Canon Announces Two New EF Ultra Wide-Angle Zoom Lenses and White EOS Rebel SL1 Digital SLR Camera

[ahsanford]

I'm using 7D, pairing with 16-35 II... as my regular walk around lens 
wonder shall I go for the 16-35 IS? worth?

also I haven't got my wide for APS-C  , which should I go for?
I) New, 10-18 STM
II) Old, 10-22 USM

Thanks... 

On a crop?  The Sigma 18-35 F/1.8 is your walkaround.    The PZ resolution data on that lens is astonishing for a zoom -- it's on par with the 35 Art prime!
http://www.photozone.de/canon-eos/872-sigma1835f18_canon?start=1

That plus the F/1.8 walks the crop hit on small DOF back to somewhat level terms with an FF F/2.8 zoom.  Win win.  If I was still shooting crop, this would be my walkaround.

- A

[LetTheRightLensIn]

I'm using 7D, pairing with 16-35 II... as my regular walk around lens 
wonder shall I go for the 16-35 IS? worth?

also I haven't got my wide for APS-C  , which should I go for?
I) New, 10-18 STM
II) Old, 10-22 USM

Thanks... 

Guess I have to ask why?  I feel like there are so many better options for a standard zoom lens on a APS-C.  Why not the 17-55?  Or something like a 24-70 or 24-105 if you want an EF lens.

If you're willing to spend that kind of cash on a lens then I wouldn't be lured in by the low price of the 10-18, unless it proves to be markedly sharper, which seems unlikely.  So unless you want STM for video I'd stick with the tried and true 10-22.

Yeah for aps-c standard walk around I'd go for 17-55 2.8 IS or 15-85 IS or tamron 17-50 2.8. So much better range and all crisp enough to the edge on aps-c rather than the FF-able lenses.

[sparda79]

Anybody posted this yet?:-

Samples from Canon China website

http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/img/sample1_zoom.jpg


http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/img/sample2_zoom.jpg


http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/img/sample3_zoom.jpg


http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/sample.html


http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/img/sample5_zoom.jpg


http://www.canon.com.cn/products/camera/ef/lineup/widezoom/ef1635f4lis/img/sample6_zoom.jpg

[Dylan777]

Anybody posted this yet?:-

Samples from Canon China website

Thanks for sharing. Those corners look real good

[Marsu42]

Thanks for sharing. Those corners look real good

How many non-CR members viewing these shots would comment on the corners :-> ... esp. with closed aperture and this export size I'm pretty sure you'd be hard pressed to tell the difference between 17-40L, 16-35L/24 and the new 16-35L/4, Canon should have done comparison shots :-)

[Eldar]

Thanks for sharing. Those corners look real good

How many non-CR members viewing these shots would comment on the corners :-> ... esp. with closed aperture and this export size I'm pretty sure you'd be hard pressed to tell the difference between 17-40L, 16-35L/24 and the new 16-35L/4, Canon should have done comparison shots :-)

I believe Dylan made a "That looks promising.." comment. Not a "Wow that´s awesome, I want one!" comment ...

And the shots are promotion, not a review. They are still going to sell both the 17-40 and 16-35 2.8, so why on earth should they hand out comparison shots to kill one or two of them? Would not be a smart career move for anyone in  marketing, unless the motivation was to stop all sales of one model and jump start a new.

[jdramirez]

I'm so late to this conversation, but is the presumption threat the 16-35 f4L going to replace the 17-40 f4L ?

I'm not a big fan of the wide angle look so it doesn't really affect me one way or another, but I have thought about doing some freelance real estate photography on the weekends.  So obviously a wide angle is preferable for that... and I'm curious if waiting for the new lens to drop in price is worth it....

[awinphoto]

The pricing is right on this lens, easily worth spending the 275 over 17-40/4L.

16-35 II is a different ballgame though.  If you are interested in doing indoor event work, IMO the 16-35 II f/2.8L is the better purchase; there simply isn't enough light at many indoor events to use an f/4 lens.  In fact, often f/2.8 isn't even enough; f/2.8 is more useful in low light than f/4 IS at 35mm, and with shutter speed needing to be 1/100 minimum to freeze motion f/4 will hurt in the ISOs department.  A noisy picture caused by five digit ISOs or motion blur will be much more noticeable in low light than less than perfect corner sharpness, and IS aside from not being as effective at wide focal lengths also will not freeze motion.  I do have primes that are below f/2.8, but none of them at 16mm which can be useful in tight quarters like a dancefloor.  The 16-35 II is one of the rare lenses that has a UWA-wide/normal zoom range, f/2.8, and accepts filters (I don't know how I'd feel with a bulbous element at a crowded event).

