A77 SLT mirror light test (in Stock in USA, UK, Spain, Canada and Cina)
“HIDDEN”. One of the first short films shot with the A77 by philipnashphotography.
So many SAR readers still haven’t got the A77. Here is a short list of stores having the A77 in Stock: Expansys USA (Click here), Jacobs UK (Click here), Sonystore Canada (ships next week), Redcoon Spain (Click here), Amazon Cina (Click here) and in two weeks at Sonystore USA (Click here).
Now back to A77 related news:
There is a real A77 mirror measurement made by a German A77 owner. He took an A77 mirror and did a scientific test on the transmission as function of wavelength. That should finally stop the speculations on how much light is lost. The test description is in German language:
http://www.sonyuserforum.de/forum/showpost.php?p=1270217&postcount=206 (Click here for a google english translation).
This table from the same thread might help to translate the result into F-stops.
http://www.sonyuserforum.de/forum/showpost.php?p=1262520&postcount=119
In short, the test proves how the permeability is around 72-76% and it has a very “harmonious” distribution. And the light loss is indeed 1/3 EV “only”.
Stuckincustoms (Click here) wrote a quite “different” view on Sony SLT technology by (conspiracy theory included).
Mike Kobal (Click here) posted some A77 + Zeiss 24mm image samples: “There is no need to stop this lens down, already very sharp at f2 I found myself shooting in the range btw f2 to f6.3. This lens is pure awesomeness!”
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Zeiss 24mm for Alpha-mount (not for NEX!) is avaialble at Amazon, B&H, Adorama, J&R, eBay.
azamnecrone
2 years ago |No news on the new firmware upgrade for the a77?
admin
2 years ago |not yet
tobiasNEX7n
2 years ago |good to see a scientist do an independent mirror test and give A77 owners peace of mind
Steve Jones
2 years ago |Yes, somebody is watching her. Easily identified, he’s carrying a Sony A77.
Marek
2 years ago |I wonder why Mike Kobal covered all logos on his A77 with black tape.
tobiasNEX7n
2 years ago |yeah, I wondered too, I guess it is a street photography thing
Rolf
2 years ago |With 60 degrees angle, the transmission fluctuates around 70%, which corresponds to 1/2 stop of light loss.
ShakyA77
2 years ago |yup, that must be it, the trend not to show logos on classic street cameras, the new Leica M9-P, pure black, no name, not even red dot, same goes for the Fuji X Pro1, no logo and type in the front, all black and the same for the limited edition Fuji X100
Nice shots again by Mr. Kobal, seems he really likes that lens-ups sorry, meant to post this in response to the Marek comment
harpo
2 years ago |I would like to see your data on that. Can you kindly post a link to your research as the German fellow did?
The Lotus Eater
2 years ago |The light loss is NOT 1/3 EV, it’s around 2/3 EV.
Loss of 1 EV would be 50% light loss, so obviously 30% light loss caused by the SLT mirror diverting some light to the AF sensor is not 1/3 EV – it’s 0.6 EV or nearly 2/3 EV.
Rolf
2 years ago |EV’s are not linear
1/3 EV is 21% loss (79% transmission)
1/2 EV is 29% loss (71% transmission)
2/3 EV is 37% loss (63% transmission)
1 EV is 50% loss
The Lotus Eater
2 years ago |What is the exact light loss of the SLT mirror? My understanding is that it is 30% or thereabouts, which according to your figures is at least 1/2 EV. Nowhere near the 1/3 EV that is claimed.
BTW, my figures were taken from David Kilpatrick’s A77 review on photoclubalpha.com.
**Edit** This is taken from the comments section of DK’s A77 review:
“Just to clarify, the relationship between semi-transparent mirror transmission versus stops of light loss is #stops=-Log_2(t), where t is the transmission. For 30% reflection/70% transmission, the loss of stops is 0.51. A 1/3 stop loss is about 21%/79%, and 2/3 stops loss is 37%/63%, all assuming absorption is negligible. The Sony patent US20100277637 indicates a transmission across the visible range which is very close to 70% (Figs. 10-14).”
Assuming Sony is correct, then the light loss is approximately 0.5 stop or 1/2 EV. 1/3 stop loss is constantly bandied around, but it just isn’t correct. I think a lot of people think 30% loss = approx. 1/3 EV.
