Crop sensors need cropped lenes

[joseph james]

Perhaps this section of the essay addresses that concern:

http://www.josephjamesphotography.com/equivalence/index.htm#purpose

We can compare systems in many different ways. The five parameters of Equivalence are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison. In addition, it is important to interpret the results of the comparison in the context of the circumstances where the conditions of the comparison are valid.

The point of photography is making photos. As such, one doesn't choose the particular system to get images which are equivalent to another system. A person chooses a particular system for the best balance of the factors that matter to the them, such as price, size, weight, IQ, DOF range, available lenses, and/or operation. By understanding which settings on which system create equivalent images, the difference in their capabilities is more easily understood.

You are implying that the guy who cannot afford to spend eleven grand on a 500mm lens or thirteen grand on a 600mm lens is "artificially handicapping" the comparison when all he can use is his 400mm lens on both a FF and APS-C camera. I would call it a literal handicap, imposed not artificially, but by a real-world lack of funds.

Fair point. I have amended that portion of the Essay:

We can compare systems in many different ways. The five parameters of Equivalence (same perspective, framing, DOF, shutter speed, and display size) are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison. Of course, this is not to say that there are not most certainly instances where a photographer is limited due to size, weight, and/or finances and would therefore compare systems within those constraints. However, it is important to interpret the results of the comparison in the context of the circumstances where the conditions of the comparison are valid.

Thanks for pointing that out!

Your last paragraph there is a good one, and is entirely relevant in the case where someone has not yet already bought into a system, and has the option of determining up front which setup will best service their needs within their budget. I guess I am more concerned with the alternative case, where someone has already bought into a system, and is considering the most cost effective upgrade that will improve their results. If money is an object, and one cannot afford to buy the best lenses available for the system they already own, an upgrade from a 7D to a 7D II (assuming an increase in pixels and upgrade to AF performance and accuracy), for example, is probably better than an upgrade from a 7D to a 5D III. I am not sure your equivalence framework would help such an individual to make that determination.

Equivalence only applies when comparing systems. If you are not comparing systems, then there is no point in invoking Equivalence.

 

[jrista]

Perhaps this section of the essay addresses that concern:

http://www.josephjamesphotography.com/equivalence/index.htm#purpose

We can compare systems in many different ways. The five parameters of Equivalence are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison. In addition, it is important to interpret the results of the comparison in the context of the circumstances where the conditions of the comparison are valid.

The point of photography is making photos. As such, one doesn't choose the particular system to get images which are equivalent to another system. A person chooses a particular system for the best balance of the factors that matter to the them, such as price, size, weight, IQ, DOF range, available lenses, and/or operation. By understanding which settings on which system create equivalent images, the difference in their capabilities is more easily understood.

You are implying that the guy who cannot afford to spend eleven grand on a 500mm lens or thirteen grand on a 600mm lens is "artificially handicapping" the comparison when all he can use is his 400mm lens on both a FF and APS-C camera. I would call it a literal handicap, imposed not artificially, but by a real-world lack of funds.

Fair point. I have amended that portion of the Essay:

We can compare systems in many different ways. The five parameters of Equivalence (same perspective, framing, DOF, shutter speed, and display size) are simply guidelines to comparing systems on the basis of the most similar visual properties of the final photo, and are certainly not a mandate that systems must be compared in such a fashion. Therefore, it is important to specify the purpose of the comparison, and then not artificially handicap one or the other system with the conditions of the comparison. Of course, this is not to say that there are not most certainly instances where a photographer is limited due to size, weight, and/or finances and would therefore compare systems within those constraints. However, it is important to interpret the results of the comparison in the context of the circumstances where the conditions of the comparison are valid.

Thanks for pointing that out!

Glad to be of service. Thanks for the amendment!

Your last paragraph there is a good one, and is entirely relevant in the case where someone has not yet already bought into a system, and has the option of determining up front which setup will best service their needs within their budget. I guess I am more concerned with the alternative case, where someone has already bought into a system, and is considering the most cost effective upgrade that will improve their results. If money is an object, and one cannot afford to buy the best lenses available for the system they already own, an upgrade from a 7D to a 7D II (assuming an increase in pixels and upgrade to AF performance and accuracy), for example, is probably better than an upgrade from a 7D to a 5D III. I am not sure your equivalence framework would help such an individual to make that determination.

Equivalence only applies when comparing systems. If you are not comparing systems, then there is no point in invoking Equivalence.

Ok, good to know there is an appropriate frame of reference. I do appreciate the details you've laid out. Once I fully read the article, it all made a lot of sense. I think it may be a bit unconventional, which is why it may not be as intuitive to the average photographer. Not that the conventional way of thinking about photography is correct (it is clearly not.)