On the other hand, for landscape work this new 16-35 f/4L IS looks like an easy winner over the 16-35 II f/2.8.

So it depends what you are going to do with it, as is often the case   IMO, 16-35 II f/2.8L remains king for now for event photography.

I'll definitely pick this one up, shortly after my daughter is born my bills are all in order...  As far as the 2.8 vs 4 debate, i've been well vocal enough on this...  and for giggles, as a weekend long event we were hired for to do photography coverage for, (all indoors) we played with different lenses and combinations...  Needless to say, Regardless whether it was F4 or 2.8, we needed flash.  And 2.8 made the DOF even more shallow and unforgiving than the F4 was to boot.  In the end, i instructed my assistant photographer, and my wife and I to use our 24-105's.  Had Flash, chewed through batteries but got a good thousand or so images after culling that were sharp, ISO was ok (manually set at around 4000 which on our 5d3 and 6D came out gorgeous), and flash...  I personally feel the argument that you NEED 2.8 for indoors is just wrong.  If F4 cant pull it off, 2.8 really isn't going to buy you much latitude, and you have a narrower DOF.  1.4 and such is even tougher with DOF, especially for event coverage.  It's good for artistic expression and isolating subjects, but shooting groups of people, shooting moving subjects, shooting events, you will likely still need flash or ISO to get good shots, and with modern cameras, ISO is becoming even better.  I've had indoor wedding shots around 20,000 ISO that came out gorgeous with minimal noise...  It is what it is.

[Etienne]

The pricing is right on this lens, easily worth spending the 275 over 17-40/4L.

16-35 II is a different ballgame though.  If you are interested in doing indoor event work, IMO the 16-35 II f/2.8L is the better purchase; there simply isn't enough light at many indoor events to use an f/4 lens.  In fact, often f/2.8 isn't even enough; f/2.8 is more useful in low light than f/4 IS at 35mm, and with shutter speed needing to be 1/100 minimum to freeze motion f/4 will hurt in the ISOs department.  A noisy picture caused by five digit ISOs or motion blur will be much more noticeable in low light than less than perfect corner sharpness, and IS aside from not being as effective at wide focal lengths also will not freeze motion.  I do have primes that are below f/2.8, but none of them at 16mm which can be useful in tight quarters like a dancefloor.  The 16-35 II is one of the rare lenses that has a UWA-wide/normal zoom range, f/2.8, and accepts filters (I don't know how I'd feel with a bulbous element at a crowded event).

On the other hand, for landscape work this new 16-35 f/4L IS looks like an easy winner over the 16-35 II f/2.8.

So it depends what you are going to do with it, as is often the case   IMO, 16-35 II f/2.8L remains king for now for event photography.

I'll definitely pick this one up, shortly after my daughter is born my bills are all in order...  As far as the 2.8 vs 4 debate, i've been well vocal enough on this...  and for giggles, as a weekend long event we were hired for to do photography coverage for, (all indoors) we played with different lenses and combinations...  Needless to say, Regardless whether it was F4 or 2.8, we needed flash.  And 2.8 made the DOF even more shallow and unforgiving than the F4 was to boot.  In the end, i instructed my assistant photographer, and my wife and I to use our 24-105's.  Had Flash, chewed through batteries but got a good thousand or so images after culling that were sharp, ISO was ok (manually set at around 4000 which on our 5d3 and 6D came out gorgeous), and flash...  I personally feel the argument that you NEED 2.8 for indoors is just wrong.  If F4 cant pull it off, 2.8 really isn't going to buy you much latitude, and you have a narrower DOF.  1.4 and such is even tougher with DOF, especially for event coverage.  It's good for artistic expression and isolating subjects, but shooting groups of people, shooting moving subjects, shooting events, you will likely still need flash or ISO to get good shots, and with modern cameras, ISO is becoming even better.  I've had indoor wedding shots around 20,000 ISO that came out gorgeous with minimal noise...  It is what it is.

