# f2.8 vs f4 with today's high ISO cameras?



## bigtwinky (Dec 7, 2009)

I have a few upgrades in mind in the next 6 months, one being a camera body the other being a telephoto lens.

I know the benefits of f2.8 vs f4, mainly the DOF and the 1 extra stop of light, but with today's cameras achieving the high ISO that was only a thought 3-4 years ago, are the benefits still there?

Sure, on my current XSI, which I cringe if I have to go over ISO 400, the extra stop from 2.8 would be beneficial.  But what about on a more recent camera, where shooting 3200 ISO is pretty clean and 6400 is still fine?
I'm a Canon shooter so I'm weighing the differences between the 70-200 f/2.8 IS and the 70-200 f/4 IS.  The f/4 seems so much lighter and less bulky, has IS, is known to be one of if not the sharpest Canon zoom out there.  Does the f/2.8 still have a major leg up on the f/4?

A friend of mine and I were discussing this the other day, and with his 5D MkII, he went with the f/4 instead of the f/2.8 mainly due to size and weight.


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## Shockey (Dec 7, 2009)

I shoot the d700 and f3. When shooting people I always shoot at 2.8 or 4.
Of course you have to have the very best lenses to shoot at 2.8 or it won't be sharp.

Mainly for depth of field and secondarily for shutter speed.

The f4 should be fine for you unless you are shooting weddings and portraits then you will probably wish you had the 2.8. Also for wildlife the 2.8 if very useful in the early and later part of the day.


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## Overread (Dec 7, 2009)

I would say with the high ISOs possible now its a lesser concern then in the past, but that wide aperture glass still holds its value. First there is the depth of field option as yousay, which is a creative tool and extends what you can possibly create with the lens. 
Further there is the light issue, sure ISO can go higher now but that just means you'll stay out later (darker) when shooting - at some point your ISO will reach its limit and your aperture too - f2.8 at that time will seem mightly attractive.

Weight wise I don't mind the 2.8 version of the lens, but I would encourage you to go for the IS edition of it (more cost I know). 

Another consideration is teleconverters, f2.8 lens can take a 1.4TC and only drop down to an f4 lens - and if your using a higher end camera body chances are you can get away with a 2*TC without too much trouble (and keep your AF). Of course this might not be a concern for the uses that you intend to use the lens for.


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## Dao (Dec 7, 2009)

I think this is really a personally choice.  And it depends on whether you need to do low light photography often.

I am sure someone will want both high ISO camera and F/2.8 IS lens.  Personally, I may go with the F/4 version for weight saving.  However, some wedding photographers will go with both to get the best image they can get.

If weight is not an concern, I will for sure go with a faster lens if cost is not an issue.


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## itznfb (Dec 7, 2009)

No matter how good the ISO performance is on the body, you still want to be shooting at the camera body's lowest native ISO. Obviously unless your intent is creative noise. Though f4 is still fast and sufficient for the majority of daytime photography.


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## CWN (Dec 7, 2009)

If the f/4 is sharp at f/4 you should be OK since that's where a lot of people with the f/2.8 are shooting anyway.

But like mentioned, for things like portrait work or weddings you'll appreciate that f/2.8 aperture.


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## manaheim (Dec 7, 2009)

Hey man... Keeping in mind that the F2.8 lenses tend to be better optical quality as well, the actual light capabilities of the lenses aren't the only factor.  Just something to consider.


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## wiredhernandez (Dec 7, 2009)

I placed an order for th F4 the other day. I have read in several places that the F4 is more sharp the then 2.8 ... I went to another camera shop and looked at a used unit and the first thing the sales girl said was it was sharper than the 2.8 as well so I feel good about that... Will suit 85% of my shots anyway at that anyway... much lighter too


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## Overread (Dec 7, 2009)

Remember we are talking about an f4 L and an f2.8 L lens - both are very sharp and the "f4 is sharper than the f2.8" is not that big a difference. Infact I would argue that in most cases outside of ideal studio controled shoots you could not see much of a working difference between the two lenses (of course you would see a difference were you trying to shoot at f2.8   )


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## robertwsimpson (Dec 7, 2009)

click here to see the difference at 100% crop, 100mm f/4.  the photo is the f/2.8, and if you mouse over, it's the f/4

from the above link, I would say that the f/4 lens is sharper than the f/2.8 at f/4.  the only thing that the f2.8 shows better at f/4 is less vignetting (which is only slight anyway).  

