SLT a55

[Neonsquare]

@Dusty
Why? From where did you think the EVF image comes from?
The good thing about this is that it doesn't make a big difference if you use the EVF or the display. The SLT technology makes autofocusing using main sensor liveview feel like any DSLR - which is a really nice feature. The SLT is a very pragmatical concept: you get a big bright 100% view and you can always see what you control even in the viewfinder. It works astonishingly well and feels like a well thought out thing. The EVF is certainly different to a typical DSLR Viewfinder but different doesn't mean just worse (or better). It works as a viewfinder and it works very well as that. I was really surprised how much this camera feels like a normal DSLR and at the same time it can offer things like histograms, grids, levels, options, controls all within the viewfinder.

I know, you don't want all this stuff. Hammer an pick is enough for your stone carving and even then - collecting this old dusty stuff is actually more your thing than actually taking photos isn't it?

[Neonsquare]

It's actually n+1 actuations in serial modes and not 2*n

[Greg Beetham]

I could be wrong but I thought the 10 fps mode was a kind of movie capture at lower resolution. The main thing I don't like about all this 'electronic' stuff is the amount of battery power wastage that is entailed; the main sensor is 'on' all the time you want to actually see through the VF or use the rear screen for LV and the shutter is held open as well, whereas a standard DSLR with an optical VF doesn't need the main sensor turned 'on' too see through the VF and there is no electronic VF to waste power on either.
The shutter itself is probably as good as you can make it, I doubt it's any better than the one in the A700 though, and as it's in a body that is half the price at introduction it might not even be as good.
Greg

[David Kilpatrick]

Two points: every actuation of a NEX or A55/33 shutter equals two actuations of a normal shutter, because the shutter closes, fires, then opens again.

Secondly, the 10fps mode is a full raw capture or raw+jpeg sequence at 16 megapixels, just as the 7fps mode in NEX is full res raw or R+J.

Finally, as I have found out tonight trying to make a small movie, the A55 overheats fast and the movie quality while good is not actually as good as the NEX-5 (which overheats much later - I have been able to get a maximum of 7 minutes out of the A55).

David

[bfitzgerald]

You don't think that the shutter assembly may have been made to higher tolerances, given that it's also expected to be driven at 10 fps?

It could be but then we'd have seen numbers banded about such as tested to 100k actuation etc etc.
It will be interesting to see how long these shutters last. I've yet to kill a Minolta shutter ok unlikely on a film body but the 5d's been used a lot.

[redsim74]

It could be but then we'd have seen numbers banded about such as tested to 100k actuation etc etc.

Would we really though? MTBF figures are a lottery anyway. Though as you say, we'd have to wait to find out.

On a side note, tried an A55 for the first time this afternoon. Not liking that on/off switch placement, I turned the camera off at least three times while trying to use the front dial. Shutter noise was extremely quiet compared to my A700, even in 10fps mode. EVF seemed quite usable given my quick play.

[David Kilpatrick]

You soon get used to the on/off switch, though Sony decided to make it go the wrong way relative to NEX.

One thing the EVF has shown me is how severe the vignetting on the CZ 16-80mm is at 16mm. You can see, precisely, the effect at f/3.5 and at f/11 etc, and at different focal lengths. It is so extreme in comparison with the 18-55mm that I'm seriously considering using the 18-55mm instead of the CZ. Visually it looks like 2 stops loss towards the corners.

I thought it was my filter, which I appear to have removed at some point and lost (a very thin B+W). But it is not. I fitted a Rodenstock filter, with a front thread able to accept the lens cap (the B+W could not). It does not make any difference on the 100% view with filter or not. The vignetting, including really dark corners, is present with or without.

Despite this we are going to do a week's travel shooting and leave the A900 and A700 behind. A550, A55, NEX-5 - fives all the way.

David

[redsim74]

David,

There's probably quite a few things I'd have to get used to in the event I actually bought one. The interface seemed a little bit alien coming from an A700. Not natural to me at all.

I had the 18-55 attached to the camera and it was my first experience with a Sony SAM lens, it seemed relatively quick to focus and not as noisy as I have been led to believe. Previewed images seemed rather soft even at f/8 when at 55mm, though I have no idea what sharpness settings, etc were set in camera.

The Sony rep demoed the 3D Panorama images on a glorious, huge Sony 3D TV for me. Have to say that I was more impressed by that than I expected to be. They were obviously hand picked examples but much better than any other 3D images/video I've seen.

