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02-18-2015, 11:54 AM   #136
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QuoteOriginally posted by philbaum Quote
... Sony managed to preserve useful signal to noise levels into very high ISO territory.
Look at the graph again. Notice for both the A7S and the D810 anything much above ISO 6400 is capturing crap for dynamic range (that's why the scale is 'red' on the side). And you need to subtract 2 to 3 stops from that chart to get actual usable DR. So heck with the noise when the resulting tonal scale sucks to beat all hell at the higher ISOs.

02-18-2015, 12:44 PM   #137
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QuoteOriginally posted by Rondec Quote

People for whatever tend to focus on the extremes and yes, at iso 6400 a full frame camera is better. ... I just don't know many people who do those things a whole lot.
I do the majority of my indoor shooting at auto-iso, up to 6400 or one stop higher and I have a ton of shots hitting ISO 6400. Nice, clean shots

If you never are shutter-speed constrained in low light, if you don;t care about more DOF control or DR in lower light, there may not be as much point to a FF camera.

In my experience, the reason why people buy DSLRs in the first place is because of that stuff, though.


QuoteQuote:
Griping about not seeing a difference between photos at web resolution is the point. That's what most people are doing with their photos -- printing them at 8 by 10 and smaller and posting at 2000 pixels and smaller on the web. So, no, most of them won't see a difference.
But Norm's quiz examples are all much smaller than even that!

.

---------- Post added 02-18-15 at 01:53 PM ----------

QuoteOriginally posted by philbaum Quote
Thanks for the reference link by the way. Jay, given that this is the way the market tends to be moving, i.e. more pixels, do you have any comments about how the design of the A7s sensor relates to this discussion. Not trying to argue the point about more pixels at all, but somehow Sony managed to preserve useful dynamic range into very high ISO territory. I don't even care about discussions of why someone would want a camera like this - just trying to understand how this eccentric design managed to achieve a different, but useful result. (Or anyone else who has some useful comments about this design feature) (Not trying to pitch Sony here, but this sensor to me is one of the most interesting things that came out of 2014) Graph is courtesy of DXOmark of course.

[/url][/IMG]
What I've seen written about the A7s suggested that this was Sony's pixel tech they wanted to preserve for themselves for a while, and that the methodologies would work their way into other higher-MP sensors in the near future. Similar to the path we took from D700 -> D800 or D3 -> D4. A7s represented the sweet spot they could currently reach economically while allowing them an upgrade carrot for the next iteration: same SNR/DR through the ISO range, but with more MP.
02-18-2015, 01:20 PM   #138
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QuoteOriginally posted by jsherman999 Quote
I do the majority of my indoor shooting at auto-iso, up to 6400 or one stop higher and I have a ton of shots hitting ISO 6400. Nice, clean shots

If you never are shutter-speed constrained in low light, if you don;t care about more DOF control or DR in lower light, there may not be as much point to a FF camera.

In my experience, the reason why people buy DSLRs in the first place is because of that stuff, though.




But Norm's quiz examples are all much smaller than even that!

.

---------- Post added 02-18-15 at 01:53 PM ----------



What I've seen written about the A7s suggested that this was Sony's pixel tech they wanted to preserve for themselves for a while, and that the methodologies would work their way into other higher-MP sensors in the near future. Similar to the path we took from D700 -> D800 or D3 -> D4. A7s represented the sweet spot they could currently reach economically while allowing them an upgrade carrot for the next iteration: same SNR/DR through the ISO range, but with more MP.
I would argue that learning flash is a better way to get clean results in low light settings, than buying a full frame camera. It isn't to say that you can't have good results at iso 6400, but my results at iso 800 with a touch of bounced flash will be better with APS-C. The biggest problem to me is not that noise is high in these images -- you can usually fix that -- it is that dynamic range drops significantly. This will be fine in black and white photos, but maybe not so good with color.

Iso 800 with bounced flash.