I'm actually shocked at what that shows.  I'd say that if you don't plan on shooting in super low light or trying to achieve a super shallow DOF, I'd go with the f/4.


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## sinjans (Dec 7, 2009)

Robert, 

You have made a great point. I am looking for the right deal on a 2.8, but maybe if the 4 is around i may now go with that one. I


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## bigtwinky (Dec 7, 2009)

> Hey man... Keeping in mind that the F2.8 lenses tend to be better optical quality as well


 
I've read that the f4 has better optical quality than the f2.8.  So its 1 stop more light, better DOF vs weight, cost.  Shooting on my XSI, f2.8 for sure.  Shooting with an ISO 6400 capable camera, I'm not sure.



robertwsimpson said:


> click here to see the difference at 100% crop, 100mm f/4. the photo is the f/2.8, and if you mouse over, it's the f/4
> 
> from the above link, I would say that the f/4 lens is sharper than the f/2.8 at f/4. the only thing that the f2.8 shows better at f/4 is less vignetting (which is only slight anyway).
> 
> I'm actually shocked at what that shows. I'd say that if you don't plan on shooting in super low light or trying to achieve a super shallow DOF, I'd go with the f/4.


 
See, thats what got me thinking and making this post.  I read as well that the 70-200 f/4 is the sharpest Canon zoom lens out there today.  While I agree that the difference between it and the f/2.8 is probably not huge, it still remains sharper.

So I figured that super low light could be better handled with the more modern cameras that can go high ISO.  When you are limited to 400,800 ISO, then yes, 2.8 will be better than 4.

Shooting at 1/30, f/4, ISO 800 would be nicer to shoot at 1/60, f/2.8 ISO 800, depending on what you are shooting, as you are getting a higher shutter speed.  However, with something like the 5D Mk II (from what I read) you can work with ISO 6400 really nicely...which means 1/250, f/4, ISO 6400.


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## robertwsimpson (Dec 7, 2009)

I'd be hesitant to shoot at f2.8... I mean, if you're going for super-sharp, you're not going to want to do that anyway.


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## itznfb (Dec 7, 2009)

robertwsimpson said:


> I'd be hesitant to shoot at f2.8... I mean, if you're going for super-sharp, you're not going to want to do that anyway.



The Canon 70-200mm f/2.8 and Nikon 70-200mm f/2.8 are perfectly capable of producing "super-sharp" results @ f/2.8. Many people want to do that and do it every day with great success.


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## inTempus (Dec 7, 2009)

Let's not forget that for autofocusing, the f/2.8 lenses will offer superior performance.  If you're shooting in low light, having a f/2.8 lens doesn't just offer an extra stop of light it also offers your f/2.8 sensitive AF points the ability to kick in.  That means faster and more accurate autofocus.


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## Wolverinepwnes (Dec 7, 2009)

you can never go wrong with an F/2.8!!! never!


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## robertwsimpson (Dec 7, 2009)

hey, what do I know, I mean I'm only talking about REAL data.  I guess I should talk about other people instead of show actual information.


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## battletone (Dec 7, 2009)

robertwsimpson said:


> hey, what do I know, I mean I'm only talking about REAL data.  I guess I should talk about other people instead of show actual information.


Well, maybe so, but a lot of professionals use the 2.8 with great success.  Numbers and specifications are all great, but if something requires charts with perfectly straight lines and other test equipment to see a ever so slight difference, then as far as I am concerned, there is no difference.
As inTempus said, it has better AF.  If that is so, then I think the image quality issue is almost moot compared to cost/weight/speed/AF.


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## robertwsimpson (Dec 7, 2009)

well, you can't deny that the f/4 is sharper.  That's all I'm saying.  Maybe it's not enough to notice, maybe it is.  it's probably not enough of a difference to make it anything more than personal preference, but hey, just about everything we buy is based on personal preference, so why not a camera lens?


