Larger sensor just a luxury?

[Helen B]

Are you saying that if there were equivalent lenses for ff and crop sensor, dynamic range, noise, price, color, etc. will be the same for both formats? Resolution is already agreed on, so we're good, but for the rest I wouldn't believe it until I see it.

Speaking for myself, here's one thing I've said:

... although lenses do generally get faster as the coverage goes down, it isn't quite in proportion to the format size.

Which hopefully shows my overall practical view of this particular type of comparison.

I think I understand what you are saying now.... how about this example....

Canon 40D (x1.6 crop)
50mm @ 30mm aperture. 30 = 50/x. x=50/30. So f/stop is ~1.7.
Subject distance is 5 feet.
Depth of field is .19 feet.

5D Mk2 (FF)
Equivalent focal length is 80mm.
x= 80mm/30mm aperture... x= ~2.7
Subject distance is 5 feet.
Depth of field is ~.19 feet.

Notice that the density of the light is not the same. The crop lens must be capable of transmitting much more light than the full frame. To put it another way, if you have a lens at 2.8 on a full frame, and the same lens at 2.8 on a crop, the 2.8 lens on a full frame is capable of much smaller DoF. Is this getting close to what you are asking?

The two lenses have the same entrance pupil diameter, therefore although the 'density of the light' (illuminance) is not the same because of the different f-numbers, the 'amount of light' (luminous flux) is the same over the frame.

Where's that summary of the 231 posts in this thread???

Here's one I prepared earlier:

I'll have another attempt at summarising what EW is trying to compare. This time I'll expand on the basic conditions with the direct consequences of those conditions. These parameters are collected by reading through the thread, and they are fairly consistent, though often vaguely stated.

He's doing a 'same picture' comparison with two cameras that have different formats but the same number of sensels (same megapixels) and the same 'size' of lens.

'Same picture' in this case means:
Same subject;
Same subject distance;
Same field of view (therefore different focal lengths for the two different formats); and
Same final image size.

Same lens size has been clarified to mean same entrance pupil size. This implies:
Same luminous flux (and same radiant flux, because the two will be proportional in this case); and
Different f-numbers (a simple and obvious consequence of holding the entrance pupil the same while varying the focal length).

The consequence of having the same number of sensels and the same entrance pupil diameter is that each sensel receives the same 'amount' of light (the same luminous flux). (Of course this assumes a constant sensel area efficiency between the two formats - ie the same proportion of incident light is captured by the sensels of each format.)

The consequence of having the same entrance pupil size but different focal lengths is that the DoF is the same - so it is the 'same picture', as intended in this comparison.

End of description of conditions. ******************

While it is true that the smaller the format the easier it is to make high quality, very fast lenses there are practical and theoretical limits to this for lenses in air. There's the theoretical limit set by optics and thermodynamics: f/0.5. There's the observation that there are very few photographic lenses for any format that are faster than f/0.9. There may be a potential problem with the angles of incidence on a sensor with very fast lenses. It's a good idea, therefore, to separate the understanding of the theoretical parts of this discussion from the practical limitations, while knowing that these limitations exist.

*************************

Helen, can you decode this one?

Given that both of the lens are the same size, both will get. Since APS-C sensors' pixel are denser, the light that falls on it is also denser, given that the lens are the same size as full frame. Light in the lens in full frame is spread out more so photons will be more spread out and less dense. Not sure if I'm right too.

I cannot understand how light will become more or less dense based on the sensor it is hitting, all other things being equal of course.

Here's my translation, given the comparison parameters stated above:

Given that both of the lenses [have the same entrance pupil diameter] both will get [the same luminous flux]. Since [An] APS-C sensor's pixels are denser [than those of a larger sensor with the same number of sensels], and the light that falls on it is also denser [has greater luminance] given that the lens has the same [entrance pupil diameter] as the full frame lens [of the focal length that gives the same field of view because we are taking the 'same picture'.] [The same luminous flux] Light in [from] the full-frame lens is spread out more so photons will be more spread out and less dense.

Is that any clearer?

Or the shorter version:

I think you are asking the wrong question about luxury. As the committee has already decided, luxury shall be punished. You should be asking "Are larger sensors irrelevant?" That is much easier to answer, because everyone knows that relephants are large. Even the baby ones.

