So You Wanna See the Difference Between Full Frame and Cropped Sensors?

[WayneF]

You did not compare them equally. For all things equal, these should be compared as they actually were. The DX image is cropped, specifically it should be shown only 2/3 the size of the FX (which then also makes the same subject be same size), because, the same lens would of course project exactly the same size subject. You did not show that same image projected by the same lens. The DX frame is already seriously cropped (to 2/3 dimensions), and should be shown that way, because the same lens at same distance obviously projects exactly the same image view, no matter which camera.

That is real world. However, you introduced additional magnification changes in one of them.

Prove it!

? It is common knowledge (check manuals) that the D300 DX sensor is 23.6 × 15.8 mm (page 409). The D700 FX sensor is 36.0 × 23.9 mm (page 428), which is 1.5x larger than DX.
I suspect you already knew that. It is pretty much the whole difference of DX vs FX, the entire point.

There are two significances... One is that a smaller DX image requires 1.5x more magnification to appear same size as FX (and DOF is entirely about subject magnification).

Two is that (if using same lens standing at same place), that DX only captures a smaller central portion of the SAME image projected by the SAME lens... DX obviously sees the exact same image, just cropped smaller around the edges. We know this stuff. We have to fit any conclusions in around the obvious facts.

We can of course use different lenses and stand at different places and see different views, but these are magnification changes again.

By the time the post processing was done, there is no doubt I was completely soused. But I will bet a dollar to a doughnut there was very little difference in any re-sizing, because I have a process.

Yes, that was the problem, it was my point. You increased the magnification of the DX, out of proportion to the FX. You resized unequal items to be same size, but they are not.

So here's my challenge to you WayneF, do your own bloody study of the DX versus FX with the most common lens choices and post your results to enlighten the masses (or the unwashed multitude, if that is your preference) to prove me wrong. Otherwise, STFU.

I didn't say you were wrong. You did what you did, and got what you got. I said you unfairly compared unequal items, and then failed to make the real point.

But OK, see FX - DX Lens Crop Factor . Which is my version. It is not about DOF, it is about what DX/FX means, and how they differ, and some advantages/disadvantages, including DOF.

 

[Braineack]

You increased the magnification of the DX, out of proportion to the FX. You resized unequal items to be same size, but they are not.

no he didn't. He posted the image exactly as it would straight out of the camera, both resized for 400x600px.

why would he have posted a 233x400px image compared to a 400x600px image? Why would someone resize differently based solely on the sensor size?

The whole reason there's a 35mm equivalent rating to lenses, is because the shot taken on a DX at 50mm, appears just like a shot taken at 75mm on an FX.

I didn't say you were wrong. You did what you did, and got what you got. I said you unfairly compared unequal items, and then failed to make the real point.

are you suggesting the monkey's aren't the same? Do you watch Mythbusters by any chance and also hater scientific method? what was unfair, did the FX camera get paid for the shoot but the DX worked for free?

His point wasn't to show the difference in DOF, or the advantages/disadvantages. His point was to visually demonstrate the differences in sensor size and how the crop works. Something many people still can't wrap their heads around because these simple discussions on a simple theory always turn into long drawn matches in semantics, misunderstanding, and pure self-loathing. His post accomplished exactly the intent, in a visual, easy-to-understand way.

If you'd like to illustrate the differences in DOF/background between the two at various focal lengths with the camera in different positions to achieve the same framing, by all means do it.

 

[WayneF]

You increased the magnification of the DX, out of proportion to the FX. You resized unequal items to be same size, but they are not.

no he didn't. He posted the image exactly as it would straight out of the camera, both resized for 400x600px.

why would he have posted a 233x400px image compared to a 400x600px image? Why would someone resize differently based solely on the sensor size?

Kundalini's work and post were good, and I suspect it only suffered from oversight, what he could have said.

Basics: Camera images are formed by two major components... the image projected by the lens at X resolution, and the capture of it by the sensor or film at Y resolution. Then we can manipulate it by how we prepare and show them.

You are saying pixels are pixels, we have what we have. But there is a lot more, and I am speaking of the "image", and its "area" and thus its resolution. The dimension that those pixels capture reflects the resolution projected by the lens, which definitely also affects the image - it is the image, the lens makes the image (the sensor merely tries to reproduce it). To make the point be obvious, if we enlarge (magnify is the operative word) a small area of it, like say 100x100 pixels, and show it large on the monitor screen size, it really does not compare well (looks crummy). Not the same thing at all. OK, 100 vs 400 vs 600 is merely speaking about degree, but it is the same point. Equal is equal, and not is not. I am speaking of reproducing and comparing the same captured image from the lens. You are speaking of the size of the container you keep it in.