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## inTempus (Dec 7, 2009)

robertwsimpson said:


> hey, what do I know, I mean I'm only talking about REAL data.  I guess I should talk about other people instead of show actual information.


Interesting site, I've looked at it many times.

The sample you've posted shows very little difference between them, IMHO.  If I were taking pictures of closely spaced straight lines for a living, I would certainly want the f/4 lens.  

Given the marginal differences (which could be differences between bodies not just designs) I don't think I would trade my f/2.8 for an f/4.  My f/2.8 lens produces amazingly sharp images.  That coupled with its superior AF capabilities (as I often shoot in low light), I'll keep the f/2.8 version.  Heck, it's so sharp that if Canon introduces a replacement I'm going to be very reluctant to sell my copy to buy the new version.


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## Derrel (Dec 7, 2009)

The difference in resolving power in the example Robert linked us to is very,very slight--the resolution is in fact not the biggest difference; what the samples show is that the 70-200 f/4 is demonstrating only very marginally higher resolution, but significantly higher *contrast* than the 2.8 lens. Regardless, the 70-200 f/4 L-IS is regarded as an excellent lens. it's not like it is a second-tier, slower consumer zoom--it's a lightweight pro lens, designed for size and mobility. And, yeah....I grew up with Kodachrome 64 and Tri-X 400--today we have ISO 1600 that looks better than Tri-X at 800...and we get full-color. Kodachrome 200, introduced around 1987,looked like crap compared to an EOS 5D at ISO 800. So,yeah, f/stop has lost *some* value over the years, in one sense. But in another, it still counts.

The old expression, "a rising tide lifts all boats," might apply; with better High-ISO cameras, the better cameras get improved picture making capabilities as do the lesser-spec'd cameras. The things I liked about about the 70-200 f/4 L that I borrowed, a pre-IS model with the 67mm filter size, were how small and light is seemed compared to a bigger lens like a 70-200 2.8, Nikon 100-400, or Sigma 100-300mm f/4 HSM. The smaller Canon just felt "light and small", and I think it might draw a bit less attention on the street than those bigger lenses.

ONly you can decide for yourself if the size,weight, price, and bulk of the 70-200 in f/2.8 is worth it com pared with the f/4 version; with shorter focal length lenses, likely to be used indoors, I think the faster f/2.8 lenses offer MUCH better focusing, due to both improved light gathering, more out of focus when OOF for the phase detection system, and the opportunity to actually use the lens set to f/2.8 or f/3.2 or so, indoors or outdoors in low light. With a short lens, you can shoot at f/2.8 at 1/8 second and not get too much camera motion or subject motion, so on a 16-35 f/2.8 versus say the 17-40 f/4-L, the wider aperture of the 16-35 (or 24-70) is actually more "usable" in the real world, whereas at say 135mm, f/4 at 1/60 second is a recipe for subject motion blur,and you'll need to use flash. At least this is the way I look at it.

Recently, I went to a college football game and carried my 5D with 24-105 f/4-L and even at ISO 1250 indoors, I was unable to stop motion blur of people moving...I wish I would have carried a faster-aperture lens. At night, after the game, the shots I got outside the stadium could have really benefitted from a fast-aperture lens like an f/1.8, again, even at ISO 1250...


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## Dao (Dec 7, 2009)

> ONly you can decide for yourself if the size,weight, price, and bulk of the 70-200 in f/2.8 is worth it com pared with the f/4 version



I agree with you Derrel.  I believe OP should already know how good each lens is.  And know all the facts that people present here before hand.  But really, I do not think we can give you advice on which one to get since it is really a personal choice.  

Either case, it is a great for what it gear for.  Good luck.


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## wescobts (Dec 7, 2009)

I am fortunate enough to have the Nikon 70-200mm VR, and it's a great lens. But I find myself leaving it home sometimes when I don't feel like lugging it around, and that is a shame. I have been considering the 180mm 2.8 prime as an alternative because of the weight and size. Tough choice


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## itznfb (Dec 7, 2009)

I've borrowed a 180 f/2.8 as an alternative while hiking. It's a great alternative. Amazing prime lens.


