[Aristophanes]

I think the driving force behind standardizing should be a labor or cost savings. Don't see any of that in standardizing crop factors.

I'd rather the photographic industry be forced to standardize on image formats, e.g. DNG RAW. Right now it appears that camera image standards are all over the map and forces thousands of owners to buy new software just so their camera images will be recognized - year after year. Thankfully, we have one voltage standard throughout the US. Thankfully, the USB connector is being standardized for electronic devices around the world instead of each manufacturer selling their own patented devices. Apparently the USB connector was developed by an Intel engineer who was tired of need to have so many different cable connectors around.

Nothing personal, but if you want to standardize something, pick something that will help mankind and our efficiency

Markets and private capital often abhor standards. They replace private contract with state regulations.

DNG has been submitted for ISO status. PDF went this route.

[Cannikin]

I'm not sure how super close, ultra shallow DOF proves any point either way. Any camera, even compacts, can get shallow DOF in absolute terms with a long enough lens or being close enough. Having a larger sensor system in such situations just means you go from an unrecognizable background to an obliterated one. That doesn't interest me in the slightest. Nor does showing a macro shot with a cell phone prove that cell phones can "do shallow DOF" in any meaningful way.

The real difference lies in wide angle shallow DOF. Being able to subtly blur a background so that it is still recognizable, and making portions "pop" out of it to give a sense of depth (what I think of as the "3D effect") is not something that's easy to do. 35mm can do it without too much effort. Smaller sensors can do it as well, but they generally require specialized lenses with more compromises involved. I took these with the E-M1 and the Voigtlander 17.5mm f/0.95 @ f/0.95:



This one tests the limits of how much blur you can get when the subject is at a distance:




Here's that last one at f/5.6. Lots of clutter, little sense of depth. Not my taste:


Now I had to use a manual focus, manual everything lens for these. Likewise, you need the Samyang 24mm f/1.4 on Pentax APS-C to do this, and believe me AF would be very handy, as nailing shallow depth of field with a wide angle is a lot harder to do manually than with a longer lens, because everything looks like it's in focus in a small viewfinder. 35mm f/1.4 on FF can do this angle of view, have shallower depth of field at a distance, and AF. And I would also like it a little wider, say 24mm f/1.4 on 35mm. The fastest APS-C (16mm f/2) and m4/3 (12mm f/1.6) lenses of this AOV cannot do this effect to a meaningful degree.

[ElJamoquio]

And yes, he said that noise is NOT related to DoF "per se" but to aperture. Yeah, he started backing down on his words. I have yet to get a reply from him regarding how he measured SNR because it defies physics LOL!

Interesting. How does it defy physics?

[jsherman999]

So which of your shots is impossible to capture with a m43 :-D

The purpose of the last few low-aperture, environmental shots were in response to your m43 shots in which you seemed to imply m43 was good for getting deeper-DOF environmental portraits. I was simply showing how you could get the same thing on larger formats by simply stopping down. (as if that should need to be shown, but your non sequitur example suggested it needed to in this case )

FF and aps-c are supersets of m43. You can always stop down the larger formats to match the smaller ones, you can't always go the other way because they don't make the lenses that would always allow that.

[cali92rs]

The purpose of the last few low-aperture, environmental shots were in response to your m43 shots in which you seemed to imply m43 was good for getting deeper-DOF environmental portraits. I was simply showing how you could get the same thing on larger formats by simply stopping down. (as if that should need to be shown, but your non sequitur example suggested it needed to in this case )

FF and aps-c are supersets of m43. You can always stop down the larger formats to match the smaller ones, you can't always go the other way because they don't make the lenses that would always allow that.

Wait a second, you can stop down a FF lens too? I thought with FF it wasn't even possible to get an entire face in focus...from the talk around here I thought FF lenses couldn't get more than an eye in focus

[dtmateojr]

The purpose of the last few low-aperture, environmental shots were in response to your m43 shots in which you seemed to imply m43 was good for getting deeper-DOF environmental portraits. I was simply showing how you could get the same thing on larger formats by simply stopping down. (as if that should need to be shown, but your non sequitur example suggested it needed to in this case )

FF and aps-c are supersets of m43. You can always stop down the larger formats to match the smaller ones, you can't always go the other way because they don't make the lenses that would always allow that.

I meant, show us a shot that cant be done with a m43. Any shot. In return, I'll show you a shot that you can't do with a full frame. Deal?

I'll give you a headstart: shoot a 300mm at 1/10s handheld.

