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04-07-2012, 04:09 AM   #61
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QuoteOriginally posted by Philoslothical Quote
I give up. It's pointless to try to correct or educate someone who has their fingers firmly impaled within their ears.
But this is a very difficult area because of terms used, which are specific and sometimes not very 'natural' compared to spoken language.
If you're not writing in your main language (which is the case for me) it goes even worse

French isn't better: Rapport de grandissement, rapport de grossissement etc. isn't exactly straightforward vocabulary.
In fact I don't even know for sure what "magnification" is supposed to mean in this very context. So I can't even really argue with any of you

04-07-2012, 08:23 AM   #62
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QuoteOriginally posted by atlnq9 Quote
No you are missing the definition of magnification. Look at what I have been saying about magnification for a lens and what I have been saying about magnification to image.
The photographic definition of magnification is what everyone else (including me) has been saying.

Your definition of magnification is not a common one. I'm not even saying it's a worse definition, but it's confusing when people use two different meanings for the same word.
04-07-2012, 08:24 AM   #63
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Try this. Well I can't figure out hoe to keep PentaxForums from resizing the image.
Attached Images
 

Last edited by atlnq9; 04-07-2012 at 08:31 AM.
04-07-2012, 08:46 AM   #64
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Where everyone gets lost is that the sensor size is different for the film and aps-c. At 1:1 a 2 mm insect will have the same size image on both, it just that the 135 film will have more area around it. If people would print the aps-c at 23.7 x 15.7mm and the 135 at 36 x 24 it would be a better comparison.

04-07-2012, 08:51 AM   #65
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QuoteOriginally posted by Digitalis Quote
this was taken with a Nikon D3s with the Nikkor 105mm f/2.8 VR lens - I switched the D3s to 5.1mp DX crop mode and then back to full 12mp FX mode.
Both of these images were both taken with the camera on a tripod and the Nikkor 105mm f/2.8G ED VR with the focus fixed at 1:1 magnification.
The problem is that these images have been enlarged from the sensor size. For a true comparison of 1:1 on both, the should have prints of

23.7 x 15.7mm and 36x24mm or both enlarged the same amount or ideally both. The final enlargements should result in pictures of a different size.
04-07-2012, 08:56 AM   #66
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QuoteOriginally posted by ElJamoquio Quote
The photographic definition of magnification is what everyone else (including me) has been saying. Your definition of magnification is not a common one. I'm not even saying it's a worse definition, but it's confusing when people use two different meanings for the same word.
No, as Blue said photgraphers get confused about magnification, even more so about different sensor sizes. This is why you get questions saying "is 1:1 still 1:1 on apsc" or "you can't compare macro across different sensor sizes"... The true definition of magnification is as I have stated it and makes since no mater what it is used on. This is exactly how lens manufactures use it.

It just get lost in translation to how photographers use the term. The term in itself defines what it is magnification: magnified (or larger) so then magnification ratio would describe how magnified (or how much larger). (It can work backwards too as in smaller so 0.5x would be smaller than real life)

It is confusing stuff and most photographers have never heard it explained properly so they come with ideas peiced together from other photgraphers that were in same boat about not understanding it.

QuoteOriginally posted by Blue Quote
The problem is that these images have been enlarged from the sensor size. For a true comparison of 1:1 on both, the should have prints of 23.7 x 15.7mm and 36x24mm or both enlarged the same amount or ideally both. The final enlargements should result in pictures of a different size.
See post #45.



Ok think I got it. See if this helps. The correct method eliminates all the errors in comparing different sensor sizes. And makes it easy to explain how the working distance for a 100mm on apsc is the same as 150mm on FF when targeting the same magnification to same print size...











Last edited by atlnq9; 04-07-2012 at 05:14 PM.
04-07-2012, 04:01 PM   #67
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You're still not grasping that in photography, pixel resolution has nothing to do with magnification. At least, not directly. You're just going to further confuse a lot of people here, and that irks me. Here are a few photography terms you need to be familiar with.

1. Magnification.
Magnification is a property of the lens, as has been said. It determines how the size of the subject compares to the size of the sensor. When the subject appears on the sensor at the same size as exists in life, that is said to be 1:1 or 1x magnification. If the subject appeared ten times larger on the sensor than it is in life, that would be 10:1 or 10x magnification. That would be getting into the microphotography range.

