A57 v A77 Image quality

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bfitzgerald
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A57 v A77 Image quality

Unread postby bfitzgerald » Thu Jun 12, 2014 11:26 pm

I've done a few tests firstly high ISO, lighting is an energy saving bulb

Both cameras set to M mode, identical exposure times 1/50s ISO 3200, f4
A57 reports the EV is +0.3, A77 +0.7 for the same exposure (multi segment metering)

Raw files in LR 5... 0 on both NR sliders

A57 v A77.JPG
A57 v A77.JPG (129.15 KiB) Viewed 4796 times


A57 v A77 2.JPG
A57 v A77 2.JPG (108.91 KiB) Viewed 4796 times
Last edited by bfitzgerald on Thu Jun 12, 2014 11:33 pm, edited 2 times in total.

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bfitzgerald
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Thu Jun 12, 2014 11:32 pm

Same files with NR 25 on both colour and luminance NR (which is fairly normal setting for me) output both to 16mp (screen)

16mp jpeg.JPG
16mp jpeg.JPG (91.38 KiB) Viewed 4796 times


jpeg 16mp 2.JPG
jpeg 16mp 2.JPG (72.91 KiB) Viewed 4796 times


16mp jpeg 3.JPG
16mp jpeg 3.JPG (141.14 KiB) Viewed 4796 times

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bfitzgerald
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Thu Jun 12, 2014 11:54 pm

Output both to 6mp files which is likely a more realistic output for print size


6mp jpeg compare.JPG
6mp jpeg compare.JPG (102.72 KiB) Viewed 4796 times



I did a capture on the A77 jpeg and raw

jpeg raw.JPG
jpeg raw.JPG (102.2 KiB) Viewed 4796 times


I have not done an in depth jpeg v raw comparison..yet.

Conclusions so far, the A77 is def giving more real exposure than the A57 at high ISO settings with identical ISO and exposures. This could indicate the A57's ISO values are overstated more than the A77's. The A77 does have a bit more chroma noise esp shadows, but not as much as I thought it would If I match the actual picture brightness (ie ignoring the exposure and getting the same result picture wise or near to it) from the cameras there are 2 ways of looking at it

The A57 will have less noise chroma and luminance because it's had more exposure, or the A77 underexposes even more will certainly show more noise than these shots do. However once I take into account the different real exposure that's happening, I think the differences are not much. At sensible output levels there isn't a lot to pick hairs with.

I would say though, if you shot at ISO 3200 on the A77 and used the default metering (multi segment) you're asking for more trouble than you are on the A57. Both cameras do tend to give less exposure than I think is appropriate (even though the A77 is letting more light in). I have to test the metering more to spot any differences here, this is why I used the same exposures for this test.

Though I would add face detection does influence the exposure so real world people shots in lower light might not require as much or any significant exposure adjustment. The metering can react to areas or light and dark I have to investigate this more. In real world I'd add a bit more exposure to the A57 at high ISO, I would suggest adding a bit more on top for the A77

Jpeg v raw will look into this more. The shots are 100%, this isn't a high detail scene but the jpegs struggle more with coloured areas esp reds (from what I've seen so far) this shows on the shot above, the red blotching effect. There is more luminance noise than I'd like, but will test this on a finer detail subject.

I did try adding more chroma NR on the jpeg file in LR5, it did improve it a bit (though not entirely removing the problem)
Will do some more tests shortly

So far I would say the reason the A77 is regarded as a noise monster is likely more to do with the conservative metering (pulling up underexposed ISO 3200 in post can be done..a bit, but you can't go mad) Even if you don't pull the images up in post in many cases you are not giving enough exposure and simply making things worse noise wise (the noise pattern tightens up with better exposure, easier to clean up) Blow for blow any differences are not significant taking into account normal output sizes, though there isn't a lot of point having 24 or even 16mp files at this high ISO level. I might do a higher ISO test, I consider 3200 to be usually as high as I sometimes need to go, though both cameras are capable of ISO 6400 with reasonable printable results, subject to more careful processing and you can't screw up the exposures at that sensitivity

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bfitzgerald
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Fri Jun 13, 2014 4:25 pm

Ok resolution test both cameras at ISO 100, raw, 35mm f1.8 I picked a prime lens so nobody would complain about resolution. It does have cheapo build, but optically it is capable and sharp no question.

