Playback magnifies steps

[detlef]

Hello.

 

Does anybody know the playback magnify steps? Is max magnify 100% crop? There are 28 possible magnify steps. How much zoom is one step? And is there an onscreen indicator like the indicator for zoom in the manuel focussing mode? Nothing found ...

 

Kindly regards.

[adwb]

i think when you press c3 or c2 on the older bodies the first view is 100%

[detlef]

Nobody knows that exactly? I found really no information about this. PDF, web, forums.

[addicted2light]

On the A7r (mk I) the first step is 7x, the second 14x, if I recall correctly.

 

Considering the last step I'm pretty sure is 100% that makes the intermediate step 50%.

[adwb]

old thread seem to confirm  first load is 100%.  I know I read that in a ebook but I cant find it for you sorry,

https://www.dpreview.com/forums/post/54249665

[Golem]

But 100% of exactly what ?  

  

If XX% referred to the image-on-sensor then a

100% view of that would fill only about half of

the monitor. The unzoomed initial playback is

already about a 200% version of an image that

was projected by the lens onto the sensor. 

  

Just ran a quick check on an a6000 and a max

zoom the playback image represents a partial

view of a total image or print thaz about 40"/1m

in width.

  

So when you speak in XX%, I can't figger out

the XX% of WHAT ? Please explain/specify ?

[addicted2light]

But 100% of exactly what ?  

  

If XX% referred to the image-on-sensor then a

100% view of that would fill only about half of

the monitor. The unzoomed initial playback is

already about a 200% version of an image that

was projected by the lens onto the sensor.

 

 

100% usually refers to a rendering where at 1 pixel on the screen (whatever that screen might be, so 100% is screen-dependant, so to speak) will correspond 1 pixel of the image (i.e. 1 pixel as captured by the sensor).

 

I agree that's confusing, though...

[Golem]

On the A7r (mk I) the first step is 7x, the second 14x, if

I recall correctly.

 

Considering the last step I'm pretty sure is 100% that

makes the intermediate step 50%.

   

But 100% of exactly what ?  

  

If XX% referred to the image-on-sensor then a

100% view of that would fill only about half of

the monitor. The unzoomed initial playback is

already about a 200% version of an image that

was projected by the lens onto the sensor. 

  

Just ran a quick check on an a6000 and a max

zoom the playback image represents a partial

view of a total image or print thaz about 40"/1m

in width.  

   

So when you state "Considering the last step

I'm pretty sure is 100%", what I read outa that

is that the thing we're discussing "percentage-of"

is an uncropped 40"/1m wide print. And I rather

doubt that a fairly large gallery-sized print is the

unit of measure for referencing magnifications. 

  

So when you all speak in XX%, I can't figger out

the "XX% of WHAT" ? Please explain/specify ? 

[Golem]

100% usually refers to a rendering where at 1 pixel on the screen

(whatever that screen might be, so 100% is screen-dependant, so

to speak) will correspond 1 pixel of the image (i.e. 1 pixel as

captured by the sensor).

 

I agree that's confusing, though...

   

Firstly, please excuse the timing on my second post here

[this one being my third]. You were replying to my first post

while I was typing my second post.  

  

Anywho, if "1 pixel on the screen will correspond 1 pixel

of the image" .... does it "correspond" in size ? or what ? 

 

Size must be part of this discussion cuz we're talking about

percentages as image magnification. However, I'm unable

to follow the pixel-for-pixel idea since a 100% pixel-for-pixel

representation on the playback screen of the camera would

fill only half the screen, and THAT situation doesn't jibe with

the rest of the discussion where "100%" refers to a playback

image thaz been zoomed to some greater size [larger than

the monitor screen - therefor cropped]. 

   

So at the moment, the only thing that mathematically makes

sense is that the answer to "100% of exactly what ?" is that

the "exactly what" is a 40"/1m wide print. And I'm pretty sure

thaz is NOT a general-use standard of reference for image

size, or for percent/degree of image magnification.

[Golem]

Just me here again ... not meaning to be a pest but, I do see

a way in which "pixel-for-pixel correspondence" could make

sense when stated as "XX%".  

 

Since you explained [but I'm possibly not understanding it]

that these percents are "viewing screen dependent", it would

make some sense that when ALL the pixels of an image are

included on the screen, and the image exactly fits the screen,

then that is 100% ... regardless of screen size.

  

It then follows that if the image is twice linear the image size

displayed on it, then that is 50%. If the screen shows a crop

of the image, and the full image ... if it were visible ... is 3X

linear the size of the display screen, then that is a 300% view. 

  

Above is the only grasp I have of "screen dependent" image

size stated as XX%. But it doesn't jibe with the percents I see

tossed around in this discussion of playback image size ... so

I'm not understanding any statements of image magnification

as XX% magnification :-(   

   

------------------------------------------------------------------------------  

  

Sometimes pixel peeping lens testers, or perhaps someone

comparing high ISO noise levels, or any other IQ tester, will

post images called "100% Crops". In practice I just ignore the

numbers and think "OK, a highly magnified view for inspection".