2. Optical Resolution.
Also a property of the lens, optical resolution determines a lens' sharpness, or how small the details are that it can resolve at a given magnification. This is usually measured in line pairs per mm. I'm not going into this one in detail, there's no need. One just needs to be aware of it to prevent confusion later.

3. Pixel resolution.
After you take the shot, you're dealing with a 2D representation of the scene, the digital photograph. The size of this on your screen, or in print - the number of pixels it occupies expressed by height and width - is its pixel resolution. Usually this term is truncated to simply "resolution", because it's so commonly used when discussing anything viewed on a computer screen.

4. Print Dimensions
When you are about to send the digital photograph off to a printer, there are a number of decisions to be made. DPI (dots per inch), aspect ratio, print dimensions (the final print's size, usually in inches. e.g. 4x6", 8x10"). DPI translates the number of pixels in your digital photograph into how close together, or how compressed the ink dots in the paper print are. A typical LCD screen displays pictures at around 72 PPI (pixels per inch) whereas the optimal for printing is around 300 DPI (dots per inch). As a result, prints of the typical quality are much smaller than they appear on your screen, or in your graphics editor.

Now, let's put these terms together in a few short scenarios.

1. You have a macro lens on your DSLR that reaches 1:1 magnification natively - lucky you. You shoot a tiny insect with it, let's say a fruit fly (drosophila sp.), at 1:1, but aren't too impressed because the bug is so tiny, you can't see too much detail yet. You can see the shape of it, that it has wings, and legs. The eyes look a bit shiny but no real detail. Well, live and learn, you file away that shot for now. We'll call it "Shot #1"

2. You really want to see what's going on with that bug, so you break out the big guns, and use extension and a microscope objective to capture this sucker. Now you can resolve a whopping 10:1 magnification. For the purposes of this explanation, I'm going to omit the difficulties associated with shooting like this such as micro thin depth of field and lack of light needed. So you get set up and now that little drosophila nearly fills your frame! Awesome, you can see each little plate on its carapace, every hair on its legs, and you can make out some of the cells in its eyes. Great, snap the shot. We'll call this "Shot #2"

3. Back at your computer, you process the shots. You do the usual post work, sharpening a little, maybe boosting contrast a bit, whatever. You start with Shot #1, which isn't very impressive, but now you're curious how it will compare. So, you crop out a small section with the bug, and save it for screen/web use at say 400x300px (remember, it was a tiny bug to begin with, so without enlarging it in post (and losing detail that way), there's not a whole lot to work with. Moving on.

4. Shot #2 loads up, and you're pleased. It's sharp and in focus, and needs only minor corrections. So, you crop out a much larger portion, as the bug nearly fills the frame in this one. Just removing a bit of unnecessary border, really. Thing is, your crop is still 3270x2186px large. You want to use this on your monitor, so you crop a little more for aspect ratio, and then scale it down to a common size of 1600x1200px before saving it.

5. Next, you compare those images side by side. We'll suppose that you have dual screens on your computer for this. So you open up each shot, one per screen. You're amazed how much more detail is visible in Shot #2, but Shot #1 is rather small, so you scale it up on your screen by a factor of four. Now both shots fill their screens, displaying as 1600x1200px. Now the difference is as clear as day. Shot #1 is just a blur, very rough, no fine details visible at all. Shot #2 shows every single hair on that little fly, definition on the cells of its tiny compound eye, etc.

6. So you decide to try this comparison the other way now. You drop down Shot #1 to its native 400x300px size, and you scale down Shot #2 to match, reducing its size by a factor of four. Putting them side by side on one screen, you can instantly see that Shot #2 still retains much of its fine detail. If you squint, you can still see the lines of the eye cells, etc. Shot #1, of course, looks just like it did in your editor. It's OK-ish, but nothing special. The fine details of the critter are of course still absent.

Conclusions you can draw from this:

1. Magnification + Optical resolution determine the amount of detail, how small the structures are that you can capture.

2. You cannot increase magnification in post processing. Enlarging the pixel dimensions of an image does not increase the level of detail, just the opposite. Detail is lost by blowing up an image.

3. You cannot decrease magnification in post processing, either. Reducing an image's pixel dimensions in post can make it appear sharper, but there is still a net loss of detail. There has to be, you're using less pixels to represent the same subject.

4. Magnification only has to do with the difference between the size of the subject, and the size of the sensor. Viewing or printing a photograph at different sizes does not change the magnification of the subject. It just changes the size of the print or image.

