p.147 #1 · Official: Sony A7 and A7R Fullframe Mirrorless
Lee Saxon wrote:
Well sure, but then what's the point of these cameras? I thought the whole reason we bought mirrorless was to use smaller / more efficiently-designed lenses.
#1: The cameras themselves are much, much smaller than FF SLR:s.
#2: The lenses are obviously designed in a way that could not be done with a mirror. They are also small, but perhaps not as small as you had expected.
#3: You can use a huge range of MF glass with little or no effort.
If that advantage doesn't materialize, or we don't care about it, there are FAR better cameras available (even if you demand an EVF).
p.147 #3 · Official: Sony A7 and A7R Fullframe Mirrorless
Jonas B wrote:
I have a question for those owning the A7 and the FE 55/1.8:
In the case of the Sony RX1 the lens stops down as soon as you turn the aperture ring. That means light measuring, AF (and MF) all are done at the working aperture. This is true for the range from f/2-f/8 I think, then it doesn't stop down further until the image is taken. I very much like the way camera behaves in this case as you get full control over focal plane, DOF, flare, focusing and what not all the time.
Is it the same with the A7 and the FE 55/1.8?...Show more →
The A7(r) has two modes of operation for this. When "Live View Display" is set to "Effect ON", the body will keep the aperture stopped down to the dialed-in value in the manner you described for the RX1 (except it doesn't limit it to f/8). When set to "Effect OFF", the body will keep the lens wide-open and only stop down the aperture when you half-press the shutter (MF mode); for AF it will focus at the widest aperture and then stop-down once focus has been acquired.
p.147 #4 · Official: Sony A7 and A7R Fullframe Mirrorless
snapsy wrote:
The A7(r) has two modes of operation for this. When "Live View Display" is set to "Effect ON", the body will keep the aperture stopped down to the dialed-in value in the manner you described for the RX1 (except it doesn't limit it to f/8). When set to "Effect OFF", the body will keep the lens wide-open and only stop down the aperture when you half-press the shutter (MF mode); for AF it will focus at the widest aperture and then stop-down once focus has been acquired.
p.147 #6 · Official: Sony A7 and A7R Fullframe Mirrorless
snapsy wrote:
When set to "Effect OFF", the body will keep the lens wide-open and only stop down the aperture when you half-press the shutter (MF mode); for AF it will focus at the widest aperture and then stop-down once focus has been acquired.
Also, if shooting in lower light situations, not with a wide open aperture, setting Effect OFF can improve focus speed; this is also a useful setting to choose to make achieving focus possible where it might not otherwise be possible.
p.147 #8 · Official: Sony A7 and A7R Fullframe Mirrorless
snapsy wrote:
The A7(r) has two modes of operation for this. When "Live View Display" is set to "Effect ON", the body will keep the aperture stopped down to the dialed-in value in the manner you described for the RX1 (except it doesn't limit it to f/8). When set to "Effect OFF", the body will keep the lens wide-open and only stop down the aperture when you half-press the shutter (MF mode); for AF it will focus at the widest aperture and then stop-down once focus has been acquired.
I also tested this with FE55, every click in aperture mode changed aperture physically except f/5.0 and f/5.6 it kept the physical aperture even value was changed in LCD; going smaller or larger, distance doesn't matter. Haven't tested FE35.
Might not be enough for some to choose the Sony, but it certainly is to me.
+1.
The weight delta increases when comparing the A7r and D800, too (another 150 grams).
With no fatigue I can carry in-hand the A7r with a FE35 or FE55 all day long by itself or mounted to a not overly light Feisol CF monopod. I did not find this to be the case with my D800, regardless of lens mounted. Bulk is just as important a factor and there - no contest.
Last year was my least productive year as a photographer ever and the heavier and much bulkier / less portable D800 + associated gear had everything to do with that. Given my needs, fortunately the balance of trade-offs and benefits tips in favour of the A7r and I'm not missing the things the D800 does better.
p.147 #12 · Official: Sony A7 and A7R Fullframe Mirrorless
carstenw wrote:
Why would you want to compare the Zeiss 35/1.4 to the Sony-Zeiss 55/1.8, size-wise?