Note: EW has since accepted that he worded the original poorly.

This thread really is a mess now - it does feel like it is going round in circles, flogged to death, turning and turning in the widening gyre. The falcon cannot hear the falconer; Things fall apart; the centre cannot hold; Mere anarchy is loosed upon the world.

 

[bratkinson]

Now that the subject has been flogged to death, I've come up with a different answer than all of the above.

Luxury is in the eye/mind of the beholder.

Is driving a Cadillac rather than a Chevrolet a luxury? If you make, let’s say, $200,000 per year, a Caddy is just a ‘nice car with all the bells and whistles’. But if you are a working stiff making perhaps $40,000 per year, a Cadillac is more than a luxury, it’s an impossible dream. Perhaps to the $200K earner, a Rolls Royce would be a luxury…or a Lambourghini…

In the photography world, is a full-frame sensor a luxury? A similar question 40 years ago would have been “is a 35mm SLR a luxury?” when Kodak was selling Instamatics by the millions and there were lots of 35mm viewfinder cameras that gave good results. I know…I used both in the ‘60s and ‘70s. Ultimately, I wanted better results than what I could get with even a good quality viewfinder camera. So I bit the bullet and bought an SLR and several lenses (All Canon, by the way). I got the results I desired.

Yes, us croppers are quite aware that even better results are available with a full-frame body. When I wasn’t getting the IQ I wanted with a 30D and 2 EF-S lenses, I knew it was time to upgrade. But picking up even a used 5D II in decent condition is more than I want to pay to get a picture. So I put my money on a couple of L lenses and a 60D. For now, I’m at the point of ‘meeting the need’ to get the IQ I wanted. On the other hand, if you’re a college student, any DSLR and kit lens is a luxury! It all depends on ones’ frame of reference.

Perhaps, someday, I’ll replace or add-to my 60D with a good used 5D II. But at the moment, I’m still paying for my latest acquisitions. So, for now, a full frame body is a luxury to me...in my mind.

edit: The other side of the coin is that of a professional. Professional results usually require professional tools. So a full-frame body is a requirement...and NOT a luxury.

 

[usayit]

Unless you are a professional photographer, having a camera at all is a luxury.

(I know not really on topic... first thought that came to mind)

 

[EchoingWhisper]

Oh, again, I suggest you to read this - http://www.thephotoforum.com/forum/...larger-sensor-just-luxury-12.html#post2498739. With the same entrance pupil diameter, two lenses (in two different format) with the same equivalent focal length would produce the same depth of field and amount of light.

I think I understand what you are saying now.... how about this example....

Canon 40D (x1.6 crop)
50mm @ 30mm aperture. 30 = 50/x. x=50/30. So f/stop is ~1.7.
Subject distance is 5 feet.
Depth of field is .19 feet.

5D Mk2 (FF)
Equivalent focal length is 80mm.
x= 80mm/30mm aperture... x= ~2.7
Subject distance is 5 feet.
Depth of field is ~.19 feet.

Notice that the density of the light is not the same. The crop lens must be capable of transmitting much more light than the full frame. To put it another way, if you have a lens at 2.8 on a full frame, and the same lens at 2.8 on a crop, the 2.8 lens on a full frame is capable of much smaller DoF. Is this getting close to what you are asking?

Density of light (illuminance) is different, but amount of light hit on the surface of the sensor (luminous flux) is the same, therefore, they're as capable of transmitting light as each other, only that the light in the DX lens hit a smaller image circle, therefore light is denser.

 

[EchoingWhisper]

Crop sensors aren't bad, they just don't perform as well in low light given the same amount of pixels and the same tech in the camera, they don't provide the DOF that portrait photographers and a lot others are looking for at any given length, and if you're not specifically looking for extra reach, it gets you where you want to be with your lenses.

A canon 17-40 f/4 is nothing special on an APS-C sensor. It's an upgrade to the kit lens imho. If you toss it on a FF camera though, it because a fantastic lens.

And the reason I don't have an even larger sensor than I currently do is because of money. If prices were all the same, I'd take a medium format digital camera with a good set of primes over my 5D MKII 7 times out of 10.

Oh, again, I suggest you to read this - http://www.thephotoforum.com/forum/...larger-sensor-just-luxury-12.html#post2498739. With the same entrance pupil diameter, two lenses (in two different format) with the same equivalent focal length would produce the same depth of field and amount of light.

