Is the Canon EOS R7 the next camera to be announced? [CR2]

[privatebydesign]

I'm not sure I understand this statement: "if you crop all else being equal you change DoF."

When I first read this it sounded like you were saying that If I take a 3000 x 2000 px. image in photoshop and crop out a 1000 x 500 section of that image that the depth of field magically changes. I can understand how the perception would change if you change the viewing distance or enlarge the image, but why would the depth of field change simply by cropping an image? Certainly that image is already set in stone, so to speak, and cropping alone could not change the depth of field.

After re-reading what you wrote, I now interpret your statement to mean that cropping a full frame image down to the same dimensions as an APS-C image will produce the exact same image and depth of field. (all other factors being equal). That, by the way, is exactly what I have said in this discussion. But, is it really correct to say that you are changing the depth of field? Isn't the depth of field for that cropped portion of the image exactly the same as it was before the cropping? How could the depth of field possibly be changed by simply throwing away pixels?

I think the aspect of this you truly don’t grasp is that the final output magnification (how big the subject is on screen or in print and how close you are to it) is fundamental not only to equivalence but to depth of field as well.

In your first scenario where you simply crop out the center 1000 x 500 pixels of your 3000 x 2000 image and that center section remains the same size then the dof stays the same, however that is not equivalence because your image is now smaller. If you enlarge that center section to the same area of your original image then yes, the dof reduces. You are applying a crop factor of 0.31 so your dof reduces by that factor. That is if your uncropped image was shot at f4 the cropped portion when reproduced at the same area as the entire shot has 4 x 0.31 applied, or equivalent dof of f1.24.

In a real world situation like that you are talking about the ‘focal length limited’ situation. Do this to prove this to yourself. Take a picture of a distant small bird at f8, your dof calculator says at f8 and the focus distance you should have 18” of depth of field. When the entire image is on your screen the bird looks totally in focus. Now zoom in to 100%, that is the same as cropping or using a crop sensor. Suddenly only half the bird is in focus, what changed? Only the magnification. But if we agree that is the same as cropping or using a crop camera that proves that to all intent and in practical understanding the sensor size (or the amount of a sensor area you use) impacts the dof.

Don't forget dof is what is in acceptable focus. In the entire frame the bird is entirely acceptably sharp, yet when viewed at a larger magnification suddenly the tail feathers and one foot are not acceptably sharp.

I'm also interested in your other statement:

"Depth of field relies on only two factors after you determine what is ‘acceptable focus’. The size of the lens pupil. The size of the subject as you are looking at the image output. THAT IS IT."

I certainly don't disagree with your statement as a scientific fact. But from a practical matter, how does this differ from saying (as I did) that depth of field is determined by aperture, focal length and distance to subject? Hardly anyone knows the size of the lens pupil of their lenses. You probably do, but most people don't. So why is it not acceptable shorthand to use the aperture and the focal length? Two things that people do know.

Similarly, why is "distance to subject" not an acceptable shorthand for "size of the subject as you are looking at the image output." Here, I understand that we may be talking about different things when we refer to "subject." I am thinking about the typical situation where one is taking a picture of another person. Generally speaking, how close the photographer is to that person (coupled of course, with the focal length of the lens) will determine the size of the subject as you are looking at the image output.

In other words, if I am taking a picture of my wife with a 200mm lens on a full frame camera, I have a general idea of how much of the frame I want to fill with her face and how much I want of the background to show. I adjust my distance from subject to roughly correspond to the size of the subject that I will be looking at in the image output. At the same time, if I want to decrease the depth of field for the background, I may adjust the distance between her and the background. Again, I'd like to know why this is not acceptable shorthand for your more precise technical definition.

Because aperture, focal length and distance to subject don't include other variables required to determine dof; magnification and 'acceptable focus'. It's like asking the question 2x?=?, your wording doesn't give anybody enough information to determine the dof. Find a dof calculator that only requires aperture, focal length and distance to subject to work out the dof, they all require more information than that, principally sensor size. Sensor size determines the CoC or commonly accepted 'acceptably sharp', and once you know that CoC, or factor for acceptably sharp, you can determine the rest. But it is all predicated on same sized output in your comparison.

Distance to subject in isolation tells you nothing about dof.

