Camera Labs

That's what I thought too, Gordon . Indeed, it limits the camera for sports/action photography. I'd have liked to see at least 2 seconds of 12 fps shooting. I.e. like 24-25 RAWs.

On the one hand, it seems to be something like RAM for a computer, hence my reference to a buffer memory upgrade. Nikon did that for their D3 - a service which has only recently been discontinued.

On the other hand, Pentax released a firmware update for its K-5 camera in 2010, which allowed for longer continuous shooting. I think originally it could shoot up to 8 RAW frames and after the update it could shoot up to 20 RAW frames...

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

If the limiting factor is flushing the image sout of the buffer to the memory card, then a firmware update could support newer faster cards in the future for 'deeper' buffering. But that burst on the Sony is all about actual ram in the camera as you suspect, and there's no way they'd do a memory upgrade on a consumer camera. As you said, only one of the top Nikon pro bodies offered this, and it wasn't cheap either.

So I think we're stuck with the limited buffer on the A77.

I'm afraid we are indeed .

Have just checked how much the D3's buffer memory upgrade costed upon announcement:

"£300+VAT in the UK, and $500+tax in the USA."

It certainly isn't cheap, but I'd still pay that just to get a decently sized buffer. It's actually funny that Sony doesn't offer a large buffer, as they have offered a rather large buffer on their entry-level models, such as the A55 (20 RAWs*) and the A580 (22 RAWs*).

* According to Sony's official specifications.

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

It might still stand to be seen exactly how fast the caemra can offload from in-camera RAM to memory card - my NEX3 for example has a tiny buffer - so can't handle much burst at 7fps before running into the limit. However the difference in performance using a standard class 6 SD card that I started with, and Sony's MS pro Duo HG HX card is really astounding - with the SD, at around 10 frames, the 7fps JPGs would slow drastically, to around 3fps...with the HX card, the 7fps JPGs can run for 28 frames before slowing.

I wonder if a similar thing may be the case with the A77 - that Sony tuned it to work much faster or better with their high-speed memorystick cards on the offload, in which clearing the buffer faster might eek up the performance to something closer to 2-2.5 seconds of burst at 12fps.

Of course, two other points worth mentioning - many sports and action shooters don't enter burst mode and just leave their finger on the shutter for 50 frames. I myself use 7fps bursts all the time tracking flying birds, though typically I might fire off short staccato bursts of 3-7 frames for 1/2 to 1 second, break for 1/2 to 1 second, burst again, etc off and on throughout a 5 or 6 second sequence - during that time, I might fire 3 or 4 bursts of 3 to 7 frames each.

And the second point worth mentioning is that when not using the special aperture-locked high-speed 12fps shooting mode, the A77 also sports a 'regular' 8fps mode, with full focus tracking AND metering. I should think the buffer can last longer in the 8fps mode, which is still among the fastest cameras out there, and you also get to continually meter.

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Justin Miller
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!

Galleries:
http://www.pbase.com/zackiedawg

I've been thinking about the 8 fps mode myself, Justin .

However, the buffer will be full after 13 RAW frames - not enough for even two seconds of 8 fps shooting, which would require a buffer of 16 RAW frames.

I'm really still puzzling over Sony's decision to use such a small buffer memory, considering the rather large buffers of the A55/A580, the A550 and the A450...

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

My guess is it actually ISN'T really a smaller buffer than those cameras - just that it fills much faster with 24MP photos than with 14/16MP photos!

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Justin Miller
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 200-500mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony NEX5N / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / Pentax K adapter / Konica K/AR adapter / bunches o' Konica & Pentax lenses!

Galleries:
http://www.pbase.com/zackiedawg

That could be the case indeed.

But still, one would expect an APS-C flagship camera (that's what the A77 is after all) which is capable of doing 12 fps to have a decently sized buffer.

The D300S for instance, can shoot at 8 fps and has a buffer of about 17 RAWs. The 7D, can shoot at 8 fps as well and has a buffer of 24 RAWs...

Don't get me wrong, I'm not asking for Sony to upgrade the buffer memory to say, 36 RAW images. I'd be extremely happy to have 24-25 RAWs at the moment. But as Gordon said, I'm afraid we're stuck with it .

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

Ball park calculation suggests you need around half a GB of ram to hold 13 frames at 24MP, assuming the raw is 14 bit stored packed. If it was consumer DRAM as used in PCs then it is damn cheap to put a LOT more in. I don't know if DRAM is used though. There may be technical limitations requiring more exotic and expensive memories.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

I've checked the Chipworks.com teardown of a Nikon D7000 and the only reference to memory I could find was this:

"4 x Nanya NT5TU64M16GG 1-Gb DDR2 SDRAM"

Hence I'd think Nikon (as well as Sony ?) uses RAM like one would put in a computer...

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

Interesting... 4Gbit would be half a Gbyte. However from earlier estimates the D7000 buffer in pixel terms is about half that of the A77. So I wonder if Nikon are reserving ram for other uses, or are storing it in a less space efficient manner, which could improve performance. Or they might be intentionally not using as much as they could for some reason.

Regardless, generic DDR2 is cheap enough although without looking at the spec I don't know if those modules might be exotic versions.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

I was lead to believe it's a special type of memory, but getting hold of these specs is difficult. Either way, they wouldn't be room for affordable full sized, or even laptop sized DIMMs in a camera body, so size is a definite constraint.

Hi everyone, I've finally completed my A77 preview - apologies for the delay, but you are at least getting 6000 words of analysis!

See my Sony Alpha SLT-A77 preview!

Thanks Gordon! Great preview. I can't wait to see the full review and some sample images from a production model camera.

Now that is an excellent read, Gordon . As you said in the preview, we'll have to do with short, high-speed bursts at 8 fps, I'm afraid.

Are you going to test these new cameras with the new UHS-I SD cards, Gordon, or the latest Sony MemorySticks ?

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

I think I will need to test them with both types of cards to really see the limitations of the buffer in practice...