For example, I think most photographers would most likely consider photographing at f/2.8, regardless of sensor size, if they had the option and wanted a thin depth of field. That they would have to photograph at a narrower aperture on a larger sensor in order to produce equivalent results with a smaller sensor is, I think, not generally how most photographers think. Even in the context of evaluating a camera system for purchase.

 

[Loswr]

For example, I think most photographers would most likely consider photographing at f/2.8, regardless of sensor size, if they had the option and wanted a thin depth of field. That they would have to photograph at a narrower aperture on a larger sensor in order to produce equivalent results with a smaller sensor is, I think, not generally how most photographers think. Even in the context of evaluating a camera system for purchase.

I'd actually say especially in the context of evaluating a FF purchase. I think there are quite a few people out there used to shooting wide open on APS-C, whether that's f/2.8, f/1.8, or even f/1.2, who then get a FF camera and slowly come to the realization that they need to stop down to get what they're used to having within the DoF to be in focus with the larger sensor.

 

[Pi]

For example, I think most photographers would most likely consider photographing at f/2.8, regardless of sensor size, if they had the option and wanted a thin depth of field. That they would have to photograph at a narrower aperture on a larger sensor in order to produce equivalent results with a smaller sensor is, I think, not generally how most photographers think. Even in the context of evaluating a camera system for purchase.

There is another side to it. Most crop camera photographers would shoot at f/2.8 (with the 17-55, or 70-200, etc.) not because they do not want to go get shallower DOF but because they cannot (say, with those zooms). When they try FF, they may discover that more than often, there is nothing wrong with the f/2.8 DOF on FF, and learn how to shoot and compose even then. This is something difficult to evaluate before you try. I am coming from film, so I did not need much convincing.

 

[Rocky]

For example, I think most photographers would most likely consider photographing at f/2.8, regardless of sensor size, if they had the option and wanted a thin depth of field. That they would have to photograph at a narrower aperture on a larger sensor in order to produce equivalent results with a smaller sensor is, I think, not generally how most photographers think. Even in the context of evaluating a camera system for purchase.

There is another side to it. Most crop camera photographers would shoot at f/2.8 (with the 17-55, or 70-200, etc.) not because they do not want to go get shallower DOF but because they cannot (say, with those zooms). When they try FF, they may discover that more than often, there is nothing wrong with the f/2.8 DOF on FF, and learn how to shoot and compose even then. This is something difficult to evaluate before you try. I am coming from film, so I did not need much convincing.

You are basically saying the same thing as Neuro in a oppsoite way.
For someone comming from film, I am surprised that you call "Exposure Value" as "a vague term you just invented"
Every half way decent phtographer will know the difference in DOF between APS-C and FF. They do not need to physically evaluate it. Please give us fellow photographer some credit.

 

[Pi]

You are basically saying the same thing as Neuro in a oppsoite way.

No, I am saying the opposite thing. That you may find out that you do not need to stop down, very often at least.

And not everybody is coming from film, many people started with crop cameras. Give some credit to the younger generation.

For someone comming from film, I am surprised that you call "Exposure Value" as "a vague term you just invented"

I explained that already.

 

[Rocky]

You are basically saying the same thing as Neuro in a oppsoite way.

No, I am saying the opposite thing. That you may find out that you do not need to stop down, very often at least.

And not everybody is coming from film, many people started with crop cameras. Give some credit to the younger generation.

For someone comming from film, I am surprised that you call "Exposure Value" as "a vague term you just invented"

I explained that already.

I did not say you say the opposite thing. I said you are saying the same thing as Nuero in an opposite way.
Understanding DOF has got nothing to do with film and has got nothing to do with the younger generation. You are just implying that people do not understand DOF without film back ground,. That is a very blunt and offending statement.
You did not explain why you call "Exposure Value" as "a vague term you just invented". You just admitted you do not know anything about "exposure value" even with your back ground on film.

 

[Pi]

I did not say you say the opposite thing. I said you are saying the same thing as Nuero in an opposite way.

But I am not.

Understanding DOF has got nothing to do with film and has got nothing to do with the younger generation. You are just implying that people do not understand DOF without film back ground,. That is a very blunt and offending statement.

Not really. Photography is a hobby. EDIT: I stand corrected. For many, it is a profession. Most people enjoy taking photos and do not or do not want to understand the technicalities. Nothing offending with saying that. Even when you understand it, you may not know what it actually means in practice if you have not tried it. For example, the myth that f/1.2 - f/1.4 on FF means razor thin DOF, is well and alive and is often cited as a reason not to go FF because who wants to shoot with such DOF.