I wish I'd taken the time to try the A580 while I was there but we were on metered parking and already 30 mins over the limit when we got back to the car!

[bakubo]

Despite this we are going to do a week's travel shooting and leave the A900 and A700 behind. A550, A55, NEX-5 - fives all the way.

Those 3 cameras will be a pretty nice, small, and light combo. I think I read yesterday that you were taking the A55 and NEX-5. Why did you decide to add the A550? Is it just so you will have an OVF in case it is needed? Or, because the A55 might ghost in some cases?

Certainly, the A55 is attractive for travel. Of course, A-mount lenses don't get smaller, but the body is nice and compact. It reminds me of a super-duper upgrade to the Minolta D7i I had some years ago. Too bad Sony can't make a 28-200mm f2.8-3.5 zoom of the same good quality and pretty small size for it.

[edrice]

On a side note, tried an A55 for the first time this afternoon. Not liking that on/off switch placement, I turned the camera off at least three times while trying to use the front dial. Shutter noise was extremely quiet compared to my A700, even in 10fps mode. EVF seemed quite usable given my quick play.

I can't tell you how many times I've turned off the A55 while trying to change the aperture. I'm starting to settle down now and can outwit it. I can just imagine Sony engineers giggling in a corner about this.

Another thing I've done accidently is change the ISO. I'm still trying to think back the sequence of events that led to this, but I was pressing the down arrow for some reason but don't remember why and wound up at 3200 ISO without realizing it and continued shooting in that mode for a while. I do remember the high shutter speed flashing at me in the viewfinder at times but was distracted and ignored it for the moment and kept shooting. I never realized anything was amiss until looking at the shots in Bridge and everything appeared to be fine but I was astounded when I discovered that these shots were at 3200 because the only real giveaway was the exif data in Bridge. I went back out and reshot one of the them at lower ISO for comparison's sake and found so little practical difference in noise. This was my first actual experience with higher ISO in the A55 and a welcome change from earlier Alphas. But I still don't know how I got there.

Ed

[Greg Beetham]

David I think what we are sortof all hanging out for is a comparo between the A55 and the A580; I guess you could do a review of the A580 seperately later if cameras, timelines etc. are not convenient, and Sony made sure of that; but too me it's a critical crossroad situation at the moment between the SLT and the DSLR and a comparison between these two is exactly what is needed for many right now, including me.
Greg

[Neonsquare]

Two points: every actuation of a NEX or A55/33 shutter equals two actuations of a normal shutter, because the shutter closes, fires, then opens again.

Are you sure? I thought it works like this

1) Shutter is open (LiveView)
2) Shutter is closed before photo
3) Open shutter
4) Expose sensor for shutter time
5) Close shutter
6) Open shutter (LiveView)

So on one single photo you have two open/close combos.

On serial mode it is like this:

1) Shutter is open (LiveView)
2) Shutter is closed before photo
3.1) Open shutter
3.2) Expose sensor for shutter time
3.3) Close shutter
3.4) serial ends -> 4 else 3.1
4) Open shutter (LiveView)

So for a 10 frame series it is 1 LiveView open/close combo and 10 normal shutter actuations. This may also be the whole reason why they cannot show LiveView between the frames and therefore show the shot frames.

So the serial modes do not stress the shutter much more than it would be on a normal DSLR on that level. On the other side 10 FPS (11 actuations) is stress enough I think.

Secondly, the 10fps mode is a full raw capture or raw+jpeg sequence at 16 megapixels, just as the 7fps mode in NEX is full res raw or R+J.

Yes - there is actually little difference to the former serial modes. If you shoot 10FPS in AF-C you cannot choose the aperture or ISO. This is because the aperture is fixed for two reasons: Two allow focus tracking at 10FPS and because the mechanics of the aperture control mechanism only works for up to 6 FPS. (Hey isn't mechanics cool? ). Since the aperture is fixed the SLT can only use shutter time and ISO to control exposure. The current automatic seems to try to hold ISO quite low which is actually not a good idea if you want to freeze frame fast action on fast shutter speeds. You actually CAN choose aperture and ISO when switching over to AF-S - the SLT then behaves more like the A550 on 7FPS mode in that the focus and exposure are fixed on the first frame. If you want both - full control over exposure AND AF-C tracking you have to use the 6FPS serial mode. So the SLTs provide alot of different options for different use cases.

Finally, as I have found out tonight trying to make a small movie, the A55 overheats fast and the movie quality while good is not actually as good as the NEX-5 (which overheats much later - I have been able to get a maximum of 7 minutes out of the A55).