Oh, again, I suggest you find me a lens that I can use on an APS-C canon that's equivalent to the 24-70 f/2.8 on a FF DSLR that gives me the same DOF, apertures, distortion characteristics, and IQ.

Theory is all well and good and you can twist numbers around all you want, but until you start making your own lenses, it doesn't matter how much match you attempt to do to make a crop sensor look more appealing to you.

Olympus makes a 35-100 f/2 that's equivalent in FOV to a 70-200, most of which are f/2.8 constant aperture lenses. At f/2 and 100mm, it's still going to have a larger DOF than the 70-200 @ 200mm shooting with an f/2.8 aperture. Sure, you could find a 200mm lens to put on a 4/3 sensor, but then your field of view would be at 400mm compared to a FF camera.

Online Depth of Field Calculator

Another thing to factor in is that M4/3 and APS-C are rarely used by professionals, that's why there is less of a market to create fast (and often expensive) lenses.

 

[EchoingWhisper]

Actually, there is already a 25 mm f/0.95 designed for M4/3 - that's why I used it in my example. There are also very fast zooms that will almost cover M4/3, like a 16-44 f/1.1, 9.5 - 57 f/1.6 and 10-100 f/2.2.

I thought we'd been over all this before...

Best,
Helen

Sorry Helen, I haven't read the entire thread front to back like you have. Don't have the time, or care to.

It seems that for the price of a 25mm f/.95 I could get a 5Dmk1 and a 50mm f/1.8 (or used f/1.4) for the same price, shoot it at f/2 and get the same effect... But also have access to less prohibitively expensive lenses to get the same effects on a M43 camera (and they'll also autofocus.)

I can't find information on either of the other lenses you listed.

The reason it is so expensive is because there is a low demand for it. Those who buy it are really collectors, tell me, how many professional photographers use M4/3rds?

 

[o hey tyler]

Actually, there is already a 25 mm f/0.95 designed for M4/3 - that's why I used it in my example. There are also very fast zooms that will almost cover M4/3, like a 16-44 f/1.1, 9.5 - 57 f/1.6 and 10-100 f/2.2.

I thought we'd been over all this before...

Best,
Helen

Sorry Helen, I haven't read the entire thread front to back like you have. Don't have the time, or care to.

It seems that for the price of a 25mm f/.95 I could get a 5Dmk1 and a 50mm f/1.8 (or used f/1.4) for the same price, shoot it at f/2 and get the same effect... But also have access to less prohibitively expensive lenses to get the same effects on a M43 camera (and they'll also autofocus.)

I can't find information on either of the other lenses you listed.

The reason it is so expensive is because there is a low demand for it. Those who buy it are really collectors, tell me, how many professional photographers use M4/3rds?

That's exactly what I'm saying. I personally wouldn't get a M43 camera because of the fact that it would be extremely expensive to do what I'd want to do, but with less capabilities. I can understand people that want to shoot with those bodies, I guess. But to me, it's just not practical... Because I can get the effect I desire with a larger format with more capabilities for less money.

There may be professional photographers that use M43 cameras, but not many as their "go to" body... Or at least I wouldn't think so.

 

[EchoingWhisper]

And do take notice of my original thread title (I know I worded it wrongly), I'm not talking about the camera as a whole, but only the sensor.

 

[bazooka]

Density of light (illuminance) is different, but amount of light hit on the surface of the sensor (luminous flux) is the same, therefore, they're as capable of transmitting light as each other, only that the light in the DX lens hit a smaller image circle, therefore light is denser.

I'm not up to speed on luminous flux. Perhaps someone can school me. Here is a reference I found on a physics forum....

Illuminance is the amount of light coming from light source landing on a surface. Remember "I" in illuminance is for light incident on a surface.
Luminance is the amount of light leaving a surface. Remember "L" in luminance for leaving a surface.
Flux is the flow of light thru a surface.

How do these terms fit into photography? (Sorry if this is off-topic but it seems like it's been a long time since I've actually learned something from reading theads this long)

 

[Village Idiot]

Oh, again, I suggest you to read this - http://www.thephotoforum.com/forum/...larger-sensor-just-luxury-12.html#post2498739. With the same entrance pupil diameter, two lenses (in two different format) with the same equivalent focal length would produce the same depth of field and amount of light.