The test shot is a normal scene outside

DSC00003.jpg
DSC00003.jpg (230.46 KiB) Viewed 4763 times


Both images are exported from raw to 24mp. I've not layered any extra sharpening bar the conservative LR defaults

Looking at 1:1 (100%)

Capture 100%.JPG
Capture 100%.JPG (122.35 KiB) Viewed 4763 times


Let's peep some more to just really dig deep into this 200%

200%.JPG
200%.JPG (104.84 KiB) Viewed 4763 times

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Re: A57 v A77 Image quality

Unread postby ValeryD » Fri Jun 13, 2014 4:28 pm

bfitzgerald wrote:.....
I did a capture on the A77 jpeg and raw

Conclusions so far, the A77 is def giving more real exposure than the A57 at high ISO settings with identical ISO and exposures.
....

It's very good test, but it's A77V (old, first version of a77) It would be great to make same test with new a77-II and we can see a big different with a new 24mp and the old 24mp matrix in Sony a77 and Sony a77-II. Or compare old a77 with new a77-II.
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bfitzgerald
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Fri Jun 13, 2014 4:40 pm

Not content with 200% views I went even further into this

300%


Capture 300%.JPG
Capture 300%.JPG (101.4 KiB) Viewed 4767 times


The next is the kind of extreme pixel peeping even a die hard pixel peeper would find a bit over the top 800% and 8:1

800%.JPG
800%.JPG (87.06 KiB) Viewed 4767 times



Conclusion..even with an optically good prime lens, the difference between 16 and 24mp is virtually none. I can see very slightly better definition in the tree base/stump crop..a bit in favour of the A77. That kind of peeping would be equivalent to barn sized prints..and on that I doubt anyone would notice the difference.

I don't doubt if someone pulled a MF 50mp+ body out of the bag they would resolve more details. I'd also expect a full frame 24mp to be a little improved v the APS-C bodies (due to the larger sensor) My thoughts are as they were before, marketing more than substance. You can print big with 16mp subject to good processing and exposure and decent optics you can make superb exhibition sizes prints, 24mp offers little real advantage in terms of real world results.

I'll pull the Dynax 5d out just to see how much better the newer higher resolution sensors are. There will of course be a difference..but once you get to a certain point (on the sensor size) you are adding very little overall. Same from full frame pixel lovers asking for 100mp images, there comes a point where you're just wasting storage space

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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Fri Jun 13, 2014 4:42 pm

ValeryD wrote:
bfitzgerald wrote:.....
I did a capture on the A77 jpeg and raw

Conclusions so far, the A77 is def giving more real exposure than the A57 at high ISO settings with identical ISO and exposures.
....

It's very good test, but it's A77V (old, first version of a77) It would be great to make same test with new a77-II and we can see a big different with a new 24mp and the old 24mp matrix in Sony a77 and Sony a77-II. Or compare old a77 with new a77-II.



You won't be able to tell unless you can see what's happening with the same exposures and seeing what happens real world. I don't doubt the A77II is improved, though having had a quick look at some raw files (in IDC with NR to 0), it is a very minor improvement and probably not relevant or visible or significant in any way. But I have no idea how the camera meters, if it is much more aggressive with exposure in low light you will see users being happier.

I will wait to see what the results are in ACR though as I use that mostly. The results from the newer jpeg engine seem to show simply more noise reduction being applied.

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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Fri Jun 13, 2014 10:22 pm

Just for fun I tested the 5d v the A77 at 16mp
This is slightly cruel to the 5d as 6mp images won't scale up to 16mp very well (they work ok though for 10mp)

5d 16mp.JPG
5d 16mp.JPG (83.79 KiB) Viewed 4754 times


5d 16mp 1.JPG
5d 16mp 1.JPG (111.31 KiB) Viewed 4754 times


Clearly there is a notable difference in fine details, though bear in mind this is an extreme enlargement aka a massive poster print with your nose inches away.
I have printed the 5d a lot and it's capable of making decent enlargements even at A3 if done with care (and with normal viewing distances)

I will try to test a few more lenses, but so far I think once you get to a certain point on a sensor pixels wise..adding more has less and less effect depending on how many you have to start with. I'll do a few more lenses to test just to make sure but I'd be surprised if there is a significant difference in details looks so far like 24mp is more to do with marketing than real world results.

Which is basically what I was saying all along.

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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Sat Jun 14, 2014 11:23 pm

Carrying on with my testing I tried the 50mm f1.7 on both bodies
Again same aperture and target

Both exported to 24mp

200%

Capture.JPG
Capture.JPG (78.86 KiB) Viewed 4736 times


And 300%

300%.JPG
300%.JPG (74.03 KiB) Viewed 4736 times


At 100% it's near impossible to tell any difference, I can see some slight improvement on the crazy insane 200/300% crops
Maybe £1000+ lenses can show more, my experience of both of those primes is they are very capable stopped down. I may try the 90mm macro which is also capable, but so far the minor difference in details is not worth losing sleep over.

