A700 vs A900 vs A77 autofocus

[adakshi]

I have A700, using it for almost 3 years. I am quite happy with it except Focus accuracy. Even with my 70-200G and using central double cross AF point in AF-A or AF-S, I miss-focus in broad daylight(3 out of 10). This is worse with other lenses like 50 1.4 and 135 1.8. Using outer AF points is more prone to miss focus. Low light situation is pathetic, I can't use outer AF points with my 135 1.8 at all.

Also I find AF speed is sluggish in AF-C, unless I use SSM lens.

My daughter has turned 2 and if I need to capture right moments I need a reliable and fast AF. I understand no camera can give me 100% success rate, but A700 is definitely not up to that work.

I am thinking of upgrading to A900 or A77. I'd like to know your opinion about A900 and A77 AF system. How accurate is AF system and how fast. Has anyone upgraded from A700 to A900 or moved from A700 to A77?

I really don't care much about noise. I rarely shoot higher than 1600 and if I am printing real BIG, probably those are landscape shots taken at ISO 200.

I read many reviews about SLT vs SLR, I personally prefer SLR but AF accuracy and speed is more important to me.

I'll either move to A900 or A77 or if nothing works in Sony world, I'll be forced to move to other system, but that would be my last option.

Last not the least, how is the video quality in A77, I don't find many samples in internet.

Appreciate your help.

[Mark K]

I moved from A700 to A850...shortly after my 2nd A700 which I also liked very much. IQ was a huge improvement, and to me that still is the most important feature. The AF system both was the same. There was however a huge improvement in AF speed and accuracy after moving from A850 to A77. However, the A77's AF cannot be compared with those more advanced systems found in Nikon or Canon professional cameras. There is still more hunting and blurring. ISO noise is also a limitation to faster AF...or otherwise I can shoot up to 6400 iso without worrying. That is the market segment where Nikon D4/or Canon 1Dx aim at.
I believe the upcoming A9x should have a better AF system, or otherwise the 5D III will be a better choice, offering faster AF, similar IQ comparing to A900.

[adakshi]

I moved from A700 to A850...shortly after my 2nd A700 which I also liked very much. IQ was a huge improvement, and to me that still is the most important feature. The AF system both was the same. There was however a huge improvement in AF speed and accuracy after moving from A850 to A77. However, the A77's AF cannot be compared with those more advanced systems found in Nikon or Canon professional cameras. There is still more hunting and blurring. ISO noise is also a limitation to faster AF...or otherwise I can shoot up to 6400 iso without worrying. That is the market segment where Nikon D4/or Canon 1Dx aim at.
I believe the upcoming A9x should have a better AF system, or otherwise the 5D III will be a better choice, offering faster AF, similar IQ comparing to A900.

Thanks. Appreciate your help. What about image quality in A77 compared to A700 at low ISO. Any improvement there?

[Mark K]

A77 is an amazing low ISO camera..which I have to thank Sony for giving us. Incredible amount can be squeezed out from a77's raw file.

[[SiC]]

I have the A700 too, and two youngsters of the age two and five. Definitely sound to me like there might be a problem with your camera. I don't have any really expensive glass though (see my sig).
I've only had the A700 for about 8 months though so someone else with a 700 might wanna fill in their experience.

BR,
/Zeb!

[Dr. Harout]

To say "I have moved from a700 to a77" would not be correct. You should say: "I have upgraded from a700 to a77"...
And this in many ways.
The AF is much faster and definitely more reliable.
The a700 used to hunt sometimes with the 70-300 G, but not the a77
Low ISO (which I love) is exceptional.
I had serious doubts before "switching" (re. upgrading) concerning the EVF, now I'm comfortable with it specially with manual focusing.
Focus tracking with fast moving objects is great (though, have to admit, didn't try extensively).
Video wise: it crops a bit, which is not an issue for me. Otherwise it's great too.
So, bottom line: go the whole hog.
You can't imagine how I love that ISO 50

[kaled_201299]

I moved from the Dynax 5D to the A77 so can't comment on the A700, but I can give you my impressions of the A77. Like you a considerable amount of my photography right now is of my two young children so your needs seem very similar.
AF performance from 5D to A77 was a considerable improvement in speed and accuary. Indoor shooting does not pose any issues with locking onto subjects. However, I will say that I do get some slightly blurry shots and my observation is that the sheer resolving power of the 24 MP sensor means you have to get it bang on. I've the 1680CZ and also just bought the 1650 f2.8 - initially I wasn't going to get the latter lens, but I'm glad I decided to do so.
I can't claim to have done any direct comparisons, but my subjective view is that with indoor shooting the faster lens locks on more quickly and I suspect it is a combination of factors including the ssm, faster aperture. Compared to the CZ, this lens also gives me just enough extra shutter speed at ISO800 to reduce subject movement (kids!).
EVF is a non issue for me - it works very well and I was out over the weekend in bright sunshine and didn't even think about the technology.
One other great benefits I've found for taking shots of kids with the A77 is the high fps (3 or 8 fps) available - it is so difficult to anticipate the exact moment when 3 moving subjects are all looking, smiling, still enough etc and firing off a short continuous burst has really given me an increased success rate.
Finally, video is great and 1080p50 and I shoot all the time using this camera. I will however say that the 16-50 lens delivers better AF performance than the CZ and noise is also noticeable with the latter lens.

[cosmonaut1959]

Though I have never used the a700, I have the a850 and a77. The a77 focuses very quickly and accurately. The only bug I have with the a77 is when I am shooting my daughters soccer games an fire a burst of several shots it takes to long to process the files and I miss a shot. Also it is slow to process after one shot if set to single shot mode. The EVF blanks out and reads "processing" for a few seconds. Coming from a traditional OVF that is hard to get use to. If the buffer isn't full I should have the option for another shot, just sayin"

[pakodominguez]

A700 and A850/A900 AF is basically the same.
A77 is supposedly better (I don't expect less from a 4 years younger camera) and better: Face Recognition will help you tracking your kid (look on Gary Friedman blog, he had a post about it...)

[adakshi]

Finally I bought A900 and A77 both. I plan to keep both and sell A700.

I think I got rid of the miss-focus issue of A700 by blowing air near to AF sensor area. I think I had dirt or something there and my A700 is working fine now. With A900 and A77 I get AF micro adjust feature and all my lenses are super sharp now.

I am impressed with A77's AF speed but I think A900 is more accurate with the central AF point. I took a couple of pics of water scooters moving randomly, well those are big objects in water so no cam should have any problem focusing. Still I got 100% success with A900 in AF-C mode with center AF and each image is tack sharp. A77 was quicker to focus but not that accurate plus noise is a big problem for A77. I don't get the sharpness once I go past ISO 400.

All these images are from A900 and 70-200G lens and heavily cropped.







DSC00017_DxO by adakshi, on Flickr