You did not explain why you call "Exposure Value" as "a vague term you just invented". You just admitted you do not know anything about "exposure value" even with your back ground on film.

Wrong, read again. But feel free to beat on that drum as long as you want.

 

[insanitybeard]

For example, the myth that f/1.2 - f/1.4 on FF means razor thin DOF, is well and alive and is often cited as a reason not to go FF because who wants to shoot with such DOF.

Can you expand on this? Why is this a myth? I agree it depends on a number of variables, focal length, subject distance etc, but f1.2 CAN yield a very thin depth of field. Or is it the term 'razor' you find misleading?

 

[Loswr]

For example, the myth that f/1.2 - f/1.4 on FF means razor thin DOF, is well and alive and is often cited as a reason not to go FF because who wants to shoot with such DOF.

Ahhh, so it's a myth that you can get 'razor thin' DoF at f/1.2 - f/1.4 on FF. More semantics? Or are you merely stating that DoF thinner than the length of my 5 year old's button nose is technically thicker than a razor, so a ~1 cm DoF isn't razor thin? How about the MP-E 65mm at f/2.8 and 5x mag on FF, is that razor thin? (Oh, and by the way, that's another very valid scenario in which your favorite concept, equivalence, doesn't apply - macro shooting at max magnification, the lens' MFD doesn't change with sensor format, so the FoV isn't equivalent.)

As for citing thin DoF as a reason not to go FF, I guess you're saying the great unwashed masses of hobby photographers shooting APS-C are incapable of understanding that an f/1.2 lens can be stopped down, something easily understood by someone who comprehends the concept of exposure value so thoroughly that they fail to even recognize the term. :

 

[daltech]

One of my main problems with all this kit is the weight, carrying 40Kg on a trek to a wild life photo opertunity can be a pain.

When the 7D2 comes out the thing that would get me to buy one would be if light weight lens were available with similar quality to the L series but making use of the reduced diameter needed for the smaller sensor. (While they are at it they can reduce the price as the elements aren't as big. )

The 7D is 820g, and the 5D Mark II, is 860g, not much differences !? The 1Dx at 1,340g I would notice the difference but the 7D and 5D, nope !?

If you're taking 40Kg of gears with you, perhaps you forgot to think of what you want vs. need on this outing !?

 

[Don Haines]

"Exposure Value" is a vague term you just invented.

;D

Old CR proverb say:

He who say Neuro make up stories before doing google search look like very silly fellow

( And you've got such a sophisticated nick name ! )

Love it.... I've got an old light meter, probably 40 or so years old, and it's also marked in EV.... It's nice to know it was in widespread use for a half century or more before Neuro "made it up" yesterday.... This would imply that Neuro has a time machine, so I shall never doubt his predictions!

 

[Don Haines]

Take a look at the EF 28-135 F5.6 lens and the EFS 18-135 F5.6 lens. They are the same width, the same length, within a few grams of the same weight. Surely if there was a size advantage of one format over the other, these two lenses would not be almost identical???

 

[Pi]

For example, the myth that f/1.2 - f/1.4 on FF means razor thin DOF, is well and alive and is often cited as a reason not to go FF because who wants to shoot with such DOF.

Can you expand on this? Why is this a myth? I agree it depends on a number of variables, focal length, subject distance etc, but f1.2 CAN yield a very thin depth of field. Or is it the term 'razor' you find misleading?

Since the thread was cleaned up, for a good reason, I want to reply to you again. When you focus close, it is. When not, it is not. Check out Joe's gallery (who posted here yesterday), he has amazing shots with his 50L on FF, wide open; many of them with deep DOF.

Of course, f/1.2 can yield a razor thin DOF but it does not "mean" razor thin DOF.

 

[Sporgon]

Can you expand on this? Why is this a myth? I agree it depends on a number of variables, focal length, subject distance etc, but f1.2 CAN yield a very thin depth of field. Or is it the term 'razor' you find misleading?

Since the thread was cleaned up, for a good reason, I want to reply to you again. When you focus close, it is. When not, it is not. Check out Joe's gallery (who posted here yesterday), he has amazing shots with his 50L on FF, wide open; many of them with deep DOF.

Of course, f/1.2 can yield a razor thin DOF but it does not "mean" razor thin DOF.
[/quote]






If you focus a 50mm 1.2 wide open on FF at about 70 meters you'll get from around 40 m to infinity in focus. If you focus a 40mm at f11 at about 7 meters you'll get from about 3m to infinity in focus. So in this context the 50 1.2 would be very unforgiving wide open in comparison.

