L Lenses for crop bodies

[candc]

the aps-c system is wider, the ff longer on the tele end. the 200-400 has a built in extender getting you 560 f5.6 the sigma is 300 x 1.6=480 f2.8 and the ff system has better iso performance so the aps-c system uses faster lenses to help compensate for this.

The Sigma is 480/4.5 equivalent and will be so soft on crop at that FL that the 100-400 for a fraction of the cost will be better on FF, even if you apply NR to reduce the 2/3 stop difference.

See here how the Sigma performs on FF, and imagine how would be on crop:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=113&Camera=453&Sample=0&FLI=7&API=0&LensComp=803&CameraComp=453&SampleComp=0&FLIComp=5&APIComp=1

The other comparisons are not equivalent either.

the lens is a f2.8 regardless of what body its on, it will have a shallower dof on ff but its still 2.8, the ff equivalent to 300mm on aps-c is 480 the bare lens is excellent on apc-c which is the point of comparison. if you still want to use teleconverters as i also do with it then you want to use the canon extenders. i also tried the kenkos and they are very good but the 2x overexposes by one stop?. i don't understand why those samples at tdp look so bad. the old lens sample looked better with the tc's and the new one is sharper so it seems backwards?

anyway: the shots below are all with the canon 2xiii the squirrel and rusty ball are 600, the cat is 240

 

[candc]

... the 70d has a better af system than the 6d...

In your 'Sigma system' any advantages of the 70D's AF system would be thrown away by the Sigma lenses' worse AF performance. I'd bet most or even all of your 6D + Canon lens combos would beat the 70D + Sigma lens combos for AF speed and accuracy.

that is a hard one to judge. the sigmas do have af problems that you need to correct with the dock and thats a big hassle. once you do that they are pretty good. the af speed on the 120-300 is acceptable to me. it has no problems tracking bif ai servo, even with the 2xiii attached, you need to set the lens to speed priority for that though. i would guess the 200-400 has faster af but the sigma is acceptable

 

[Marsu42]

I'd bet most or even all of your 6D + Canon lens combos would beat the 70D + Sigma lens combos for AF speed and accuracy.

That might be true for speed, but I'd wager to guess not necessarily for accuracy because ...

1. the 3rd party lack of speed would be to gain an adequate accuracy, and the 6D system (unlike 1dx/5d3) doesn't have seem to have the closed loop system and cannot use the improved accuracy of Canon's latest lenses.

2. the missing x-point @f2.8 of the 6d will loose a lot of accuracy in real world comparisons even with a Canon lens so the 70d+Sigma with a better center point might be more than up on par.

Last not least, the af performance of either system in absolute terms is very good even if there are relative differences, meaning the optical performance matters more for usual print/view sizes and not shooting sports or events.

 

[rs]

the aps-c system is wider, the ff longer on the tele end. the 200-400 has a built in extender getting you 560 f5.6 the sigma is 300 x 1.6=480 f2.8 and the ff system has better iso performance so the aps-c system uses faster lenses to help compensate for this.

The Sigma is 480/4.5 equivalent and will be so soft on crop at that FL that the 100-400 for a fraction of the cost will be better on FF, even if you apply NR to reduce the 2/3 stop difference.

See here how the Sigma performs on FF, and imagine how would be on crop:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=113&Camera=453&Sample=0&FLI=7&API=0&LensComp=803&CameraComp=453&SampleComp=0&FLIComp=5&APIComp=1

The other comparisons are not equivalent either.

the lens is a f2.8 regardless of what body its on, it will have a shallower dof on ff but its still 2.8, the ff equivalent to 300mm on aps-c is 480

Yes, the lens is f2.8 regardless of what body it is on - but it is also 300mm regardless of what body it is on. However, if you want to look at it in FF equivalence, then a 300/2.8 lens on 1.6x crop behaves like a 480/4.5 lens. It doesn't stop it from being a 300/2.8. But calling it a 480/2.8 is wrong.

If your argument was true, my iPhone 5 with its 4.1mm f2.4 lens is a 33/2.4 - as a complete system it would be better in low light and able to give a narrower DoF than my 5DII and 24-70 II can at 33mm.

 

[chauncey]

Abject futility is defined as...comparing camera/lens quality based on internet images.
To expand a little, assuming normal print size and competent photographer...one cannot discern camera/lens brand from a print.