I agree with most of what you say. I shoot my 16-35 2.8L II at 5.6 - 11 most of the time, and I probably use f/16 more than I use f/2.8 on that lens.

 f/ 1.4 DOF can be difficult to get a subject in focus, but mostly on lenses >50mm FL. I think the 24 1.4 is not hard to get the whole subject in focus unless you are  less than 5 ft away. The 35 f/2 IS is not hard to get a sharp focus on subjects at f/2, and I suspect the 35 f/1.4 is not much harder either.

[awinphoto]

The pricing is right on this lens, easily worth spending the 275 over 17-40/4L.

16-35 II is a different ballgame though.  If you are interested in doing indoor event work, IMO the 16-35 II f/2.8L is the better purchase; there simply isn't enough light at many indoor events to use an f/4 lens.  In fact, often f/2.8 isn't even enough; f/2.8 is more useful in low light than f/4 IS at 35mm, and with shutter speed needing to be 1/100 minimum to freeze motion f/4 will hurt in the ISOs department.  A noisy picture caused by five digit ISOs or motion blur will be much more noticeable in low light than less than perfect corner sharpness, and IS aside from not being as effective at wide focal lengths also will not freeze motion.  I do have primes that are below f/2.8, but none of them at 16mm which can be useful in tight quarters like a dancefloor.  The 16-35 II is one of the rare lenses that has a UWA-wide/normal zoom range, f/2.8, and accepts filters (I don't know how I'd feel with a bulbous element at a crowded event).

On the other hand, for landscape work this new 16-35 f/4L IS looks like an easy winner over the 16-35 II f/2.8.

So it depends what you are going to do with it, as is often the case   IMO, 16-35 II f/2.8L remains king for now for event photography.

I'll definitely pick this one up, shortly after my daughter is born my bills are all in order...  As far as the 2.8 vs 4 debate, i've been well vocal enough on this...  and for giggles, as a weekend long event we were hired for to do photography coverage for, (all indoors) we played with different lenses and combinations...  Needless to say, Regardless whether it was F4 or 2.8, we needed flash.  And 2.8 made the DOF even more shallow and unforgiving than the F4 was to boot.  In the end, i instructed my assistant photographer, and my wife and I to use our 24-105's.  Had Flash, chewed through batteries but got a good thousand or so images after culling that were sharp, ISO was ok (manually set at around 4000 which on our 5d3 and 6D came out gorgeous), and flash...  I personally feel the argument that you NEED 2.8 for indoors is just wrong.  If F4 cant pull it off, 2.8 really isn't going to buy you much latitude, and you have a narrower DOF.  1.4 and such is even tougher with DOF, especially for event coverage.  It's good for artistic expression and isolating subjects, but shooting groups of people, shooting moving subjects, shooting events, you will likely still need flash or ISO to get good shots, and with modern cameras, ISO is becoming even better.  I've had indoor wedding shots around 20,000 ISO that came out gorgeous with minimal noise...  It is what it is.

I agree with most of what you say. I shoot my 16-35 2.8L II at 5.6 - 11 most of the time, and I probably use f/16 more than I use f/2.8 on that lens.

 f/ 1.4 DOF can be difficult to get a subject in focus, but mostly on lenses >50mm FL. I think the 24 1.4 is not hard to get the whole subject in focus unless you are  less than 5 ft away. The 35 f/2 IS is not hard to get a sharp focus on subjects at f/2, and I suspect the 35 f/1.4 is not much harder either.

Thanks for your reply.  I would say that it isn't so much that it's hard to get focus as that the DOF is so thin, especially for indoors and shootings, lets hypothetically around 8-10 feet, if I were to shoot a small group, or even a couple, at 1.4 the DOF is still less than a foot (2.8 on average about 1.5 feet).  That would be tough to pull of in a studio setting let alone a grab shot, wham bam thank you mam kinda thing.  So, since most people equate needing fast lenses FOR INDOOR EVENTS, that 1.4 or 2.8 is still very thin. I would estimate the vast majority of event indoor work still settles at around 5.6-8 so most small group shots are in focus, which throws out the advantage of 2.8 or faster anyways.  Now there can be that argument that it may let more light into the lens for AF, and that's always nice, but at the inherent tradeoffs such as weight, cost, and bang for the buck), IMHO Meh

[Marsu42]

I'm so late to this conversation, but is the presumption threat the 16-35 f4L going to replace the 17-40 f4L ?

