Alpha 900 launch: Press Conference Part 3

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Part 3 of the conference presentations, transcribed from a recording by Shirley Kilpatrick. This section deals with the revolutionary new adjustable focusing screen and viewfinder which enables error-free 100 per cent viewing, and the reasons Sony chose to make a 24.6 megapixel full frame sensor. To start reading with the first Part, go to Part 1.

Thank you Katsumo-san. Good afternoon everyone! My name is Yoichi Tsusue, in charge Sony’s engineering division, camera group. So thank you very much for attending today for our Alpha new product announcement. I’m head of the Alpha 900 developing team, and today I have come to Edinburgh on behalf of a couple of hundred engineers.

The Alpha 900 is the top of the rank order for the Alpha series. All engineers in my team enthuse their spirit into the development of every specification and function. Today I would like to talk about two key aims. Firstly, the high-image quality which we aim with the world’s highest 24.6 million pixel; and secondly our determination towards realising the highest precision viewfinder and how it was achieved.

Starting with the first point, why are we focusing on the highest number of pixels? The product concept is to convert passion into expression with true high image quality. The concept of ‘true high image quality’ we true to achieve by condensing more information in one image, and we produce a natural and realistic sensation.

Alpha 900 is the top of the Alpha series, so we aim to wholly utilise the high performance of G and Carl Zeiss lenses, both high performance lenses of the Alpha series; and for this our choice was for 24.6 million pixels.

The pixel quality consists of lens which passes light to a sensor which receives light, and the engine which processes the information. Our engineers utilise the image engineering technology in each of these; by putting all these together, high image quality is obtained. As you know, Sony has its own technology to manufacture high image quality of CMOS sensors. Taking full advantage of this we have developed the highest 24.6 million pixel full-frame sensor. And, of course, the EXMOR technology, which is a Sony original high quality picture technology, has been integrated.

Why 24.6 million pixels? Let me show you how detailed the image is with this chart. As you can see the high performance lenses like Carl Zeiss and G lenses have the potential to reproduce high frequency, meaning extremely detailed information.

When the sensor which receives the light coming through the better lens has 12 million pixels*, it isn’t able to receive such high frequency; on the other hand, by making it 24.6 million pixels, as you can see it can receive a higher frequency of information making a more effective use of the lens potential.

*Here Tsusue-san is clearly referring to 12 megapixel full frame sensor not to the Alpha 700, etc.

On the right hand side you can see the result of that resolution test. 12 million pixel and 24 million pixel makes this kind of difference. You can obviously see that the high pixel enables good use of the lens performance. Some of you might be worried about increasing noise as a result of increased number of pixels.

The 24.6 million pixel on the Alpha 900 is realised on the full frame sensor, as you may know so pixel pitch is not narrower compared to the APS-size 12 million pixel sensor on the Alpha 700. The sensor area is twice as large avoiding the pitch too narrow, but enabling twice as many pixels. One point four times in resolution without sacrificing performance by pixel! Dual BIONZ processes this huge size image data of 24.6 million pixels at high speed, combined with Sony’s high image-quality engineering technology – thus we achieve true high image quality which makes good use of the lens performance, and could only be enabled by 24.6 million pixels.

About our determination towards realising the highest performance viewfinder and how it was achieved: In the development of the Alpha 900 viewfinder our target was to achieve the best performance optical viewfinder. Our goal was to have the best performance viewfinder – to exceed the Dynax 9 which is considered to be the best viewfinder within over 20 years history of the Alpha mount SLR camera system – which started from Minolta 7000, the world’s first autofocus SLR.

We aimed for a viewfinder which exceeds all of the – professional – others currently in the market. To create the best performance viewfinder we realise these three points.

First – how to make framing accuracy. Framing performance is the most important function of a viewfinder. By adding an adjustment mechanism in the finder frame and adjusting the comparative position with image sensor in every single unit at the manufacturing line in the factory, precise 100 percent coverage was enabled.

Secondly – top class wide view. By designing an optimal shaped pentaprism from huge optical engineering data accumulation, and by using a high-power condenser lens (which uses high index glass), we succeeded to enlarge the magnification ratio and the view angle. By this we achieved top class wide viewing angle, and that’s including full-frame professional models.

The third point to achieve the best performance viewfinder is highest optical performance. By utilising a high power condenser lens, it firstly eliminates distortion and minimises aberration which affects sharpness in eyepiece lens optics. The distortion caused here is corrected perfectly with the high-powered condenser lens, thus achieving best optical performance.

Note: the condensor lens is sited immediately above the focus screen, between the screen and the prism. This was shown on another presentation slide.

The distortion is reduced to less than 20% of Dynax 9, which is virtually zero level. Also for comatic* aberration it is reduced to half from Dynax 9 which already had very low level. This means we have achieved a viewfinder with no distortion in the entire field. Even for optical brightness this tests better in comparison with Alpha 700, it shows with AR**-coating on every optical surface beyond viewfinder screen. It achieves extraordinary brightness compared with other top end models in the market.

*this is correctly transcribed and was shown on the screen – the aberration of coma

Alpha 900’s viewfinder with perfect framing capability, wide view, no distortion in the entire field and with extraordinarily bright optical performance – we are confident that amongst our own and other brand model ranges this is the ultimate viewfinder.

Apart from what I mentioned there are other integrated functions of the light-weight 850g Alpha 900, in spite of its high performance and the newly developed intelligent preview. Alpha 900 is deserved of the top passion of our engineers, including me, to develop Sony’s flagship model. I strongly appreciate your keen attention in the following workshops during the course of the day! Thank you very much for your attention.


Nick Sharples: Thank you, Tsusue-san. A very impressive technological achievement, I’m sure you’ll all agree, but the proof of any camera is in the quality of images it produces. You’ll all have the opportunity to try out those images tomorrow morning. Before then, however, and to end our press conference this afternoon we have a real treat. Duncan McEwan has been photographing the Scottish landscape for over 40 years and is recognised as one of Scotland’s outstanding and pre-eminent landscape photographers. We gave Duncan an Alpha 900 about two weeks ago to try out for himself and he’s kindly agreed to come back this afternoon and give us his impressions of the Alpha 900.

Next part: Duncan McEwan’s talk with a selection of his images


  • I’m still interested in hearing the continuation of this, just as it was getting interesting and Duncan was stepping up onto the stage…

  • Just wanted to add my appreciation to Sony for listening to the photographers who wanted a fine still camera. The viewfinders was paramount. And they focused on the viewfinder instead of a lot of tripe like video and live view. Sony also managed to squeeze in a very effective image stabilization. And most important, they were not tempted to soften the image quality of a camera built for resolution by applying too much noise reduction. It’s a low iso camera built to capture color and detail, and that’s what it was supposed to be. The image quality is stunning. Thank you Sony. CHaCHa

  • There is a possibility I’ll get a camera before setting off to photokina on the 20th, but the pressure I am under with photokina, with the Nikon D90 arriving for test this week, with a magazine to attempt to produce profitably after photokina (extremely difficult task as everyone has spent their money and there is no advertising) – well, if I don’t get to spend a day shooting with it in Cologne before the fair opens, I may have a camera and no way of testing it practically.


  • Thanks – any idea when we will see your review of this Alpha 900 in practice, with some of the lenses ?

  • Great articles as always 🙂


    David Bo

  • Just to add my voice to the appreciation of these transcripts; I really enjoy the insights to the thinking and working of the teams that create these cameras. It’s quite boggling to think of 200 engineers working on the A900 project, and I like the connection to heritage, even if they can’t quite bring themselves to utter the M-word.

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