[dtmateojr]

You will forgive me for not subscribing to absolutes like that? The statement doesn't mean much to me anyway, since I never shot film.







Not necessarily. If the FF has the same amount of pixels, each pixel would have less noise to begin with. So the noise floor on that sensor is lower as well. Maybe your theory holds true if the pixels are the same size. But even then the random nature of noise would make for a finer pattern.

The sensels of the K5 and D800 are exactly the same. They are the same sensor that's why their REAL SNR performance are the same (see the graph I posted). Sensel size matters NOT sensor size. That's why in film, higher ISOs have bigger granules (more grainy). In film a 135 frame or a 8x10 sheet of Velvia are exactly the same emulsion. Same is true with K5, D7000, D800, D810. They differ in the CPU but sensor is the same.

Anyway it doesn't matter if you believe what I'm saying. I have given you proofs from DXO. Before you buy a FF though think about whether paying more than double for what essentially is the same camera is really worth it.

[Class A]

I'm telling you, if you take a cropped shot with an A7 or 1D or 810 or whatever, the dynamic range in the cropped section does not suddenly decrease or its noise level increase!

So can we all send our crop jobs / enlargements jobs to you because you figured out how to crop into an image without increasing noise?

What does not change is noise-per-pixel or dynamic range per pixel. As the number of pixels change, of course image noise and image dynamic range are affected.

When you double the amount of pixels, you also double the range of darkest (0) to brightest (all pixels at full capacity) image values.

This increase in representation dynamic range translates into the respective increase in scene dynamic range when you increase the sensor surface. If you spread the same scene projection over a larger area (e.g. FF image circle instead of APS-C image circle) then the light intensity per pixel is lower, in other words, you have more headroom to capture brighter scene parts.

Of course it is true that physical lens apertures don't change when the format changes or properties of film emulsions don't change when one applies a physical crop. However, a reasonable comparison must take into account that different enlargement factors are involved. After all, we don't look at large format images using 9cm x 6cm prints and shots taken with the Q using 6.17mm x 4.55 mm prints.

No one can seriously argue that when looking at 8x10 prints of images taken with a 6x9 camera and the Q (same sensor technology or film emulsions) there wouldn't be a dynamic range and noise advantage to the large format.

The argument that considering output size as well is not possible as too many variations are possible is not valid since one simply needs to require the same output size for all formats, no matter what it is.

Of course, the above does not prevent anyone using a larger format to print bigger nor is it intended to make everyone take the same pictures (using different settings), thus negating possibilities of larger formats. It is just meant to provide a framework for fair comparisons when it comes to claims like "My small format lens is smaller and lighter than your large format lens, but just as bright“.

[Class A]

Here is a simple analogy that may help some to understand why changing the format does affect more than just the angle of view.

One can adapt a small format lens to a bigger format by using a teleconverter. Any APS-C lens will work fine on an FF camera when paired with a 1.5x TC. After all, a TC just enlarges the image circle of a lens.

Normally this enlargement is intended to provide a "zoom in" effect and this naturally happens when the format is kept the same and the imager (sensor or film) hence crops into the enlarged image circle. However, we can also use a TC as a format adapter.

Now everyone accepts that a TC, when used normally as a focal length enhancer, not only changes the FOV (or focal length, if you prefer to look at it this way) but also entails a light loss. A regular 1.4 TC is known to cause the loss of one stop. This light loss is not due to attenuation by the lens elements, it is caused by the cropping out of all the light that the lens collected that is now projected outside the imager (sensor or film).

Note that the 1.5 crop factor between FF and APS-C corresponds exactly to the "bit more than a stop“-advantage that is often attributed to FF, just as you would expect from using the TC format adapter approach.

So what "equivalence" tells you is that if you want to compare lenses between different formats then to make a fair comparison between focal lengths and widest apertures, you should be comparing the values after having made the lenses format compatible, e.g. by attaching a TC to the smaller format lens. The TC obviously needs to provide the correct magnification (crop factor quotient between formats) and will result in the respective modifications to the lens parameters.

