What Magnification Approximates 1:1 View on Camera Screen?

lectrolink · 07-11-2012, 01:16 PM

I have a K-x with 2.7" screen. I shoot RAW at 12MP. When viewing photos on my camera's screen, my magnification choices are 16x, 14x, 11x, 9.5x, 8x, 6.7x, 5.7x, 4.8x, 4x, 3.4x, 2.8x,2.4x, 2x,1.7x,1.4x, 1.2x. Which magnification level approximates a 1:1 view on my little camera screen when using full resolution settings, matching the size of a 100% crop of the original (non-resized) image on my computer monitor?
Comparing a 3" thumbnail image with the large (same physical image size) view on a PF lens test image, it looks to be maybe around an 11x magnification for the k-x screen size, but not sure about this.
Trying to get a handle on what is a reasonable level of in-camera magnification for judging lens sharpness. 16x just seems too much magnification for this purpose.

br.davidson · 07-11-2012, 01:33 PM

I've wondered about this same question myself. After enough practice, you tend to learn what to look for to judge sharpness on the screen. Eventually you get a feel for the "look" of all the different things that affect sharpness (camera movement, subject movement, DOF, focus, fringing, lens aberrations, etc).

If you load an image into your raw software and zoom that in to 1:1, you could probably match the same image zoom level on your camera. That would probably be close enough.

wlachan · 07-11-2012, 01:40 PM

The question itself is flawed because computer monitors come in different sizes and resolutions. Also, the camera just plays back a snapshot of the original raw so there is really no way to judge the actual raw quality from the camera display. I don't have the K-x but I have found 8x to be meaningful on judging expecting sharpness from my Ds & Km. The actual raw conversions will always be sharper. I reckon every camera is different though.

newarts · 07-11-2012, 03:15 PM

Originally posted by wlachan

The question itself is flawed because computer monitors come in different sizes and resolutions. Also, the camera just plays back a snapshot of the original raw so there is really no way to judge the actual raw quality from the camera display. I don't have the K-x but I have found 8x to be meaningful on judging expecting sharpness from my Ds & Km. The actual raw conversions will always be sharper. I reckon every camera is different though.

The question is well posed as the op specified a 2.7" display on a K-x.

The K-x's lcd screen is about 55mm wide & the sensor is 23.6mm wide; this is an enlargement ratio of 550/236=2.33x

The K-x's sensor is 4288 pixels wide which corresponds to a 100% crop print 4288pix times 0.19*mm/pix = 814.6mm wide, corresponding to a magnification of 814.6/23.6 = 34.5x total. As the LCD screen itself has a magnification factor of 2.33, I think it follows that a magnification factor of 14-16X on the K-x's LCD screen is equivalent to about a 100% crop print.

The K-x's max LCD magnification (16x) is equivalent to, or a little beyond a 100% crop.

Dave in Iowa

*My LCD's screen has 0.188mm wide pixels.

Last edited by newarts; 07-11-2012 at 04:09 PM. Reason: add dimension to pixel pitch; Concise conclusion.

lectrolink · 07-11-2012, 06:04 PM

I like your math, Newarts, but I am curious how you got that the width of each pixel on a k-x screen is .188mm. If there are 230,000 "dots" (as Pentax calls the pixels) on the 55 x 42mm k-x screen, does this not imply that the screen has ~550 pixels on the wide side and ~420 on the short side (550 x 420=231,000)? If there are 10 px per mm, that works out to a pixel width of .1mm, not .188mm as you state. If we substitute .1 for .18, we come up with a final magnification equivalent of about 8x, not 15. Am I wrong?

newarts · 07-11-2012, 07:07 PM

My laptop's LCD pixel pitch is 0.188mm. Sorry.

I used it as a reasonable display pixel size.

It is consistent with the K-x lcd display itself being 1:1 at 16x I think.

