As you have seen from the latest DxOmark test there is a sensible image quality difference between the translucent [shoplink 3617]A55[/shoplink] and the classic [shoplink 3028]A580[/shoplink] DSLR. The main cause is very likely the semitransparent mirror that reflects 30% of the light to the AF sensor.That’s why I ask you to share your opinion about the importance to have a “flip-up” mode for the translucent mirror that would allow you to take picture without having the light loss. Let Sony know what you think!
[poll id=”28″]
Thanks!
79 Responses
I’m a little worried about taking night time photos of brightly-lit objects. I’ve seen a few tests where some horrible glare can occur with that mirror still down.
It’s only a problem if you do long exposures and if you pixel-peep or blow the image up to an abnormal size. If you’re doing pro work then you wouldn’t be buying an a55 anyways. I’ve taken a lot of night shots with my a55 and it’s great. I have to look VERY hard to see the ghosting…but that’s only on street lights. Not sure what specifically you might be taking photos of.
i may also add that some or much of the ghosting phenomenon that has been blamed on the translucent mirror, might actually be unrelated to that mirror and may occur on non-SLT digital cameras as a result of internal reflections between the sensor and the lens. In order to blame ghosting on the translucent mirror, we need to shoot a control image with a DSLR or other non-SLT camera, if that camera produce a ghosting-free image while the A55/A33 produce ghosting under the same conditions, then yes, we can say with certainty it is the bad of the SLT. i am yet to see such a controlled test proving the culpability of the SLT design. have seen example of SLT & non-SLT both producing what looks like ghosting:
http://forums.dpreview.com/forums/read.asp?forum=1037&message=36854045
Thanks to the both of you. I do remember two reviews that showed the ghosting, and it’s not a typical ghosting (three vertical lines parallel to each other), but I’m at work and cannot spend a lot of time looking for those reviews here. I’ll look when I get home tonight.
hmmm… flip up mode… only if the SLT design remains the same. What if the phase detection sensor is embedded into the main sensor, like HX100v? There will be no need for flip up mode.
Also, what if Sony use OLED screen to display the image from the main sensor for AF and view finding, instead of a mirror? That may be another way to do without the flip up mode.
I read these two technology from this site some time ago, and it is just my guess.
You can’t use oled for displaying image to AF sensor. Learn more about phase detection af:)
And pdaf on sensor means no need for mirror at all.^^
You are basically asking for a better Nex.
The ability to flip a switch so that the mirror is fixed or so that it can move would be a very amazing feature. Opens up the possibilities of the best of both worlds. The full amount of available light hitting the sensor for photographs, and continuous autofocus for filming. Not to mention being able to turn it off would open a world of possibilities of soft focus transitions during video which would be really ideal.
None the less I will still be purchasing the a77 when it comes out 🙂
I was thinking about this before as well. But with the rapid advancement in sensor technology, you don’t need a flip-up mode anymore. Adding an extra motor into the camera will just increase the cost; and the mirror flipping causes vibration, noise, and delay synchronization with the main shutter. All you need is the next generation back-illuminated sensor that can shoot in hundreds of thousands ISO. There is no going back to the old-school DSLR, one only need to think about the future.
Problem isn’t lack of sensivity but reduction of sensivity from it’s full potential and artifacts cause by sensor, as for example increase of violet CA, increased flares, double images of overburn areas, and so on.
The artifacts you mentioned mostly come from the lens optics, but not from the translucent mirror. I have a FF Zeiss lens and I seen none of the problems you mentioned in any situation.
Nope, I’m actually aware of lens problems. But all the stuff I listed occurs with lenses that work perfectly fine on A580.
rubbish.
There are issues with the design. Admittedly they are very specific to some situations and depending on what you expect can be a non-issue. But they are there.
http://www.kurtmunger.com/sony_translucent_mirrorid181.html
@mike_2008 Great argument.
Yep, Vlad pretty much nailed what I mean in the link provided. I understand all the excitement around SLT but let’s not be blind.