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## lamergod (Dec 7, 2009)

Sure,you can use a f4 lens and pump the iso to 100,000ISO,the sharpness will lose to a f2 8 lens when stopped down to f4

Another thing is noise,well you could probably say that i'm alright with noise,another about high ISO is colour!The higher the ISO the less colour range you lose


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## camz (Dec 7, 2009)

That's a tough one Pierre.  In addition to what has been mentioned I think if you are more of a natural light shooter I'd go with the 2.8(which I did).  If you were a strobe or flash photographer I'd go with the f4 b/c even with the current rebate there's more then a $500 dollar difference which can go towards a good flash and a set of triggers which should even out the price between the two. 

Also with the F4 if forced to shoot at a high ISO by one stop, there's also Noise Reduction software to help you along the way if the $500 difference does not justify the cost of an extra stop of light.  Just a thought..


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## FrankLamont (Dec 8, 2009)

Solid low-noise performance comes from noise reduction, which after a while starts to soften your images.

That aside, I'd pick fast lenses until it gets to about f/1.8, which is the limit... after that, the DOF is just too thin, and a bit of shifting can mean slight out of focus.


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## iflynething (Dec 8, 2009)

If you can afford 2.8 glass, there is NO reason not to get it.

High ISO is there if you NEED it not just an excuse to get a "slower" lens

~Michael~


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## Garbz (Dec 8, 2009)

manaheim said:


> Hey man... Keeping in mind that the F2.8 lenses tend to be better optical quality as well, the actual light capabilities of the lenses aren't the only factor.  Just something to consider.





Overread said:


> Remember we are talking about an f4 L and an f2.8 L lens - both are very sharp and the "f4 is sharper than the f2.8" is not that big a difference. Infact I would argue that in most cases outside of ideal studio controled shoots you could not see much of a working difference between the two lenses (of course you would see a difference were you trying to shoot at f2.8   )



Actually you can see a difference but it's not what you may expect. Nearly all lenses perform worst wide open so normally I'd side with manaheim in that the f/2.8 would be sharper than the f/4 when used at f/4. 

However this is not the case. The f/4 is supremely sharper in all tests I have seen at every aperture. It's a beast of a lens. So much so that the results would be field relevant, especially at 200mm shot at f/4!


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## c.cloudwalker (Dec 8, 2009)

Salut Pierre

I'm looking at buying the same focal range you are but I'm not a fan of zooms. Back in the film days they were nowhere near the quality of primes. Today, they seem to have gotten much better but from what I read they are not perfect. And, the in-between focal lengths are just a few steps. Walking is the cheap man's zoom 

From what I read, with a 70-200 your actual usable range would be something like 80-190. I have not actually checked this, just throwing a number to explain my reasoning. Also, with the more complex build of zooms, to have a fast one you have to 1/ pay quite a bit more and 2/ add on the weight. 

So this is what I have decided to buy for myself.

EF 85 f1.8 Everything I've read about this lens makes it seem very good and friends who own it are quite happy with it. And, it's only 425g.

Then, the EF200 f2.8. Same thing with what I've read and been told. Very good lens. But it is not IS and 765g so that had me worried. Most people I have talked to however tell me they don't have a problem handholding it. Most of them did add that they wouldn't go to any heavier lens without the IS. 

So this is what I'm looking at: faster than the fastest zoom you're thinking about and lighter for a little more than $500 savings. If you were to go with the f4, it is about the same price as my combo but slower. And all I have to do to save that money and have, I think, better lenses is to walk a bit more than you would with a zoom.

Not having a zoom does not bother me since I have never had one and that didn't keep me from getting the shots. Even when doing weddings which, as I told someone recently, I shot with one lens and a doubler.

Just something to think about.


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## seekinglight (Dec 8, 2009)

What are you going to be photographing? I own the 70-200mm f4L to photograph Cross Country and Track and Field. Plenty of light outdoors and because I can get close to the action I can still get shallow depth of field. 