P.S.: The reverse format adapter (from larger to smaller format) also exists in the form of a speed booster (e.g. by Metabones). As expected, it makes the adapted lens not only change its apparent focal length, but also its apparent widest aperture (it becomes faster). Before someone claims "marketing trick", the same speed-enhancing format changing trick has been used by Zeiss for their legendary 50/0.7 lens. The latter is constructed as a 70mm f/1 lens with an integral "condenser" (0.7x TC) attached.

[osv]

In film photography you can't even bump the ISO. The "equivalent" method is called push processing.

good grief...

"Film speed is based on an ISO number... Film with a low ISO number, from 25 to 50, is said to be “slow film” because of the slower shutter speeds required to photograph when using them. Film with an ISO from 64 to 200 is called medium speed film, while film with a rating of ISO 320 or higher is often referred to as “fast film” because it can allow for faster shutter speeds under less than ideal conditions.

...The ISO rating given to the film you buy is an optimal film speed and is the setting to use when the film will be processed normally according to the manufacturers directions. You can “push” or “pull” your film by setting your camera at a different ISO rating from the films rating and process accordingly. "
Understanding Film Speed

---------- Post added 07-13-15 at 05:55 PM ----------

I agree with everything above. You stated equivalent conditions properly (assuming similar levels of sensor technology).

he failed to mention fov, you can't have equivalence when the shots don't match:

"DEFINITION OF EQUIVALENCE
Equivalent photos are photos of a given scene that have the:

Same Perspective

Same Framing

Same DOF, Diffraction, Total Amount of Light on the Sensor

Same Shutter Speed

Same Brightness

Same Display Dimensions"
Equivalence

[drypenn]

Did they have 'equivalence wars' when film users abandoned their 'full frame' cameras for APSc or, like me, did most of us just carry on snapping and adapted to the new format without worrying about equivalence ?

They would have had such a war, but alas, there was no internet yet during that time, so they had no battlefield to conduct the war!

Isn't technology a wonderful thing?

[dtmateojr]

good grief...



"Film speed is based on an ISO number... Film with a low ISO number, from 25 to 50, is said to be “slow film” because of the slower shutter speeds required to photograph when using them. Film with an ISO from 64 to 200 is called medium speed film, while film with a rating of ISO 320 or higher is often referred to as “fast film” because it can allow for faster shutter speeds under less than ideal conditions.



...The ISO rating given to the film you buy is an optimal film speed and is the setting to use when the film will be processed normally according to the manufacturers directions. You can “push” or “pull” your film by setting your camera at a different ISO rating from the films rating and process accordingly. "

Understanding Film Speed

---------- Post added 07-13-15 at 05:55 PM ----------





he failed to mention fov, you can't have equivalence when the shots don't match:



"DEFINITION OF EQUIVALENCE

Equivalent photos are photos of a given scene that have the:



Same Perspective



Same Framing



Same DOF, Diffraction, Total Amount of Light on the Sensor



Same Shutter Speed



Same Brightness



Same Display Dimensions"

Equivalence

Box speed of film is equivalent to your digital base ISO. That's 100 for D800 and 200 for my old D700.

Push processing was implemented because you could not change the film's box speed. If you only had ISO 400 and you are shooting a concert you will have to use f-stop and shutter speed combinations as if you were shooting at ISO 3200. Then when you send your film to the lab you tell them to push by 3 stops because of the severe underexposure. The result is more grain, very contrasty and you lose a lot of DR. This is essentially what bumping up the ISO means.

End of lecture.

[osv]

Push processing was implemented because you could not change the film's box speed. If you only had ISO 400 and you are shooting a concert you will have to use f-stop and shutter speed combinations as if you were shooting at ISO 3200.

wrong again.

if you used a film speed that was too slow for the job you made a mistake.

it's no different than shooting digital at iso400 when you should have shot it at iso3200.... underexposed is underexposed, it's got nothing to do with pushing the film.

"Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to measure the sensitivity of digital imaging systems."

[audiobomber]

Sensor size does not affect how the lens behaves.