5. Reread conclusion #1, above. Nothing you do in post can change the size of the structures in your subject that you can resolve. These are properties of the lens, exclusively*. Magnification (as it pertains to photography) is taken out of play as soon as you click the shutter release.

This is how it works in photography. You clearly need to learn and accept this, else you will continue to do other people the disservice of confusing them, or slowing down their own learning process. I sincerely hope this helps you get on the right track, and maybe it will make sense to others who are a bit fuzzy on the issue.

Also, please don't send me any more PMs boasting about your credentials. Arguments from authority don't do much for me. Neither do arguments from popularity. This is all objective, factual material. There's no need for that.

*I'm not going to delve into how different qualities of sensor, size of photosites on the sensor, or pixel density on the sensor affect this. It's beyond the scope of one post.
04-07-2012, 05:36 PM   #68
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Yeah I have better ways to spend my time. Have fun all. That comment you made about me not listening to you can turn right around. I agree completely with you right up to when you don't think magnification is affected by viewing size.

Here is a simple quote to leave you with, not sure what the original source is; but, it has been quoted by many credible and sometimes borderline credible sites (such as Wikipedia).
QuoteQuote:
Unfortunately, magnification is could be a misleading parameter. It depends on a final size of a printed picture, and therefore varies with variation in picture size. Editors of Journals and Magazines routinely resize a figure to fit the page, making any magnification number provided in the figure legend incorrect. Scale Bar (or Micron Bar) is a bar of known length displayed on a picture. The bar can be used for measurements on a picture. When a picture is resized a bar is resized with also. If a picture has a bar, the right magnification can be easily calculated. Ideally, all pictures intending for publication/presentation should be supplied with a scale bar; magnification is optional. All but one (of a limestone) micrographs, presented on this page do not have a micron bar; supplied magnifications are the wrong ones (they were not calculated for pictures of present size).


04-07-2012, 06:53 PM   #69
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Viewing size can't be predicted. There is no way to know a viewer's monitor's properties, dot pitch, pixel size, etc. There is no way to predict or control how large an image appears on their screen. There's no way to control how someone may resize or zoom a shot. Hell, if you upload to Flickr, it automatically generates half a dozen sizes for you. Where photography is concerned, viewing size is a garbage metric, and not tied to magnification.

Also, the fact remains that changing the viewing size of an image only distorts it. I could take a picture of a flower from six feet away, blow it up to four meters across, and by your standard it would be "magnified" well into the macro range. That's just stupid. So what if pixels are six cm squared, it's bigger, so it's magnified. Do you have any idea how dumb that sounds? Or how willfully obtuse you sound?

Perhaps in parts of the scientific community your definition has more meaning, but not here.

QuoteOriginally posted by atlnq9 Quote
magnification is could be a
That's just awesome, btw.
04-07-2012, 09:49 PM   #70
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Wow, this thread certainly took a turn for the worse while I was gone. Everybody seems so combative, both sides seem to be saying the same thing in different ways.

I think I phrased what I was trying to say incorrectly as well, maybe I can clear things up.
.
.
.
I think we can all agree that given any camera, and any subject, a longer lens will allow you to fill the frame with the subject at a longer distance. Thus the 180mm, being longer than the 100mm, will enable you to be farther away from that subject while still filling the frame.

Can we all agree on this?
04-07-2012, 10:54 PM   #71
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QuoteOriginally posted by RXrenesis8 Quote
I think we can all agree that given any camera, and any subject, a longer lens will allow you to fill the frame with the subject at a longer distance. Thus the 180mm, being longer than the 100mm, will enable you to be farther away from that subject while still filling the frame.
certainly
04-08-2012, 07:17 AM   #72
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QuoteOriginally posted by Philoslothical Quote
You're still not grasping that in photography, pixel resolution has nothing to do with magnification. At least, not directly. You're just going to further confuse a lot of people here, and that irks me. Here are a few photography terms you need to be familiar with.

1. Magnification.
Magnification is a property of the lens, as has been said. It determines how the size of the subject compares to the size of the sensor. When the subject appears on the sensor at the same size as exists in life, that is said to be 1:1 or 1x magnification. If the subject appeared ten times larger on the sensor than it is in life, that would be 10:1 or 10x magnification. That would be getting into the microphotography range.