BlackLegSanji
2 years ago |Except that the guy measured the light transmission to be 72-76% or 74% average or a decrease of 0.43EV, which is closer to 0.33EV than your 0.60EV
The Lotus Eater
2 years ago |Not my 0.6 EV, David Kilpatrick’s 0.6 EV!
Sony’s patent “indicates a transmission across the visible range which is very close to 70%”, so who’s correct? I assume they measured it too.
Spoon
2 years ago |You’re basing it on the original patent and initial approximate given by Sony. We’re now looking at the second generation and we know Sony has made some changes, atleast to the coatings.
Measurements by DXO also hint at a “loss” of slightly less than 1/2 of a stop in the case of the A77, where the A55 showed half a stop.
There’s been several people now that measured the loss for the A77/A65 using different methods (metering with and without mirror, scene exposure with and without, transmission of light, etc.) and they all concluded between 1/3 and 1/2 of a stop. Certainly nowhere near 2/3.
beware
2 years ago |“So many SAR readers still haven’t got the A77.”
thats because it’s far from perfect !!!
The Lotus Eater
2 years ago |Name a perfect camera… good luck with that.
SonyA77
2 years ago |Or it’s not in stock.
Jeff Moreau
2 years ago |I trust you more than I trust the Sony store, but as recently as Tuesday they assured me that the SLT-A77 (Body only) I ordered from them in mid-December won’t arrive here until April. I would *much* rather see it in 2 weeks, as you (and their website) currently suggest!
Mike
2 years ago |Very good video sample, excellent colour grading. Unfortunately aliasing is still very visible. It seems Sony still hasn’t sorted it out. I’m curious to see the video quality of Fuji Pro X, though it’s primary a still camera. They claimed the sensor has sorted the aliasing issues on stills, not sure about the video because of the codec and compression.
ShakyA77
2 years ago |doubtful video will be better on the fuji then on sony cameras
doug
2 years ago |Video on the Fuji Pro X is more of an afterthought. It’s primarily intended to be a stills camera. Clearly, if you’re interested in shooting video, Sony is the way to go.
Denis
2 years ago |Like how the stabilizer works in video. Loved it with Pentax K-5 as well, miss it in NEX-5N. I hope Pentax or Sony will introduce mirrorless with stabilizer.
doug
2 years ago |Image stabilization (OSS) in the NEX series is built into the lenses, not the body. Several E-mount lenses have OSS, such as the 18-55mm kit zoom for the NEX-5n and the 50mm f/1.8.
Denis
2 years ago |I know about OSS, but I don’t want to stick to Sony. So I’m not buying E-mount lenses.
Mike
2 years ago |The test was actually made by an Austrian forum user, not German…
Denis
2 years ago |Oops
Denis
2 years ago |1:)
travelshots
2 years ago |SLT-Mirror measurement: The transmission of the mirror as emplaced in the A77 (60°)is shown by the green graph in the second diagram. You can see that the average transmission is about 72% (values seem to be between 68 and 77 in this graph, higher values represent less light loss). The second diagram does not show the whole visible spectrum (~380-780nm.) and the transmissivity increases obvioulsly slightly at the shorter wavelengths.
As 71% transmissivity equals to 0.5EV loss, you can easily derive that the light loss in the mirror is nearly exactly 0.5EV or slightly less.
By the way, the guy who did the measurement is Austrian and not German.
Cody
2 years ago |Has anyone tried the new OLED EVF?
SonyA77
2 years ago |Yes, plenty of people have the A65/77, including me.
James
2 years ago |It is the cats meow, I have had the a700 and still have my Minolta 7D I now have the A77 I think the EVF is hands down the best way to frame your shots and that people who bad mouth it are not thinking right or have never used it. The EVF lets you know your getting exact focus, and the exposure and WB you want before you fire the shutter, how can anyone complain. people say a OVF is more natural but hey I care about the image I’m capturing not the camera owning expereince.
SonyA77
2 years ago |Because it’s Sony and gives Canikon users an excuse to knock an excellent camera. They do it mostly out of fear.
Clifton
2 years ago |Great, more stats that no one really understands, now we can use them to argue with people who also don’t really understand them.
Alexey Ozerov
2 years ago |BTW little video made on club concert – A77 CZ24-70 –
no any edition just point shoot and upload – camera on hand no steadycam – Im not often make video – prefer still picture.
http://youtu.be/66ii_oTYtIg