The overheating is mostly an issue with the super steadyshot - which the NEX doesn't have. If you switch it off it will take movies alot longer (>20 minutes). You could then either use some OS lens as offered by Sigma, a steadycam camera stabilizer, monopod, tripod or just hold it without shaking

ciao,
Jochen

[Dr. Harout]

Two more words about the EVF.
What do we see in OVF while changing aperture and/or shutter speed and/or ISO ? the answer: the same thing except for some arrows going left or right underneath the view in the viewfinder.
In EVF whenever changing any of the 3 settings (A, S or ISO) you see something different. Change it to your taste. Any filter mounted is seen through EVF, unlike OVF. Try a gradual filter and contemplate the changes in the viewfinder with or without DOF preview.
Filter users will be fond of SLTs, that's for sure.

This much for now and back to learning the SLT way.
Did I say I dislike the only one control wheel (same feelings for the A100 and now this).

[Dr. Harout]

Can anyone explain this on the a55
Whenever I point the remote control towards the camera and push any button there's a purplish red circle appearing on the LCD/EVF. I tried many times even in total darkness and there it was.
So, my question, is the a55 sensitive to IR and does this explain the extra sharpness of that camera?
And a second question: how does it affect overall on the picture?

[Armen Gharib]

Hi Doc
I think I have a few scientific versions to highlight the situation you described above..
In case of SLR where the mirror is moved to accept the irradiation of information let's say, hot mirror is needed to construct on additional highly transparent glass substrate which brings it's contribution to some kind of losses. Hence in case of SLR and P&S cameras which I maintained many times we have glass substrate+infrared blocking coating+optical glue(gluing glass to the CMOS or CCD). All this system together can contribute of 5-7% or more optical losses generally.
In case of SLT like a-55 there is already a mirror which is not moved and there is no need to deposit infrared blocking coating on the sensor and it can be directly deposited on the surface of stable mirror which is always at the same position even in the shooting mode. Hence the light strikes to the mirror and infrared component is filtered over there. Hence here we have no losses practically because only a few houndred nanometer coating is deposited on the surface of mirror and the losses of the glass and the glue is being eliminated. But anyway I am not sure and the version I described would be the smartest way that Sony could implement and it has really lots of technological difficulties, because one or two layers are not enough t solve the light dispersion, homogeneity and infrared problems of the camera (actually all the elements should be low dispersive).
Now about the fact that you recorded.. Because your camera is sensing a few mW power of the infrared emitter of the controller in the regime of fast exposures, it means that the sensor is too sensitive to the IR light. Note, that ordinary controller light's LED emitter's wavelength is under 850 nm which I have measured for a few times last year with the help of my spectrophotometer. IR blocking filters generally block all the IR region after 700nm and the fact that your camera sense that light means that it should be sensitive at least up to 900nm but the problem is how many percents of IR light it accepts. Sony's Silicon sensors usually sense up to 1100nm which is the li,it corresponding to the band gap of Silicon or to the absorption threshold of Silicon. I checked with my IR modified cameras that the mixture of IR and visible lights sharpen some particular details of the images and record of some sharpness which David is reporting is justified in this case because some amount of IR should sharpen the things which extensively emit IR. But I think that that much transmittance of IR is not acceptable anyway and that can be eliminated in case of some voltage is applied to the sensor at the capture mode. With the help of some voltage the IR sensitivity of CMOS sensor can somehow be controlled. But anyway the fact is that there is some sensitvity of IR and I guess like 20 percents of less in that region which can be even favorable in case of right electronic and processing solutions which sony has implemented I think. And if a few percent IR transmitting coating is easier to make technologically in the stack of multilayer coatings.
We can definitely determine the IR sensitivity range of a-55 by varying the wvaevelength of incident radiation using moncochromator. In case of I have some time I will implement it. a-55 users should also be careful with capturing the sky, I think a-55 should take better and sharper pics of skies and green, becasue theres are the most common emitters of IR in case of landscape, and you can also experience in using IR filters and capture sunny landscapes. If it sets the exposure automatically less than 10 seconds then it is more sensitive than the SLRs but I think that it will set not more thab 3 secs:)) I don't know why:))
Thank you for interesting experiment Doc, in case of having a time I will try to implement difefrent experiments..
One thing more:)) will you allow to put out of order your a-55, because in that case I will clarify everything I can even measure the coatings ta our lab
Sorry for being so boring