2. Optical Resolution.
Also a property of the lens, optical resolution determines a lens' sharpness, or how small the details are that it can resolve at a given magnification. This is usually measured in line pairs per mm. I'm not going into this one in detail, there's no need. One just needs to be aware of it to prevent confusion later.

3. Pixel resolution.
After you take the shot, you're dealing with a 2D representation of the scene, the digital photograph. The size of this on your screen, or in print - the number of pixels it occupies expressed by height and width - is its pixel resolution. Usually this term is truncated to simply "resolution", because it's so commonly used when discussing anything viewed on a computer screen.

4. Print Dimensions
When you are about to send the digital photograph off to a printer, there are a number of decisions to be made. DPI (dots per inch), aspect ratio, print dimensions (the final print's size, usually in inches. e.g. 4x6", 8x10"). DPI translates the number of pixels in your digital photograph into how close together, or how compressed the ink dots in the paper print are. A typical LCD screen displays pictures at around 72 PPI (pixels per inch) whereas the optimal for printing is around 300 DPI (dots per inch). As a result, prints of the typical quality are much smaller than they appear on your screen, or in your graphics editor.

Now, let's put these terms together in a few short scenarios.

1. You have a macro lens on your DSLR that reaches 1:1 magnification natively - lucky you. You shoot a tiny insect with it, let's say a fruit fly (drosophila sp.), at 1:1, but aren't too impressed because the bug is so tiny, you can't see too much detail yet. You can see the shape of it, that it has wings, and legs. The eyes look a bit shiny but no real detail. Well, live and learn, you file away that shot for now. We'll call it "Shot #1"

2. You really want to see what's going on with that bug, so you break out the big guns, and use extension and a microscope objective to capture this sucker. Now you can resolve a whopping 10:1 magnification. For the purposes of this explanation, I'm going to omit the difficulties associated with shooting like this such as micro thin depth of field and lack of light needed. So you get set up and now that little drosophila nearly fills your frame! Awesome, you can see each little plate on its carapace, every hair on its legs, and you can make out some of the cells in its eyes. Great, snap the shot. We'll call this "Shot #2"

3. Back at your computer, you process the shots. You do the usual post work, sharpening a little, maybe boosting contrast a bit, whatever. You start with Shot #1, which isn't very impressive, but now you're curious how it will compare. So, you crop out a small section with the bug, and save it for screen/web use at say 400x300px (remember, it was a tiny bug to begin with, so without enlarging it in post (and losing detail that way), there's not a whole lot to work with. Moving on.

4. Shot #2 loads up, and you're pleased. It's sharp and in focus, and needs only minor corrections. So, you crop out a much larger portion, as the bug nearly fills the frame in this one. Just removing a bit of unnecessary border, really. Thing is, your crop is still 3270x2186px large. You want to use this on your monitor, so you crop a little more for aspect ratio, and then scale it down to a common size of 1600x1200px before saving it.

5. Next, you compare those images side by side. We'll suppose that you have dual screens on your computer for this. So you open up each shot, one per screen. You're amazed how much more detail is visible in Shot #2, but Shot #1 is rather small, so you scale it up on your screen by a factor of four. Now both shots fill their screens, displaying as 1600x1200px. Now the difference is as clear as day. Shot #1 is just a blur, very rough, no fine details visible at all. Shot #2 shows every single hair on that little fly, definition on the cells of its tiny compound eye, etc.

6. So you decide to try this comparison the other way now. You drop down Shot #1 to its native 400x300px size, and you scale down Shot #2 to match, reducing its size by a factor of four. Putting them side by side on one screen, you can instantly see that Shot #2 still retains much of its fine detail. If you squint, you can still see the lines of the eye cells, etc. Shot #1, of course, looks just like it did in your editor. It's OK-ish, but nothing special. The fine details of the critter are of course still absent.

Conclusions you can draw from this:

1. Magnification + Optical resolution determine the amount of detail, how small the structures are that you can capture.

2. You cannot increase magnification in post processing. Enlarging the pixel dimensions of an image does not increase the level of detail, just the opposite. Detail is lost by blowing up an image.

3. You cannot decrease magnification in post processing, either. Reducing an image's pixel dimensions in post can make it appear sharper, but there is still a net loss of detail. There has to be, you're using less pixels to represent the same subject.

4. Magnification only has to do with the difference between the size of the subject, and the size of the sensor. Viewing or printing a photograph at different sizes does not change the magnification of the subject. It just changes the size of the print or image.