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Re: A57 v A77 Image quality

Unread postby classiccameras » Sun Jun 15, 2014 9:55 am

Nikon certainly use pixels as a selling point as do Sony now, Canon not so much as they have this attitude if it aint broke don't fix it which is why they have stayed with 18mp for so long. Barry your excellent tests show just how much or how little extra pixels have done to IQ. In the real world, theres not much between the two. Is it several hundred pounds better? Hmm. Cameras are reaching the stage of diminishing returns.

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Re: A57 v A77 Image quality

Unread postby Birma » Sun Jun 15, 2014 9:41 pm

All else being equal, what else do you use to differentiate? There are many 'serious' photographers who have switched to 36 megapixels., or are hoping to get it. Perhaps not something everybody actually needs, but then some of us rarely move off 100 iso and look how many reviews obsess over 400k+ iso. It is a bit like cars really. Any new car can get you very reliably from A to B whether a budget Kia or an Italian super-car. Cameras now are all very capable. I suppose there is always a certain delight in trying to get the best bang for your buck though :)
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Mon Jun 16, 2014 1:32 am

I was just curious to see what differences there are in resolution (and high ISO)..so far not a lot, but I will try a few more lenses over time.
Serious is more to do with mind set than pixels. I'm sure there are some valid reasons to look at 36mp if you need it, most don't.

No doubt a FF 36mp camera will show more details, bigger sensor. I think the point is once you get to a certain level resolution wise, adding more has less and less effect. 6mp to 16mp pretty big jump..16 to 24mp you already have quite a lot of resolution to start with. If they ever shove more than 24mp on APS-C I'd be amazed if you can ever see the difference. But like I said I will try other lenses, those 2 are pretty sharp though

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Re: A57 v A77 Image quality

Unread postby classiccameras » Mon Jun 16, 2014 11:46 am

Thats about right Barry, over populated sensors has been the biggest challenge to the manufacturers, tightly packed sensors [too many in my book] with the added noise problems, they seem to have cracked this, but I think Fuji's sensor design is a fresh approach and is proving very sucessful.
I think my 57 is staying with me.

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Re: A57 v A77 Image quality

Unread postby mikeriach » Mon Jun 16, 2014 12:57 pm

Barry, I think you have demonstrated that the law of deminishing returns does indeed apply to digital cameras as well.
I have to say that I wouldn't rush to buy a camera with more pixels just because of the count as I'm quite happy with my current bodies.
Perhaps some of my glass might begin to show weaknesses with ever increasing MP.

For me any upgrades will be due to:
- a dead or dying body
- significantly improved IQ/noise
- significantly improved focusing (accuracy and speed)
- significantly improved handling
- significantly improved battery life

A friend of mine who shoots with a pair of Nikon D80s decided that things had moved on sufficiently for him to consider an upgrade so went to the local shop to look at D5000/7000 series bodies. He emailed me last night to say he'd bought a D800 with grip and new 80-400 (£4200). I nearly fell off the chair! That must have been one hell of a salesman. I think he'll see the difference.

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bfitzgerald
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Re: A57 v A77 Image quality

Unread postby bfitzgerald » Mon Jun 16, 2014 2:09 pm

Well Mike there are other reasons I agree, you get better build, AF assist, GPS, more options and customisation, higher flash sync, AF tuning. sealing. Some of those are handy, some less so. I was actually more interested in the GPS when I wander out in remote locations it is handy to not have to take notes, I'm a bit puzzled why they took that out the MkII, that's a turn off, wifi is only handy for remote control and I rarely do that.

IQ wise you gain very little going from the A57 to the A77, the DR might be slightly better (hard to see it though) some differences in real exposure and metering really if you want more image quality then off you go to full frame if you are willing to pay the premium for it. Personally I have no worldly need for 36mp not even near it for what I do it would be entirely wasted.

I'm sure some think they need more pixels, but I put that down to marketing powers more than field use. Still the A77 is good nicely made and responsive and a good deal right now. A65 is don't bother..for £100 less there is no point at all. I still feel the A57 has a lot to offer, larger buffer, most of what you would need and you can still bag one for a good price on ebay.

For 90% of folks there is no need to upgrade over that model, unless you need the handling/extra bits.
No doubt 12mp to 36mp would show a difference..still think though that the entire pixel thing is hugely overblown


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