5d mkII vs 50D in terms of AF

[te4o]

I mainly shoot landscapes, but I occasionally use AF for other subjects. The 5D II will be a great upgrade and I'll get it with the Zeiss 18mm.

Get the 21/2.8 or the 25/2. Better IQ and colours

does anyone use the EG-S focus screen on a 5DII with f1.4 lenses to MF? I'd be interested to hear their esperience with them
I use the CZ 35/1.4 with an EgS - it's better than nothing but there are many more costly and better alternatives like brightscreen.com
35 is wide enough to be usable as MF even at 1.4 - and the CZ has a smooth focusing ring. Don't know about Canon MF, it's so wobbly that an EgS won't make a big difference...

[sawsedge]

The AF factor has kept me out of the lower end FF market.

When both of these cameras came out, I had the choice to buy either.  I picked the 50D for the improved AF.  The AF system on the 5D2 is the same as the 5D, which is the same as the 20D.   I had issues with my 20D at times.  I have fewer problems with the 50D.  Ironic that the 7D came a year later with much better AF.  ;-)

For my uses, I felt the IQ differences are minimal.  Check this out:  http://wyofoto.com/EOS_IQ_shootout_2008/EOS_shootout_2008.html   The only flaw with his comparison is using the same post processing.  The cameras have different sensors... different signal processing... and require different settings in post.  I took his sample files and did a little different sharpening on the 50D file... and got it to look as good at low ISO.  I generally don't need high ISO, but with good NR I get clean images up to ISO 1600 easily, and I've found I can do a good job with 3200 as well... on the 50D.  I haven't experimented a lot with 3200 yet. 

Until you really push the print size and ISO together, I can't see any major differences in print.

For my uses, which does not *usually* include poster-sized prints, I have zero qualms with my prints from the 50D.  I'm talking up to 13"x19".  I came from 35mm film, and even the 20D blew my K64 and F100 slides away, so I just don't worry about it much. 

Having said all that... their is one factor that would get me to buy a full-frame model... that is the desire to use certain lenses at the wide side, like the Zeiss 21mm.   If you have a specific lens or set of lenses in mind, then FF might be the right choice for you.

[briansquibb]

Finaly its harder to keep your camera haning over your shoulder at a party with a flash attached.

Also, something Im still trying to get used to, is that the slightest movement from you or your subjekt might mean you loose focus. FF and fast lenses is demanding in a way I did not understand when I upgraded from my 30D and f/4 zooms.

Hang your camera from a harness

If you are able to AF then use SERVO mode to hold focus whenever possible

[awinphoto]

The center point of the 5d2 and the 6 invisible "assist" points are nice, but the rest of the focus points are not cross points like the 50D... In the center point the 5d is as good if not a slight edge but if you like composing WITHOUT recomposing after you locked focus and using your outside points, the 50D wins... kinda takes you back to the 30D days.... Reminds me of DigitalRev's video comparison of the 7d vs 5d2... they said the 7d's AF was kinda a smart-ass, always knowing where you want to focus on, and the 5d2 is kinda depressing.   

[Caps18]

I use a 50D at work, but I have a 5Dm2 at home.

Price is a consideration, and if you are using longer telephotos to take astro photography, the 50D is probably better.

But, I have a 16-35mm, and it creates great pictures on the 5Dm2.

I am a basic focus guy, so I don't do very much in the AF arena that is demanding.  I even focus in live view with the AF-On button...

[contrastny]

I mainly shoot landscapes, but I occasionally use AF for other subjects. The 5D II will be a great upgrade and I'll get it with the Zeiss 18mm.

Get the 21/2.8 or the 25/2. Better IQ and colours

does anyone use the EG-S focus screen on a 5DII with f1.4 lenses to MF? I'd be interested to hear their esperience with them
I use the CZ 35/1.4 with an EgS - it's better than nothing but there are many more costly and better alternatives like brightscreen.com
35 is wide enough to be usable as MF even at 1.4 - and the CZ has a smooth focusing ring. Don't know about Canon MF, it's so wobbly that an EgS won't make a big difference...

I'll look into those as well, but I really want something wider than 21mm and has threads for filters. I know I can stitch, but I don't want to do that to tons of images.

[contrastny]

The AF factor has kept me out of the lower end FF market.