That's my guess, Canon cannot make much money from the current 17-40L's price which has cashback rebates all the time, and I don't see them releasing a previously rumored 17-50/4-ish lens with this 16-35/4 actually on the market.

Esp. since releasing lenses with shorter zoom range is beneficial to Canon: most likely better iq for high mp sensors and people are marketed into buying more lenses: Instead of one 24-105L you'll now end up with three: 16-35/4, 24-70/4, 70-xyz.

[Etienne]

The pricing is right on this lens, easily worth spending the 275 over 17-40/4L.

16-35 II is a different ballgame though.  If you are interested in doing indoor event work, IMO the 16-35 II f/2.8L is the better purchase; there simply isn't enough light at many indoor events to use an f/4 lens.  In fact, often f/2.8 isn't even enough; f/2.8 is more useful in low light than f/4 IS at 35mm, and with shutter speed needing to be 1/100 minimum to freeze motion f/4 will hurt in the ISOs department.  A noisy picture caused by five digit ISOs or motion blur will be much more noticeable in low light than less than perfect corner sharpness, and IS aside from not being as effective at wide focal lengths also will not freeze motion.  I do have primes that are below f/2.8, but none of them at 16mm which can be useful in tight quarters like a dancefloor.  The 16-35 II is one of the rare lenses that has a UWA-wide/normal zoom range, f/2.8, and accepts filters (I don't know how I'd feel with a bulbous element at a crowded event).

On the other hand, for landscape work this new 16-35 f/4L IS looks like an easy winner over the 16-35 II f/2.8.

So it depends what you are going to do with it, as is often the case   IMO, 16-35 II f/2.8L remains king for now for event photography.

I'll definitely pick this one up, shortly after my daughter is born my bills are all in order...  As far as the 2.8 vs 4 debate, i've been well vocal enough on this...  and for giggles, as a weekend long event we were hired for to do photography coverage for, (all indoors) we played with different lenses and combinations...  Needless to say, Regardless whether it was F4 or 2.8, we needed flash.  And 2.8 made the DOF even more shallow and unforgiving than the F4 was to boot.  In the end, i instructed my assistant photographer, and my wife and I to use our 24-105's.  Had Flash, chewed through batteries but got a good thousand or so images after culling that were sharp, ISO was ok (manually set at around 4000 which on our 5d3 and 6D came out gorgeous), and flash...  I personally feel the argument that you NEED 2.8 for indoors is just wrong.  If F4 cant pull it off, 2.8 really isn't going to buy you much latitude, and you have a narrower DOF.  1.4 and such is even tougher with DOF, especially for event coverage.  It's good for artistic expression and isolating subjects, but shooting groups of people, shooting moving subjects, shooting events, you will likely still need flash or ISO to get good shots, and with modern cameras, ISO is becoming even better.  I've had indoor wedding shots around 20,000 ISO that came out gorgeous with minimal noise...  It is what it is.

I agree with most of what you say. I shoot my 16-35 2.8L II at 5.6 - 11 most of the time, and I probably use f/16 more than I use f/2.8 on that lens.

 f/ 1.4 DOF can be difficult to get a subject in focus, but mostly on lenses >50mm FL. I think the 24 1.4 is not hard to get the whole subject in focus unless you are  less than 5 ft away. The 35 f/2 IS is not hard to get a sharp focus on subjects at f/2, and I suspect the 35 f/1.4 is not much harder either.

Thanks for your reply.  I would say that it isn't so much that it's hard to get focus as that the DOF is so thin, especially for indoors and shootings, lets hypothetically around 8-10 feet, if I were to shoot a small group, or even a couple, at 1.4 the DOF is still less than a foot (2.8 on average about 1.5 feet).  That would be tough to pull of in a studio setting let alone a grab shot, wham bam thank you mam kinda thing.  So, since most people equate needing fast lenses FOR INDOOR EVENTS, that 1.4 or 2.8 is still very thin. I would estimate the vast majority of event indoor work still settles at around 5.6-8 so most small group shots are in focus, which throws out the advantage of 2.8 or faster anyways.  Now there can be that argument that it may let more light into the lens for AF, and that's always nice, but at the inherent tradeoffs such as weight, cost, and bang for the buck), IMHO Meh

f/2.8 is not that thin DOF as you go to UWA. A 50 mm FL at 6 feet away f/2.8 gives DOF 0.78 ft (very thin, and difficult to manage), whereas a 24mm FL gives 3.4 feet, which is more than enough. At 15 feet away for a group, 24mm lens gives a whopping 36 feet of DOF. The razor thin concern doesn't apply at ultra wide.

