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Equivalence: Math or Myth?

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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 21 February 2018 at 09:48
Originally posted by Photosopher Photosopher wrote:

Big difference I learned from the a900 to expose for shadows and a99 expose for highlights. They handle the extremes differently. When a900 is kept at low iso, the highlight range is splayed out differently enough that it doesn't clip the same as higher iso.

I have no technical knowledge as to why. It's just something I've noticed repeatedly, and shot for with a900 over the years. There used to be some chatter on this forum years ago about the differences of a900 tonal range at lower iso's. Maybe it was a dream I had.

Don't think you're dreaming! I've not used as many DSLRs as many of you guys have, but I certainly do notice the difference between the A58 and A900. As you say, you can expose for shadows (or at least non-highlight areas) with the A900 and get some chance of the highlights not saturating, but that doesn't work on the much-more recent A58, where I need to take some action. Maybe different guys worked on the electornics and software and/or had different direction.

Though interestingly, according to DXOmark the A58 and A900 have the same DR and nearly the same sensitivity as the A900, as despite its much smaller pixel area the A58 has much lower noise and a higher QE.
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
 



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Jonas A-R View Drop Down
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Post Options Post Options   Quote Jonas A-R Quote  Post ReplyReply Direct Link To This Post Posted: 21 February 2018 at 17:41
Originally posted by Miranda F Miranda F wrote:

Originally posted by Jonas A-R Jonas A-R wrote:

Whether you saturate your sensor or not depends entirely on the metering and exposure relative to saturation capacity of the sensor. There is nothing preventing you from a metering strategy preventing saturation on the a58

True, and I do that. But it takes more effort


And it has nothing to do with the size of the sensor. Just to get that clear.
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 22 February 2018 at 10:57
Originally posted by Jonas A-R Jonas A-R wrote:

Originally posted by Miranda F Miranda F wrote:

Originally posted by Jonas A-R Jonas A-R wrote:

Whether you saturate your sensor or not depends entirely on the metering and exposure relative to saturation capacity of the sensor. There is nothing preventing you from a metering strategy preventing saturation on the a58

True, and I do that. But it takes more effort


And it has nothing to do with the size of the sensor. Just to get that clear.


Agreed. It is presumably the result of decisions made about the electronics and firmware that process the output of the sensor.
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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sybersitizen View Drop Down
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 12 March 2018 at 20:20
I want to share the results of another quick equivalence experiment that I just conducted. This one involves the A55 + Sony 18-55 II against the Sony DSC-RX100III with its much smaller sensor but much faster lens. (I figure the brief deviation away from strictly interchangeable lens systems will be accepted in the name of science.)

The cameras were set thusly using the maximum apertures of the lenses ...

Shortest setting:
A55:       1/30s, ISO 400, f/3.5, 18mm (27mm FF equivalent)
RX100III: 1/30s, ISO 100, f/1.8, 9mm (24mm FF equivalent)

Longest setting:
A55:       1/30s, ISO 400, f/5.6, 55mm (82mm FF equivalent)
RX100III: 1/30s, ISO 125, f/2.8, 26mm (70mm FF equivalent)

A few things have to be acknowledged. First, these cameras and their sensors are not of the same generation. Second, I found it a little challenging to figure out the exact ISO settings required to produce equivalent exposures, so there was a deviation of 1/3 stop (100 vs. 125) in there. Third, my real goal here was not to confirm equivalence theory, but to confirm that this compact camera can produce images equivalent to (and maybe even better than) the A55 and kit lens. The A55 has served well as my primary travel camera since 2010 ... but I'm now interested in alternatives much smaller than that.

Here are the RAW files:

http://thesybersite.com/public/DSC00026.ARW RX100III short
http://thesybersite.com/public/DSC00027.ARW RX100III long
http://thesybersite.com/public/DSC02686.ARW A55 short
http://thesybersite.com/public/DSC02687.ARW A55 long

The exposures were chosen to accommodate the outdoor highlights while letting the interior stuff go dark. The idea is to raise those shadows in PP and compare the overall results.