 

[Rienzphotoz]

anyway: the shots below are all with the canon 2xiii the squirrel and rusty ball are 600, the cat is 240

Kind sir, are you aware that Squirrels and balls are banned in CR ... it has been confirmed that Squirrels are indecent folk ... we went through several indecent Squirrels, who destroyed our faith in the Squirrel community ... therefore, we find your intentions (for posting photos of Squirrel, ball and what not) most disturbing ;D
For further guidance on the Squirrel folk, please see page 4 and 7 of: http://www.canonrumors.com/forum/index.php?topic=15358.45
;D ;D ;D

 

[Pi]

anyway: the shots below are all with the canon 2xiii the squirrel and rusty ball are 600, the cat is 240

You got a good reply above, I just want to comment on the IQ of the images you posted. Even downsized to 2-3mp, they do not pass a pixel-peeper's test. A slightly cropped 200mm image from FF would make your 240mm look like taken with a cell phone; and if I crop a 200mm image from 20mp on FF to get approx. 600mm, I would get a 2.2mp image still sharper than your 600 one. Your images seem to demonstrate that investing in expensive lenses on a crop body is a waste of money.

 

[Loswr]

I'd bet most or even all of your 6D + Canon lens combos would beat the 70D + Sigma lens combos for AF speed and accuracy.

That might be true for speed, but I'd wager to guess not necessarily for accuracy because ...

1. the 3rd party lack of speed would be to gain an adequate accuracy, and the 6D system (unlike 1dx/5d3) doesn't have seem to have the closed loop system and cannot use the improved accuracy of Canon's latest lenses.

That sounds like a reasonable theory. But the issues that I've read about with Sigma AF, which I have experienced the handful of times I've tried one of their lenses (either borrowed or in a shop) was that the focus is inconsistent. When it hits, it's as accurate as the Canon lenses. But the frequency of misses is a lot higher, in some cases so high as to make the lenses unusable for my purposes.

Yes, the lens is f2.8 regardless of what body it is on - but it is also 300mm regardless of what body it is on. However, if you want to look at it in FF equivalence, then a 300/2.8 lens on 1.6x crop behaves like a 480/4.5 lens. It doesn't stop it from being a 300/2.8. But calling it a 480/2.8 is wrong.

+1

I'm not sure why some people seem to think the "crop factor" is some magic thing that defies the laws of optical physics. In general, current crop sensors have higher pixel density than current full frame sensors, meaning the crop sensor puts more pixels on your target (but that's not the case for the T3 vs. the D800, for example). That only matters if the resolution of an image cropped from the full frame sensor is insufficient for your output needs, and even 18 MP FF cropped to the APS-C field of view gives sufficient MP for reasonably large prints.

The only real "crop factor advantage" is that the sensors are cheaper, and thus the cameras they are in are also cheaper.

 

[Marsu42]

The only real "crop factor advantage" is that the sensors are cheaper, and thus the cameras they are in are also cheaper.

... and the mirror is smaller, so with the same level of engineering of the 1dx a crop body could get a much higher fps than a ff - at least it's my guess that the mirror size and mass is the limiting factor. Of course this is very unlikely to happen even with the 7d2 since mirrorless gets a much, much higher fps at no cost.

Another "crop factor advantage" that comes to my mind is that you can put it into smaller (and shallower mirrored) bodies, I always found that a crop sensor in a 7d size body looks very strange and lost.

Sony currently is going for latter, here in Germany the environment is plastered with Sony adverts not only telling us they own 50%+ of the sensor market, but showing their new mirrorless aps-c right next to their traditional dlsr line, comparing the size in a way favoring the mirrorless design as it has the same iq in a smaller package.

 

[Pi]

Another "crop factor advantage" that comes to my mind is that you can put it into smaller (and shallower mirrored) bodies, I always found that a crop sensor in a 7d size body looks very strange and lost.

Not really, because they are designed to take EF lenses as well. The flange distance is the same as with the FF bodies even thought EF-S lenses can protrude closer to the sensor.

 

[Marsu42]

Not really, because they are designed to take EF lenses as well. The flange distance is the same as with the FF bodies even thought EF-S lenses can protrude closer to the sensor.

Right, good point, I forgot about this - of course the small Sony mirrorless will take different lenses just like eos-m or need an adapter for the traditional system.

 

[candc]

anyway: the shots below are all with the canon 2xiii the squirrel and rusty ball are 600, the cat is 240

You got a good reply above, I just want to comment on the IQ of the images you posted. Even downsized to 2-3mp, they do not pass a pixel-peeper's test. A slightly cropped 200mm image from FF would make your 240mm look like taken with a cell phone; and if I crop a 200mm image from 20mp on FF to get approx. 600mm, I would get a 2.2mp image still sharper than your 600 one. Your images seem to demonstrate that investing in expensive lenses on a crop body is a waste of money.