[Cannikin]

That's why you have a lens, right? To make the light fall on the sensor. And when you have a lens, you have a f-stop. A f-stop is a f-stop regardless of sensor size, regardless of aperture. Can't you see how this relates to a tain gauge?!

And yes, he said that noise is NOT related to DoF "per se" but to aperture. Yeah, he started backing down on his words. I have yet to get a reply from him regarding how he measured SNR because it defies physics LOL!

Unfortunately, an f-stop is not an f-stop when it comes to light gathering power, no matter what many m4/3 people may chant. I am a m4/3 user, but not a fanatic, and I readily accept this reality. Ask NASA why an iPhone with an f/2.4 aperture doesn't have 100 times the "light gathering power" of the Hubble Space Telescope with its whopping f/24 (that's twenty four) relative aperture, and it is not "pixel size".

Light gathering power for a given object in the field of view (this "object" can be the entire field of view itself) is a function of absolute aperture only. This has been well-established centuries before the invention of photography.

A 50mm f/1.0 (50mm aperture) has the same light gathering power as a 100mm f/2.0 (50mm aperture). A 50mm f/2.0 has 1/4 the light gathering power of a 100mm f/2.0. Put a 100mm f/2.0 lens on any camera of any sensor size, and the total light gathered from any given object in the frame will be the same. The amount of detail resolvable for a given object will be higher for the lens with the larger absolute aperture due to diffraction (not the "diffraction limit" type which involves pixel density, but the ability to separate incoming light from adjacent points of light). Why doesn't the object get 4 times brighter then if you go from 50mm f/2 to 100mm f/2? Because then the object will take up 4 times more area in the frame, but any particular detail on the object will have 4 times more light ("signal") associated with it. Again, this "object" may be the entire field of view itself when comparing equal AOV across different formats.

This phenomenon is easily observable by shooting stars, which are very faint and small enough not to muddy the issue with sensor size/exposure area (most stars are significantly smaller than 1 pixel at common focal lengths). Put a 50mm f/1.0 or a 100mm f/2.0 on any camera of any sensor size and the lenses will be able to resolve the same stars. Put a 50mm f/2 on any camera and you will not resolve the same stars. Likewise, if you use a 24mm f/2.0 on 35mm and 12mm f/2.0 on m4/3, they will have about the same FOV, but the FF will see stars that the m4/3 will not at the same exposure settings because of light gathering power.

Relative aperture or "f-stop" is a geometrically derived shorthand for generating equal luminous flux (light per unit of solid angle) factoring out focal length assuming uniform incoming light. It is useful for one thing only: exposure, that is the same perceived brightness of incoming light. Everything else, total light gathered per FOV (and by extension SNR), resolvable detail and DOF are dependent on absolute aperture. This is why an iPhone with a tiny 1.6mm aperture will never resolve any detail as small or faint as the Hubble with its massive 2400mm aperture, no matter what the f-stops say.

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Last edited by Cannikin; 04-17-2014 at 08:50 PM.

[dtmateojr]

AFAIK a telescope cant be compared directly to a photographic lens. Will have to dig up on the explanation but you just can't compare them. With telescopes, aperture is everything.

[ElJamoquio]

With telescopes, aperture is everything.

Don't agree.

a telescope cant be compared directly to a photographic lens

Don't agree. There's crossover both ways.

[Cannikin]

AFAIK a telescope cant be compared directly to a photographic lens. Will have to dig up on the explanation but you just can't compare them. With telescopes, aperture is everything.

I don't want to muddy the issue further by delving into telescope construction, but if you find a reference explaining this please share it. I'm no expert in telescope construction, but as my understanding, they are merely simple lens (or mirror) constructions that don't need lots of corrective elements for things like a flat focal plane, distortion, focusing range or variable aperture. Since it's really just direct a optical path through it, with no internal aperture diaphragm, the aperture is merely the direct light observing area, i.e. the front objective element/the mirror, but the principles of aperture are the same.

Anyway, here's a reference that goes into the role of absolute vs relative aperture (f-stop) in light gathering for photography which deals directly with photographic lenses (scroll down to the section labeled "Clear Aperture Size"): How to Pick a Lens for Milky Way Photography – Lonely Speck

[dtmateojr]

Here's the explanation on why aperture is everything for telescopes: http://en.m.wikipedia.org/wiki/F-number

Jump to the discussion on Focal ratio in telescopes.

Everything else, total light gathered per FOV (and by extension SNR), resolvable detail and DOF are dependent on absolute aperture.