An extreme example here: 24mm f/1.4 at 15 feet still has a DOF of 11 feet (but Canon's 24 1.4L is very soft in the corners at 1.4, different issue).

16mm f/2.8 at 6 feet away still has a very easy to manage DOF of 11 feet. Even as close as 3 feet, gives about 2 feet DOF.

So, f/2.8 really can help indoor photography for ultrawides without causing DOF problems.

[dlleno]

f/2.8 is not that thin DOF as you go to UWA. A 50 mm FL at 6 feet away f/2.8 gives DOF 0.78 ft (very thin, and difficult to manage), whereas a 24mm FL gives 3.4 feet, which is more than enough. At 15 feet away for a group, 24mm lens gives a whopping 36 feet of DOF. The razor thin concern doesn't apply at ultra wide.

An extreme example here: 24mm f/1.4 at 15 feet still has a DOF of 11 feet (but Canon's 24 1.4L is very soft in the corners at 1.4, different issue).

16mm f/2.8 at 6 feet away still has a very easy to manage DOF of 11 feet. Even as close as 3 feet, gives about 2 feet DOF.

So, f/2.8 really can help indoor photography for ultrawides without causing DOF problems.

yea.   so f/2.8 can help isolate the subject from the background as well.  in your example, the DOF extends from about 2 feet in front to 9 feet behind, which may be pushing it for subject isolation but still  doable (you would more likely be stepping back and zooming in to 21 mm for example, for better results --  But to continue the example:   at f/4 (still 16mm and subject distance of 6 feet)  you loose almost all hope of subject isolation from the background because everything 34 feet behind the subject  is in focus.     so in this particular example, the f/2.8 lens has a hope of capturing a venue feature like a candelabra or whatever, with some isolation from the background, but the f/4 lens has little hope.  I doubt very many people/group shots are taken at 16mm and 6 foot distance... but I'm not a wedding 'tog so I'm open to correction here  

[awinphoto]

The pricing is right on this lens, easily worth spending the 275 over 17-40/4L.

16-35 II is a different ballgame though.  If you are interested in doing indoor event work, IMO the 16-35 II f/2.8L is the better purchase; there simply isn't enough light at many indoor events to use an f/4 lens.  In fact, often f/2.8 isn't even enough; f/2.8 is more useful in low light than f/4 IS at 35mm, and with shutter speed needing to be 1/100 minimum to freeze motion f/4 will hurt in the ISOs department.  A noisy picture caused by five digit ISOs or motion blur will be much more noticeable in low light than less than perfect corner sharpness, and IS aside from not being as effective at wide focal lengths also will not freeze motion.  I do have primes that are below f/2.8, but none of them at 16mm which can be useful in tight quarters like a dancefloor.  The 16-35 II is one of the rare lenses that has a UWA-wide/normal zoom range, f/2.8, and accepts filters (I don't know how I'd feel with a bulbous element at a crowded event).

On the other hand, for landscape work this new 16-35 f/4L IS looks like an easy winner over the 16-35 II f/2.8.

So it depends what you are going to do with it, as is often the case   IMO, 16-35 II f/2.8L remains king for now for event photography.

I'll definitely pick this one up, shortly after my daughter is born my bills are all in order...  As far as the 2.8 vs 4 debate, i've been well vocal enough on this...  and for giggles, as a weekend long event we were hired for to do photography coverage for, (all indoors) we played with different lenses and combinations...  Needless to say, Regardless whether it was F4 or 2.8, we needed flash.  And 2.8 made the DOF even more shallow and unforgiving than the F4 was to boot.  In the end, i instructed my assistant photographer, and my wife and I to use our 24-105's.  Had Flash, chewed through batteries but got a good thousand or so images after culling that were sharp, ISO was ok (manually set at around 4000 which on our 5d3 and 6D came out gorgeous), and flash...  I personally feel the argument that you NEED 2.8 for indoors is just wrong.  If F4 cant pull it off, 2.8 really isn't going to buy you much latitude, and you have a narrower DOF.  1.4 and such is even tougher with DOF, especially for event coverage.  It's good for artistic expression and isolating subjects, but shooting groups of people, shooting moving subjects, shooting events, you will likely still need flash or ISO to get good shots, and with modern cameras, ISO is becoming even better.  I've had indoor wedding shots around 20,000 ISO that came out gorgeous with minimal noise...  It is what it is.