 

[neuroanatomist]

Find a dof calculator that only requires aperture, focal length and distance to subject to work out the dof, they all require more information than that, principally sensor size. Sensor size determines the CoC or commonly accepted 'acceptably sharp', and once you know that CoC, or factor for acceptably sharp, you can determine the rest. But it is all predicated on same sized output in your comparison.

Tried that approach. But hey, maybe the second third eighth seventeenth try will succeed.

 

[Lee Jay]

I think the aspect of this you truly don’t grasp is that the final output magnification (how big the subject is on screen or in print and how close you are to it) is fundamental not only to equivalence but to depth of field as well.

In your first scenario where you simply crop out the center 1000 x 500 pixels of your 3000 x 2000 image and that center section remains the same size then the dof stays the same, however that is not equivalence because your image is now smaller. If you enlarge that center section to the same area of your original image then yes, the dof reduces.

This is all correct, I'm just going to provide a visual aid. Same image.

 

[tbgtomcom]

I was watching a Peter Gregg video on this rumor, he specifically mentioned this site. He's saying there's no way that this would be a crop sensor camera because it's a single digit camera model number. Apparently Peter never heard of the 7D which was crop sensor even though the 1D, 5D and 6D were all full frame. I'm encouraged by the talk of a crop sensor for the lineup and hope that it uses the 90D sensor.

 

[neuroanatomist]

I was watching a Peter Gregg video on this rumor, he specifically mentioned this site. He's saying there's no way that this would be a crop sensor camera because it's a single digit camera model number. Apparently Peter never heard of the 7D which was crop sensor even though the 1D, 5D and 6D were all full frame. I'm encouraged by the talk of a crop sensor for the lineup and hope that it uses the 90D sensor.

I guess he's never heard of the M2, M3, M5 or M6 either.

 

[AlanF]

The last thing Boris needs now is to be attacked on Canon Rumors.
He never made any claims about sensor size and depth of field.
He only said the chances of getting a shallow depth of field with an Olympus micro 4/3are the same as getting decapitated by a frisbee or of finding Elvis.
It could be the last straw and force him to resign fire some more minions

Did you mean his getting even a shallow depth of feeling?

 

[Blue Zurich]

I was watching a Peter Gregg video on this rumor, he specifically mentioned this site. He's saying there's no way that this would be a crop sensor camera because it's a single digit camera model number. Apparently Peter never heard of the 7D which was crop sensor even though the 1D, 5D and 6D were all full frame. I'm encouraged by the talk of a crop sensor for the lineup and hope that it uses the 90D sensor.

Does he have a video on equivalence?

 

[unfocused]

First of all, thanks for responding in a polite and reasonable manner. I really need to get some work done this afternoon, but I also want to beat this dead horse just a bit longer because I think you and I are pretty close to understanding one another. My apologies to all the other forum participants who have had to endure this overly long discussion.

I think the aspect of this you truly don’t grasp is that the final output magnification (how big the subject is on screen or in print and how close you are to it) is fundamental not only to equivalence but to depth of field as well.

It's not that I don't grasp this. It is that I thought it was so self-evident that it didn't need to be said.

In your first scenario where you simply crop out the center 1000 x 500 pixels of your 3000 x 2000 image and that center section remains the same size then the dof stays the same,

Yes, and that's really been my point all along.

...however that is not equivalence because your image is now smaller. If you enlarge that center section to the same area of your original image then yes, the dof reduces...

Totally understand. My error here is in the technical definition of equivalence. I believe the point you are trying to make is that when you use "equivalence" in respect to depth of field, you are using it to describe all the elements from exposure to final output, which are needed to produce an "equivalent" image.

Please indulge me for a minute here. I've long since surrendered on the use of equivalence in this way. I personally don't like it because I think it leads to confusion. I have seen too many examples here on this forum where the concept is "explained" to new photographers who then walk away thinking that an exposure of f5.6 - 1/125 sec. - ISO 400 will be different depending on the size of the sensor because someone has said that a f5.6 lens on a full frame camera is "equivalent" to an f8 lens on a crop sensor camera. To explain it simply, it's as though light meters (which you and I remember) factor in the size of the film and give a different exposure if you are using 135mm film or 120 film.