02-18-2015, 01:33 PM - 2 Likes   #139
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QuoteOriginally posted by Rondec Quote
I would argue that learning flash is a better way to get clean results in low light settings...r
Yep. I just don't like how flash disrupts the scene, changes the activity, sometimes halts it. I want my shooting to be as unobtrusive as possible. Plus if flash is overdone even a little it (IMO) ruins the scene more than any noise does. Some people do it well and it looks great, I'm just not a fan of flash personally.

02-18-2015, 01:38 PM   #140
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QuoteOriginally posted by Rondec Quote
This will be fine in black and white photos..
No, not even for color converted to a gray scale images. If anything, BW is all about tonal scale too except for those that want to imitate that small format film pushing and crushed tonal scale look. And somehow me thinks most people who finally get their FF Pentax DSLR will be shooting that way more than their APS-C. Here, everyone argues over the two saying their is not much difference. But soon as you have one and get use to editing those files, you'll notice more.
02-18-2015, 02:16 PM   #141
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QuoteOriginally posted by tuco Quote
No, not even for color converted to a gray scale images. If anything, BW is all about tonal scale too except for those that want to imitate that small format film pushing and crushed tonal scale look. And somehow me thinks most people who finally get their FF Pentax DSLR will be shooting that way more than their APS-C. Here, everyone argues over the two saying their is not much difference. But soon as you have one and get use to editing those files, you'll notice more.
Oh, I plan to get a full frame camera. I just think there is more than one way to skin a cat. Folks getting poor results with APS-C will continue to get poor results with full frame. Those who are getting great results with APS-C, but are pushing the edge of what it will do, will do better with full frame.
02-18-2015, 04:15 PM - 1 Like   #142
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QuoteOriginally posted by philbaum Quote
Thanks for the reference link by the way. Jay, given that this is the way the market tends to be moving, i.e. more pixels, do you have any comments about how the design of the A7s sensor relates to this discussion. Not trying to argue the point about more pixels at all, but somehow Sony managed to preserve useful dynamic range into very high ISO territory. I don't even care about discussions of why someone would want a camera like this - just trying to understand how this eccentric design managed to achieve a different, but useful result. (Or anyone else who has some useful comments about this design feature) (Not trying to pitch Sony here, but this sensor to me is one of the most interesting things that came out of 2014) Graph is courtesy of DXOmark of course.

[/url][/IMG]

From the work done by Jack Hogan, JimKasson and Bobn2 the A7”s uses a switchable conversion gain that we first seen in Aptina sensors and marketed as DRPix. At around iso1600 we can see the a7’s does something abnormal to previous sony sensors.

“Conversion gain is pretty much the reciprocal of the capacitance of the parts which connect the collected to the read transistor gate. What it controls is the 'gain' from e- to output voltage (since Q = CV). This controls both input referred read noise (assuming that read noise is a voltage noise, it will be translated to photoelecrons by the capacitance - i.e 1/CG.). It also controls the FWC, sine in a CMOS design it is the swing of the output transistor that is the limit. Thus small capacitance gives low read noise and low FWC. High capacitance gives high read noise and high FWC. The switchable conversion gain technique (patented by Aptina and branded DRPix) has a capacitor in the pixel which can be switched in at low ISOs and switched out at high ISOs.'

So what it looks like they are able to do with the A7’s below iso 1600 is to implement a High capacitance which gives a higher read noise but with a larger FWC, Above 1600 they switch to a smaller capacitance which inturn gives a lower read noise but also with a lower FWC.

There was a good paper on how Aptina was to implement this and the original article I sniped this from but I cannot find it at this time.
02-18-2015, 06:09 PM   #143
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QuoteOriginally posted by Rondec Quote
I would argue that learning flash is a better way to get clean results in low light settings, than buying a full frame camera. It isn't to say that you can't have good results at iso 6400, but my results at iso 800 with a touch of bounced flash will be better with APS-C. The biggest problem to me is not that noise is high in these images -- you can usually fix that -- it is that dynamic range drops significantly. This will be fine in black and white photos, but maybe not so good with color.

Iso 800 with bounced flash.

