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A7s!

horshack

New member
Maybe you could please show me / us with real world example how shot of scene whose DR was not fitting one of sensor would end up better DR wise from downsized A7R file than shot of same scene taken with A7S without any downsizing?
Here is a comparison of the D800 vs Df (and 6D) at ISO 100, 5 shots underexposed and pushed 5 stops in post, all downsampled to the same output size of 8MP. Since the DR of all 3 cameras exceeds the normal 7-8 stops rendered in a JPEG this is the only method to demonstrate base ISO DR. The Df is a proxy for the A7s since their base ISO DxoMark scores are very close, and of course the D800 for the A7r since they share the sensor. D800 on left, Df in the middle, 6D on the right.

 

horshack

New member
Thanks for the explanations re mpix & DR & ... .

In looking at some recent cameras, the differences that seem to run counter to the more_pixels/area = higher_DR should be seen as evidence of some associated processing going on?

I.p., taking the 16mpx Pentax K5 II as a base, w/16mpx,
we can increase to 24 mpx per APS-C size with Sony A6000,
or retain the 16mpx and increase density/reduce size per ...
with the Olympus E-M5 (Sony sensor) or Panasonic GX7.
YET, K5-a6000-EM5-GX7 DxO DR values are, resp.: 14.1, 13.1, 12.3, 12.2.
?

-d.
You have to compare the same technology sensor in order to compare different pixel densities, which these all aren't. Absent identical technology implemented in varying densities the fallback is to compare the very best high density sensor (D800) to the very best low density sensor (A7s/Df) and in that comparison the pixel metrics I described with respect to both Low and High ISO hold true.
 

ZoranC

New member
Here is a comparison of the D800 vs Df (and 6D) at ISO 100, 5 shots underexposed and pushed 5 stops in post, all downsampled to the same output size of 8MP.
Thank you but I don't believe that is what I was asking for, especially not to compare _both_ being downsampled.
 

ZoranC

New member
Here are the raws if you'd like to perform your own comparison at a different resolution. The following link is only good for 5 days:

D800 and Df ISO 100 -5EV Raws
Thank you for the link but those files are still not illustrating what I was talking about. Was DR of scene you took within DR of a sensor to start with? Could you have taken that shot without underexposing while still fitting DR of a scene within DR of a sensor?
 

horshack

New member
Thank you for the link but those files are still not illustrating what I was talking about. Was DR of scene you took within DR of a sensor to start with? Could you have taken that shot without underexposing while still fitting DR of a scene within DR of a sensor?
It's pretty close; based on the histogram there are deep shadows and the highlights are relatively close to clipping. Btw I offered you the raws as a courtesy; I'm guessing from our previous discussions that you're still not ready to embrace the pixel-level explanations regarding DR I presented earlier. I think your remaining sticking point is the fact that a larger pixel has a larger saturation capacity, so yes it can hold more light (highlights) vs a smaller pixel. But again, the total light capture of the smaller pixels will be equal to the single larger pixel, so the total saturation on a per-area basis remains the same. An analogy is a bedroom with one large window vs one with 4 small windows, but where the total surface area of the windows in both rooms is the same. In that scenario the same amount of light will enter each rooom.
 

ZoranC

New member
It's pretty close; based on the histogram there are deep shadows and the highlights are relatively close to clipping.
Pretty close to clipping is not same as "clipped period". Previous one is "I am pretty close to losing data but I haven't lost any" while later one is "I lost data, period". Huge and crucial difference between the two.

An analogy is a bedroom with one large window vs one with 4 small windows, but where the total surface area of the windows in both rooms is the same. In that scenario the same amount of light will enter each rooom.
This discussion is not about how much light is trying to enter room, it is how much of it can be absorbed. Here is a different, maybe better, analogy: Water is pouring into one large bucket with enough volume that is making that bucket overflow. Placing three smaller buckets with same total capacity instead will not make any difference in how much water can be poured in before water starts getting spilled on a floor, they too will overflow at exactly same total volume amount as that single larger bucket.
 

horshack

New member
Pretty close to clipping is not same as "clipped period". Previous one is "I am pretty close to losing data but I haven't lost any" while later one is "I lost data, period". Huge and crucial difference between the two.
That's true - I checked my image db and don't have a comparison with both at highlight saturation.