I would not consider f4 for indoor sports. In indoor sports where I'm often shooting at 1600 ISO and 1/640 sec at f2.0 or even f1.4 I consider f2.8 too slow. 

I consider f2.8 to be too slow for indoor sports. If I had a higher ISO camera I would enjoy lower noise ISO 1600 shots, not go to higher ISO with slower lenses to get the same amount of noise. I have considered that the new cameras might make the 70-200 f2.8 more usable for indoor sports.


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## manaheim (Dec 8, 2009)

I missed that they were both L lenses.  Sorry.


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## c.cloudwalker (Dec 9, 2009)

L does not always mean much. Although an L zoom will most probably be better than a non-L zoom, it may not be better than an non-L prime.


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## inTempus (Dec 9, 2009)

c.cloudwalker said:


> L does not always mean much. Although an L zoom will most probably be better than a non-L zoom, it may not be better than an non-L prime.


I agree, I've compared the F/1.4 50mm to the f/1.2L 50mm and I swear you couldn't tell any difference in the IQ when eyeballing the images side-by-side. 

I've found the same to be true of the f/1.8 85mm vs. the f/1.2L 85mm.  I actually think the 85 f/1.8 is a better all around lens.  I've often considered selling my 85L and replacing it with the faster focusing non-L version, then taking the difference and buying yet another lens.


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## MrLogic (Dec 9, 2009)

inTempus said:


> I've found the same to be true of the f/1.8 85mm vs. the f/1.2L 85mm.  I actually think the 85 f/1.8 is a better all around lens.



This is what the great Ken Rockwell has to say about these lenses:



[FONT=Arial, Helvetica, sans-serif]"This Canon 85mm f/1.8 is very good. It's more resistant to ghosts and flare than the Canon 85mm f/1.2L II.[/FONT]

and:

[FONT=Arial, Helvetica, sans-serif]"The Canon EF 85mm f/1.8 USM is an easy lens to recommend. It's much better than you expect, so if you're reading this because you think you want one, then just go get one. You'll love it![/FONT]
[FONT=Arial, Helvetica, sans-serif]
[/FONT]​ [FONT=Arial, Helvetica, sans-serif]The only things the five-times as expensive Canon 85mm f/1.2L II does better is lighten your wallet, fatten the weight hanging around your neck and it's a little sharper in the far corners, full frame, wide open.[/FONT]
[FONT=Arial, Helvetica, sans-serif]
[/FONT]​ [FONT=Arial, Helvetica, sans-serif]The f/1.8 focuses much faster and easier, and is an all-around more satisfying lens than the f/1.2. The f/1.2 is for weird things like astronomy where you absolutely, positively need f/1.2."[/FONT]​

Canon 85mm f/1.8


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## inTempus (Dec 9, 2009)

OMG, please delete your post.  That's not nice.  I can't have that dolt agreeing with me.


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## robertwsimpson (Dec 9, 2009)

85mm f1.8 vs 85mm f1.2 @ f/1.8

is it just me or is the L lens much sharper at f/1.8 than the other lens? I don't think they're even until about f/4

maybe in practice it's less pronounced, but there is a definite difference.


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## inTempus (Dec 9, 2009)

I'm sure there is a difference, but the question becomes is there a noticeable difference in real world pictures and is that difference worth $1400.

The 1.8 looks better in some respects than the 1.2, and in other respects the 1.2 looks better than the 1.8 in the linked to test IMHO.


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## robertwsimpson (Dec 9, 2009)

how? I mean, I get the whole "is it worth the extra $1400?" argument, which I don't think so, but I see more vignetting and less sharpness and contrast in the 1.8 in every interval.  Like I said, when it gets to f/4, they look pretty much exactly the same.  I was surprised to see the amount of CA on the f1.2 when shot wide open.  the black looks purple.


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## c.cloudwalker (Dec 9, 2009)

inTempus said:


> c.cloudwalker said:
> 
> 
> > L does not always mean much. Although an L zoom will most probably be better than a non-L zoom, it may not be better than an non-L prime.
> ...



Wow, inTempus, you mean we can actually agree on something... WINK!