When both of these cameras came out, I had the choice to buy either.  I picked the 50D for the improved AF.  The AF system on the 5D2 is the same as the 5D, which is the same as the 20D.   I had issues with my 20D at times.  I have fewer problems with the 50D.  Ironic that the 7D came a year later with much better AF.  ;-)

For my uses, I felt the IQ differences are minimal.  Check this out:  http://wyofoto.com/EOS_IQ_shootout_2008/EOS_shootout_2008.html   The only flaw with his comparison is using the same post processing.  The cameras have different sensors... different signal processing... and require different settings in post.  I took his sample files and did a little different sharpening on the 50D file... and got it to look as good at low ISO.  I generally don't need high ISO, but with good NR I get clean images up to ISO 1600 easily, and I've found I can do a good job with 3200 as well... on the 50D.  I haven't experimented a lot with 3200 yet. 

Until you really push the print size and ISO together, I can't see any major differences in print.

For my uses, which does not *usually* include poster-sized prints, I have zero qualms with my prints from the 50D.  I'm talking up to 13"x19".  I came from 35mm film, and even the 20D blew my K64 and F100 slides away, so I just don't worry about it much. 

Having said all that... their is one factor that would get me to buy a full-frame model... that is the desire to use certain lenses at the wide side, like the Zeiss 21mm.   If you have a specific lens or set of lenses in mind, then FF might be the right choice for you.

I'm mainly looking to get a FF for less diffraction with smaller apertures. The Zeiss 18mm seems like a great lens, but I'm also open to other suggestions for ultra wide lenses that will accept filters. And eventually the Canon TS-E 24mm f/3.5.

[MartinvH]

How does the 5DII AF compare to the T2i/550d or similar T3i/600d ?
Similar centre point ,lousy off-centre points ?

The individual points are similar in terms of performance between 5DII and the Rebel/xxxD cameras.  The center is cross-type with one f/2.8 line and one f/5.6 line, outer points are single-orientation f/5.6 (vs. the 40D-60D cameras where the center point is a dual cross with f/5.6 orthogonal lines and f/2.8 diagonal lines, and the outer points are f/5.6 crosses). 

However, the relative spread of the 5DII AF points is worse - in fact, the 5DII has the least AF point spread of any current Canon camera (including the T3/1100D).  All of the others manage to get an AF point at least somewhere in the approximate neighborhood of a rule-of-thirds intersection, but the 5DII doesn't come close.

Thanks for this info, I could not find this detailed AF comparison information on The-digital-picture.com or any other site.
This info keeps me on the side of the ones waiting for what is coming (and saving money for that occasion) instead of buying now a discounted nice but 2008 technology 5D Mark II with a focus system even older.

[sawsedge]

I'm mainly looking to get a FF for less diffraction with smaller apertures. The Zeiss 18mm seems like a great lens, but I'm also open to other suggestions for ultra wide lenses that will accept filters. And eventually the Canon TS-E 24mm f/3.5.

I've also done some testing of diffraction.  I tested it on 35mm years ago, and found going down to f/16 was OK.  I read that diffraction was a bigger issue with crop, and tested it on both my 20D and 50D... and again found acceptable results down to f/16.  I don't see any noticeable real-world difference.  f/22 is too soft for my taste with all systems, but f/16 is OK.  Even the-digital-picture notes that the DLA is more of a calculation than real issue.  If you compare images side-by-side, you can see some image quality loss as you stop down, but as a picture on its own, no issue.  Other factors such as motion, lens quality, DOF, and precise focus are more important.

Again, if you want a superwide, you have more choices with FF.

The best wides I'm aware of are the Zeiss 21mm, Canon 24 f/1.4L, Canon 24mm TS-E.  I've also read that the Olympus OM 21mm lenses are little gems, not quite as nice as the Zeiss, but an excellent value, and easily adapted to EOS.

[dtaylor]

I'm mainly looking to get a FF for less diffraction with smaller apertures. The Zeiss 18mm seems like a great lens, but I'm also open to other suggestions for ultra wide lenses that will accept filters. And eventually the Canon TS-E 24mm f/3.5.

Diffraction doesn't impact any format more than any other for the same FoV and DoF. This is true from 4/3rds through large format.

That said, there are some lens options which call for FF. If you buy a 17mm T/S or a 24 f/1.4L, you probably want the stated focal length, not the cropped focal length. And T/S lenses don't work well with the flash housing on the crop bodies. (FF bodies don't have a built in flash.)

There are of course excellent UWA zoom options available now for crop if the goal is simply to go wide. Tokina 11-16 f/2.8, Canon 10-22, Sigma 8-16, etc.

[neuroanatomist]

Diffraction doesn't impact any format more than any other for the same FoV and DoF. This is true from 4/3rds through large format.