For anyone who wants to check it out, it's interesting to note that although the zoom range of the RX100III is wider than that of the A55 + kit lens (24-70 vs. 27-82 FF equivalents), the higher resolution of the RX100III means that its images can be cropped to 16mp and almost exactly match the FOV and resolution of the A55.

Another interesting thing is the very strong barrel distortion produced by the RX100III at the wide end. This is of course fully correctable with RAW converters that recognize the camera, such as those from DxO and Phase One. It's also automatically corrected with in-camera JPEGs. And speaking of JPEGs, the JPEG engine in the RX100III is better than the A55's and allows high ISO NR to be completely turned off if desired.

Again, sorry for the diversion into compact camera territory ... but I wanted to show that in a very practical sense, understanding equivalence has been of assistance to me in making some buying decisions.

Edited by sybersitizen - 12 March 2018 at 20:45
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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 12 March 2018 at 20:37
Thanks, Ray!

These premium compact cameras certainly perform well. How do you find the handling?
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 12 March 2018 at 20:49
Originally posted by QuietOC QuietOC wrote:

These premium compact cameras certainly perform well. How do you find the handling?

For now I'll give the same reply I gave Photosopher in the future of A-mount thread, where I mentioned I also have the Sony HX90V ...

They're tiny! I come close to dropping them every time I use them because there's so little to hang onto. On the other hand, the tininess is greatly appreciated when I'm not actually shooting. The user interface is ... well, it's Sony ... so I'm accustomed to it.

The HX90V has the smaller sensor and the 720mm equivalent zoom range and GPS (with not just coordinates embedded in the image files, but also continuous tracking saved to a text file), so it's best for outdoors. The RX100III has the larger sensor and bounceable flash and faster lens (with much shorter zoom range), so it's best for indoors and low light.
 



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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2018 at 14:22
I found the smaller Sony pocket cameras so tiny they feel like toys. I prefer the Canon range (eg S100) for that reason - they feel better made and nicer to handle. But I agree that smaller cameras can do a good job most of the time. A lot does depend on the processing inside, not just the lens.

But it shows that it is possible to get good lens IQ in a small package for a small sensor. As QuietOC said in another thread, we're paying a heavy price for the 135 film fixation in DSLRs. And the prpoblem with equivalence is, that it does assume the possible lenses are actually available ...

I'd like to see some decent long fast primes and zooms made specifically for APS-C and at a sensible price. In A-mount there isn't an APS-C-only AF lens longer than xx-300mm in zoom or (unbeleivably!) 60mm in prime. How mad is that?

And even if you allow FF lenses, so long as they're small, lightweight, reasonably but cheap, you're limited to 90-100mm f2.8.

If that doesn't change, maybe more of us will be choosing non-interchangeable-lens cameras with fixed wide zooms in them.

Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2018 at 15:02
Originally posted by Miranda F Miranda F wrote:

In A-mount there isn't an APS-C-only AF lens longer than xx-300mm in zoom or (unbeleivably!) 60mm in prime. How mad is that?

It is better than E-mount where the longest APS-C lens is a 55-210 F4.5-6.3 zoom.

There is a fairly small 100-400 F4-6.3 for Micro Four-Thirds. Fuji has a 100-400 F4.5-5.6 that is no smaller than the 70-400G or FE 100-400 GM. I'd just look for a Minolta AF 100-400 F4.5-6.7 APO.

We are lucky that the Tamron 150-600 F5-6.3 G2 is available in A-mount.

Edited by QuietOC - 13 March 2018 at 15:07
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
A6000 LA-EA1 6.5 16 20 30 50 60 16-50 18-55 55-210
600si: 20 24 28 50 100M 135 24-85 24-105 28-105 35-70 35-105 70-210 75-300 100-200
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sybersitizen View Drop Down
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2018 at 16:31
Originally posted by Miranda F Miranda F wrote:

I found the smaller Sony pocket cameras so tiny they feel like toys. I prefer the Canon range (eg S100) for that reason - they feel better made and nicer to handle.