Taken with the same lens at the same distance, DX is of course cropped smaller than FX. Smaller is the word we should keep in mind. It is the only difference, and again, magnification becomes the thought.
But otherwise, the FX and DX images are of course exactly the same image (it was after all the same lens, the same projected image). We are merely trying to reproduce that image.
And yes, FX 600x400 and DX 400x267 pixels would show the SAME AREA from the SAME LENS (a fair comparison).
If shown representing actual original size, we see that DX is smaller, but we also see that image from same lens is the same (and it has original resolution).
If we enlarge the smaller one to instead be bigger too, we have arbitrarily changed things (namely, magnification and resolution), now unequal, not the same thing.

His point wasn't to show the difference in DOF.

That is a valid point, he never said he was. As mentioned before, I got into this old thread due to my error, which is still not clear to me how. I think it was linked elsewhere. Sorry about that, but his images are quite good to serve a very good point (which ought to be stated).

 

[Braineack]

I hereby decree, by order of the King, that all images posted by DX cameras on TPF be sized 1.5x smaller than images from FX cameras.

Likewise, all thee subjects who wish to print their photos and hang on their walls, must print images from DX cameras 1.5x smaller than they would from FX cameras.


you're arguing such a stupid and dumb point. for what?

 

[WayneF]

I hereby decree, by order of the King, that all images posted by DX cameras on TPF be sized 1.5x smaller than images from FX cameras.

No, only if the entire point was to specifically compare them both to each other (to show their specific differences)... fairly. It is not a difficult concept.

 

[Braineack]

That's just silly, and you know it, but you don't want to concede because this is the internet.

You're suggesting his test was bad/flawed/invalid, because he resized both images to the same dimensions; a constant. But you're treating that as if it's a variable that made a difference in the comparison, which is stupid. Because if you're going to compare two photos, you're going to compare them at the same image size.

I'm certain, had he posted one photo at 267px and the other at 400px, you'd be bitching that they weren't the same size...

 

[WayneF]

That's just silly, and you know it, but you don't want to concede because this is the internet.

You're suggesting his test was bad/flawed/invalid, because he resized both images to the same dimensions; a constant. But you're treating that as if it's a variable that made a difference in the comparison, which is stupid. Because if you're going to compare two photos, you're going to compare them at the same image size.

I'm certain, had he posted one photo at 267px and the other at 400px, you'd be bitching that they weren't the same size...

I never said bad/flawed/invalid. Sure, comparing final user results is valid enough, but comparing resolution needs to compare same things. I pointed out that the two pictures did not compare the same lens at the same size, which is correct (and is a fundamental principle). And I said that the second did not say the conclusion, which it didn't, but yes, I was thinking DOF, the thread had in fact turned that way, and the OP had even later mentioned DOF.

No, I would not have bitched about a fair comparison that actually shows real. I was asked above for my "own bloody study", to which I provided the link to FX - DX Lens Crop Factor
It shows it both ways, enlarged to same size (commonly done) and also still original size (to show the concept and comparison of original - what subject is actually about). It was trying to make point of what DX/FX is. But it is easy to see that DX enlarged to FX size can suffer (1.5x more magnification reduces resolution). And the magnification reduces DOF, but the necessary equivalent-view using shorter DX lens or longer distance compensates DOF - but not for loss of resolution from magnifying smaller image to be larger (pixel density only tries to reproduce lens resolution, it can never add scene resolution - so lots of ifs and buts to debate).

However, still true that bigger normally does win perceptually - we see big things better, even if less clearly. We like big things. Big wins, about every time. It is a reason FX is big, to allow it (wide lenses are the other reason). But comparisons ought to be fair, and should actually compare, all other things equal.

You may be aware that in the old days, we had several film sizes. 35mm film was extremely popular, but larger film was preferred commercially. 120 medium roll film was the same film emulsions, but it was used because their prints needed less magnification, and results were clearly better - they would sell. Sheet film carried this to extremes, for same reason - same film emulsions, but in spite of the hardships of smaller apertures and much less DOF from much longer lenses. An 8x10 inch film sheet can produce an 8x10 inch contact print. Ever seen a contact print? Compared to 35mm? That is about magnification of the image (on the same film and print emulsion). Magnification is an extreme concept in photography. But when we always use the same gear, we lose sight of it. Some don't even know, cannot even imagine. But DX cropping the lens view smaller is the same thing as smaller film cropping the lens view smaller.