One should realize that every piece of glass in front of the camera sensor will produce some sort of optical artifact. Lens coating is there to minimize such phenomenon. A purist might argue that the cleanest possible picture is to remove all lenses and take a shot with only the sensor exposed to the most unaltered light source. Or one can try taking a picture by removing the “un-coated” UV protector each time. Asking for flip-up mode only brings the old stuff on the table again. Improvement to the great SLT tech should be put towards having better coating on the translucent mirror or introduce electric reflectance/translucency control into the mirror.
flip-up mirror can make a77 really great camera.
Do we know for sure A77 and A99 will have mirrors? AF does not need it, with proper cooling liveview can be read off the main sensor…I wonder seems NEX-7 woudl be far better camera – same Af speed, same sensor, possibly 1/4 of the size and weigth
“no mirror” construction which seems possible too with phase detect AF now integrated in to the main sensor may be indeed obviates this question.
While mirror is required (May be A77) I would like it to be movable. May be my ignorance but despite the technical miracles in A55 I am a bit hesistant to spend my cache on it.
Let’s see what sony is up to.
For 77 we know it for sure. Currently CDAF is miles behind PDAF on SLR lenses, so any kind of no-mirror camera would fail for sports or fast action photography unless you make special lenses for it. PDAF on sensor isn’t precise enough. It works on compact cameras with small sensor and by this: big DOF. I understand whole this optymism about on-sensor PDAF but we are miles away from actually using it in any large-sensor camera with large-aperture lenses. It isn’t a matter of 1-2 years as some assume.
DxO has shown that SLT with still mirror isn’t acceptable in any pro SLR. Sorry but if I pay that much cash for camera I want to pull maximum out of it. Not maximum -30% cause someone cut few bucks on option of flipping the mirror. Not even to mention occasionall articactis on night photos or overburn areas…. Sorry but lack of this feature in A77 (or whatever else high grade camera is going to be released) would be a big turn down, propably the biggest failure the camera to come can have.
Agreed
Agreed.
Completely disagree. Numbers don’t really mean much. Real-life examples tell the truths. I’m an active SLT user, so I know how good the pictures are.
Yes, that’s true, pictures are stunning, noone can deny it. But… they could be better. How much better? Well, 1/3rd EV isn’t very much, most of people won’t see difference, but… it’s that much.
All the more reason for an a7xx SLR version as well as the SLT a77.
For whatever reason Sony has made the A33/A55 mirror way too close to the lens mount to allow flipping with lens. It would be even harder to accomodate a FF mirror. I am not optimistic about this feature being implemented. However, a user removable mirror could serve as a compromise for the rare occasions (street lights at night…) when CDAF or MF can be used. Just make sure your don’t touch the mirror surfaces, or you will see a lot of ghosting.
The mirror is closer to the lens mount because it is more vertical (not at 45 degrees) for creating a compact camera (by placing the phase detect AF module under the flash and not under the EVF) and for reducing the double reflection (ghosting) amplitude.
If the mirror hinge was in it’s usual focal plane (like in a classical Alpha DSLR), the such angled mirror would be very long with the hinge placed higher, so in the end the mirror could not flip up.
The only solution was to place the hinge upfront. That way, when the mirror is raised, it protrudes only a little from the lens mount.
not “for creating a compact camera”, the have to maintain the same register (flange) distance of the A-mount regardless of the angle of the mirror. i believe the mirror was positioned at a more vertical than 45º in order for it to be able to reflect light to the AF sensor located at the top of the mirror chamber not to reduce the depth of the camera as done in mirrorless designs.
There are 2 problems that make difficult a moving pellicle mirror Sony SLT camera:
1) the thin pellicle is probably not strong enough for the mechanical shocks that a normal SLR mirror supports at each end of the run; so at best it would slowly make the transition between “pellicle mirror” and “mirrorless”;
2) the pellicle mirror as implemented by Sony has a larger angle than the usual 45 degrees with the horizontal axis – i.e. the mirror is placed closer to the vertical for a better integration of the phase detection AF module; that makes the mirror protrude from the lens mount in the “up” position (it would bang into the back of the lens).
fully agree + in an interview of the SLT design team they said moving mirror wasn’t possible.
🙂
What about if it slides up?
I can see it slide sideways into the grip in a thicker body (a very thick A99) but no way up (there is no space there). Another idea would be a down flipping mirror (with the hinge at the bottom) or a vertical hinge allowing the mirror to flip to the right or left (like in a porro SLR design) e. g. Olympus E-300 & E-330.