Oh, again, I suggest you find me a lens that I can use on an APS-C canon that's equivalent to the 24-70 f/2.8 on a FF DSLR that gives me the same DOF, apertures, distortion characteristics, and IQ.

Theory is all well and good and you can twist numbers around all you want, but until you start making your own lenses, it doesn't matter how much match you attempt to do to make a crop sensor look more appealing to you.

Olympus makes a 35-100 f/2 that's equivalent in FOV to a 70-200, most of which are f/2.8 constant aperture lenses. At f/2 and 100mm, it's still going to have a larger DOF than the 70-200 @ 200mm shooting with an f/2.8 aperture. Sure, you could find a 200mm lens to put on a 4/3 sensor, but then your field of view would be at 400mm compared to a FF camera.

Online Depth of Field Calculator

Another thing to factor in is that M4/3 and APS-C are rarely used by professionals, that's why there is less of a market to create fast (and often expensive) lenses.

This is wrong. The majority of cameras sold are crop sensor cameras. That's how Canon and Nikon make all their money. The 5D MKII may have been an immensely popular camera and changed the face of amateur videography, but I'm pretty sure that Canon sold many more rebels, XXD and 7D cameras than they have 5Ds. There os a much lager market to sell crop lenses to.

 

[Helen B]

Here's one opinion of the future: Trey Parker on the future of the DSLR

Not everyone wants shallow DoF, of course. In many documentary/photojournalism situations you are trying to get deep DoF in poor light. You also want to carry as little weight as possible.

Density of light (illuminance) is different, but amount of light hit on the surface of the sensor (luminous flux) is the same, therefore, they're as capable of transmitting light as each other, only that the light in the DX lens hit a smaller image circle, therefore light is denser.

I'm not up to speed on luminous flux. Perhaps someone can school me. Here is a reference I found on a physics forum....

Illuminance is the amount of light coming from light source landing on a surface. Remember "I" in illuminance is for light incident on a surface.
Luminance is the amount of light leaving a surface. Remember "L" in luminance for leaving a surface.
Flux is the flow of light thru a surface.

How do these terms fit into photography? (Sorry if this is off-topic but it seems like it's been a long time since I've actually learned something from reading theads this long)

Here's what I wrote in reply to you in post #256:

"The two lenses have the same entrance pupil diameter, therefore although the 'density of the light' (illuminance) is not the same because of the different f-numbers, the 'amount of light' (luminous flux) is the same over the frame."

Illuminance is what you call the density of the light falling on the sensor, and luminous flux is what you call the amount of light. Some people may find it easier to visualise in more common power units: illuminance (which can be measured in lux, equal to lumens/square metre) is like watts/square metre and luminous flux (which can be measured in lumens) is like watts. (a lumen is the light equivalent of a watt) In fact irradiance is measured in watts/square metre and radiant flux is measured in watts. The difference is that lumens are only watts with a spectral weighting applied so they represent a human's spectral response. Does that make more sense? I'll be more than happy to elaborate on any of this... Exhaust your subject and exhaust your audience, that's what I always say.

Best,
Helen

 

[bazooka]

Hmmm.... trying to compute, not having much success.

Ok, when I think of density of light, I think of it's brightness, but it seems my density of light concept is wrong. Or what tonal value a single pixel will have given a certain aperture. So that would be luminous flux?

And if illuminance is measured.... sorry, I think I smell smoke. I should stop thinking about physics.

 

[memento]

Oh, again, I suggest you find me a lens that I can use on an APS-C canon that's equivalent to the 24-70 f/2.8 on a FF DSLR that gives me the same DOF, apertures, distortion characteristics, and IQ.

17-55 is pretty close.

 

[bratkinson]

I don't remember my physics classes from eons ago either. But luminous flux sounds like the equivalent of gallons per minute...eg, garden hose vs fire hose...

 

[Village Idiot]

Oh, again, I suggest you find me a lens that I can use on an APS-C canon that's equivalent to the 24-70 f/2.8 on a FF DSLR that gives me the same DOF, apertures, distortion characteristics, and IQ.

17-55 is pretty close.

But at 17mm it should have more barrel distortion than a 24mm lens on a FF camera.