Dave in Iowa

emalvick · 07-17-2012, 01:23 PM

If you know the resolution of the LCD and you know the image resolution can't you just compare the two to get the appropriate zoom.... As a simple example (not related to a specific camera or image resolution) if your sensor is going to take a 6000 x 4000 image and your LCD is say 600 x 400 then you'd need a 10 x zoom to see a 600 x 400 portion (100%) of the original 6000 x 4000 image. I don't think you need to worry about the actual pixel size or pitch; you just want it so that each pixel on the LCD is a pixel on the original image.

Of course, the reality isn't quite that simple as I am guessing that depending on the camera's resolution and the LCD you won't be able to get the perfect match, but you should be close fairly easily. I thought I remember doing something like above for my K10d. I haven't really thought much about it with the K5 as I find 100% crops much more disturbing to look at... the added resolution sometimes makes me obssessive about sharpness or the apparent lack of when looking at 100% when the prints are just fine.

maltfalc · 07-17-2012, 03:56 PM - **1 Like**

image dimensions = 4288 x 2428 pixels
lcd = 320 x 240 pixels
when the photo is displayed with it's width matching the width of the lcd, that's considered 1x.
4288 / 320 = 13.4

newarts · 07-17-2012, 04:50 PM

Originally posted by emalvick

If you know the resolution of the LCD and you know the image resolution can't you just compare the two to get the appropriate zoom.... As a simple example (not related to a specific camera or image resolution) if your sensor is going to take a 6000 x 4000 image and your LCD is say 600 x 400 then you'd need a 10 x zoom to see a 600 x 400 portion (100%) of the original 6000 x 4000 image. I don't think you need to worry about the actual pixel size or pitch; you just want it so that each pixel on the LCD is a pixel on the original image.........

I don't think that's right: I think it would be right if the camera's LCD pixel size were the same as that of a standard display. My laptop's display has a pixel pitch of about 0.19mm, while the K-x's pixel pitch is about 50mm/550 = 0.09mm, about half that.

It all depends on how far you hold your head from the screens you are looking at. If your head is the same distance from either screen then the camera's 1 LCD pixel:1 sensor pixel image must be magnified by about 2 to look the same as the 100% image shown on a laptop.

Dave in Iowa

lectrolink · 07-17-2012, 11:11 PM

Reading the new K-30 review, the reviewer states on the Recommended Settings page that setting the Quick Zoom to 8X results in a 100% view. This corresponds pretty closely to what I calculated for the K-x.

maltfalc · 07-18-2012, 03:11 AM

newarts and lectrolink, just stop already. you're spouting absolute nonsense. the answer is 13.4X.

emalvick · 07-18-2012, 08:15 AM

Originally posted by newarts

I don't think that's right: I think it would be right if the camera's LCD pixel size were the same as that of a standard display. My laptop's display has a pixel pitch of about 0.19mm, while the K-x's pixel pitch is about 50mm/550 = 0.09mm, about half that.

It all depends on how far you hold your head from the screens you are looking at. If your head is the same distance from either screen then the camera's 1 LCD pixel:1 sensor pixel image must be magnified by about 2 to look the same as the 100% image shown on a laptop.

Dave in Iowa

But to me, the value in pixel peeping at all, which is really what we're talking about, is if each pixel on the LCD screen is showing one pixel in the photo. Yes, that may not be possible given that would require the exact correct zoom, but working with the pitch guarantees that won't happen. I guess if the pixel pitch is that different, than I could see an issue, but I know that in pixel peeping on my LCD that I tend to be harsh on myself because I zoom to the point where one image pixel is larger than an LCD pixel, and that is where things start to look terrible, even when the photo is ok. Granted, the same thing can happen on the PC, too, which is part of why I'm trying to actually quit looking at 100% crops or extreme crops. I feel like I'm often obsessed with finding flaws in my photos rather than appreciating when they look good at normal viewing distances and sizes.

**PPPPPP42** · 07-24-2012, 09:15 AM

Looks like OP may have done this himself already, but for the math class:

1. Copy, not move, the image from the camera to the computer.
2. Open the image in your photo editing program and boost the zoom to 1:1.
3. Hold the K-x with the same image displayed in the LCD next to your monitor and zoom in until they look the same size and note the camera zoom.