In all cases the important thing when designing such a camera is to have equal distances [mirror to main_sensor]= [mirror to AF_sensor] without introducing the AF sensor into the main light path and that is difficult with articulated mirrors at steep angles. That’s another reason for the front mount of the A55 mirror.
“there is no space there” In A55 no, but in general there can be made some space. A900 has mirror folding up. Alternative would be to fold it down.
“There are 2 problems that make difficult a moving pellicle mirror Sony SLT camera” – there’s one huge difficulty: Sony doesn’t use Pellicle mirror. See the wikipedia.
If the mirror flips then isn’t that essentially just an slr then… whats the point in making it slt
constant AF during video, constant AF during continuous shooting – these are two huge advantages.
Couldn’t agree.
Engineering is compromises all the way round. Actually only see two things – 30% light loss and some negligible pixelpeeper artefacts. ISO advantage of A580 is negligible, it is the same as you stop down your lens for 1/3. If you belive in ISO up to hundreds of thousands, why you are so mad about 1/3 of stop? Lose in resolution is fiction. According to David Kilpatrick, A55 images is more detailed than from A580. I think, DxO scores is artificial, but it is another story.
There is several huge advantages related to SLT tech.
1. AF tracking during video and fast shooting. It is rumoured even 16 fps for A77 and even 10fps will be not possible in any A770 level classic DSLR for price under 1000.
2. Live View with AF is actually the same as point 1.
3. AF is faster and more precise because no need for mirror moving and it stays more precise in position. Also AF system tracks all the time and has more info about some moving subjects etc.
4. All time MLU. May be for APS cameras is not so huge impact, but A900 mirror induced vibration is substantial problem if relatively long (less than 1/60s) exposures is used. In addition with A55 is possible MLU and fast bursts for example for bracketing instead on A900 it is impossible.
5. Camera could be smaller. May be for A77 it is not a big advantage, but any way there could be some space for other things.
6. In B&H A55 is only about 50USD cheaper than A580, but A55 have 10fps instead of 7fps for A580.
Only thing I really don’t like is EVF. It remembers me crappy cell phone screens some 8 years ago. Understand me right, I’m not against possibility of SLT camera mirror moving if I could keep all mentioned advantages.
Agreed. A55 is ideal for me because I REALLY wanted a smaller camera this time.
According to David Kilpatrick, A55 images is more detailed than from A580. I think, DxO scores is artificial, but it is another story. – well according to every comparison pictures I’ve seen so far – it’s other way around, A580 has visible advantage over A55. It’s not about numbers. Numbers just confirm actual observation. 🙂
Yes, the advantages are HUGE I dare to say, but… there’s the other side of the coin too.
I have been using A33 for a while, every picture I took is free of artifacts. So I don’t understand what’s the problem. The pictures I took are brighter and far better than the A550 I had. With multi-frame noise reduction, the camera is a treasure while taking pictures in low light.
If you don’t actually own and have tested a SLT camera, making assumptions here are non-sense.
Test labs can be biased and inaccurate, test for yourself!
Can someone please remind me what the advantage of the pelix design is when it comes to taking pictures?
Faster burst rate at a cheaper price
@daniel – the pelix solves a few gnarly problems in slr design. It supplies a continuous image to focusing sensors while an image or video is being shot, and so that focus is maintained and can adjust to movement. This allows better focus tracking during capture, and because a mirror doesn’t have to be moved out of the way for stills, the shooting rate can increase. A typical slr has to move it’s mirror to take a still or video, so focus is a problem. Here’s a link to a comparison between an A55 and Canon 550D http://www.youtube.com/watch?v=kHPaVD0pHpQ
I prefer as little glass in the way of the optical path as possible and while 1/3 EV is not much, I would be willing to pay the additional cost of including a moving mirror. An mirror arrangement similar to the one on the A900 where the mirror not just flips but also lift should allow the mirror to fit inside the A-Mount
http://images.anandtech.com/reviews/cameras/2008/sony-a900-handson/a900-mirror.jpg
My impression is that the pelix is not meant for photography but for one specific type of photography. For people not doing Action/sport/burst or video, this offers little advantage. I can’t see a studio photographer being excited about the a900 being discontinued, no replacement for a long time, and then once it comes it has compromised image quality.