My distaste for the term is solely based on trying to avoid that confusion, but frankly, I've given up on trying to convince others to avoid using the term.

...You are applying a crop factor...In the entire frame the bird is entirely acceptably sharp, yet when viewed at a larger magnification suddenly the tail feathers and one foot are not acceptably sharp.

Never disputed any of this, never thought it was part of the discussion.

What seems to have set people off was that I tried to make the point that, all other things being equal, there is not going to be any difference in depth of field between a picture taken with a crop sensor camera and one taken with a full frame camera and cropped to the same dimensions. Exactly what you have said, but for some reason this seems to upset others. The only way that this is not true is if you begin to introduce other variables -- changing where you are standing, enlarging one image more than another, switching lenses, etc.

It's exactly the scenario we started with. If this is different from what you are saying, please explain.

As for the rest of your post, I'll accept your understanding of DOF calculation, because I have never had the need to do an extensive precise depth of field calculation. Like most people, if I want to get an idea about depth of field, I just press the depth of field preview button.

 

[privatebydesign]

What seems to have set people off was that I tried to make the point that, all other things being equal, there is not going to be any difference in depth of field between a picture taken with a crop sensor camera and one taken with a full frame camera and cropped to the same dimensions.

I don't believe that to be true, certainly people that understand equivalence would say the same thing, can you point me to posters that have said otherwise? All other things being equal includes viewing the subject at the same size.

I have seen too many examples here on this forum where the concept is "explained" to new photographers who then walk away thinking that an exposure of f5.6 - 1/125 sec. - ISO 400 will be different depending on the size of the sensor

The exposure won't be different, the image characteristics, principally the depth of field and noise will be different depending on the sensor size/film size.

My error here is in the technical definition of equivalence.

That is a semantic argument the like of which you often accuse others of. There is no difference between the definition of equivalence and the 'technical definition' of equivalence. You are either comparing apples to apples or you are not. You are comparing same sized reproduction ratio/magnification or you are not.

 

[unfocused]

The exposure won't be different, the image characteristics, principally the depth of field and noise will be different depending on the sensor size/film size.

Right. What I am saying is that new photographers who read this forum get confused between equivalence as it relates to depth of field and exposure equivalence and come away thinking that sensor size affects exposure. They get that impression because some people (not you) make statements like "an f5.6 lens on full frame is equivalent to an f8 lens on a crop sensor," without explaining that they are referring to depth of field and not exposure.

That is a semantic argument the like of which you often accuse others of. There is no difference between the definition of equivalence and the 'technical definition' of equivalence. You are either comparing apples to apples or you are not. You are comparing same sized reproduction ratio/magnification or you are not.

Sorry, I apparently didn't write this clearly enough. What I was trying to say is that equivalence has multiple definitions and they are context dependent. As we just referenced, exposure equivalence is not the same as depth-of-field equivalence. Alfred Stieglitz referred to his photographs of clouds as Equivalents, meaning they were equivalent to his thought, hopes, aspirations, despairs and fears. I did not mean anything negative by using the word "technical."

 

[Jethro]

This is all correct, I'm just going to provide a visual aid. Same image.

View attachment 202388

That was really useful, thank you ...

 

[neuroanatomist]

This is all correct, I'm just going to provide a visual aid. Same image.

Your example sums up that particular issue very effectively:


If I may be permitted to take a liberty with your example, the scenario that @unfocused seems fixated on is this one:


I don't think anyone would suggest that there's a difference in the DoF between those two images. But I don't think many people would see any point in comparing those two images.

 

[Lee Jay]

Please indulge me for a minute here. I've long since surrendered on the use of equivalence in this way. I personally don't like it because I think it leads to confusion. I have seen too many examples here on this forum where the concept is "explained" to new photographers who then walk away thinking that an exposure of f5.6 - 1/125 sec. - ISO 400 will be different depending on the size of the sensor because someone has said that a f5.6 lens on a full frame camera is "equivalent" to an f8 lens on a crop sensor camera. To explain it simply, it's as though light meters (which you and I remember) factor in the size of the film and give a different exposure if you are using 135mm film or 120 film.

My distaste for the term is solely based on trying to avoid that confusion, but frankly, I've given up on trying to convince others to avoid using the term.

