# How many lenses could you mount on a 5DMkIII?



## jc88 (Oct 29, 2010)

With rumours flying around about a 25mp+ 5DMkIII likely to see our stores next year, how many of the current lineup of Canon lenses have the resolving power to utilise such a large sensor?

Honestly I see this move to big sensors as an excuse for Canon to update their lenses and bully consumers into update their current equipment if they want to utilise a new FF system with proper AF. /2cents.


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## Grendel (Oct 29, 2010)

Pretty much any lens that came out during the last year or so and then some. I don't think that there will be a shortage of good lenses for a 25MP FF.


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## epsiloneri (Oct 29, 2010)

jc88 said:


> With rumours flying around about a 25mp+ 5DMkIII likely to see our stores next year, how many of the current lineup of Canon lenses have the resolving power to utilise such a large sensor?



It's hard to know, because the way lenses are measured (at least at review sites) they use current generation Canons that would not sample the lens at that resolution in FF. For the central APS-C part you can compare to, say, 7D pixel densities (which are much higher than the current FF lineup). For the region in FF outside APS-C I don't know how you would know (unless the current lenses are already oversampled).



jc88 said:


> Honestly I see this move to big sensors as an excuse for Canon to update their lenses and bully consumers into update their current equipment if they want to utilise a new FF system with proper AF. /2cents.



I see nothing wrong with that... if you really want/need the higher resolution you're welcome to, but it's not like they're forcing you. The lenses you have wont get worse.


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## jc88 (Oct 29, 2010)

epsiloneri said:


> jc88 said:
> 
> 
> > Honestly I see this move to big sensors as an excuse for Canon to update their lenses and bully consumers into update their current equipment if they want to utilise a new FF system with proper AF. /2cents.
> ...



You haven't considered the number of people who will upgrade from a 5DMkII for reasons other than a larger sensor, such as those moving away from the awful AF system.


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## Flake (Oct 29, 2010)

Not very long ago I posted a piece on the theoretical resolution of lenses, and it's not as simple as some might believe. The actual maxima depends on the colour because of the wavelength of light.

Of greater importance is the resolution at the borders and the corners. On the current 5D MkII lenses like the 17 - 40mm f/4 L have virtually no resolution in the corners wide open at 17mm. When images are reduced in size the resolution across the image is reduced and the effect can be very noticeable. On a camera with fewer MP (such as the D3) this effect is no where near as noticeable because the difference between the centres & the borders is less. The solution would be a complete new lens mount with a larger image circle, or perhaps a different sensor shape, square perhaps, or even circular. We are still being driven by the legacy of 35mm film Leica has broken the mould with the S2, but I somehow doubt that many Canon users would be pleased if their precious lens collections was suddenly obsolete. (I wouldn't!)

As for replacement of lenses it's never going to be a perfect solution, no matter how good a lens is physics dictate that the corners will never be as good as the centre, the question each individual has to decide on is how good does it need to be for you to say it's good enough?


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## epsiloneri (Oct 29, 2010)

jc88 said:


> You haven't considered the number of people who will upgrade from a 5DMkII for reasons other than a larger sensor, such as those moving away from the awful AF system.



I don't see how an increased pixel count nor improved AF is going to force people to update their lens collection. It's not like their current lenses would perform worse with a new camera (hopefully...). I agree that an increased pixel count doesn't _add_ much if you're oversampling your lens resolutions, but it doesn't make the lenses worse. The only problem would be file sizes, if you insist on shooting full resolution and don't have the resources to back it up. Low S/N could be another area, unless you can bin efficiently. But let's not exaggerate those problems, it will not be a factor 2 different. It will in any case not force anyone to buy new lenses.


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## epsiloneri (Oct 29, 2010)

Flake said:


> no matter how good a lens is physics dictate that the corners will never be as good as the centre



Are you saying it is physically impossible to construct a lens which is better in the corners than in the centre?