What I’m saying while this feature might appeal to a lot of consumer level shooters, I’m guessing that at the professional level this might meet a bit of resistance.
I think that for action/sport/burst the reverse is true. High frame rate dslrs use predictive autofocus that may or may not predict correctly. The slts continually track movement and change focus based on actual movement. Also, did you notice that the A55 was metering more accurately in the you tube video? Doesn’t that matter?
Studio photographers make up a small proportion of total sales. The A55 has performance of bodies costing 10X as much – isn’t straight ahead value worth anything?
Also, which company is changing out their high end cameras quickly? When did the D3x come out – well it uses the A900 sensor, so the times that they’ve been on the market are about the same. Look for slower turnover during the economic downturn – camera companies have to recoup research and development costs, and MAKE MONEY with their various echelons – don’t expect a turnover any faster in the future! BTW, who said the A900 is discontinued? Weird.
I think the action photographers make for a small part. For studio, landscape, portrait there is no advantage.
About the A900 – I bet you’ll see a replacement much later than for the Nikon D3x. Also while not exactly a replacement there is the D3s. The problem for now is the A700 – 4 years, no incremental upgrades, discontinued without nothing on the horizon. The way it is going the A900 will end up the same.
the other thing I’m wondering is why was there an a580 and a560 launched/announced simultaneously with the a55 and a33, while there seems no indication of a77 having a new three digit option
Someone mentioned that SONY may make the SLT mirror also function as the IR filter. If this is true, the mirror has to stay down for visible light photography.
http://www.sonyalpharumors.com/sony-a900-discontinued-but-no-replacement-in-sight/
It looks to me that sony put their eggs in the consumer-level basket. Look how far apart the release dates of a580, a560, a55, a33, a390 and a290. they couldn’t finish the a700 emplacement because they didn’t care to. They have only certain amount of research and production capacity, and the higher level cameras are taking a backseat.
When it comes to important features for me, I look at the pelix design as a gimmick. Others might find it important. I would rather have that extra 30% of light and more consistent focus/metering. The pelix design IMO doesn’t improve either, just let’s you do it while you’re taking video or burst. If I want video I’ll get a video camera, and I won’t have to convince myself that my DSLR’s jello is less shaky.
anyway, that’s my $0.02, I’m certainly aware that not everybody feels like this and don’t pretend to represent any group. Just my preference 🙂
Yes, that’s true that Sony puts all it’s focus on consumer market – it was known since A200/300/350 release – Sony officials told dozens of times that company is going to focus on entry level and than build all the way up.
Now we are at mid-range stage and slowly (too slowly IMO) entering high-end – after that the regular updates of cameras should come as it’s in every other company.
BTW: Sony doesn’t use pellicle mirror. Pellicle mirror is like a thin foil, something completely different than SLT mirror.
Hi Daniel, I agree somehow with you. Somehow. I had a look at the a55 EVF and I didn’t find it convincing. The image is too busy…. Might be fine for video, but at still photography, which pulls its power from the stillness, the EVF is too busy for my taste to be representative for the final photo. If an a55 would be my next a900… brrrr…
But let’s give Sony a chance. They said that the a77 will be an amazing camera beyond our expectations. And don’t let us forget the advantages of an EVF. If Sony manages to eliminate the disadvantages — why not?
And, third: Building fine cameras is a nice thing. But the manufacturer has to make money in order to be able survive and to build the fine stuff… So it is the right way IMHO: Make money in the mass market to have it for investments in the fine stuff.
quote:
“there is a sensible image quality difference between the translucent A55 and the classic A580 DSLR. The main cause is very likely the semitransparent mirror that reflects 30% of the light to the AF sensor.” end quote.
the translucent mirror is likely the cause behind the lower DXO ISO score, but not the color or DR scores, because the A33 actually beats the A560 in color & DR in spite of the translucent mirror (check the DXO scores of the A580/A55/A560/A33 below, for each camera the four given numbers refer to overall score, color depth score, DR score & ISO score respectively).
A580: 80 — 23.8 — 13.3 — 1121
A55: 73 — 23 — 12.4 — 816
A560: 70 — 22.5 — 12.3 — 817
A33: 70 — 22.8 — 12.6 — 591
that’s not “beating” The A33 and A55 color and DR scores are within margin of error. If you test a different A55, you will see the same amount of differences.