Acoarst, that works. And since ALL the test pix are referred to

as "100% Crops" at least I know they are all the same degree

of magnification so the comparison is legitimate. Usually these

100% crops are accompanied by the uncropped image as well,

so I can visually assess degree of magnification. But I always

just ignore the "100% Crop" label as simply meaningless. And

it's looking like that is truly the situation. Or is it ? ?

[addicted2light]

Just me here again ... not meaning to be a pest but, I do see

a way in which "pixel-for-pixel correspondence" could make

sense when stated a XX%.  

 

Since you explained [but I'm possibly not understanding it]

that these percents a "viewing screen dependent", it would

make some sense that when ALL the pixels of an image are

included on the screen, and the image exactly fits the screen,

then that is 100% ... regardless of screen size.

  

It then follows that if the image is twice linear the image size

displayed on it, then that is 50%. If the screen shows a crop

of the image, and the full image ... if it were visible ... is 3X

linear the size of the display screen, then that is a 300% view. 

  

Above is the only grasp I have of "screen dependent" image

size stated as XX%. But it doesn't jibe with the percents I see

tossed around in this discussion of playback image size ... so

I'm not understanding any statements of image magnification

as XX% magnification :-(

Don't worry, you're not a pest, I was just out for a run

 

Now this is how I understand this fact, obviously I might well be wrong.

 

With "screen dependant" what I meant was that if an image is 6000 pixel wide, and you see it on a 1000px wide screen (i.e. a physical pixel of the screen is used to render a physical pixel of the original image), then when you will be seeing said image at 100% it will require 6 full horizontal scrolls of the screen to see it the entire image (and a 6x zoom factor). We are only considering pixels here, so a 3" Lcd display and a 32" display will sport the same magnification, as long as they have the same resolution (even if obviously the image will look much bigger on the 32" screen).

 

If instead you see that same 6000px wide image on an hypothetical 8k display (7680px wide) then you will be seeing the image at 100-and-something % (please don't make me do the math ) even before zooming in.

 

This would explain why, for example, even if to my knowledge the Lcd on the A7 and A7r are identical their playback zoom factors are different (I think 12 vs 14x), given that one generates 6000px wide images and the other ~7500px wide ones.

[detlef]

DPreview thread just think C2 is 100%, He doesn't know:

 

"C2 button, which then zooms straight to 100%(?)"

 

/////

 

"On the A7r (mk I) the first step is 7x, the second 14x, if I recall correctly."

 

And third step 21x and step 28 = 196x?

 

"Considering the last step I'm pretty sure is 100% that makes the intermediate step 50%."

 

28th step must be more than 100%. I'm sure it is more.

 

With 100% i mean 100% view, actual pixels in Photoshop or 100% zoom in Capture One. Biggest possible view, without digital zoom or 100% crop for pixelpeeping

 

Maybe biggest zoom on A7 (1gen) maybe 280%, this matches with 28 steps, each step 10%, then it is possible C2 goes directly to 100%.

 

But i don't know is that right or not. Anybody must know this exactly.

[detlef]

There's something wrong.

 

C2 jumps to step 20. If this is 100%, then every step is 5%. Max zoom on my A7S (28 zoom steps) with this parameters is 140% (28*5%). Maybe, maybe not.

[Guest all8]

Take a picture of a ruler, placed left to right of frame.

 

Zoom to the maximum on the rear screen, note the "distance" on the ruler from left to right edge of zoomed image, then in C1 or PS, crop the same distance, export, count the horizontal pixels and compare to the horizontal resolution of the rear display. Repeat for all 28 zoom levels if you want    

 

I would expect that 100% means one pixel of the image is displayed to one pixel of the display    

[addicted2light]

DPreview thread just think C2 is 100%, He doesn't know:

"C2 button, which then zooms straight to 100%(?)"

/////

"On the A7r (mk I) the first step is 7x, the second 14x, if I recall correctly."

And third step 21x and step 28 = 196x?

"Considering the last step I'm pretty sure is 100% that makes the intermediate step 50%."

28th step must be more than 100%. I'm sure it is more.

With 100% i mean 100% view, actual pixels in Photoshop or 100% zoom in Capture One. Biggest possible view, without digital zoom or 100% crop for pixelpeeping

Maybe biggest zoom on A7 (1gen) maybe 280%, this matches with 28 steps, each step 10%, then it is possible C2 goes directly to 100%.

But i don't know is that right or not. Anybody must know this exactly.

Just to be clear, with first and second step I mean the two times you press the button in the magnified view (1 press 7x zoom, 2nd press 14x), not the first two steps of the various incremental zoom ratios you get rotating the wheel!

 

I didn't think of that because I never use the incremental values, heck I don't even use the first step, I want to check my images directly at the maximum zoom level...

 

Now I can get back cutting my pizza

[detlef]

First time pressing C2 jumps directly to "wheel zoom step 20", but again pressing C2 do not again jump several steps. I must press C2 9* for max possible zoom.

 

I really don't understand why Sony do not explain this in manual. For me it's an interesting fact to know the max possible zoom as a % value. And to know exactly C2 (zoom step 20) is really 100% or not.

 

@timde:

"I would expect that 100% means one pixel of the image is displayed to one pixel of the display :rolleyes:"

 

You can't an image with 500*500px display 1:1 on a 320*200 vga screen ... only a part ... with 100% zoom. But i'm sure you know that