That is plain nonsense. "Absolute aperture" in millimeters would be a static value based on the actual physical reality of a physical lens diameter and the physical size of the aperture.

Put a converter on your lens and the absolute aperture doesnt change as your physical object doesnt change, but the photographic result incl. DoF changes a lot. The resulting F-Stop changes but the absolute aperture not.

[jsherman999]

I meant, show us a shot that cant be done with a m43. Any shot. In return, I'll show you a shot that you can't do with a full frame. Deal?

Do you have all the manual focus Voigtlander f/0.95 lenses for your m43? If you do, then you'll be able to approximate what I can get with my autofocus $110 50 f/1.8d, a $200 35 f/2, $285 85 f/1.8d, etc

Go for it!


BTW those are reportedly great lenses.

I'll give you a headstart: shoot a 300mm at 1/10s handheld.

So are you sticking with an equivalence discussion, or are you moving completely into the 'crop = reach' camp? It's not complete fallacy as it does show some practical shooting realities, in that with long telephoto, pixel density taken into account, with high-quality smaller formats (not P&S) you can get similar results for a lot less size and money than FF... But if money and size is not an object (think: Olympic, professional sports photographers on the sidelines - not shooting m43,) and we stick with equivalence, there's nothing an m43 camera can't do that aps-c or FF can't do there either with telephoto.

But maybe if I get time I will show an equivalent 300mm shot anyway, these threads are always better with images!

---------- Post added 04-18-14 at 07:58 AM ----------

That is plain nonsense. "Absolute aperture" in millimeters would be a static value based on the actual physical reality of a physical lens diameter and the physical size of the aperture.

Put a converter on your lens and the absolute aperture doesnt change as your physical object doesnt change, but the photographic result incl. DoF changes a lot. The resulting F-Stop changes but the absolute aperture not.

?? TC is effectively changing the focal length, though, by cropping/magnifying. Or am I misunderstanding your assertion.

[Rondec]

Do you have all the manual focus Voigtlander f/0.95 lenses for your m43? If you do, then you'll be able to approximate what I can get with my autofocus $110 50 f/1.8d, a $200 35 f/2, $285 85 f/1.8d, etc

Go for it!




So are you sticking with an equivalence discussion, or are you moving completely into the 'crop = reach' camp? It's not complete fallacy as it does show some practical shooting realities, in that with long telephoto, pixel density taken into account, with high-quality smaller formats (not P&S) you can get similar results for a lot less size and money than FF... But if money and size is not an object (think: Olympic, professional sports photographers on the sidelines - not shooting m43,) and we stick with equivalence, there's nothing an m43 camera can't do that aps-c or FF can't do there either with telephoto.

But maybe if I get time I will show an equivalent 300mm shot anyway, these threads are always better with images!

---------- Post added 04-18-14 at 07:58 AM ----------



?? TC is effectively changing the focal length, though, by cropping/magnifying. Or am I misunderstanding your assertion.

Just to put in a plug for the Voigtlanders. Yes, if you are just talking pure depth of field, they are expensive ways to get there, but the rendering of the Voigtlanders is going to be a significant step above your 50mm f1.8. Somehow, Jay, you narrow lens discussions to depth of field, whereas there are five or six other factors that determine if a lens is prized or not. You 50mm is a fine lens, but it isn't anything particularly special, either.

[jsherman999]

Just to put in a plug for the Voigtlanders. Yes, if you are just talking pure depth of field, they are expensive ways to get there, but the rendering of the Voigtlanders is going to be a significant step above your 50mm f1.8. Somehow, Jay, you narrow lens discussions to depth of field, whereas there are five or six other factors that determine if a lens is prized or not. You 50mm is a fine lens, but it isn't anything particularly special, either.

Granted. We were sticking to an equivalence discussion (I thought,) but it's true, the two VL lenses are going to be sharper - but they need to be, as their results are magnified 2x compared to FF. And although a garden-variety 50mm is 'nothing special', all 50mm's are pretty doggone sharp, even sometimes at f/2. My 50 1.8D does very well on my D800. There may be other IQ factors like color transmition, flare control and bokeh too.

Two big factors to keep in mind: The VLs are MF only, and the 17 and 25 go for over $2000 combined. If you're choosing m43 for cost reasons and want to shoot widish-normal to approximate FF, you just blew your cost control

But if you want to shoot m43, cost doesn't matter and you're OK with MF... that's a pretty sweet combo (good M43 body + VL 17 + 25f/0.95) although the VL's aren't small.

.