People make things WAY too complicated.

I don't know what you can tell from the crappy LCD image even zoomed other than whether or not it was focused right or movement blurred, pixel peeping on that things sucks, and as I recall you are seeing the JPEG version.

maltfalc · 07-24-2012, 10:34 PM

Originally posted by PPPPPP42

Looks like OP may have done this himself already, but for the math class:

1. Copy, not move, the image from the camera to the computer.
2. Open the image in your photo editing program and boost the zoom to 1:1.
3. Hold the K-x with the same image displayed in the LCD next to your monitor and zoom in until they look the same size and note the camera zoom.

People make things WAY too complicated.

I don't know what you can tell from the crappy LCD image even zoomed other than whether or not it was focused right or movement blurred, pixel peeping on that things sucks, and as I recall you are seeing the JPEG version.

riiiiiight, because every monitor on the planet has the exact same ppi as the k-x's lcd. i really hope you're not a math teacher. for the third time, the answer is 13.4X.

lectrolink · 07-30-2012, 12:41 PM

Maltfalc is right: the answer is 13.4x. I thought that 230,000 "dots" resolution claimed by Pentax meant pixels, but now I see it is the number of pixels tripled-- they are counting each Red, Blue and Green photosite as a "dot". So screen resolution for the K-x is a lowly 320 x 240 px. This marketing sleight-of-hand similarly applies to the (higher) claimed resolution for K-5/K-30.

07-11-2012, 01:16 PM	#1
lectrolink Senior Member Join Date: Apr 2010 Location: Los Angeles Photos: Gallery Posts: 189	What Magnification Approximates 1:1 View on Camera Screen? I have a K-x with 2.7" screen. I shoot RAW at 12MP. When viewing photos on my camera's screen, my magnification choices are 16x, 14x, 11x, 9.5x, 8x, 6.7x, 5.7x, 4.8x, 4x, 3.4x, 2.8x,2.4x, 2x,1.7x,1.4x, 1.2x. Which magnification level approximates a 1:1 view on my little camera screen when using full resolution settings, matching the size of a 100% crop of the original (non-resized) image on my computer monitor? Comparing a 3" thumbnail image with the large (same physical image size) view on a PF lens test image, it looks to be maybe around an 11x magnification for the k-x screen size, but not sure about this. Trying to get a handle on what is a reasonable level of in-camera magnification for judging lens sharpness. 16x just seems too much magnification for this purpose.

07-11-2012, 07:07 PM	#6
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	My laptop's LCD pixel pitch is 0.188mm. Sorry. I used it as a reasonable display pixel size. It is consistent with the K-x lcd display itself being 1:1 at 16x I think. Dave in Iowa Last edited by newarts; 07-11-2012 at 07:17 PM.

07-24-2012, 09:15 AM	#13
PPPPPP42 Site Supporter Join Date: Jan 2012 Location: Wisconsin Photos: Albums Posts: 947	Looks like OP may have done this himself already, but for the math class: 1. Copy, not move, the image from the camera to the computer. 2. Open the image in your photo editing program and boost the zoom to 1:1. 3. Hold the K-x with the same image displayed in the LCD next to your monitor and zoom in until they look the same size and note the camera zoom. People make things WAY too complicated. I don't know what you can tell from the crappy LCD image even zoomed other than whether or not it was focused right or movement blurred, pixel peeping on that things sucks, and as I recall you are seeing the JPEG version. Last edited by PPPPPP42; 07-24-2012 at 09:22 AM.

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07-11-2012, 01:33 PM	#2
br.davidson Senior Member Join Date: Jul 2011 Location: Kent, WA Posts: 138	I've wondered about this same question myself. After enough practice, you tend to learn what to look for to judge sharpness on the screen. Eventually you get a feel for the "look" of all the different things that affect sharpness (camera movement, subject movement, DOF, focus, fringing, lens aberrations, etc). If you load an image into your raw software and zoom that in to 1:1, you could probably match the same image zoom level on your camera. That would probably be close enough.