I don't, but I clicked on the link and started playing with the drop-down list of lenses. The Distagon yields a distorted picture. It could be an incident, but this was only the second lens that I mounted. Should I just believe that all the other lenses are correctly rendered?
p.147 #13 · Official: Sony A7 and A7R Fullframe Mirrorless
Samuli Vahonen wrote:
I also tested this with FE55, every click in aperture mode changed aperture physically except f/5.0 and f/5.6 it kept the physical aperture even value was changed in LCD; going smaller or larger, distance doesn't matter. Haven't tested FE35.
Samuli
Yes, with "Live View Display" set to "Setting Effect ON", in A mode the aperture changes physically as you change the aperture dial. With "Setting Effect OFF", it stays wide open until a half-press of the shutter release is done. All for the FE35.
p.147 #14 · Official: Sony A7 and A7R Fullframe Mirrorless
Just a general note, the Nikon AF-S DX 35mm f1.8 G works shows minimal vignetting on the A7 for close focussing. Which isn't surprising, since I already used this lens on the full frame D700 for low-light shooting with great effect.
On another note, still waiting for delivery of my FE 35 and LA-EA4...
p.147 #15 · Official: Sony A7 and A7R Fullframe Mirrorless
carstenw wrote:
Yes, with "Live View Display" set to "Setting Effect ON", in A mode the aperture changes physically as you change the aperture dial. With "Setting Effect OFF", it stays wide open until a half-press of the shutter release is done. All for the FE35.
Checked FE35, it acts logically, different physical aperture size with f/5.0 and f/5.6 (as well as any aperture, but hard to see difference between f/20 and f/22, the aperture is so small that it's even difficult to see blade movement).
Tested more FE55 and it seems that when moving from f/4.5 to f/5.0 there is change in physical aperture size, but no change when going after that from f/5.0 to f/5.6. However half pressing shutter closes lens from f/5.0 to f/5.6. So the weird behaviour only happens when in normal live view mode, for shooting f/5.6 work correctly.
p.147 #16 · Official: Sony A7 and A7R Fullframe Mirrorless
Taylor Sherman wrote:
Well - so my A7 won't recognize a single SEL lens that I mount!
I've tried:
16/2.8
30/3.5
35/1.8
55-210
They all just sit there dumbly at f/22 and no AF, with the camera acting the same as if it had a legacy lens attached (no aperture info).
It's as if my electronic contacts just don't work. This is the first time I've tried it so I haven't noticed it yet in the three weeks I've had the camera.
Anyone else heard of this?
Update: it's working now. I grabbed the 18-55 off of my wife's Nex-6 and tried that; same thing, the first time I powered it up. I took it off again to compare the pins on the A7 to the N6 and make sure all were present/OK on the A7 (yes), put it back on, and voila. Now all my E-mount lenses are working suddenly.
p.147 #17 · Official: Sony A7 and A7R Fullframe Mirrorless
Samuli Vahonen wrote:
Tested more FE55 and it seems that when moving from f/4.5 to f/5.0 there is change in physical aperture size, but no change when going after that from f/5.0 to f/5.6. However half pressing shutter closes lens from f/5.0 to f/5.6. So the weird behaviour only happens when in normal live view mode, for shooting f/5.6 work correctly.
Samuli
hmmm...I just tried my A7r+FE55 and I can both hear and see the aperture moving for every 1/3 f/stop, including f/5 -> f/5.6.
p.147 #18 · Official: Sony A7 and A7R Fullframe Mirrorless
Toothwalker wrote:
Unclear. 11 bits cannot support the purported dynamic range of 14 EV.
Edit: A bit depth of 11 bits does no justice to a dynamic range of 14 EV. Or is it a matter of definition - again? If the dynamic range (the ratio of the largest non-saturating input signal to the smallest detectable input signal) is 14 EV, I would use at least 14 bits to store the information.
