 50D at a good price and it will give me the increased fps I want plus a more rugged body. What I would really like to know from those of you with firsthand experience is how the AF compares between the two models? Is the 50D AF noticeably faster/more accurate? Of course I'd love a 7D, but the money isn't available! Thanks in advance for your views.

Welcome back - things have changed around here, just a few days ago the forum backbone was changed, so we're all still getting used to it.

Unfortunately, I can't offer any first hand experience with either body, but I can offer some specification-based observations. The 400D has 9 AF points, only the center point is a cross type (which can detect features in multiple orientations, making it more likely a focus lock will be achieved). The 50D also has 9 AF points, but all of them are cross-type. Also, the center point on the 400D is more precise and accurate with f/2.8 or faster lenses, because one of the two lines in the '+' shaped AF point is f/2.8 sensitive. The 50D also has enhanced function with f/2.8 or faster lenses, but instead it's a dual-cross point with an f/2.8-sensitive 'x' superimposed on the f/5.6-sensitive '+'. That means the 50D center point is more likely to get a lock with the f/2.8 part of the sensor. Basically, the 400D uses the same AF sensor used in the 20D and 30D. The 40D got a new sensor, and that has been reused in the 50D and 60D (i.e. it's still current, but then so is the T3i/600D's - it's the same one in your 400D).

As for AF speed, the 400D uses Digic2 whereas the 50D uses Digic4 - two generations faster, and the AF speed and AI Servo AF tracking will be better because of that.

One more point - and this one is critical if you have any 'fast' lenses. The 50D offers autofocus microadjustment (AFMA), a feature that lets you calibrate the AF system for each specific lens. With f/2.8 and faster lenses, or even slower lenses if they're telephoto and used near for close subjects, AFMA is a big plus. Any time that the DoF gets thin, any small focus errors are more evident - being able to correct those by using AFMA means a lot more in-focus shots. AFMA was one reason I went from a T1i/500D to a 7D, and I'll never buy another camera that doesn't have AFMA.

Second neuro's welcome back.

I have not used the 400D, but neuro's observations seem spot on to me. I have a 50D and it is a great body. If you can get one in almost new condition for a good price, and that is your current budget I would not hesitate. Not to take away from the 7D, but keep in mind that the 50D was the top of the APS-C sensor line until the 7D came out. Although I do not use mine as much as I once did, it still performs very well.

well I would offer a first hand comparison since I have owned both of these, however when I made my upgrade I also upgraded lenses so its hard to make a fair comparison. With that said, I loved how much of an improvement the 50d was in just about every area. I do remember being impressed with the AF but that was probably more from the faster lenses than the camera.

Thank you all for your posts, it looks like I will see improved AF with the 50D. The AFMA will also be a very useful upgrade (and not available on the 60D?!!). Time to splash the cash and buy the 50D.

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Originally Posted by cian3307

Thank you all for your posts, it looks like I will see improved AF with the 50D. The AFMA will also be a very useful upgrade (and not available on the 60D?!!). Time to splash the cash and buy the 50D.

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I upgraded from a 450D to a 50D and at that time my friend used a 400D. While I already was thinking that my 450D was way better than his 400D, the 50D was an even bigger difference. It's amazing.
If I were you I'd definitely buy the 50D and to be very honest, I personally think that the 50D is a better value than the 7D. Unless video plays a major role in the equation that is.
I did feel that the output of the 50D was a little on the pink side, so I had made a special camera profile for it at the time. Other than that, it's a great camera and you might not even have the same "issue".

Enjoy your new camera if you decide to buy it, you will definitely like it;)

Jan

It sound like you already decided, but another plus for the 50D is the 50% increase in pixels over the 400D. If you crop at all, you will notice the difference.

Pat