I agree with most of what you say. I shoot my 16-35 2.8L II at 5.6 - 11 most of the time, and I probably use f/16 more than I use f/2.8 on that lens.

 f/ 1.4 DOF can be difficult to get a subject in focus, but mostly on lenses >50mm FL. I think the 24 1.4 is not hard to get the whole subject in focus unless you are  less than 5 ft away. The 35 f/2 IS is not hard to get a sharp focus on subjects at f/2, and I suspect the 35 f/1.4 is not much harder either.

Thanks for your reply.  I would say that it isn't so much that it's hard to get focus as that the DOF is so thin, especially for indoors and shootings, lets hypothetically around 8-10 feet, if I were to shoot a small group, or even a couple, at 1.4 the DOF is still less than a foot (2.8 on average about 1.5 feet).  That would be tough to pull of in a studio setting let alone a grab shot, wham bam thank you mam kinda thing.  So, since most people equate needing fast lenses FOR INDOOR EVENTS, that 1.4 or 2.8 is still very thin. I would estimate the vast majority of event indoor work still settles at around 5.6-8 so most small group shots are in focus, which throws out the advantage of 2.8 or faster anyways.  Now there can be that argument that it may let more light into the lens for AF, and that's always nice, but at the inherent tradeoffs such as weight, cost, and bang for the buck), IMHO Meh

f/2.8 is not that thin DOF as you go to UWA. A 50 mm FL at 6 feet away f/2.8 gives DOF 0.78 ft (very thin, and difficult to manage), whereas a 24mm FL gives 3.4 feet, which is more than enough. At 15 feet away for a group, 24mm lens gives a whopping 36 feet of DOF. The razor thin concern doesn't apply at ultra wide.

An extreme example here: 24mm f/1.4 at 15 feet still has a DOF of 11 feet (but Canon's 24 1.4L is very soft in the corners at 1.4, different issue).

16mm f/2.8 at 6 feet away still has a very easy to manage DOF of 11 feet. Even as close as 3 feet, gives about 2 feet DOF.

So, f/2.8 really can help indoor photography for ultrawides without causing DOF problems.

Totally fair enough, but under very few circumstances you would ever want to use 24mm for group shots... way too much distortion on the edges, even with the best of lenses...  the guys in the middle of the frame would look good, the poor guys on the end would look huge.  That being said, it is what it is... 

[Etienne]

f/2.8 is not that thin DOF as you go to UWA. A 50 mm FL at 6 feet away f/2.8 gives DOF 0.78 ft (very thin, and difficult to manage), whereas a 24mm FL gives 3.4 feet, which is more than enough. At 15 feet away for a group, 24mm lens gives a whopping 36 feet of DOF. The razor thin concern doesn't apply at ultra wide.

An extreme example here: 24mm f/1.4 at 15 feet still has a DOF of 11 feet (but Canon's 24 1.4L is very soft in the corners at 1.4, different issue).

16mm f/2.8 at 6 feet away still has a very easy to manage DOF of 11 feet. Even as close as 3 feet, gives about 2 feet DOF.

So, f/2.8 really can help indoor photography for ultrawides without causing DOF problems.

yea.   so f/2.8 can help isolate the subject from the background as well.  in your example, the DOF extends from about 2 feet in front to 9 feet behind, which may be pushing it for subject isolation but still  doable (you would more likely be stepping back and zooming in to 21 mm for example, for better results --  But to continue the example:   at f/4 (still 16mm and subject distance of 6 feet)  you loose almost all hope of subject isolation from the background because everything 34 feet behind the subject  is in focus.     so in this particular example, the f/2.8 lens has a hope of capturing a venue feature like a candelabra or whatever, with some isolation from the background, but the f/4 lens has little hope.  I doubt very many people/group shots are taken at 16mm and 6 foot distance... but I'm not a wedding 'tog so I'm open to correction here

The 70 200 2.8 and 24-70 2.8 can use f/2.8 for subject isolation at 50 mm and above, roughly speaking, but f/2.8 in ultra wides is all about more light and nothing about shallow dof.  The 24 f/1.4 is pretty much the only ultra wide that can achieve an effective shallow dof, and you still have to get in fairly close and stay at 1.4