You understand that those are taken with with the 2xiii attached? You don't need to do that to get 240, its a 120-300. You would have to shoot 960 on ff to get the same field of view as 600 on the crop Even if you could crop a 200mm ff image that much and get good results, you can't see what your shooting

 

[candc]

anyway: the shots below are all with the canon 2xiii the squirrel and rusty ball are 600, the cat is 240

Kind sir, are you aware that Squirrels and balls are banned in CR ... it has been confirmed that Squirrels are indecent folk ... we went through several indecent Squirrels, who destroyed our faith in the Squirrel community ... therefore, we find your intentions (for posting photos of Squirrel, ball and what not) most disturbing ;D
For further guidance on the Squirrel folk, please see page 4 and 7 of: http://www.canonrumors.com/forum/index.php?topic=15358.45
;D ;D ;D

He's not a bird but he lives in a tree,
If I had a gun he'd be a fricassee.

Sorry for the infraction, I was not aware of the bylaw, it won't happen again.

 

[Loswr]

You would have to shoot 960 on ff to get the same field of view as 600 on the crop Even if you could crop a 200mm ff image that much and get good results, you can't see what your shooting

I see you're still thinking the crop factor is some sort of magic. Do keep in mind that it's called a "crop factor" not a "magnification factor." A 600mm lens (native, or 300 mm with a 2x TC) delivers the same magnification at the back of the lens, no matter what camera it is mounted on.

Perhaps you've read the specification of a good crop camera like the 7D and noticed that the viewfinder magnification is 1.0x, which sounds superior to the viewfinder magnification spec of a camera like the 5DIII, which is 0.71x. However, viewfinder magnification is not comparable across format size. That's because the specification is based on use of a 50mm lens, and that lens will give a different field of view depending on sensor format. Once you compensate for the crop factor by multiplying the VF magnification specification by the inverse of that crop factor, you find that the 7D delivers an equivalent 0.62x magnification.

Okay, having said that, the above applies for taking "the same picture", which is different than the situation you describe where you are using the lens on two different bodies at the same subject distance. In that case, you would compare the raw viewfinder magnification specs. But, the difference between them is not the 1.6x of the crop factor, but rather closer to 1.3 or 1.4x. Empirically, I can assure you I have no difficulty seeing things in the viewfinder of my 1D X with a 600 mm lens, and cropping the image to the APS-C field of view.

 

[sdsr]

canon does make some good lenses for aps-c but they don't really have a complete system. sigma does you can get

70d $1200
sigma 8-16 $600
sigma 18-35 $900
sigma 50-150 $1000
sigma 120-300 $3600 its a ff lens but seems better suited as an aps-c wildlife lens to me
thats $7,300
that will get you a system that performs very well and is comparable to the system below

5diii $3400
16-35 $1700
24-70ii $2300
70-200ii $2200
200-400 $12000
that's $21,600

the aps-c system is wider, the ff longer on the tele end. the 200-400 has a built in extender getting you 560 f5.6 the sigma is 300 x 1.6=480 f2.8 and the ff system has better iso performance so the aps-c system uses faster lenses to help compensate for this.

all and all there are some advantages to the ff system but $14,300 worth?

dpr says that the raw files from the 70d and 6d are indistinguishable up to about iso 3200, the 70d has a better af system than the 6d so i think you have to use the 5diii as a comparison model for now, the 7dii will probably be more equal

I think there are a few mistakes in your analysis, even leaving aside problems with inconsistent autofocus. When you say that according to dpr "the raw files from the 70D and 6D are indistinguishable up to about ISO 3200", and assuming they do say such a thing (surely they don't) what exactly were they referring to? Noise? The various other factors we refer to as "image quality"? If so, I don't believe them and have seen nothing in any other review site to suggest that's true; my experience with recent Canon crop bodies and 5DII, 5DIII and 6D doesn't either. Whether the AF system of the 70D is better than that in the 6D rather depends on what you're shooting.

Anyway, one could as easily come up with a FF system that's vastly cheaper than the one you assembled, and I bet the resulting images would nevertheless be better than those created by your crop system (which would still be very good, of course):

6D - $1500-$1900 (depending on sales)
17-40L c. $800 (often much less)
Canon 24-105L c. $800 but even cheaper if bought as the 6D's kit lens
Canon 70-200 f4 IS (c. $1100 on sale) or 70-300L (c. $1300 on sale)
Canon 100-400L c. $1500 but often less on sale

The lenses you list for your FF selection may perform better still, but they're all Canon's most expensive in each category; if you're going to list them for FF, you might as well put them on your crop list too - they work on both, after all. If you insist on f2.8 lenses, feel free to substitute Tamron equivalents for 24-70 and 70-200; but note that, as others have explained, 2.8 on crop doesn't perform the same as 2.8 on FF. And the only reason why your Canon FF system doesn't go as wide as your Canon crop system is that for some reason you stayed with Canon for the FF system; Sigma makes a lens for FF that's exactly the same range as the 8-16....

