[BrianR]

Person APSC has a small garden. Person FF has a large garden. There is a rain downpour for one hour. Certainly the total amount of rain in Person FF's garden is larger. But will it be more wet and muddy? No.

Two different aspects have to be kept separately:

• total whatever and
• per area whatever

Both have some effects. Total --> noise, per area --> brightness

Good analogy and worth running with.

Person FF and person APSC are able to plant the same amount of tomato plants per unit area of their gardens. Chickweed per unit area is also the same on average, but it's randomly distributed around the garden and is especially prevalent in the shady areas since chickweed tolerates lower light than a tomato plant. If we plant these gardens in a warm but often overcast location like Vancouver, it's even analogous to an 18% grey target.

Person FF gets more total fruit at the end of the summer and goes on to have a saucier fall*.


*Converting your tomato harvest to sauce should be analagous to downsampling

[normhead]

I am honestly so tired of this topic, I can't bring myself to contribute....

Someone should write a sticky.

But then it's been explained a million times and folks like the above post still don't understand it, so what would be the point doing it one more time?

[Pål Jensen]

What you gain from a bigger sensor are options. With a bigger sensor you can work at shallower DoF at the same F-stop if your (longer) lens offers it, thus capture greater total amounts of light and this way improve noise level, or be further away from being diffraction-limited when stacking macros etc.

You don't gain any options with a biggers ensor; just get different options; arguably less useful ones. Getting hardly any DOF in your images, and having to to use a smaller aperture to get sufficient DOF, is not an advantage generally judging from the images people are actually taking. Besides, you get less maximum magnification with the larger format and hence less options. When it comes to macro and APS 1:1 image covers 50% more of the frame than the same on FF.

---------- Post added 03-22-16 at 02:28 PM ----------

Two different aspects have to be kept separately:

• total whatever and
• per area whatever

Both have some effects. Total --> noise, per area --> brightness

Unfortunately, some have not understood that the F:numbers on the lens, the stop system on the shutterspeed and ISO values (ie the exposure system and theory of reciprocity) are based on the latter....

[Kerrowdown]

F1.2 would be a disaster of yet another magnitude

Some of us... are looking forward to that challenge.

[normhead]

I'm putting this as a sticky on my desk top, so i never have to write it out again, anyone who'd like to suggest improvements feel free.

Equivalence

There are three components that affect an image. Field of view, and shutter speed and Depth of field. To produce an “equivalent image” all must be the same.

If we start with an image taken with an APS_c camera taken at the following settings.

ƒ5.6 , 100 ISO, 1/100s

To take the same image on a full frame sensor, the first thing you need to do is normalize the depth of field to ƒ8. If you don’t normalize the DoF you are taking different images an no comparison can be made.

Changing the shutter speed can affect motion blur in moving objects so to have the same image the shutter speed should be the same.

so we now have
ƒ8 to normalize DoF,
1/100s to normalize an motion blur

to compensate for stopping down to ƒ8 we have to increase the ISO of the full frame image, also one stop.
but in doing so, we create more noise, and let in half the light.

So the equivalent exposure on the FF will be ƒ8, 1/100s 200 ISO.

At 200 ISO the image will be created with half the total light that the 100 ISO image was created with, on the Full Frame, which happens to be the same amount of total light that the 100 ISO image will be created with on APS-c.

In the end, for an image taken with the same DoF, the same Field of View, the same time of exposure… the amount of light collected by the sensor will be the same, and the noise will be the same.

For any image that can be taken by both cameras, ( and that is about 87.5% if you count the 8 stops from ƒ1.4 to ƒ22 as your possibilities ) of all possible images, everything is the same to produce the same image.
Noise is the same
Total light is the same.
Depth of field is the same
Field of View is the same.
Shutter speed is the same.
Low light performance is the same.

That is equivalence.

The advantage to the full frame sensor is that it has one stop of narrow Depth of Field that cannot be taken on APS-c.

The advantage to APS-c is if and only if the Megapixels of both cameras are the same, there is 1.5 times more magnification with long glass or macro. That is the only way you get it all. The K-1 partially makes up for that by having 36 MP, but not completely. To completely make up the advantage the FF would have to be 51 MP as opposed to a K-3 24MP image. But the extra megapixels of the K-1 does negate any advantage of using a K-5 or any 16 MP camera, because it's the same number of megapixels in crop mode that the 16 megapixel camera is.

To get the thing that a camera excels at on one format, you have to give that up if you switch to the other format., which is why the majority of us who are contemplating a K-1 are contemplating running the two formats side by side.

That will be true, unless the pixels on the two different formats are the same size and efficiency, so that when you crop the larger format, you get exactly the same image you'd get on the smaller format. That would make the smaller format redundant, although possibly still desirable for size and weight considerations.