I actually enjoy opportunities to use flash, in my case manual flash with radio triggers. But it doesn't work for some applications where flash range is not sufficient or for indoor events where flash is forbidden, such as my playhouse rehearsals. I've read of folks using the A7S for astrophotography for color shots of our galaxy where long exposure times cause too much distortion due to movement of our planet. So there is no one solution but your point is valid.

02-18-2015, 07:57 PM   #144
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QuoteOriginally posted by Rondec Quote
I would argue that learning flash is a better way to get clean results in low light settings, than buying a full frame camera. It isn't to say that you can't have good results at iso 6400, but my results at iso 800 with a touch of bounced flash will be better with APS-C. The biggest problem to me is not that noise is high in these images -- you can usually fix that -- it is that dynamic range drops significantly. This will be fine in black and white photos, but maybe not so good with color.

Iso 800 with bounced flash.


Hey - Great photo BTW!
02-18-2015, 10:11 PM   #145
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QuoteOriginally posted by Rondec Quote
I would argue that learning flash is a better way to get clean results in low light settings, than buying a full frame camera.

I think your pic shows that it's useful to have that technique, Rondec, whatever the format!

This is my delightful sister-in-law, a spontaneous shot with a Stofen diffuser:



Last edited by clackers; 02-18-2015 at 10:18 PM.
02-18-2015, 10:47 PM   #146
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QuoteOriginally posted by Rondec Quote
I would argue that learning flash is a better way to get clean results in low light settings, than buying a full frame camera. It isn't to say that you can't have good results at iso 6400, but my results at iso 800 with a touch of bounced flash will be better with APS-C. The biggest problem to me is not that noise is high in these images -- you can usually fix that -- it is that dynamic range drops significantly. This will be fine in black and white photos, but maybe not so good with color.

Iso 800 with bounced flash.

I am in agreement with you on flash photos; actually if it is done correctly, flash light often brings on the natural color of the subject's dress better than just from the indoor artificial light.
02-19-2015, 06:33 AM   #147
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I'm with Rondec about the flash.

So many times we look at a photo and say, "boy this camera does not do well at ISO 1600." However, the shot with the lighting at hand is probably not really exposed well, and the raw processor has compensated, pulling up shadows or lightening up the entire photo.

Last Christmas, I mistakenly left my K3 on a higher ISO (2000) while taking a set of photos with a Graslon diffuser on a Metz AF64. Unless you drilled down into the 24mp to get 100% or more viewing, you would not know it was taken at higher ISO. Noise is not noticeable. (The background is PP) If you nail the exposure (more likely with flash), you get a lot more out of any size sensor.
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02-19-2015, 07:53 AM   #148
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Here is the child's eye at 100%. It is not perfect sharpness as the child was turning as I took the shot, but IMO pretty darn good for ISO 2000. It looks very nice in an 11x14ish print.

A well exposed shot with controlled lighting does wonders for the perception of noise.

A flash does add a distraction, but so does a honking big lens. This shot was taken with the DA*50-135, which is not small. However to duplicate its range in FOV the new FF zoom is half again as long bigger in diameter and more than twice as heavy.

Like Rondec, I am sure I will get a FF body at some point, but the times when it really makes a difference for my needs may be rare.
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02-19-2015, 08:21 AM   #149
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So are you guys saying use difused fill flash indoors and outdoors to keep ISO down, sort of?


I still don't have a flash.


Thanks.


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02-19-2015, 08:22 AM   #150
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This is another shot at iso 800 (of my long suffering daughter) with mixed flash and window light. The reality is that most cameras do well in settings where the light is decent. If you have decent light, you can easily shoot iso 6400 on a APS-C camera without bad results.



I understand that "available light" photography is important in certain settings. You can't use flash when shooting most sports and I'm sure there are other venues where it just isn't allowed, but the end result isn't going to be great. I've seen plenty of ESPN/SI photos where the noise was pretty bad, but it didn't distract from the image, because it was what was in the image that was important, not the noise.
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