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## Flake (Oct 29, 2010)

Yes!
Cosine 4 applies to the edges so does Cosine 3 I've never seen a lens even perform as well at the corners and edges as the centre on a 35mm system. Of course some are better than others, and if you use a FF lens on a crop system there's less of a problem, but you aren't using the corners & edges


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## Justin (Oct 29, 2010)

The sensors aren't bigger. They are denser. When you compare the APS-C sensors with the full frame ones, the density is still not close. What you have to worry more about is what one poster described as the relative resolved resolution in the center versus the corners. With older lens designs we will continue to see the contrasts between these areas of the image exacerbated. I'd guess the 100 2.8 IS L, 17 and 24 tse, 70-200 2.8 IS L II, and most of the super telephoto lenses vers. I and II will shine corner to corner on a new dense 30+ mpx sensor. Older lenses, less so. What I resent is that the new tech starts out at msrp and drops precipitously within 6-9 months then levels off or goes up over time. There shouldn't be such a penalty for first adopters. While not really analogous in terms of tech, I appreciate Apple's behavior with its pricing. I just wish as early adopters didn't get penalized so much for being willing to try new tech. 



jc88 said:


> With rumours flying around about a 25mp+ 5DMkIII likely to see our stores next year, how many of the current lineup of Canon lenses have the resolving power to utilise such a large sensor?
> 
> Honestly I see this move to big sensors as an excuse for Canon to update their lenses and bully consumers into update their current equipment if they want to utilise a new FF system with proper AF. /2cents.


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## Edwin Herdman (Oct 29, 2010)

Re: How many lenses could you mount on a 5DMkIII?

The answer is...one at a time!

"Resolving power" and all these other close-if-not-entirely-subjective criteria people put in...you can have a "sharp enough" 50mm but it won't take the place of a 300mm or a wide angle, so you have to shoot with what you've got.

In terms of the question about whether Canon has enough lenses to resolve new sensors...I'm sure they're working on it.


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## kubelik (Oct 29, 2010)

Edwin Herdman said:


> Re: How many lenses could you mount on a 5DMkIII?
> 
> The answer is...one at a time!



haha, this is probably the most accurate answer of all. people are currently using lenses on their 5D and 5DII's that aren't capable of resolving at the necessary level ... doesn't mean you can't go out shooting with those lenses. I've even grabbed shots with my clunky old Sigma 70-300 Macro on the 5DII when I didn't have anything else at hand ... not the best shots, but far from terrible.

a lot of people on this forum will recommend less pixel peepeing, less stressing over is-my-gear-good-enough?, and more thinking about is-my-photography-good-enough? ... I'm one of those people. use whatever lenses you got and make something of it


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## richy (Oct 29, 2010)

Plenty of lenses will work just fine. Re the 'awful' AF, thats just daft. Sure it isn't as great as a 1 series but it doesnt cost as much either. AF issues are more likely due to a lack of skill.

On corner sharpness, very true, the way round it is to work to a larger image circle if its very important. TS lenses have larger image circles and un tilted / shifted they are some of the sharpest lenses across the whole frame you can get.


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## Flake (Oct 29, 2010)

The 70 - 200mm f/2.8 MkII IS L is an amazing lens, but having bought the 100mm IS L Macro to replace the previous non IS one, well I'm not so sure it's worth the extra cost. Optically it's not really any better than the old one and the H-IS is largely ineffective at macro distance. The hood only leaves a 5cm gap at macro causing shading and scaring insects away. It's completely unuseable. Then there's the issue of attaching macro flash, you need the 67C adaptor which for reasons best known to Canon is the most expensive one in the range even dearer than the 72C. Just to make things worse the filter threads on the lens are plastic (plastic threads on an L lens??!!!!!) So if the adaptor is cross threaded it ruins the lens itself! and the adaptor has to be attached & removed everytime the lens is used as the lens can won't fit without. Then there's the tripod ring which costs a whopping Â£130 but it won't work on a macro plate if you have a battery grip or a 1D series camera.

Optical excellence is one thing but surely the external design of a lens what's included and what's not, and the pricing of basic accessories count towards the whole?

If I was asked to advise if an upgrade from the 100mm f2.8 macro to the IS L version was worthwhile I'd have to say no.