Sensor size unequivocally affects FOV. Everyone agrees there. What some don't grasp is that aperture is not a true value, it is a calculation. The diameter of the iris on a Q f/2.8 normal lens is miniscule compared to the iris diameter on an APS-C f/2.8 normal. That affects the image, and it's not just FOV.

All you need to know about equivalence is, if you can take the picture you want on one camera, you can probably take it one format larger or one format smaller, the odds are 95% in your favour. But honestly, most of us know what to do with the camera we have to get the picture we want. Not because we understand equivalence, but because we've spent a lot of time learning our camera. Does the theory of equivalence mean you don't have to learn your bigger format camera? You can just think APS-c and use equivalence? Not at all, you still have to learn your new camera system.

I use equivalence with my a6000 and focal reducer. I translate FF parameters into APS-C. For example, when I use my A 135mm f2.8, I think of it as a 90mm f2 lens on APS-C. because that's what I understand. Thinking of it as a 135mm f2.8 on FF doesn't mean anything to me. 90mm f/2 I understand implicitly.

It is just meant to provide a framework for fair comparisons when it comes to claims like "My small format lens is smaller and lighter than your large format lens, but just as bright“.

So true! I've given up trying to explain to an acquaintance why his f2.8 bridge cam is not as capable as my Pentax 55-300mm f4-5.8.

Here is a simple analogy that may help some to understand why changing the format does affect more than just the angle of view.

One can adapt a small format lens to a bigger format by using a teleconverter.

The reverse format adapter (from larger to smaller format) also exists in the form of a speed booster (e.g. by Metabones). As expected, it makes the adapted lens not only change its apparent focal length, but also its apparent widest aperture (it becomes faster).

Excellent analogies.

he failed to mention fov, you can't have equivalence when the shots don't match:

"DEFINITION OF EQUIVALENCE
Equivalent photos are photos of a given scene that have the:

Same Perspective

Same Framing

Same DOF, Diffraction, Total Amount of Light on the Sensor

Same Shutter Speed

Same Brightness

Same Display Dimensions"

Good list, but Norm did account for FOV in the next post:
"Nikon D800 at ƒ4 and 50mm at 10 feet away has a DoF 8' 8.9 inches to 11'8" approx. 3 feet.
A nikon D7000 at 33mm @ ƒ2.8.. and 10 feet away has a DoF of 8' 7.8 to 11' 10" approximately 3 feet."

[dtmateojr]

wrong again.

if you used a film speed that was too slow for the job you made a mistake.

it's no different than shooting digital at iso400 when you should have shot it at iso3200.... underexposed is underexposed, it's got nothing to do with pushing the film.

"Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to measure the sensitivity of digital imaging systems."

Whatever mate
I still shoot a lot of film and I develop them as well. Reading from the internet and applying your own interpretation to the point of bending the physics of photography will get you nowhere. Carry on.

[normhead]

There is only one way to understand the difference between lenses used on different formats. Look at images. All this messing around with formulas does nothing. Look at the images and you realize 50mm FF is not the same as 35mm APS-c. It may be equivalent in FoV and DoF with proper adjustments, but in the end, it's just not.

I shoot most of my stationary subjects at every f-stop form ƒ2.8 to ƒ11 and then pick the one I like most. You have to do the same with an equivalent lens in FF or APS-c. And I can't believe you guys don't know your camera systems well enough to see a shot and "go in your head 50mm FF or, 70mm APS-c" That info should come to mind as soon as you see the scene with the camera in your hand. Honestly, if you're doing calculations in your head, I suspect you're missing out. Many times the issue is "what lens do I want to use for this picture" and it has nothing to do with format. There are times when you look at a scene and say "21 ltd." and that's what you want to use, even if you have to walk forward or back, because that lens renders the way you want that image to look. And no the 31 on FF isn't the same. That's the thing I understand least about all this emphasis on formulas and equivalence. I don't think focal length. I think how do I use the lens I think best suits the scene I have in front of me. Working out focal lengths is probably the last thing going through my mind. Accept for the crucial decision on how long a lens I want and how much I want to narrow or expand my FoV, behind my subject.

it's got nothing to do with pushing the film.