The way to avoid that confusion, and the one I personally prefer, is not to teach people new to photography the concept or math of "exposure". Exposure was invented to describe relevant parameters to chemical photography. It's simply not relevant in digital photography because we have a third parameter that's easily and quickly accessible to adjust final image brightness - amplification. Whether that's accomplished in analog with ISO, in digital with digital ISO or in post in some way doesn't really matter, it all renders the concept of exposure meaningless in digital photography.

For equivalence between images across formats, what matters is total captured light, and that's where equivalent f-stop is useful for comparisons among people used to or who learned on chemical photography and are thus familiar with exposure (illuminance-time product).

 

[JasonL]

That might be true if the owner also owns a FF body. Otherwise, the R7 also would need a wide zoom, perhaps a 10-20 f/4 and a fast and small 30mm prime.

If Canon makes an R7, might they also introduce an M7 that is 90-95% common with the R7?

I really don't think the R7 (if at the 7D2 level) would be for folks using wide angle lenses. This would be for the amateur looking for a quality alternative to dropping $20K on a pro sports/wildlife kit. Anyone looking to use the R7 as a landscape, etc. camera would probably be better suited looking at the R6. Hopefully the R7 will fall around $2500, 30mpix, with R5/6 autofocus, and great low light sensor performance. I bet Canon knows that if they can deliver that they will have an instant winner with amateur sports/wildlife shooters.

 

[lote82]

I really don't think the R7 (if at the 7D2 level) would be for folks using wide angle lenses. This would be for the amateur looking for a quality alternative to dropping $20K on a pro sports/wildlife kit. Anyone looking to use the R7 as a landscape, etc. camera would probably be better suited looking at the R6. Hopefully the R7 will fall around $2500, 30mpix, with R5/6 autofocus, and great low light sensor performance. I bet Canon knows that if they can deliver that they will have an instant winner with amateur sports/wildlife shooters.

I don't think so. Maybe sports shooters aren't interested in wide angle lenses. But as a wildlife photographer it does make sense to have a wide angle lens with you. If you go hiking you are already packed with (not only but mostly) heavy tele-lenses. Having only one small and light wide angle lens (especially Aps-c only) can give you additional landscape shots while hiking. If you ask me landscape is part of "wildlife" shooting. Maybe it's only me, but I would never take an additional ff body with ff wide angle lens with me, at least for hiking.

 

[Blue Zurich]

I don't think so. Maybe sports shooters aren't interested in wide angle lenses. But as a wildlife photographer it does make sense to have a wide angle lens with you. If you go hiking you are already packed with (not only but mostly) heavy tele-lenses. Having only one small and light wide angle lens (especially Aps-c only) can give you additional landscape shots while hiking. If you ask me landscape is part of "wildlife" shooting. Maybe it's only me, but I would never take an additional ff body with ff wide angle lens with me, at least for hiking.

The 10-22 was a great fit on the 7D

 

[Stig Nygaard]

Honestly, the only real crop-dedicated lens a R7 needs is something like a APS-C RF-S 15-50mm F/2.8. Anything longer and you might as well just get the RF 100-400 or RF 600, both of which really don't cost all that much to begin with.

A wider and better version of EF-S 17-55 f/2.8 would be very fine with me too.
I also have the EF-S 15-85mm which I consider my 1st choice for standard zoom. For me that is so well balanced between size/weight, versatility and performance, than I hardly can imagine Canon could improve it much in an RF version.

But if Canon was to make one and only one APS-C lens for RF mount, my vote would go for something a bit wider than the EF-S 10-22mm & EF-S 10-18mm zooms. I imagine with the shorter flangle distance of RF mount it would be possible to make a wider zoom without sacrificing optical performance or size/weight. Something like a 9-20mm or maybe even an 8-18mm? I have Sigma's 8-16mm, but besides being a little short in the long end, it is too heavy to qualify as the default wide-angle zoom in my camera-bag.

 

[Stig Nygaard]

I really don't think the R7 (if at the 7D2 level) would be for folks using wide angle lenses. This would be for the amateur looking for a quality alternative to dropping $20K on a pro sports/wildlife kit. Anyone looking to use the R7 as a landscape, etc. camera would probably be better suited looking at the R6.

