Recently I've explained Electronic Front Curtain Shutters and how Sony recommends when not to use it.
In the meantime, I've found the same warnings also in the A77's manual.
I've also found another explanation of why not to use it with Konica Minolta lenses. It's related to the angle of incidence of light from the lens hitting the sensor.
When Sony recently announced the SLT-A77,
and NEX-5N, one little detail in
their specification lists was mostly overlooked: They are Sony's first photo
cameras with an electronic front curtain shutter. What does this mean, how
does it work, and why use it anyway? This page provides the answers.
The display filter on the equipment table pages was re-designed. When changing the selection, the page content is updated immediately. The overview display was integrated into the filter. A permalink is offered for linking to a selection externally.
Today, Sony has also updated their lineup of system camcorders with the NEX-VG20. It's an update of the NEX-VG10, using the NEX-3C/5N's 16 MP sensor, now with 50p/60p recording, still image recording in RAW format and audio level control.
An update of the NEX-5 with the 16 MP image sensor of the NEX-3C.
Lens adapter for A-mount lenses on E-mount cameras. In contrast to the LA-EA1, this one has a semi-transparent mirror, deflecting light to phase-detect AF sensors. It also features a built-in motor for screw-drive A-mount lenses. In short, a NEX-camera using this adapter works like an Alpha SLT camera. The new lens adapter only works with the NEX-5N, NEX-7 and NEX-VG20.
Electronic Viewfinder FDA-EV1S
This viewfinder with 2.4 million dots can be mounted on the NEX-5N to provide an image preview in strong ambient light. It can not be used with earlier NEX cameras.
The new cameras are expected to be in shops from September through to November.
The rumors were intensifying over the last weeks, and finally Sony has released the successor to the DSLR-A700 today, the SLT-A77.
SLT-A77, AF DT 16-50/2.8 SSM
As the name suggests, it's a DSLR with a semi-transparent fixed mirror. 1/3 of light coming from the lens is directed to phase detect AF sensors, and 2/3 go through the mirror to fall on the image sensor. The advantage is that you get fast full-time AF. There is no black-out when taking still images, and you don't have to rely on slow contrast-detect AF when recording videos. Also, since the slow mechanical flip-up mirror is removed, very high frame rates are possible while keeping the camera affordable. In contrast to earlier live view implementations from Sony, you also do not need a secondary image sensor. The live view image is taken from the main sensor, and it's displayed on the rear display or an electronic viewfinder.
The slight disadvantage is that since only 2/3 of the light reaches the image sensor, the sensor signals need to be amplified a bit more to reach the nominal ISO rating compared to more traditional DSLRs, potentially increasing noise. Also, the semi-transparent mirror needs to be of high quality to avoid negative impact on image quality.
This principle of constructing a DSLR has been introduced already with the A55 and A33 (later replaced by the A35). Now Sony has released the A77, which implements this principle in a semi-pro body, with a more robust build, advanced features and higher specifications.
The main differences of the new camera compared to the lower-level SLTs are:
Higher resolution, 24 MP on an APS-C sensor.
Higher frame rate of up to 12 frames/s.
Better OLED electronic viewfinder with XGA resolution.
Larger, more robust construction, vertical grip (VG-C77AM), two control wheels, studio flash connector
Video recording with 1080p50/p60 and manual control
Compared to the DSLR-A700, the main differences are:
SLT with electronic viewfinder
Full HD Video recording
Higher number of AF sensors, and more cross-type sensors
Features that were introduced over time in lower-level bodies, like HDR, tilt/swivel rear display, face recognition, panorama shooting, GPS.
No CompactFlash slot!
Together with the A77, the SLT-A65 is released. It is very similar to the A77, with the following major differences:
Plastic body instead of magnesium alloy.
No top LCD
Fewer cross-type AF sensors
Slower shooting speed and minimum exposure time
No weather sealing
New kit lens AF DT 16-50/2.8 SSM
With the new cameras, Sony also released a new standard zoom lens, the AF DT 16-50/2.8 SSM. It features a large constant maximum aperture and a fast and silent SSM focus motor. The lens is also sealed against dust and moisture.
Both cameras and lens are expected to be available in shops in October/November.
This web site exists for several years now. I always make an effort to keep it up to date and comprehensive, in particular the technical pages. This causes some work from time to time, and operating the site is not free, either. I never liked the idea of having online advertisements on these pages to get some compensation. All too often you get ads for unwanted content, and ads naturally tend to become intrusive and annoying.
With Flattr there is now a mature micro-payment service that allows readers to contribute to web sites with little effort and low overhead.
So if you like this web page and you think it contains helpful information, you can now click on the Flattr button to the left (below the menu) and make a small contribution to let me operate and maintain this web site.
Same as SLT-A33, but with 16 MP sensor, higher frame rate and GPS
The innovation here is that both cameras feature a semi-transparent (pellicle) mirror. It deflects 1/3 of incoming light towards the phase detection AF sensors, and 2/3 of the light are passed through to the main sensor. The mirror stays down when recording images and video. There is no optical viewfinder. The viewfinder image is taken by the main sensor and displayed either on an electronic 1.15 M-dot LCD in the viewfinder housing, or on the large rear display. This is a variation of what I have described in “The Future of Digital SLRs”.
Sony's earlier implementation of Live View got around the problem of slow video AF by placing a small secondary sensor in the viewfinder housing and tilting one of the viewfinder prism mirrors to direct the viewfinder image towards this sensor instead of the ocular. This way it was possible to still use the faster phase detection AF system even during Live View. But the disadvantages of traditional SLR designs remained.
With the new design Sony has taken the big step forward to throw out (almost) all elements of traditional SLRs, the main mirror and optical viewfinder. The big disadvantage, slow video AF, has been avoided by employing a pellicle mirror with phase detection AF sensors. The disadvantage of pellicle mirrors, light loss for the image sensor, is compensated by reducing the noise from the sensor so that it can be operated at higher amplification factors to achieve the nominal ISO ratings.
The advantages of such a design have already been outlined in above essay:
no mechanical efforts for the mirror mechanism, matte screen, viewfinder prism
no mirror slap
much shorter viewfinder blackout (caused only by the shutter, not by the mirror)
higher frame rates can be achieved without higher mechanical effort (up to 10 fps)
100% viewfinder image is easy to achieve
electronic viewfinder can be adjusted to low light level (especially during DOF preview), and can easily display an enlarged viewfinder image, grid lines or live histogram, etc.
1200 segment ambient metering
AF in video mode just as quick as in still image mode
Sony should not stop at this point. Once you have introduced electronic viewfinders, it's easy to make them tiltable or even detachable, giving DSLRs even more flexibility.
Meanwhile, the “Advanced DSLR” previewed on PMA is not among the new cameras. It also remains to be seen if this advanced DSLR will be of the more traditional design or of the new pellicle mirror design.
The latter two lenses are clearly optimized for low price. The lens bayonet (and probably most of the rest of the lens barrel) is made of polycarbonate, and both feature the cheaper (but also noisy) SAM micro motors. Their medium speed results in very compact lenses and low weight of around 175 g. But as seen from earlier releases like the DT 30/2.8 Macro and the DT 50/1.8, this does not automatically mean that optical quality will be reason for complaints. With such conservative designs you can still expect high image quality despite the low price.