Of the stupid things you've said, that pretty much takes the cake. But here let me explain it to you again, even though you'll just claim I'm wrong....
When you push film you intentionally underexpose and then over develop. It's a basic technique that was taught in the first year of every photography class, ever. It essentially increases your ISO, and contrast, but also increases your grain size.

I do the same thing in digital, by exposing to the left which is in essence an underexposure, I then use the levels control to make full use of the limited dynamic range I've captured, effectively increasing my ISO, and because of the structure of digital files, my contrast, but also increase my noise, very much like film.

But hey dude, don't bother telling me I don't know what i'm talking about again, I know what you think of me, and so does everyone else. This is for anyone starting out who might be confused by the amount you think you know, that you know nothing about.

[Lowell Goudge]

There is only one way to understand the difference between lenses used on different formats. Look at images. All this messing around with formulas does nothing. Look at the images and you realize 50mm FF is not the same as 35mm APS-c. It may be equivalent in FoV and DoF with proper adjustments, but in the end, it's just not.

I shoot most of my stationary subjects at every f-stop form ƒ2.8 to ƒ11 and then pick the one I like most. You have to do the same with an equivalent lens in FF or APS-c. And I can't believe you guys don't know your camera systems well enough to see a shot and "go in your head 50mm FF or, 70mm APS-c" That info should come to mind as soon as you see the scene with the camera in your hand. Honestly, if you're doing calculations in your head, I suspect you're missing out. Many times the issue is "what lens do I want to use for this picture" and it has nothing to do with format. There are times when you look at a scene and say "21 ltd." and that's what you want to use, even if you have to walk forward or back, because that lens renders the way you want that image to look. And no the 31 on FF isn't the same. That's the thing I understand least about all this emphasis on formulas and equivalence. I don't think focal length. I think how do I use the lens I think best suits the scene I have in front of me. Working out focal lengths is probably the last thing going through my mind. Accept for the crucial decision on how long a lens I want and how much I want to narrow or expand my FoV, behind my subject.

.

But Norm, Honestly now..........

Why, oh why should we go out and use our cameras and learn, when we can be so much more wasteful of our time arguing about formulas.

While I am often one who uses formulas, especially when it comes to explaining how big (or not) a subject will be in the sensors field of view with a given lens at a given distance , for example, I also go out and shoot. And think about shooting from different perspectives with different lenses etc.

I agree with you 100%, Theory is great, especially for explaining why, but most people miss the application side, specifically how to take the theory, and use it to their advantage with their kits, they are too fixated on duplicating precisely someone else's work, hence all this talk about equivalence as opposed to discussing the resultant photos

[bossa]

Here is a simple analogy that may help some to understand why changing the format does affect more than just the angle of view.

One can adapt a small format lens to a bigger format by using a teleconverter. Any APS-C lens will work fine on an FF camera when paired with a 1.5x TC. After all, a TC just enlarges the image circle of a lens.

Normally this enlargement is intended to provide a "zoom in" effect and this naturally happens when the format is kept the same and the imager (sensor or film) hence crops into the enlarged image circle. However, we can also use a TC as a format adapter.

Now everyone accepts that a TC, when used normally as a focal length enhancer, not only changes the FOV (or focal length, if you prefer to look at it this way) but also entails a light loss. A regular 1.4 TC is known to cause the loss of one stop. This light loss is not due to attenuation by the lens elements, it is caused by the cropping out of all the light that the lens collected that is now projected outside the imager (sensor or film).

Note that the 1.5 crop factor between FF and APS-C corresponds exactly to the "bit more than a stop“-advantage that is often attributed to FF, just as you would expect from using the TC format adapter approach.

So what "equivalence" tells you is that if you want to compare lenses between different formats then to make a fair comparison between focal lengths and widest apertures, you should be comparing the values after having made the lenses format compatible, e.g. by attaching a TC to the smaller format lens. The TC obviously needs to provide the correct magnification (crop factor quotient between formats) and will result in the respective modifications to the lens parameters.