The statement that 11 bits cannot support a dynamic range of 14 is not strictly correct, as your edit seems to acknowledge. Any bit-depth can express any dynamic range. A greater bit-depth simply allows for more granularity in the levels recorded within a given dynamic range. Whether 11 bits does justice to the dynamic range is a qualitative judgment.
There is nothing unclear about the bit depth of the Sony RAWs. The encoding algorithm used for the Sony a7/a7R RAWs takes the original 14 bit values and maps them to 11 bit space (a bit more on this below) and then the 11 bit values are further compressed into 8 bits per pixel by delta-encoding them in fixed-length 16 pixel blocks as follows: 11-bit minimum value for the block, 11-bit maximum value for the block, 4-bit index of the minimum value in the block, 4-bit index of the maximum value, 14 7-bit deltas from the minimum value for the other 14 pixels. This uses 11+11+4+4+(14x7) = 128 bits per 16 pixels or 8 bits per pixel.
This encoding algorithm is why the a7R always produces files that are just over 36 million bytes (7360 x 4912 single color pixels multiplied by 8 bits per pixel divided by 8 bits per byte plus a small variable overhead for metadata). A good aspect of this algorithm is that it is computationally cheap as it does not need to do any data analysis and simply encodes with one pass over the data. A bad aspect is that it is not adaptive and as a result uses a fixed amount of storage which wastes space for images that don't need it and doesn't give additional space to files that would benefit from it.
Note that this encoding is doubly lossy: There is guaranteed data loss on the first step (the mapping from 14 bits to 11) and potential data loss on the second step (the delta-encoding in 16 bit blocks). The reason the second step may not lose data is that if the difference between min and max is less than 128 (the maximum value that can be expressed in 7 bits) then this step ends up being lossless. Since smooth gradients are most likely to have small deltas in values and since one is most likely to notice dataloss in smooth gradients, the second step is statistically more likely to be lossless when it counts most. It is this delta-encoding step that almost certainly explains the artifacts that some people have noticed on high-contrast transitions but these seem to me to be negligible in the grand scheme of things. The first step is for me much more concerning as it is lossy with regard to the total tonal range expressible in the RAW. Without new firmware, the a7/a7R will not produce a RAW file with more than 2048 values per channel.
Circling back to the "doing justice" comment, the 14 to 11 bit mapping is not quite as bad as it sounds as it is not a simple bit shift. A 3 bit shift would have the effect of binning every set of 8 consecutive 14-bit values into the same single value in 11-bit space. The Sony RAWs are instead mapped on a curve and devote more of the 11 bit space to the portions of the exposure range that should benefit from more tonality. I believe this is why Sony considers it "visually lossless". This mapping approach means that for example the mid tones might consider every set of 2 consecutive values the same instead of every 8. However since there are still only 2048 possible values the piper then gets paid in the shadows where 16 values might get lumped together in the down conversion. At the end of the day no matter how well they slice the 11 bits it still does limit the total tonality of the image and it means the files can't take as much processing as losslessly stored 14 bit files from the same sensor could.
p.147 #19 · Official: Sony A7 and A7R Fullframe Mirrorless
snapsy wrote:
hmmm...I just tried my A7r+FE55 and I can both hear and see the aperture moving for every 1/3 f/stop, including f/5 -> f/5.6.
It may have something to do with the amount of light available. With my NEX cameras, the cameras metered and focused at shooting aperture until you got into low light, where it switched over to focusing wide open.
p.147 #20 · Official: Sony A7 and A7R Fullframe Mirrorless
Toothwalker wrote:
I don't, but I clicked on the link and started playing with the drop-down list of lenses. The Distagon yields a distorted picture. It could be an incident, but this was only the second lens that I mounted. Should I just believe that all the other lenses are correctly rendered?
Looks like they just got the width and height of the image reversed. It should probably look like this: http://i.imgur.com/fTuC2Ii.jpg
(patience is a virtue I guess)