A noisy world on the A77

[twm47099]

David, That would have been a good answer from Sony ("We wanted the high memory data throughput performance, but that reader wasn't available in a dual slot unit") instead of the one they gave. One says we are trying to optimize a camera. The other says it was just a business price/feature decision.

tom

[redsim74]

One says we are trying to optimize a camera. The other says it was just a business price/feature decision.

tom

Or, the first is an engineering answer and the second a sales/marketing answer. Unfortunately, it's not usually the engineers answering the questions - they have a habit of being too honest!

[aramkostanyan]

David, thanks for so good review.
Did you try to compare the high ISO images (3200, 6400) from A77 down scaled to 16MP with the ones from A55?

[David Kilpatrick]

I have not done a formal comparison. To do this I would really like to use the NEX 5n, as well as the A55, and also the NEX-7, and our A580, and of course the A900. Then the effort of setting up a test becomes more interesting.

David

[aramkostanyan]

That sounds a great comparison to do.

[Mark K]

David
I also found A77 very noisy...even at base ISO like 200. I will bring a850 and a700 for comparison.

[agorabasta]

The Nex7 and 5N seem to be identical at noise, but the 7 has much higher resolution. The difference in resolution is not justified by the Mp count only, there's also a definitely weaker AA filter used in the 7. At the same time, the 7 shows less moiree aliasing.

The ISO3200 raw samples of the 5N and 7 images found at the IR are exposed differently, having 1/640s speed for the 7 and 1/500s for the 5N. Yet the 7 shows about the same noise at much higher res.
The crops below are made with identical settings except some exposure compensation to match the luminosities; the 'detail' module is switched off. Both are upscaled to 1040px size.

So it's quite clear that the 77 was intentionally crippled in noise performance for the sake of lower power consumption and higher speeds.

[agorabasta]

Here are two more upscaled crops off the same raw samples, now with the equal NR and sharpening added (equal as per Lr3.5).

The 7 clearly shows lower remaining noise, higher res and much lower moiree aliasing.

[Mark K]

Well, at one time I thought Nex5N will be the cleanest camera Sony ever made...and I was wrong. I could never explain Nex7 behaviour.
Nevertheless I brought both a850 and a77 today and my presumption a850 must be better is obviously wrong.

[agorabasta]

... and my presumption a850 must be better is obviously wrong.

That depends. The older sensors before the 16Mp one were very temperature-dependent. So a long session with a850 at 30C could make its noise unacceptable at ISO800. Same for a700/500/550, original Nex5/3, etc. The original Nex could easily overheat from 20 min of 'tourist' still shooting at 30C, and its ISO1600 looked at that far worse than 3200 from a700 ever did.

But at ambient temps of about 20C and below the 850 should be better than 77.

[alphaomega]

Agorabasta, you are just backing up my decision to purchase (eventually) the NEX-7 in preference to any of the other new Sony models. Apart from the larger sensor, with apparent god noise performance, the NEX-7 also has the built in flash, EVF and standard Alpha flash shoe. Furthermore this model will accept my newly acquired external mike suitable for Alpha models such as my A580.

[agorabasta]

Agorabasta, you are just backing up my decision to purchase (eventually) the NEX-7 in preference to any of the other new Sony models.

Good. But that's not me. That's the reality.

[Mark K]

Will anyone here agree an a580 will be a much better alternative for high ISO shooting?

[stevecim]

I guess that would depend on what you intend to shoot and your definition of high ISO
for me the EVF, quite shutter noise, better AF, for slightly more noise that will clean up fine in PP, I would get a A65/77 over the A580 any day. (keep in mind I already gave an A550)

[agorabasta]

Will anyone here agree an a580 will be a much better alternative for high ISO shooting?

The noise would be about the same as with the 5N, and then you get better ergonomics for most kinds of shooting.
So, yes, I would mostly agree.