07-11-2012, 01:40 PM	#3
wlachan Veteran Member Join Date: Sep 2006 Location: Canada Photos: Albums Posts: 2,625	The question itself is flawed because computer monitors come in different sizes and resolutions. Also, the camera just plays back a snapshot of the original raw so there is really no way to judge the actual raw quality from the camera display. I don't have the K-x but I have found 8x to be meaningful on judging expecting sharpness from my Ds & Km. The actual raw conversions will always be sharper. I reckon every camera is different though.

07-11-2012, 03:15 PM	#4
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by wlachan The question itself is flawed because computer monitors come in different sizes and resolutions. Also, the camera just plays back a snapshot of the original raw so there is really no way to judge the actual raw quality from the camera display. I don't have the K-x but I have found 8x to be meaningful on judging expecting sharpness from my Ds & Km. The actual raw conversions will always be sharper. I reckon every camera is different though. The question is well posed as the op specified a 2.7" display on a K-x. The K-x's lcd screen is about 55mm wide & the sensor is 23.6mm wide; this is an enlargement ratio of 550/236=2.33x The K-x's sensor is 4288 pixels wide which corresponds to a 100% crop print 4288pix times 0.19mm/pix = 814.6mm wide, corresponding to a magnification of 814.6/23.6 = 34.5x total. As the LCD screen itself has a magnification factor of 2.33, I think it follows that a magnification factor of 14-16X on the K-x's LCD screen is equivalent to about a 100% crop print. The K-x's max LCD magnification (16x) is equivalent to, or a little beyond a 100% crop.* Dave in Iowa My LCD's screen has 0.188mm wide pixels. Last edited by newarts; 07-11-2012 at 04:09 PM. Reason: add dimension to pixel pitch; Concise conclusion.*

07-11-2012, 06:04 PM	#5
lectrolink Senior Member Join Date: Apr 2010 Location: Los Angeles Photos: Gallery Posts: 189 Original Poster	I like your math, Newarts, but I am curious how you got that the width of each pixel on a k-x screen is .188mm. If there are 230,000 "dots" (as Pentax calls the pixels) on the 55 x 42mm k-x screen, does this not imply that the screen has ~550 pixels on the wide side and ~420 on the short side (550 x 420=231,000)? If there are 10 px per mm, that works out to a pixel width of .1mm, not .188mm as you state. If we substitute .1 for .18, we come up with a final magnification equivalent of about 8x, not 15. Am I wrong?

07-17-2012, 01:23 PM	#7
emalvick Veteran Member Join Date: Feb 2008 Location: Davis, CA Photos: Gallery Posts: 1,642	If you know the resolution of the LCD and you know the image resolution can't you just compare the two to get the appropriate zoom.... As a simple example (not related to a specific camera or image resolution) if your sensor is going to take a 6000 x 4000 image and your LCD is say 600 x 400 then you'd need a 10 x zoom to see a 600 x 400 portion (100%) of the original 6000 x 4000 image. I don't think you need to worry about the actual pixel size or pitch; you just want it so that each pixel on the LCD is a pixel on the original image. Of course, the reality isn't quite that simple as I am guessing that depending on the camera's resolution and the LCD you won't be able to get the perfect match, but you should be close fairly easily. I thought I remember doing something like above for my K10d. I haven't really thought much about it with the K5 as I find 100% crops much more disturbing to look at... the added resolution sometimes makes me obssessive about sharpness or the apparent lack of when looking at 100% when the prints are just fine.