And believe me, if I had known I was saying something agreeing with Rockwell, I would have shut up. LOL.

Seriously, as you say in your later post, there is a difference between lab tests and everyday reality. And personally I can't care about lab tests if it passes the other test.

For those who don't know me, I can only repeat that I worked for about 12 years in PJ with no pro equipment. No magazine or newspaper editor ever asked me what equipment I was using. Even when they were buying my photos rather then using their man-in-the-field's work...


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## Derrel (Dec 9, 2009)

robertwsimpson said:


> how? I mean, I get the whole "is it worth the extra $1400?" argument, which I don't think so, but I see more vignetting and less sharpness and contrast in the 1.8 in every interval.  Like I said, when it gets to f/4, they look pretty much exactly the same.  I was surprised to see the amount of CA on the f1.2 when shot wide open.  the black looks purple.



Robert,
 Yes, the black looks purple--that's chromatic aberration, which is something the 85/1.2-L suffers from pretty severely at wide apertures. It also has a green chromatic aberration as well; one color in front of the point of sharpest focus, the other color behind the point of sharpest focus--but that does not show up on a flat test chart! That purple AND green CA is now often called bokeh chromatic aberration, but the proper term is longitudinal chromatic aberration, and longitudinal CA is VERY hard to eliminate in post--as in basically impossible to eliminate; lateral chromatic aberration, ie color "fringing" is easy to eliminate, and the better new Nikon cameras know the lens by CPU EXIF exchange information,and those cameras can "map out" lateral CA from all the Nikon lenses entered into the camera profile. I suspect Canon will be introducing this same feature pretty soon on in-camera created JPEG images. It's a software thing,and it would be easily done, if it became a design priority,and it might, in time.

Anyway...yes, there is plenty of purple CA shown, and the L lens does resolve better on the test chart--BUT, in real world shooting of many subjects, CA is not as visible as it is on these test charts. As far as CA goes, a good comparison would be between the Sigma 50mm f/1.4 and the Canon 50/1.2-L; the Sigma is targeted directly AT the CANON...Sigma deliberately went after one of Canon's most highly desired lenses, and priced their lens $1,000 lower, with higher resolution and lower CA. Of course, it's a Sigma and not a Canon-L lens so for some people that makes a difference. A lot of people are purchasing lenses based on test chart and pixel-peeping, and also on status value and marketing practices; the "status" value of f/2.8 appeals to many people, as does the L-designation. Worth,price,and value are all separate things, but many people intertwine or confuse them.

What does this have to do with the OP's question? Well, looking at the Chart linked to above, the differences on the 1Ds-III at 22 MP are more pronounced than on the 1Ds-II at 16.7 MP. I think a few things are relevant here: there IS A WAY to map-out lateral chromatic aberration on in-camera JPEG images and also on RAW images, and Canon will probably work on that in the future. Also, the differences between the 1.8 and the 1.2 and the 2.8 and f/4 70-200 lenses is reasonably small,and on BigTwinkie's current camera, the difference is probably very,very slight. On a 10-12 MP sensor, especially a FF model, any lens looks good; as we go forward to the higher and higher and higher MP count sensors, like 17MP on 1.6x ie 7D, lens quality and lens characteristics become a bigger problem,and better lenses are needed. And finally, these lenses last a LONG time. In amateur use, I'd expect most Canon L lenses to last 30 years. These L-grade Canon;s are built like TANKS! These lenses will last two decades or more.

The 70-200mm f/4-L IS is the NEWEST of the Canon 70-200's; as such, it has the best design Canon could come up with for the price point. I think it is worth every penny of the asking price--the 2.8 IS model that I own is known to be weak at the longer focal lengths, and I think Canon corrected for that in the design of the newer f/4 model. Lenses have their own signatures, their own problems, and the test charts show those, but real pictures show what the lens can do. I think it really come down to, "Will I pack it, or leave it home?" ie--is the size/weight so high it'll ride on the camera, or sit at home? Most of the modern lenses now are pretty good. A few are great. Worth, price, and value; the 70-200 f/4 L-IS USM...it's got all three bases covered. What's it worth to have a small,light, pro-grade lens?


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