TT read carefully what I wrote:
1) i didn’t compare A33 to A55 but to A560
2) while the differences between A33 and A560 in DR & color scores are not huge, they are in the opposite direction to the differences between A55 and A580 in the same DR & color scores. so of the two SLT cameras available we have one (A33) that has slightly higher DR and color score than its sister DSLR (A560), while the other SLT model (A55) is considerably lower in DR and color than its sister DSLR (A580). I hope that’s clear enough to everybody, the DXO scores of the four cameras are quoted in my post above, anyone who is just looking for the truth can have a look at numbers and they speak for themselves, anybody who is trying to muddy the truth or unintentionally looking as if he/she was, should just stop or will simply be ignored and laughed at.
Color depth difference is ~1,3%. DR difference is ~2,4%. ISO difference is ~28%. Enough said.
from ISO100 to ISO200 or from 800 to 1600 there is just a 1 stop difference and according to your method of calculation that is a HUGE 50%.
from DR=12 to DR=13, it is also a 1 stop difference but according to your method it is a “negligible” 1/13 x 100% = ~ 7.7%. OK maybe 7.7% is not so negligible from DR=12.5 to DR=13 that is half a stop but again according to your calculations that’s merely 3.8%.
(half a stop is like going from iso1600 to the middle point btw 1600 & 3200, say iso2000 following your logic that diff is equivalent to 3.8% diff described above).
hint: your method of direct number calculations doesn’t make any sense and it suggests you don’t understand the notion of photographic stops, every one stop represents a doubling of the light captured whether by aperture or shutter speed or the equivalent gain from changing the ISO.
Well, I actually am aware of stops, and logarithmic scale, you know, actually due to my profession such things are every day bread & butter.
I’m just showing you that the difference between A560 vs A33 in DR and CD is in the margin of error. Difference in ISO is waaaaay beyond margin of error.
(BTW: I see you also figured out a reason why always to shoot at lowest iso possible – grats to you!)
“I’m just showing you that the difference between A560 vs A33 in DR and CD is in the margin of error.”
do you find anywhere that i made claims to the contrary of this?!! if so please point them out.
basically i was making a comparison between two comparisons:
(A580 vs A55) vs (A560 vs A33)
and that’s only in the DR and color depth scores. I never said the differences in the ISO score between each SLT and its sister DLSR are not more considerable than the differences in the DR and color scores (also between SLT vs SLR) OR that the differences in the DR and color scores between A33 & A55 weren’t negligible (didn’t make that comparison at all) OR that the difference in ISO score between A33 & A55 wasn’t considerable, i just got more than my fair share of words/statements put in my mouth (that i never uttered). probably because i pushed a red button when i said that the A55 compared to A580 doesn’t look as good as the A33 compared to A560 when it comes to the DR and color scores. for those (not necessarily you) who have trouble with this finding from DXO results, just come to terms with these numbers and live with the fact that A55 is inferior to A580 in ways which A33 is not to A560 (DR & color).
note that the differences between A55 & A580 in DR & color scores are bigger than what can be explained by margins of error according to DXO’s own definition of margin of error, you didn’t comment on that you only point to the A33 vs A560 and say it’s because of MoE.
“Difference in ISO [between A33 & A560] is waaaaay beyond margin of error.”
this is i meant to quote above and tell you i never said anything to the contrary of it as my comparisons are concerned onl with the DR & color depth department and i actually exaggerated the diff between the A33 & A560 in those 2 departments to contrast (the slightly better scores of A33 in this comparison with the considerably worse scores of A55 compared to its SLR sibling, A580).
Very unimportant… a feature 10% people think they need and would just wound up unused by 99% of them after the first week of owning the camera.
Wishful thinking they are even considering that. They made it translucent so that it doesn’t have to flip up. ..duh!
I find Camaman’s comment reasonable. Didn’t take part to the poll indeed. Sony doesn’t need to find a way of flipping the translucent mirror up. What it does have to do, is a way to make it work somehow without light loss and absolutely, and here for a semi-pro is mandatory, without any kind of artifacts. Noone buys a Sony 70-200 f2.8 to see it stained by camera’s artifacts. IMHO.