07-17-2012, 03:56 PM - 1 Like	#8
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	image dimensions = 4288 x 2428 pixels lcd = 320 x 240 pixels when the photo is displayed with it's width matching the width of the lcd, that's considered 1x. 4288 / 320 = 13.4

07-17-2012, 04:50 PM	#9
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by emalvick If you know the resolution of the LCD and you know the image resolution can't you just compare the two to get the appropriate zoom.... As a simple example (not related to a specific camera or image resolution) if your sensor is going to take a 6000 x 4000 image and your LCD is say 600 x 400 then you'd need a 10 x zoom to see a 600 x 400 portion (100%) of the original 6000 x 4000 image. I don't think you need to worry about the actual pixel size or pitch; you just want it so that each pixel on the LCD is a pixel on the original image......... I don't think that's right: I think it would be right if the camera's LCD pixel size were the same as that of a standard display. My laptop's display has a pixel pitch of about 0.19mm, while the K-x's pixel pitch is about 50mm/550 = 0.09mm, about half that. It all depends on how far you hold your head from the screens you are looking at. If your head is the same distance from either screen then the camera's 1 LCD pixel:1 sensor pixel image must be magnified by about 2 to look the same as the 100% image shown on a laptop. Dave in Iowa

07-17-2012, 11:11 PM	#10
lectrolink Senior Member Join Date: Apr 2010 Location: Los Angeles Photos: Gallery Posts: 189 Original Poster	Reading the new K-30 review, the reviewer states on the Recommended Settings page that setting the Quick Zoom to 8X results in a 100% view. This corresponds pretty closely to what I calculated for the K-x.

07-18-2012, 03:11 AM	#11
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	newarts and lectrolink, just stop already. you're spouting absolute nonsense. the answer is 13.4X.

07-18-2012, 08:15 AM	#12
emalvick Veteran Member Join Date: Feb 2008 Location: Davis, CA Photos: Gallery Posts: 1,642	Originally posted by newarts I don't think that's right: I think it would be right if the camera's LCD pixel size were the same as that of a standard display. My laptop's display has a pixel pitch of about 0.19mm, while the K-x's pixel pitch is about 50mm/550 = 0.09mm, about half that. It all depends on how far you hold your head from the screens you are looking at. If your head is the same distance from either screen then the camera's 1 LCD pixel:1 sensor pixel image must be magnified by about 2 to look the same as the 100% image shown on a laptop. Dave in Iowa But to me, the value in pixel peeping at all, which is really what we're talking about, is if each pixel on the LCD screen is showing one pixel in the photo. Yes, that may not be possible given that would require the exact correct zoom, but working with the pitch guarantees that won't happen. I guess if the pixel pitch is that different, than I could see an issue, but I know that in pixel peeping on my LCD that I tend to be harsh on myself because I zoom to the point where one image pixel is larger than an LCD pixel, and that is where things start to look terrible, even when the photo is ok. Granted, the same thing can happen on the PC, too, which is part of why I'm trying to actually quit looking at 100% crops or extreme crops. I feel like I'm often obsessed with finding flaws in my photos rather than appreciating when they look good at normal viewing distances and sizes.

07-24-2012, 10:34 PM	#14
maltfalc Veteran Member Join Date: May 2010 Location: Winnipeg Photos: Albums Posts: 396	Originally posted by PPPPPP42 Looks like OP may have done this himself already, but for the math class: 1. Copy, not move, the image from the camera to the computer. 2. Open the image in your photo editing program and boost the zoom to 1:1. 3. Hold the K-x with the same image displayed in the LCD next to your monitor and zoom in until they look the same size and note the camera zoom. People make things WAY too complicated. I don't know what you can tell from the crappy LCD image even zoomed other than whether or not it was focused right or movement blurred, pixel peeping on that things sucks, and as I recall you are seeing the JPEG version. riiiiiight, because every monitor on the planet has the exact same ppi as the k-x's lcd. i really hope you're not a math teacher. for the third time, the answer is 13.4X.

07-30-2012, 12:41 PM	#15
lectrolink Senior Member Join Date: Apr 2010 Location: Los Angeles Photos: Gallery Posts: 189 Original Poster	Maltfalc is right: the answer is 13.4x. I thought that 230,000 "dots" resolution claimed by Pentax meant pixels, but now I see it is the number of pixels tripled-- they are counting each Red, Blue and Green photosite as a "dot". So screen resolution for the K-x is a lowly 320 x 240 px. This marketing sleight-of-hand similarly applies to the (higher) claimed resolution for K-5/K-30.