AF performance on Nikon 3100 vs Canon T1i

[Hannah2]

We're upgrading our camera. On our current Canon Rebel XT & kit lens, the inaccurate AF has given us a lot of frustration (like a dark-colored subject against a white background - will NOT choose the dark subject).

My husband wants to stick with a Rebel, probably the T1i. I've heard that AF is faster & more accurate with a Nikon body/Nikon lens combo. And the 3100 does have 11 AF points (as opposed to 9 points on the T1i).

I'm also leaning toward the Nikon because apparently it has better options for off-camera flash.

If I'm going to convince my husband, the better AF will be the selling point.

Anybody know if the Nikon's AF is better than Canon's, specifically for these two cameras?

Thanks again for helping me wade through the options.

 

[KmH]

We're upgrading our camera. On our current Canon Rebel XT & kit lens, the inaccurate AF has given us a lot of frustration (like a dark-colored subject against a white background - will NOT choose the dark subject).

Pretty much any DSLR would have the same issue, because of the way AF works.

AF doesn't look at the entire scene. It only looks at that part of a scene the selected focus point covers. If there is little or no contrast, any AF system will have difficulty.

See page 56 of D3100 users manual found here http://www.nikonusa.com/pdf/manuals/noprint/D3100_ENnoprint.pdf where it describes conditions when even Nikon AF has difficulties.

My husband wants to stick with a Rebel, probably the T1i. I've heard that AF is faster & more accurate with a Nikon body/Nikon lens combo. And the 3100 does have 11 AF points (as opposed to 9 points on the T1i).

It would depend on the lens uses since the auto focus lens is not in the camera body. Canon has 2 levels of AF motor, the better one being the USM motor. All of Nikon's current consumer lenses use the same SWM motor.

I'm also leaning toward the Nikon because apparently it has better options for off-camera flash.

You are likely referring to Nikon's CLS and Commander mode. Of current Nikon's You would need to get at least the Nikon D90 to have off-camera flash control.

If I'm going to convince my husband, the better AF will be the selling point.

Actually, where the D3100 has an advantage over the T1i, is that the D3100 has color aware metering, with a 420 px RGB sensor. The T1i is color blind when it comes to metering.

Anybody know if the Nikon's AF is better than Canon's, specifically for these two cameras?

The D3100 has a 3D tracking mode the T1i doesn't have. I do not know how well it works.

In summary, I doubt the D3100 will AF significantly better than the T1i. The D3100 is to entry-level to have Nikon's CLS Commander mode to facilitate off camera flash.
The D3100 does have color aware metering, while the T1i does not.
The D3100 has significantly more usable high ISO range than the T1i has:
DxOMark - Compare sensors

 

[enzodm]

(like a dark-colored subject against a white background - will NOT choose the dark subject).

best way, in general, is not letting the camera choose where to focus. Disable automatic focus point selection, choose just one (e.g. central), focus, keep half-pressed, recompose, shoot.

 

[Blake.Oney]

I wouldn't upgrade from a Rebel to a Rebel. It's more like side grading. The Af would be better and you'd have a better camera if you upgraded to a 50D or 60D. Probably even a 40D would be better.

 

[BuS_RiDeR]

best way, in general, is not letting the camera choose where to focus. Disable automatic focus point selection, choose just one (e.g. central), focus, keep half-pressed, recompose, shoot.

+1

I agree.

 

[Hannah2]

In summary, I doubt the D3100 will AF significantly better than the T1i.

Thanks - all of your points were very helpful.

best way, in general, is not letting the camera choose where to focus. Disable automatic focus point selection, choose just one (e.g. central), focus, keep half-pressed, recompose, shoot.

This is what my husband does. I'll have to get more comfortable with it for quickly composing shots of moving toddlers.

I wouldn't upgrade from a Rebel to a Rebel.

We weren't originally planning to "upgrade" at all. We want to get a camera for a family member who has a crappy broken one and no money. A camera is over the family's agreed gift limit, but hand-me-downs are ok. :scratch:

 

[enzodm]

best way, in general, is not letting the camera choose where to focus. Disable automatic focus point selection, choose just one (e.g. central), focus, keep half-pressed, recompose, shoot.

This is what my husband does. I'll have to get more comfortable with it for quickly composing shots of moving toddlers.

this is what photographers do. Autofocus quality has to do with precision of focusing in the place you want focus, but you have to want focus in one specific place, not letting the camera decide. Said that, as I never tried a D3100, I do not know whether automatic point selection is better than Canon, even in the case autofocus is better.

Here you have some comparison (for example, d3100 is slower in shooting, which could be a problem with babies):
Nikon D3100 Review (with 18-55mm lens) - Digital cameras - CNET Reviews

 

[Hannah2]

this is what photographers do. Autofocus quality has to do with precision of focusing in the place you want focus, but you have to want focus in one specific place, not letting the camera decide. Said that, as I never tried a D3100, I do not know whether automatic point selection is better than Canon, even in the case autofocus is better.

Here you have some comparison (for example, d3100 is slower in shooting, which could be a problem with babies):
Nikon D3100 Review (with 18-55mm lens) - Digital cameras - CNET Reviews

Hmm, well, that review is disturbing about the Nikon 3100's speed.

I'll play around with manually setting the AF points. That short time that it takes to recompose the shot is enough time for a kid to move out of focus. But it's necessary in some situations, so I guess I'd better get used to it!