I'm not sure what point you're trying to make really. The relationship between dof and magnification / distance is very old news and thoroughly documented. When an experienced photographer refers to 'razor thin' depth of field he's assuming the relationship between dof and distance is well understood.

If you're trying to suggest that a larger format is just as easy to use as a smaller one you'd be wrong. Smaller is nearly always more forgiving of technique.

 

[Don Haines]

One of my main problems with all this kit is the weight, carrying 40Kg on a trek to a wild life photo opertunity can be a pain.

I can understand your problem, but APSC lenses are not going to save any weight.

I carry a LARGE pelican case and a carbon fibre tripod on canoe trips.... The reason I have stayed with APSC is that the field of view with a 400F5.6 on APSC is about the same as a 600F4 on FF, but is obviously a lot lighter. It's all about pixels on the target.... The only way the lens is going to get any lighter is if it goes to F6.3, and that means no autofocus on most Canon bodies....(that's why no current Canon lenses are slower than F5.6)

Several people in this thread have suggested that an APSC version of a lens would need smaller elements. While this is true for the last few elements, it is not for the first elements, and that means that the lens will be just as wide and almost as heavy as the FF version. Light from the entire surface of the biggest element gets focused on the APSC sensor, so making that element smaller means raising the F number.

 

[rs]

Take a look at the EF 28-135 F5.6 lens and the EFS 18-135 F5.6 lens. They are the same width, the same length, within a few grams of the same weight. Surely if there was a size advantage of one format over the other, these two lenses would not be almost identical???

There are many examples like that, such as these two similar angle of view zooms: The EF-S 18-55/3.5-5.6 kit lens has a virtually identical size/weight as the now discontinued EF 28-80/3.5-5.6.

Edit: the EF 28-90 is even lighter than the EF 28-80.

 

[Pi]

If you focus a 50mm 1.2 wide open on FF at about 70 meters you'll get from around 40 m to infinity in focus. If you focus a 40mm at f11 at about 7 meters you'll get from about 3m to infinity in focus. So in this context the 50 1.2 would be very unforgiving wide open in comparison.

I'm not sure what point you're trying to make really. The relationship between dof and magnification / distance is very old news and thoroughly documented. When an experienced photographer refers to 'razor thin' depth of field he's assuming the relationship between dof and distance is well understood.

If you're trying to suggest that a larger format is just as easy to use as a smaller one you'd be wrong. Smaller is nearly always more forgiving of technique.

The point I made is that the popular misconception about fast lenses on FF "meaning" razor thin DOF, one eye in focus only, etc., is, well, a misconception. I read this very often as an argument against FF. They do not say it is relative to something, they do not say how forgiving it is. The m43 forums, for example, are full of such statements. It does not help that the relationship between dof and distance is well understood. They are still saying it very often. I am pretty sure that they do not mean, say, 15m is razor thin compared to 100m, stopped down. EDIT: BTW, DOF grows non-linearly with distance, making in huge even in relative terms for large distances

Another point I made: you can play with DOF calculators all day but nothing replaces actual experience. Pushing the boundaries is fun and educational. A picture is worth ... well, more than a number in a DOF calculator.

 

[schill]

Another point I made: you can play with DOF calculators all day but nothing replaces actual experience. Pushing the boundaries is fun and educational. A picture is worth ... well, more than a number in a DOF calculator.

I think the line about experience ties in with how I think about lenses on a crop camera. I shoot with a 7D now and have been using a crop body for all of my digital "life" (starting with a D60). Before that, I shot film.

When I select a lens now, I never think in terms of "what is the crop equivalent of the FF lens that I want to use?" I select a lens based on my experience with lenses on a crop camera. I know what I'll get at 200mm or 300mm. I know the effects I'll see for f/2.8 or f/4, or f/8 or anything else for that matter.

Unless you are switching back and forth between ff and crop bodies and really find you need to think in terms of what you see with one on the other, I think it's mostly a non-issue. I know what a 70-200/2.8 is going to give me on my 7D.

This weekend, I shot with a 5DIII. This is the first time I've used a ff body since I put down my Elan II E for the D60. I never used the 70-200/2.8 with the Elan II E but it wasn't confusing at all. I didn't have to think about what it would show relative to the 7D. But, I did know that in familiar situations it would help to add a 1.4x teleconverter to get the reach.

Once you are actually shooting, the whole idea of equivalence and crop vs. ff lenses becomes a lot less important. A lens is a lens and a little experience makes everything pretty simple.