5. Reread conclusion #1, above. Nothing you do in post can change the size of the structures in your subject that you can resolve. These are properties of the lens, exclusively*. Magnification (as it pertains to photography) is taken out of play as soon as you click the shutter release.

This is how it works in photography. You clearly need to learn and accept this, else you will continue to do other people the disservice of confusing them, or slowing down their own learning process. I sincerely hope this helps you get on the right track, and maybe it will make sense to others who are a bit fuzzy on the issue.

Also, please don't send me any more PMs boasting about your credentials. Arguments from authority don't do much for me. Neither do arguments from popularity. This is all objective, factual material. There's no need for that.

*I'm not going to delve into how different qualities of sensor, size of photosites on the sensor, or pixel density on the sensor affect this. It's beyond the scope of one post.
In a macro lens, 1:1 or life size is what is important. Don't think about final print size, only sensor and film size.


Here are 2 analogies.

#1 Say you have a house with a garage that is 24x36 feet and a vacation house with a garage that is 24 by 16 feet and you drive a Volkswagon beetle. You can part the VW in both garages, but in one of those garages, you have more space around the VW.

#2 You are going to make a life size macro of a lady beetle Hippodamia convergens which is 7mm long.You are going to do one on aps-c digital which is 23.7 x 15.7mm and one on 135 film which is 36x24mm. At 1:1 with a D FA 100WR, lady beetle will be 7mm on the image sensor and the film. The subject and the image is life size. This is talking about the actual image on the sensor and film, not a print or enlarged image on a computer screen.
04-08-2012, 07:24 AM   #73
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QuoteOriginally posted by RXrenesis8 Quote
Wow, this thread certainly took a turn for the worse while I was gone. Everybody seems so combative, both sides seem to be saying the same thing in different ways.

I think I phrased what I was trying to say incorrectly as well, maybe I can clear things up.
.
.
.
I think we can all agree that given any camera, and any subject, a longer lens will allow you to fill the frame with the subject at a longer distance. Thus the 180mm, being longer than the 100mm, will enable you to be farther away from that subject while still filling the frame.

Can we all agree on this?
True. It also depends on what subject you are trying to make 1:1 on the sensor or film. Focal length brings FOV into the "picture." (couldn't resist the pun)
04-08-2012, 07:41 AM   #74
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QuoteOriginally posted by Blue Quote
In a macro lens, 1:1 or life size is what is important. Don't think about final print size, only sensor and film size.


Here are 2 analogies.

#1 Say you have a house with a garage that is 24x36 feet and a vacation house with a garage that is 24 by 16 feet and you drive a Volkswagon beetle. You can part the VW in both garages, but in one of those garages, you have more space around the VW.

#2 You are going to make a life size macro of a lady beetle Hippodamia convergens which is 7mm long.You are going to do one on aps-c digital which is 23.7 x 15.7mm and one on 135 film which is 36x24mm. At 1:1 with a D FA 100WR, lady beetle will be 7mm on the image sensor and the film. The subject and the image is life size. This is talking about the actual image on the sensor and film, not a print or enlarged image on a computer screen.
This is what I kept saying. To say that by enlarging a 1:1 shot in post is increasing its magnification is incorrect at best, deceptive at worst. All you can say is "It's a 1:1 shot enlarged to ..." or "It's a 1:1 shot enlarged by ..."

Another example: The image below is a 1:1 crop of a 5:1 shot of a single pixel on my monitor. As you can see, it takes about 320px squared to represent it, but that doesn't make it a 320x shot, even though it's 320x larger than the pixel it represents. It's still a 5:1 shot.



Optical magnification is all we care about. It has nothing to do with enlargement or reduction in post, it has to do with how small the structures are that we can resolve in our subject.
04-09-2012, 01:16 PM   #75
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I don't believe this could get any more confusing for me

I really tried, really I did; but the arguments presented and the examples used just made this "magnification" / "enlargement" issue become just too confusing to me.
I would like to understand what the issue, and its resolution, really is; but I would rather not hijack the original topic any further.
I have begun a new thread:
PentaxForums.comCamera Help CentralPentax Beginner's Corner Q&A Pentax “Macro” lens and the terms “Magnified” and “Enlarged”

and ask the participants of this thread to please answer my questions in that new thread.
Thank you.

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