True in regards to sensor size, in that APS-C sensors do not have inherently greater diffraction than FF for a given DoF, which is a common misperception.  But...doesn't pixel density play a role?  So, contrastny has a 50D with 4.7µm pixels and a diffraction-limited aperture (DLA) of f/7.5, whereas the 5DII has 6.4µm pixels and a DLA of f/10.2.  With the 50D at f/7.5, the same DoF would be achieved (assuming a change in focal length to compensate for FoV) at f/12 on a the 5DII.  That suggests that for a given DoF, the 5DII is actually more diffraction limited than the 50D, which is the opposite of the prevailing viewpoint.

[skitron]

Concerning the original topic, I got my 5D2 in last night and the initial impression is the center focus point is better on it than the center focus point on my 50D.

However, I quickly discovered that I much prefer the DOF characteristics of the crop body so far. Maybe the ridiculously thin DOF possible on FF has some uses at longer distances, but for anything shot inside a house it is not for me. I was rather surprised at that finding.

I like nice bokeh as much as the next person, but I like it to be in the realm of the natural. It seems f1.4 on a FF goes way, way beyond what is even remotely natural and as of now I see no use for it. Please share experiences and uses if you have them!

So it will be interesting to see how stopping down a FF to get some DOF vs being able to open up on a crop plays out with respect to ISO performance. It almost looks like it's a wash if I want the kinds of DOF I get on a crop.

For example for DOF = 1' on the 50D I set f2 for subject distance of 10' (using a true 48mm lens). For 5D2 I have to stop down to 3.2 with same lens and move subject distance 6.25' to get the equivalent shot in terms of framing and DOF.

The 1.2 difference in aperture requires higher ISO for same result, assuming same shutter. So did I really gain anything in terms of ISO performance for equivalent shots? Is the 5D2 more than 1.2 stops better than 50D in terms of ISO/noise? Or is the only real difference perspective and resolution, given same lens / equivalent shot?

[neuroanatomist]

So it will be interesting to see how stopping down a FF to get some DOF vs being able to open up on a crop plays out with respect to ISO performance. It almost looks like it's a wash if I want the kinds of DOF I get on a crop.

Or is the only real difference perspective and resolution, given same lens / equivalent shot?

Practically speaking, it's pretty much a wash.  Putting the same lens on FF, you have to get 1.6x closer for the same framing, and thus you get 1.6x shallower DoF (=1.3 stops).  The FF sensor gathers more total light, such that ISO noise is 1.6x (same 1.3 stops) better.  So, you stop down by 1.3 stops to get the DoF you want, bump the ISO by 1.3 stops to maintain the shutter speed.  Wash.

If you downsample the 21 MP output of the 5DII to the 15 MP of the 50D, you'll have a little less noise because of that. 

As you state, the perspective is different, since that's determined only by subject distance - maybe that's a good change, maybe not.  You could fix that (i.e. match perspective) by using a 1.6x longer focal length on the FF body.

An f/1.4 lens on APS-C gives you the DoF of f/2.2 on FF.  The thing is, you can set the lens to f/2.2 on FF if you prefer, but you can't get the DoF of f/1.4 on FF using an APS-C camera (at least, not conveniently, since you'd need an f/0.9 lens).  However, if you have no use for the thinner DoF then FF isn't an advantage in that area.

[koolman]

How does the 5DII AF compare to the T2i/550d or similar T3i/600d ?
Similar centre point ,lousy off-centre points ?

The individual points are similar in terms of performance between 5DII and the Rebel/xxxD cameras.  The center is cross-type with one f/2.8 line and one f/5.6 line, outer points are single-orientation f/5.6 (vs. the 40D-60D cameras where the center point is a dual cross with f/5.6 orthogonal lines and f/2.8 diagonal lines, and the outer points are f/5.6 crosses). 

However, the relative spread of the 5DII AF points is worse - in fact, the 5DII has the least AF point spread of any current Canon camera (including the T3/1100D).  All of the others manage to get an AF point at least somewhere in the approximate neighborhood of a rule-of-thirds intersection, but the 5DII doesn't come close.

neuroanatomist: Does what your explaining above mean - that even using the CENTER focusing point for focus, the 60d for example is more advanced then the 550d - as its center point has "duel cross" ? I was thinking to upgrade to the 60d - soley for the purpose of more accurate AF . Would I feel a diffrence?

[neuroanatomist]

neuroanatomist: Does what your explaining above mean - that even using the CENTER focusing point for focus, the 60d for example is more advanced then the 550d - as its center point has "duel cross" ? I was thinking to upgrade to the 60d - soley for the purpose of more accurate AF . Would I feel a diffrence?

Yes, the 60D has a more accurate center AF point than the 550D, in addition to having better (cross-type) off-center points.  In some situations, you'd notice a difference, while in others (good light, high-contrast subject) probably not.