autofocus points???

ok so im pretty new to the dslr world but im a sponge and ive been soaking in all the info i have learned and am still learning,i am looking at different models of cameras and noticing a huge diference in auto focus points,why does the much higher priced full frame 6d have much less points than the 7d and some nikons in the same price point have 51 points,is 11 or 9 points all thats really nessasary when would u need 51 points and how can u position 51 points in your view finder,i recently bought a 60d and im very happy with it but after looking at the autofocus points of the 7d i wonder if its that much better or just different,and also on a second subject i see the 7d uses compact flash when the more pricey 6d uses the more user freindly sd card,it seems the 7d is the only model in that range that uses a cf,what are the benifits if any of cf over sd,i have yet to see a laptop that i can stick a cf into,please school me on the advantages of 51 af points and cf over 11 or 9 af and a sd,thanx

99% of the time, I use one point. That's because I don't trust the camera to decide what's important to get in focus (e.g. eyes). Those times that I'm tracking a moving subject and I'm using all 9 points of my 40D, it doesn't always get it right. So I can see some potential benefit for more focal points. I'm sure others have other experiences.

Personally, I find the 19 AF points on my 7D much more helpful than the 9 AF on my 40D, but maybe not for reasons you would think. First of all, the newer AF engine on the 7D is pretty awesome, and gets focus right a lot more than it misses it. The 40D felt like it would miss a lot more, therefore I was much more inclined to use single point focus. 2nd, there are many more focus options with the 7D. You can use single point focus, group focus (uses multiple points in the same area of the frame to focus), and micro point focus (uses a point inside a point for super sharp focus). There may be more options but I am still learning the camera. I also like how even though there are 19 AF points they are more centralized in the frame,.when the older cameras seem to have the points a little more spread out. 19 AF points sometimes can be annoying when using spot focus though, since there are so many to.go through. It is nice to be able to use the joystick to select the points though, I don't think you could do that on the 40D.

How's the AF on the 60D? I would think the AF engine would be pretty good, as I think the 60D is a bit newer than the 7D.

Don't fuss about the number of focus points. The 5D went from 9 to 60 something but I find I usually cut back and only use a few of them. Mainly because I often shoot through foliage or past other people or objects, so it's easy with too many points to get it wrong when you are in a hurry.

As Jarvis suggests, the 6D has a pretty sophisticated engine driving it and I would be happy with that focussing system for my work.

More points mostly helps for shots with thin DOF. It allows you to more easily place a focus point in the proper part of the frame so it requires little to no recompose.

Having more points also helps when using expansion or all points for shots like a small BIF in the open sky.

The 6D is at it's price point due to it being FF(the 7D and likely those Nikons are crop senor), for more advanced AF system on Canon FF you need to step up to the 5DIII or 1Dx which cost even more.

Another thing to look at besides how many total AF points but how many of each type(preferable you'd want X type points as they can be faster and more accurate).

Yes, like lovemyram said, cross type points are important. I know all 19 points on the 7D are cross type, and I think all 9 were on the 40D. I would assume all 60D points are cross type, but I would check anyway. And check to see if there is any added sensitivity on any points for higher apertures (ex. added sensitivity at f2.8)

Jarvis Creative Studios wrote in post #16344516
Yes, like lovemyram said, cross type points are important. I know all 19 points on the 7D are cross type, and I think all 9 were on the 40D. I would assume all 60D points are cross type, but I would check anyway. And check to see if there is any added sensitivity on any points for higher apertures (ex. added sensitivity at f2.8)

Yes, 9 cross type points on my 60D.

thnx for clearing things up a bit,i was under the impression more must be better,im happy with my 60d i was just a little confused with the 7d and 6d and thier pricing and af points and compared to some nikons,still a bit confused with the whole cf though,why is the 7d use cf when other similar models use sd.

OP, I don't know about others, but your use of texting makes it very difficult to read your original problem statement. The lack of capitals to begin a sentence, and no spacing before a new sentence also don't help.

I started with the 40d and have had a lot between then and now. Over that time, I've noticed something interesting: Regardless of how many points I have to use/choose from, I almost always use the same 9 that are available on the 40d.

That said, the accuracy of those points can be greatly different between the models and with certain lenses.

John from PA wrote in post #16344577
OP, I don't know about others, but your use of texting makes it very difficult to read your original problem statement. The lack of capitals to begin a sentence, and no spacing before a new sentence also don't help.

^^^^+1, but we're showing our age John.

Traditionally, CF has had a faster read and write speed than SD, but SD is reportedly catching up.

The benefits of having multitudinous FPs from which to choose becomes immediately apparent when a camera is equipped with Eye Controlled Focus Point Selection.

Alas, currently no DSLR has it.

CF and SD are no different. Just a means of recording pictures on a camera. Canons had always used CF, so they kept that format for the 7D. SD is more user friendly and computer compatible, so they are transitioning to that format. These days newer computers need a card reader for CF card usually. They are different sizes but the same basic concept.

huntersdad wrote in post #16344580
I started with the 40d and have had a lot between then and now. Over that time, I've noticed something interesting: Regardless of how many points I have to use/choose from, I almost always use the same 9 that are available on the 40d.

That said, the accuracy of those points can be greatly different between the models and with certain lenses.

i could totally see how that could happen,i used 3 different fugi point n shoots and im quite used to thier menu i find myself searching my 60d for the same menu,so on a unit with say 51 points is there actually 51 little dots in the viewfinder?also a bit confused on the fps of the 6d vs 7d again im under the impression more is better,is the 7d higher because its a crop and the files are smaller?

Jarvis Creative Studios wrote in post #16344616
CF and SD are no different. Just a means of recording pictures on a camera. Canons had always used CF, so they kept that format for the 7D. SD is more user friendly and computer compatible, so they are transitioning to that format. These days newer computers need a card reader for CF card usually. They are different sizes but the same basic concept.

awsome,thanx for the info,so the 7d is quite abit older than the 6d and others with sd,i didnt know that cf was a faster format for read/write

genesimmons wrote in post #16344623
i could totally see how that could happen,i used 3 different fugi point n shoots and im quite used to thier menu i find myself searching my 60d for the same menu,so on a unit with say 51 points is there actually 51 little dots in the viewfinder?also a bit confused on the fps of the 6d vs 7d again im under the impression more is better,is the 7d higher because its a crop and the files are smaller?

Technically more is better with fps. However, if you don't need fps you are better off without it. It adds a lot of extra cost. With the focal points you only see the ones in focus in the viewfinder. At least on the 7D. While you are choosing your AF points all 19 are visible. If you are on single point mode one point is always visible. It flashes red when first focuses.