You mean: Make a miracle? Not gonna happen. All you ask for can be get with mirror flipping 🙂
If what Emopunk has asked is considered making a miracle, then SLT tech was a truly successful miracle. It is 21st century, everything is possible. Have you heard of active damper system in the car? It is using electric current to instantaneously alter the viscosity of the fluid in the damper system. Sony being in the innovative up-front, it has made significant dSLR technology break-through in just a few years since it first introduced A100.
Flip-up mode & contrast detected AF ability, plzzzzzzzzzzzzzzzzzzz
Simply allow the same “mirror flip up mode” in the A850/A900. Problem solved!
Include contrast AF no matter how bad it is just so people who take long exposure landscapes (or whatever) are not fully stuck on manual mode while the mirror is up.
Just simply point it out that the camera is designed to work with the mirror down. Anyone who spends more than 1000 USD on a camera SHOULD know how to use it properly anyway.
guys, i do not know how to vote…
what i needs is have 0.1AF, AF on video tracking/record60p + shoot still at the same time and superb ISO 😀 so i should vote which one?
the pool results say the something opposite
A moving mirror will require a bigger body to accomodate it and will make require adding the flip mechanism. I don’t think that everybody else must “pay” this price, just to please a few purists. If the camera is a DSLT leave it a DSLT. If you want a DSLR buy a DSLR.
I like the size and form factor of A55, but I would like a metal body.If the size is increasing back to the classic DSLRs sizes for A77 is a negative factor for me.
Yeah, pointless poll is pointless. The whole purpose of the DSLT was to stop the flippining up mechanism. It’s like taking a huge step, and then 10 steps backwards.
The whole purpose of the DSLT was to get phase detection AF during video and continuous shooting. Not to stop the flipping mirror – stopping the mirror flip is just a way to achieve the objective. But this way also corrupts regular, non-continuous, non-movie photos.
Adding mirror-flip mode solves this problem.
It’s not step back. It’s step forward – a step fixing many objections people have against SLT design.
There are tons of other benefits for having a camera without a flipping mirror, i.e. no vibration, no loud noise, removal of synchronization with the main shutter for enabling 10FPS. If one must have a flip-up, Canikon is the best choice and they will use the same method for at least another 10 years.
Jason, noone asks for making mirror moving all the time. What’s asked is giving an option of moving the mirror when photographer finds it necessary. 🙂
You don’t find it needed – you ignore it. I find it needed – I’d like to use it. That’s all 🙂
I’m not interest in the big cameras without Ovi.
For me old classic and new NEX good combination. Gibrid SLT definitly not the way for photographers.
The beamsplitter (translucent pellicle) is very thin: It has to be thin to avoid introducing discernible astigmatism into the image. (Google “tilted plate in converging beam astigmatism” for more info.) I’m afraid “flipping” it with any force for a “snappy” response would probably break it.
Also, there would be a discernible defocus when shooting with vs. without the beamsplitter in place, requiring the camera to move the focal plane to adjust.
dear Sony…
what I want is this camera to work with my collection of your lenses.
http://www.pentaximaging.com/slr/K-5/
SLT impresses me, but I don’t care to have it.
what I do want is a…
– weather sealed body (not just 2 of the buttons)
– durable chassis
– accurate and consistent focusing
– micro-adjustable focus (a la a900/850) fr front/back focus issues.
these are features that don’t need to be “invented”
the a700 was introduced four years ago almost. Why not provide an upgrade last year that’s like the k5? Instead the camera is discontinued, and professionals that want to keep their apsc alpha lenses were being strung along with a “maybe next quarter we’ll tell you what we have in store for you”
While not everyone buys the camera just because a replacement comes out, there are photographers that like to have a second body on shoot, and when they discontinue a camera before offering an upgrade it sends a negative message.
“The bad news, for many, will be that the Alpha 700 replacement – optimistically shown with a vertical grip, 500mm f/4 G SSM lens and a new flash – will have a fixed Translucent mirror just like the A33 and A55. Paul Genge of Sony UK confirmed to us after the presentation that it will not have a flip-up mode to allow shooting without this extra sheet of glass in place. ”
http://www.dpreview.com/forums/readflat.asp?forum=1037&message=36398113