 

[Policar]

its sharper on an a crop body than the 24-70ii.

No!

Actually, I think it likely is. Note that this is comparing both lenses used on the same APS-C body. The 24-70/2.8 II on FF will blow away te 18-35/1.8 DC on APS-C.

The Sigma is sharper at f1.8 than the 70-200mm f2.8 IS II is at f2.8, so I'm guessing it's the best zoom on APS-C unless the 24-70mm f2.8 II is dramatically better than the 70-200.

That is, on the rare occasion it takes a photo that's in focus.

 

[candc]

You would have to shoot 960 on ff to get the same field of view as 600 on the crop Even if you could crop a 200mm ff image that much and get good results, you can't see what your shooting

I see you're still thinking the crop factor is some sort of magic. Do keep in mind that it's called a "crop factor" not a "magnification factor." A 600mm lens (native, or 300 mm with a 2x TC) delivers the same magnification at the back of the lens, no matter what camera it is mounted on.

Perhaps you've read the specification of a good crop camera like the 7D and noticed that the viewfinder magnification is 1.0x, which sounds superior to the viewfinder magnification spec of a camera like the 5DIII, which is 0.71x. However, viewfinder magnification is not comparable across format size. That's because the specification is based on use of a 50mm lens, and that lens will give a different field of view depending on sensor format. Once you compensate for the crop factor by multiplying the VF magnification specification by the inverse of that crop factor, you find that the 7D delivers an equivalent 0.62x magnification.

Okay, having said that, the above applies for taking "the same picture", which is different than the situation you describe where you are using the lens on two different bodies at the same subject distance. In that case, you would compare the raw viewfinder magnification specs. But, the difference between them is not the 1.6x of the crop factor, but rather closer to 1.3 or 1.4x. Empirically, I can assure you I have no difficulty seeing things in the viewfinder of my 1D X with a 600 mm lens, and cropping the image to the APS-C field of view.

no what pi said is that you could take a image shot with ff and a 200mm lens and crop it down to the same size as an image taken with a crop camera and a 600mm lens and the ff image would be better just on the merit that it was taken with a ff camera, i don't agree with that

thats almost like saying 100% crops from a ff camera are better than full size ones taken with a crop camera. i know that some here think that way but i don't

what i said is that if you are shooting a 200mm lens on a ff camera and intend to crop to the same size as an image taken with a crop camera and a 600mm lens. thats a big difference and its going to be difficult to see. thats a good reason to use tcs also. even if the iq is the same as cropping at least you can see what you are shooting

 

[candc]

well i will start with the first lens in the list the sigma 8-16, its wider than anything except the sigma 12-24 for ff i think and the 8-16 on an aps-c body gives better results sraight up head to head than the 12-24 on a ff so thats one reason to go with a crop

 

[Pi]

You understand that those are taken with with the 2xiii attached? You don't need to do that to get 240, its a 120-300. You would have to shoot 960 on ff to get the same field of view as 600 on the crop Even if you could crop a 200mm ff image that much and get good results, you can't see what your shooting

No, I did not. Still, what is the point of using an extender to get such soft images? Just shoot without an extender and crop.

The 70-300L, or the 70-200+1.4 TX on FF cropped to 2.2 mp (0.33 crop) would look sharper, and will give you 900mm for much less. I can post such a crop downsized to the resolution of what you posted, if you insist - taken at 200mm + 1.4TC.

 

[candc]

You understand that those are taken with with the 2xiii attached? You don't need to do that to get 240, its a 120-300. You would have to shoot 960 on ff to get the same field of view as 600 on the crop Even if you could crop a 200mm ff image that much and get good results, you can't see what your shooting

No, I did not. Still, what is the point of using an extender to get such soft images? Just shoot without an extender and crop.

The 70-300L, or the 70-200+1.4 TX on FF cropped to 2.2 mp (0.33 crop) would look sharper, and will give you 900mm for much less. I can post such a crop downsized to the resolution of what you posted, if you insist - taken at 200mm + 1.4TC.

you think the squirrel shot is soft? it was iso 1600 300mm + 2xii on a crop body from about 50 yards away and its plenty sharp enough to see the individual hairs on the tail.

you think the wide angle shots i just posted are also soft?