P.S.: The reverse format adapter (from larger to smaller format) also exists in the form of a speed booster (e.g. by Metabones). As expected, it makes the adapted lens not only change its apparent focal length, but also its apparent widest aperture (it becomes faster). Before someone claims "marketing trick", the same speed-enhancing format changing trick has been used by Zeiss for their legendary 50/0.7 lens. The latter is constructed as a 70mm f/1 lens with an integral "condenser" (0.7x TC) attached.

Well said.

I tried to simplify this idea even further by using a magnifying glass as an example, which was decried instantly so I didn't bother to reply.

Also, the inverse square law regarding light fall-off, must play a factor in helping FF lenses on APS-C due to the smaller distance to the sensor, although I haven't worked out by how much.

---------- Post added 14-07-15 at 01:57 PM ----------

That's because the equivalence magic only happens when you view the picture ...

Before you view the picture it is both alive and dead.

---------- Post added 14-07-15 at 02:02 PM ----------

But Norm, Honestly now..........

Why, oh why should we go out and use our cameras and learn, when we can be so much more wasteful of our time arguing about formulas.

While I am often one who uses formulas, especially when it comes to explaining how big (or not) a subject will be in the sensors field of view with a given lens at a given distance , for example, I also go out and shoot. And think about shooting from different perspectives with different lenses etc.

I agree with you 100%, Theory is great, especially for explaining why, but most people miss the application side, specifically how to take the theory, and use it to their advantage with their kits, they are too fixated on duplicating precisely someone else's work, hence all this talk about equivalence as opposed to discussing the resultant photos

Equivalence is a useful concept while people are moving between formats, but after a while one doesn't think about it anymore. I started out with a K2, LX and MX back in the day and so I thought in terms of FF glass. When I finally got a K5 I had to relearn my relationships with Aperture, DOF, FOV and FL. After a while, as you say, you learn the nature of the gear and format doesn't really count as long as you are familiar with the gear and know how to achieve what you want.

[starbase218]

What I don't understand is this. Compact cameras and APS-C relate to each other as APS-C and fullframe do, right? Actually, the crop factor is bigger there, so any differences are a lot more obvious. I can't imagine anyone not having used a compact camera. I have an Olympus Tough TG-2 myself. So if you want to know the differences and similarities between APS-C and fullframe for yourself, just look at those formats, then imagine the fullframe goes one step further than APS-C.

edit: or, do this for fun: put a wide-angle lens on your K-3 or K-5 or whatever and force yourself to crop each image in post. Same idea. Maybe you could even use the markings on the focusing screen for framing reference (the two [ and ] lines)

[dtmateojr]

Well said.

I tried to simplify this idea even further by using a magnifying glass as an example, which was decried instantly so I didn't bother to reply.

Also, the inverse square law regarding light fall-off, must play a factor in helping FF lenses on APS-C due to the smaller distance to the sensor, although I haven't worked out by how much.

---------- Post added 14-07-15 at 01:57 PM ----------

The inverse square law does apply where distance is the focal length. So even if the aperture is larger for FF the focal length will reduce the light hitting the sensor. And that's why a f-stop is a f-stop regardless of format.

[dtmateojr]

What I don't understand is this. Compact cameras and APS-C relate to each other as APS-C and fullframe do, right? Actually, the crop factor is bigger there, so any differences are a lot more obvious. I can't imagine anyone not having used a compact camera. I have an Olympus Tough TG-2 myself. So if you want to know the differences and similarities between APS-C and fullframe for yourself, just look at those formats, then imagine the fullframe goes one step further than APS-C.

edit: or, do this for fun: put a wide-angle lens on your K-3 or K-5 or whatever and force yourself to crop each image in post. Same idea. Maybe you could even use the markings on the focusing screen for framing reference (the two [ and ] lines)

The problem with P&S is that they cram too much sensels on such tiny sensors. As previously stated, sensel size matters. That's why even in FF cameras, there are differences in performance. My D700 outperforms the D800. The K5 outperforms the K3. The biggest factor is sensel size. Older sensors outperforming newer sensors and SNR differences in identical formats is proof that sensor size does not matter.

P&S should stick to 8Mp max. 8Mp is big enough even for 2m-wide prints.