[Winder]

Are the Extra Dollars Worth the Upgrade to the Full Frame Sensor? | ilovehatephotography

[Pål Jensen]

Equivalence

There are three components that affect an image. Field of view, and shutter speed and Depth of field. To produce an “equivalent image” all must be the same.

One problem is that many images are DOF insensitive, this is when everything withing the image is in focus at the apertures in question. One example is at or near infinity. You can get exactly the same images DOF-wise at various aperture.

However, the main problem is that no one in their right mind buy an FF camera in order for it to be equivalent to an APS camera. You do not want the noise level of an APS camera when you buy an FF body. Presumably an APS owner will be happy with more noise. Insisting on equivalence between formats is totally futile as it negates the main reasons for different formats in the first place.

[jsherman999]

I'm putting this as a sticky on my desk top, so i never have to write it out again, anyone who'd like to suggest improvements feel free.

Good idea. No big objections, quibbles below.

Equivalence

There are three components that affect an image. Field of view, and shutter speed and Depth of field. To produce an “equivalent image” all must be the same.

This isn't really wrong, but IMO will cause confusion because shooters will wonder why you didn't say, for example, "FOV and exposure" instead, with DOF just being derived from that. You can see why writing a simple equivalence article can be difficult, most people will agree with the underlying facts when it's fleshed out, but if those facts are presented in a way or in an order they're not used to, it creates churn.

to compensate for stopping down to ƒ8 we have to increase the ISO of the full frame image, also one stop.
but in doing so, we create more noise

Yes, but it isn't actually the ISO bump that 'creates' the noise, it's the shooting at lower exposure that does. The ISO bump just shows you the noise that you created by reducing exposure.

So the equivalent exposure on the FF will be ƒ8, 1/100s 200 ISO.

Equivalent brightness, yes. ('exposure' is technically only SS and F-stop)

The advantage to the full frame sensor is that it has one stop of narrow Depth of Field that cannot be taken on APS-c.

Not just DOF - this also provides less noise and greater overall DR, when looking at sensors of similar generations.

The advantage to APS-c is if and only if the Megapixels of both cameras are the same, there is 1.5 times more magnification with long glass or macro. That is the only way you get it all. The K-1 partially makes up for that by having 36 MP, but not completely. To completely make up the advantage the FF would have to be 51 MP.

People will argue this well and there may be too much to go into here, but one thing to keep in mind is that in order to take full advantage of the 'more magnification' to have to have correspondingly sharper lenses on the smaller format.

To get the thing that a camera excels at on one format, you have to give that up if you switch to the other format., which is why the majority of us who are contemplating a K-1 are contemplating running the two formats side by side.

I think with the current choices, the only IQ-related reason to run both systems (vs. just K1) would be if you sometimes absolutely need the higher pixel density of the K3 and have the lenses and tripods and technique where it can really make a difference, and you don't want to or can't buy the longer lenses for FF that would even things out. Otherwise, the K1 can do everything the K3 can, and some things it can't.

[normhead]

One problem is that many images are DOF insensitive, this is when everything withing the image is in focus at the apertures in question. One example is at or near infinity. You can get exactly the same images DOF-wise at various aperture.

However, the main problem is that no one in their right mind buy an FF camera in order for it to be equivalent to an APS camera. You do not want the noise level of an APS camera when you buy an FF body. Presumably an APS owner will be happy with more noise. Insisting on equivalence between formats is totally futile as it negates the main reasons for different formats in the first place.

The noise level of APS-c is one stop worse than an FF at the same ISO. So, just use a lower ISO on your APS-c camera and a wider ƒ-stop and you have the the same noise. At the lowest ISO the differences are minimal anyway, I doubt you can tell the difference between 100 ISO FF and 100 ISO APS_c.

SO, no APS_c owners don't have to be happy with more noise and my post explains why. The only images where APS-c shooters have to be happy with more noise, are on those wide open images where the DoF is extremely shallow, and the FF is being exposed at a very high ISO. In the other 87.5% of the camera's range, the noise is the same.

But this is the kind of nonsense that gets tossed out there on a regular basis.

IN actual fact, from ISO 50-400 the images are pretty much noise free, on both FF and APS-c. And contrary to your statement, I often shoot at various ƒ-stops and select the image that looks best based on the total image with regards to DoF. DoF is important to IQ.

I've never actually heard a photographer say it wasn't before, this is a first.