I would, and already do with my 7DII. The 7DII is a not lightweight in itself, but it has by far the best controls, features and performance for me (compared to APS-C alternatives), which is absolute top priority for my camera (I'm an allrounder, but also enjoys shooting wildlife and action).

Btw, I also have the R6 because I couldn't wait to try Animal AF. The R6 is a great camera, but APS-C is still what I want because of the system I can build around it is (for me) a better balance between size/weight, versatility and performance. I have a broad collection of lenses, but my standard APS-C based kit covering (fullframe equivalent) 16-400mm, would be much too heavy to carry around as my standard kit if it was a fullframe kit:
7DII + EF-S 10-22mm + EF-S 15-85mm + EF-S 55-250mm = 2245g (1335g lenses only)

I also have wider/faster/longer/better lenses which I can swap or add to my kit depending on what my plans are for the day. But that lens-trio fills my bag 90% of the time. And I could further (and are considering it) trim the weight of the APS-C kit by replacing the EF-S 10-22mm with the EF-S 10-18mm. People tell me it is optically equally good.

 

[AlanF]

I would, and already do with my 7DII. The 7DII is a not lightweight in itself, but it has by far the best controls and features for me (compared to APS-C alternatives), which is absolute top priority for my camera (I'm an allrounder, but also enjoys shooting wildlife and action).

Btw, I also have the R6 because I couldn't wait to try Animal AF. The R6 is a great camera, but APS-C is still what I want because of the system I can build around it is (for me) a better balance between size/weight, versatility and performance. I have a broad collection of lenses, but my standard APS-C based kit covering (fullframe equivalent) 16-400mm, would be much too heavy to carry around as my standard kit if it was a fullframe kit:
7DII + EF-S 10-22mm + EF-S 15-85mm + EF-S 55-250mm = 2245g (1335g lenses only)

I also have wider/faster/longer/better lenses which I can swap or add to my kit depending on what my plans are for the day. But that lens-trio fills my bag 90% of the time. And I could further (and are considering it) trim the weight of the APS-C kit by replacing the EF-S 10-22mm with the EF-S 10-18mm. People tell me it is optically equally good.

Canon R5 + RF 16mm + RF 24-105mm f/7.1 + RF 100-400mm = 2328g. This covers your FF-equivalent 16-400mm, and because the R5 has a pixel density only slightly less than the 7DII, it has much more reach than 250mm on the 7DII.

 

[Stig Nygaard]

Canon R5 + RF 16mm + RF 24-105mm f/7.1 + RF 100-400mm = 2328g. This covers your FF-equivalent 16-400mm, and because the R5 has a pixel density only slightly less than the 7DII, it has much more reach than 250mm on the 7DII.

It doesn't cover. There's a big (and very important) hole from 16 up to 24mm. Big loss.

Also I don't think the RF 16mm and RF 24-105mm f/7.1 are up to the optical performance I want. I considered the RF 24-105/7.1 STM to my R6, to have "something". But choose the EF 24-105 STM instead because the quality in wideangle corners looked too bad to me on the RF lens. I don't know if that was a good choice or not. But I suspect at least the EF and RF lens are very similar when it comes to optical performance. I do not consider myself a pixel-peeper, but I have to say the EF 24-105 STM was a huge impulsive disappointment when I saw my first results from that lens. But considering that both the EF and the RF lens are (less than?) half the price of what I gave for the EF-S lens, I probably shouldn't have been surprised.

Which brings me to another point about Canon's fullframe lenses for both EF and RF mount. They totally lack something between budget and L-lenses when it comes to wideangle zooms and normal-zooms. USM zooms that are close or comparable to L-lens optical performance, but in a more lightweight variable-aperture build would be much more appealing to me, but totally lacks in Canon's lineup. Yes, I know it won't completely solve my weight problem, that's why I go for APS-C. But it would still make fullframe look much more appealing to me.
And you can call the EF-S 55-250mm from my APS-C kit a budget lens - and it kind of is. But optically it is actually really good.

RF 100-400mm is however a great addition to Canon's fullframe lineup. I have bought it. Partly for my R6, but hopefully also for my future R7 (I also dream about the 100-500L, and will probably start saving, if I get that R7;-))