This discussion is not about how much light is trying to enter room, it is how much of it can be absorbed. Here is a different, maybe better, analogy: Water is pouring into one large bucket with enough volume that is making that bucket overflow. Placing three smaller buckets with same total capacity instead will not make any difference in how much water can be poured in before water starts getting spilled on a floor, they too will overflow at exactly same total volume amount as that single larger bucket.
That analogy works too, with the same result.
 

philip_pj

New member
Zoran, I am thinking you are a delightful cynic, lol.

Watching the Camera Store video, Chris seems pretty clearly to suggest video shooters are going to be much happier than still shooters, but he has a leaning towards video it appears. Not surprised he gets 'blurry shots' with the a7/a7r the way he manically waves the camera around like a prop - which I guess it is.

TBH, Sony's problem with the a7s for stills shooters is that the a7 and even more so the a7r (relative to res) are so competent already - in ALL light. He used a slow zoom, presumably FE 24-70, and took a lot of images *2-3 stops higher* EVs than I often do with the a7r:

I max out at 6400/f2/1/60s in general for highly acceptable but obviously compromised quality, well handled with RAW post work...but if we say you get say, 2 stops more EV for same quality..it's either more DOF or a more 'secure' s/speed.

Not much gets past those settings of mine, that is candle light or soft light shafts from far above skylights at best, and I seldom need longer FLs than 35-55mm which helps with h/holding. I always use wide-ish apertures in low light to take advantage of the preferred bokeh of my lenses (bought in part for just this characteristic) and to take out of play unwanted shadow details - I get images I prefer that way. Just thinking aloud here how I see it. At the moment anyway; all this stuff is a moveable feast, obviously.
 

viablex1

Active member
I am never on Facebook, have a account but I hate it so I am never on it. My kids on the other hand I would love it if they stayed far away from it. Seriously I think it is a very dangerous place in many ways. My privacy is mine not the freaking worlds. I really try and keep my wife and myself far away from it and the gossip. My wife has had big health issues and that is something we keep far away from Facebook.
seconded I closed my account over a year ago and dont miss it , it's totally ridiculous!! a great decision for me.
 

iiiNelson

Well-known member
I didn't think I was in the market for a new camera but this is tempting.. Still trying to have strength to wait until after Photokina for any purchases.
 

ZoranC

New member
Zoran, I am thinking you are a delightful cynic, lol.
Thanks LOL

TBH, Sony's problem with the a7s for stills shooters is that the a7 and even more so the a7r (relative to res) are so competent already - in ALL light.
I feel you are right. I am already very happy with results from my A7R (when coupled with certain lenses) so any extra DR etc would not play huge importance to me, what I would care about is would I like files from it more than ones downsized from A7R and would it play better with my legacy lenses than A7R does.
 

Guy Mancuso

Administrator, Instructor
To me this is not a generalist type camera. It's more for a very specific type of shooting. Not saying its something not to buy as a generalist cam but I think the A7/A7r fill that bill better.
Maybe better said a 2nd cam in your system. I have 3 now so I'm covered pretty well at ISO 1600 and slower.
 

Guy Mancuso

Administrator, Instructor
Lol I known about it for awhile. It has only one shortcoming that has stopped me from buying it. The AF is not nearly as good as my A77Ii for focus tracking. Plus in this case full frame for my specific need does not help me. I would have to use a 300mm 2.8. With the A77II I get 300 with a 70-200 2.8 that I'm renting for my shows. But here 12mpx would actually be better.

My needs here are for big runway shows so I need good focus tracking. the A7 series has nice AF but continuous the A77Ii smokes it and many other models out there. So at the moment the A77II is better but after Photokinia that may change. I'm expecting quite a few surprises from Sony
 
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