[jsherman999]

... which in turn means that, by virtue of the smaller light intensity being offset by a proportionally larger sensor area, that the total amount of light on the sensor will be the same between both formats for a picture with the same shutter speed, same perspective and same resulting depth of field. Thus in turn you will have roughly the same noise level, referred to the entire picture (for assumed equal efficiency of the sensors).

What you gain from a bigger sensor are options. With a bigger sensor you can work at shallower DoF at the same F-stop if your (longer) lens offers it, thus capture greater total amounts of light and this way improve noise level, or be further away from being diffraction-limited when stacking macros etc.

^ Well put.

.

[i5_david]

Thank you guys. I thought I knew something about photography (technically) but it shows... I don't.
This is much to think about and read in a calm hour again, since I am not a physic-magician Thanks for the analogys that helped a lot.

I am honestly so tired of this topic, I can't bring myself to contribute....

Someone should write a sticky.

But then it's been explained a million times and folks like the above post still don't understand it, so what would be the point doing it one more time?

Hey bro, thanks for your helping. I read this forum for months and started to participate a few weeks. You can believe me one thing, if I would have seen this topic discussed somewhere in the internet before, I would have never bothered you here and think about even starting a fred. I read hundreds of articles, watched tons of videos, but this was something I have never seen explained or described. Mods should feel free to delete the thread and put a sticky... anyways, bottom line: thanks for trying to help me, mate!

[normhead]

One problem is that many images are DOF insensitive, this is when everything withing the image is in focus at the apertures in question. One example is at or near infinity. You can get exactly the same images DOF-wise at various aperture.

However, the main problem is that no one in their right mind buy an FF camera in order for it to be equivalent to an APS camera. You do not want the noise level of an APS camera when you buy an FF body. Presumably an APS owner will be happy with more noise. Insisting on equivalence between formats is totally futile as it negates the main reasons for different formats in the first place.

The noise level of APS-c is one stop worse than an FF at the same ISO. So, just use a lower ISO on your APS-c camera and a wider ƒ-stop and you have the the same noise. At the lowest ISO the differences are minimal anyway, I doubt you can tell the difference between 100 ISO FF and 100 ISO APS_c.

SO, no APS_c owners don't have to be happy with more noise and my post explains why. The only images where APS-c shooters have to be happy with more noise, are on those wide open images where the DoF is extremely shallow, and the FF is being exposed at a very high ISO. In the other 87.5% of the camera's range, the noise is the same.

But this is the kind of nonsense that gets tossed out there on a regular basis.

To give a really simple example. If you shoot a landscape at ƒ8, 1/60s 100 ISO, I can shoot ƒ5.6 1/120 100 ISO APS-c and have virtually the same noise, because at that ISO the difference is very small.

Instead of working in generalities, this will be much faster if you suggest an FF setting, ƒ stop, speed and ISO, you think the FF would have a noise advantage for. If you do the math, you'll discover, it's only true when the FF aperture is wide open, and you can sacrifice depth of field for better noise performance.

IN reference to your first point, one problem is that people buy FF cameras expecting dramatically better noise and low light performance, and what they get is marginally better noise and low light performance.

[ffking]

Did you see how shaky the video was? Must have been shot on a K-1

[jsherman999]

[LIST=1][*]Whatever sensor size you use, you get the same DoF control, that is what equivalency rules of thumb tells us:

1. on a larger sensor you can gain a tiny bit of less DoF on one extreme end if you want, but at the same time lose the option to get that tiny bit of more DoF.
2. on a smaller sensor you can gain a tiny bit of more DoF on one extreme end if you want, but at the same time lose the option to get that tiny bit of less DoF.

Yes, but keep in mind how this would map to real-world shooting - you will rarely (outside of non-stacking macro) ever find yourself in a situation where you just can't stop down any more, that the smaller format allows you greater DOF that the larger format just can't physically match - because often when you're getting into those situations, hyperfocal has already kicked in and any 'greater DOF' the smaller format would give you is just theoretical.

What typically happens is this: You feel the need to get more DOF with the larger format, so you have the option of stopping down to match the DOF (and noise/DR) of the smaller format. Done. Same DOF for both.

Or:

You would like less DOF to diffuse the junk in the background more, or to make your lovely subject 'pop' out of the frame more - but the smaller-format lens is already wide-open. Larger format gives you the option of getting that extra stop less DOF as long as you have a lens that has the same FOV and max f-stop.

Divorce the argument from aps-c vs. FF - imagine yourself shooting with the Q vs. the K5. With available lenses, with your typical subjects, which would give you the feel of more 'DOF control', the Q or the K5?

Now, apply that answer to K5 vs. K1.

.

[john.margetts]

I regularly use medium format, 35mm film (aka FF) and APS-C cameras and I don't worry about any of this at all. I am far too busy producing brilliant photographs.