I don't know what Sonys you're talking about, but this is the one I'm talking about:



The companion HX90V has most of the same dimensions as the RX100III, but is a few millimeters thinner front-to-back. It's still a bit deeper than the Canon.

Sony certainly makes smaller cameras, but all the capabilities of these cameras could not be contained in one of them.

Better made? I can't imagine that Canon being better made than these two Sonys.

Edited by sybersitizen - 13 March 2018 at 17:15
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2018 at 15:14
Originally posted by sybersitizen sybersitizen wrote:


Sony certainly makes smaller cameras, but all the capabilities of these cameras could not be contained in one of them.

Better made? I can't imagine that Canon being better made than these two Sonys.


Okay, thanks for the size comparison. Maybe I was wrong about that. I was also thinking about the other Canon compact I have that is larger and metal-bodied.

Re build, I think the build of the RX100 range is cheap, masty, and toylike and - quite frankly - absolute rubbish. I wouldn't pay a tiny fraction of the list price for them, as they belong in a toyshop IMHO. I feel like the flash or EVF would break or fall off if I didn't treat it extremely gently. Small things don't have to be built that way.

I'm not in general a Canon lover, but not just Canon but almost any make other than Sony makes compact cameras that feel solid and good to hold and to operate. have you been into a camera shop and picked up a Panasonic or Fuji? They feel solid.
Sorry - I like a lot of Sony stuff - but in miniature cameras they have cheapened the build too much for the price of the clever stuff inside, and if I'm buying a fixed-lens camera I can see no reason for brand loyalty. Okay, except the menu structure being familiar, provided you actually like it!

Edited by Miranda F - 14 March 2018 at 15:17
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2018 at 16:42
Originally posted by Miranda F Miranda F wrote:

Re build, I think the build of the RX100 range is cheap, masty, and toylike and - quite frankly - absolute rubbish. I wouldn't pay a tiny fraction of the list price for them, as they belong in a toyshop IMHO.

I'm guessing you're in a minority of one. The RX100 series is a wild success and well respected. (But I didn't pay the list price - got a mint condition used one, as is my habit.)
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2018 at 19:16
I checked out the RX10IV at Best Buy and didn't like it--mainly the ergonomics and operation.

I'd be inclined to go with Panasonic or Canon for this class of cameras. You still get a Sony sensor.
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
A6000 LA-EA1 6.5 16 20 30 50 60 16-50 18-55 55-210
600si: 20 24 28 50 100M 135 24-85 24-105 28-105 35-70 35-105 70-210 75-300 100-200
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2018 at 20:38
Originally posted by QuietOC QuietOC wrote:

I checked out the RX10IV at Best Buy and didn't like it--mainly the ergonomics and operation.

I'd be inclined to go with Panasonic or Canon for this class of cameras. You still get a Sony sensor.

I don't know if you really meant the RX10IV or RX100IV; they're completely different cameras, only sharing a sensor size. In either case, that's rather different from saying 'I think the build of the RX100 range is cheap, masty, and toylike and - quite frankly - absolute rubbish.'

The RX100III does precisely what I wanted it to do, and I expect it to continue doing what I want it to do when I'm on vacation overseas with it.

Myopic focus on one or two aspects of a camera is not my style, and no camera is perfect. There are significant differences in specific features among all the compact brands and models, and those matter to me as much as any other factors mentioned. There are also side benefits of staying with Sony cameras, like already being familiar with the interface and being able to use the free Capture One converter.

PS: Since this thread is supposed to be about the practical value of understanding equivalence, maybe those who want to debate pros and cons of various compact cameras can do so in The Seinfeld Thread, where such things belong.

Edited by sybersitizen - 15 March 2018 at 01:23
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 15 March 2018 at 13:51
Originally posted by sybersitizen sybersitizen wrote:

Originally posted by Miranda F Miranda F wrote:

Re build, I think the build of the RX100 range is cheap, masty, and toylike and - quite frankly - absolute rubbish. I wouldn't pay a tiny fraction of the list price for them, as they belong in a toyshop IMHO.

I'm guessing you're in a minority of one.


It wouldn't be the first time!
Miranda F & Sensorex, Sony A58, 5d, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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