Sorry that you are unable to get it.

 

[Derrel]

I AM EAGERLY WAITING for this post to appear on pay-per-view, or failing that, to be available for internet download at least, in an unauthorized, Asian-market camcorder black-market copy, filmed in Hong Kong on some guy's shaky, hand-held camcorder...

 

[astroNikon]

lol .. insert photo of someone kicking a dead horse ....


For newbies the OPs description answered the DX/FX question, which is what the target audience it was intended for.
I liked it and it helped me. :thumbup:

 

[astroNikon]

I AM EAGERLY WAITING for this post to appear on pay-per-view, or failing that, to be available for internet download at least, in an unauthorized, Asian-market camcorder black-market copy, filmed in Hong Kong on some guy's shaky, hand-held camcorder...

It's already available on DigitalRev youtube videos .. with a reenactment with characters

okay, it's not .... it sounded good though.

 

[runnah]

blah this thread makes my dick itch...

 

[Braineack]

blah this thread makes my dick itch...

what doesn't?

 

[runnah]

blah this thread makes my dick itch...

what doesn't?

a cooling balm or salve.

 

[WayneF]

I AM EAGERLY WAITING for this post to appear on pay-per-view, or failing that, to be available for internet download at least, in an unauthorized, Asian-market camcorder black-market copy, filmed in Hong Kong on some guy's shaky, hand-held camcorder...

LOL If you have objections, it would seem more useful to specify what, why, how. Do you know any details, or do you just need to be cute?

You don't think that it is overwhelmingly significant to realize (as the previous test showed, but did not comment) that the same subject magnified to the same size at the same fstop... will produce exactly the same DOF, regardless of the lens focal length or focal distance used? Technically a little less true of close distances, but seems like that ought help many confusions. I want to say that has been known 100 years, but someone would probably say, no, it was 150 years.

Without doubt, yes, it is ALL ABOUT THE CROP FACTOR. That and film size is the only way the cameras differ. Yes, sure, the smaller crop sensor does typically need to use a shorter lens, but regarding DOF too, the smaller DX sensor cropping the lens image smaller is exactly the same concept as the 35mm film size cropping a 120 negative size smaller. Ratio is even similar, 60mm : 36mm = 1.67:1

 

[Derrel]

I AM EAGERLY WAITING for this post to appear on pay-per-view, or failing that, to be available for internet download at least, in an unauthorized, Asian-market camcorder black-market copy, filmed in Hong Kong on some guy's shaky, hand-held camcorder...

LOL If you have objections, it would seem more useful to specify what, why, how. Do you know any details, or do you just need to be cute?

You don't think that it is overwhelmingly significant to realize (as the previous test showed, but did not comment) that the same subject magnified to the same size at the same fstop... will produce exactly the same DOF, regardless of the lens focal length or focal distance used? Technically a little less true of close distances, but seems like that ought help many confusions. I want to say that has been known 100 years, but someone would probably say, no, it was 150 years.

Without doubt, yes, it is ALL ABOUT THE CROP FACTOR. That and film size is the only way the cameras differ. Yes, sure, the smaller crop sensor does typically need to use a shorter lens, but regarding DOF too, the smaller DX sensor cropping the lens image smaller is exactly the same concept as the 35mm film size cropping a 120 negative size smaller. Ratio is even similar, 60mm : 36mm = 1.67:1

No, I have no objections to a resurrected, four year-old thread filled with back and forth and back and forth and lots of posturing and stuff...as I said, I'm eager to be able to get this thread as a download. As astroNikon mentioned, it's possible that the thread will be done as a re-enactment with characters playing the parts of the various participants. Keep in mind, when some guy plays necromancer, and brings a LONG DEAD THREAD back to life, it's a good idea if that guy actually reads, and understands the OP's premise before going into an entire re-hash of the original post, based on some premise that entirely misses the point of said, dead,buried, four year-old thread. And YES, when the thread was posted, back in 2010, I knew EXACTLY WHAT THE OP MEANT about a weekend day, "and no hope of driving." So yeah, I actually did know the "details". I made a comment about that--dated 2010.

Hopefully, maybe the thread could be re-worked by a new producer/director/screenwriter crew, and maybe a brand new sequel released in theaters (and on Netflix!!!!!). Maybe a PG-13 type version, with Scarlett Johansson being the model, instead of Kundalini's kinda' ugly pink monkey... WHat an idea: a whole NEW POST, by a new director/producer/screenwriter!!!!!!!!!

I'd pay $7.50 to see that in the theater, I think.