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## neuroanatomist (Oct 29, 2010)

Edwin Herdman said:


> Re: How many lenses could you mount on a 5DMkIII?
> 
> The answer is...one at a time!



I think two...







(Ok, I know they're not both directly mounted on the body, but you get the idea...)

Also, technically an extender is a lens, right?


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## that1guy (Oct 30, 2010)

I'm not too worried about it on a full frame yet. Now please no one ream me a new one if I'm not saying this exactly, scientifically, correctly, but I believe the pixel density of the current 5DII is the same/similar to a 20D. That was only 8mp on a crop sensor. Considering lots of lenses work perfectly fine on the 7D which is an 18mp crop sensor (the most densely packed sensor currently) I would say that Canon probably has a little headroom over 21mp on their full frame sensors. Basically, I wouldn't worry about it


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## kubelik (Oct 30, 2010)

that1guy, that's exactly the point I was trying to make -- thanks for doing it in a more succint fashion. basically, it's a "nothing to see here, folks" kind of deal


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## that1guy (Oct 31, 2010)

kubelik said:


> that1guy, that's exactly the point I was trying to make -- thanks for doing it in a more succint fashion. basically, it's a "nothing to see here, folks" kind of deal



No problem 

Just out of curiosity, does anyone know how many MP a full frame sensor would be if it were packed w/ the same density as the 7D? Just kind of curious and not wanting to do the math ;D


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## tzalmagor (Oct 31, 2010)

that1guy said:


> kubelik said:
> 
> 
> > that1guy, that's exactly the point I was trying to make -- thanks for doing it in a more succint fashion. basically, it's a "nothing to see here, folks" kind of deal
> ...



An FF sensor is 2.6x larger than the 7D sensor, so 18MP * 2.6 = 46.8


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## downtime (Nov 3, 2010)

Yes, it would be 46.8 is correct at the same pixel density as the 7D (5.4mp/cm2)
But if you use the same pixel density as the 5D MKII which is 2.4mp/cm2 then it would be a 21 megapixel sensor.
I think my math is right. Maybe the mathmagicians can check that. 
I'm a bit picky when it comes to pixel density. Especially when buying point and shoots. But from the impressive quality I've seen from the 7D I'm optimistic that we could see a fantastic image from a 48 MP sensor in a 36 x 24 mm format.
Though I think it might need a quad core DiGIC 6 processor haha!


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## scalesusa (Nov 5, 2010)

Certainly every EF lens that Canon has ever made will out resolve it. 

28MP is not a horribly high pixel density on FF, about 5.5 micrometer photosite size, slightly smaller than a 40D (5.7) but larger than a 50d (4.7).


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## tzalmagor (Nov 5, 2010)

downtime said:


> I'm a bit picky when it comes to pixel density. Especially when buying point and shoots. But from the impressive quality I've seen from the 7D I'm optimistic that we could see a fantastic image from a 48 MP sensor in a 36 x 24 mm format.



That's assuming the full frame lens performs as well as the APS-C lens at the corners, which would mean a lot more $s.

Canon's new EF lenses are so expensive, I'm already considering either a downgrade to the 7D or a switch to the Nikon D700. I'll wait until the end of Canon's lenses year (I expect nothing special, but I need time to save some cash anyway) and decide.


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## jouster (Nov 5, 2010)

downtime said:


> Yes, it would be 46.8 is correct at the same pixel density as the 7D (5.4mp/cm2)
> But if you use the same pixel density as the 5D MKII which is 2.4mp/cm2 then it would be a 21 megapixel sensor.
> I think my math is right. Maybe the mathmagicians can check that.
> I'm a bit picky when it comes to pixel density. Especially when buying point and shoots. But from the impressive quality I've seen from the 7D I'm optimistic that we could see a fantastic image from a 48 MP sensor in a 36 x 24 mm format.
> Though I think it might need a quad core DiGIC 6 processor haha!



Your math is right, but I don't understand the calculation. Obviously, using the same pixel density as the mark ii will yield 21MP, because the mark iii will almost certainly have the same size sensor. The mark ii is 21 MP now, so no surprise there. I doubt the mark iii will have the same number of pixels.


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