# How to get / test a good copy of a L lens?



## Marsu42 (Feb 20, 2012)

I'm going to buy a 70-300L (but the question is valid for any prime tele lens), and since these are precision optics well below the price of the hubble space telescope, there are big variances and I am wondering how to end up with a sharp / non-ca copy. Two questions:

* Where to buy: Of course I could get the lens at the pro shop 'round the corner and test/return the lens numerous times - but at a premium of at least ~200€. Now you could say I'd get what I pay for, but suppose I didn't win the lottery and have to save $$$. I intend to get the lens from Amazon (I'm in Germany) - any experiences how often and w/o problems you can return the lens if the copy is bad?

* How to test: This is my most important question: If I get the lens, no matter what the source - How do I test that the lens is a good copy? Take pictures of some chart - and then compare them to what? Obviously every L lens takes 'good' pictures, but for me it would be impossible to tell if the lens I have is one that has been returned numerous times before and then ended up with me. 

Thanks for your input, just now I really have no idea how to tell a good copy from a bad one...


----------



## neuroanatomist (Feb 21, 2012)

See http://www.canonrumors.com/tech-articles/how-to-test-a-lens/.

Minimally, shoot blue sky wide open to check for symmetrical vignetting (lack of that means decentering).


----------



## Axilrod (Feb 21, 2012)

I think you're slightly overestimating the importance of hunting for a "good copy" of a lens. It's not like you have a 50/50 chance of getting a good one, I would just try 2-3 different ones and see if you notice any major differences. I think you'll notice that most of them perform very well there is just the occasional copy that's perfect and may perform slightly better.


----------



## Mt Spokane Photography (Feb 21, 2012)

Marsu42 said:


> I'm going to buy a 70-300L (but the question is valid for any prime tele lens), and since these are precision optics well below the price of the hubble space telescope, there are big variances and I am wondering how to end up with a sharp / non-ca copy. Two questions:
> 
> * Where to buy: Of course I could get the lens at the pro shop 'round the corner and test/return the lens numerous times - but at a premium of at least ~200€. Now you could say I'd get what I pay for, but suppose I didn't win the lottery and have to save $$$. I intend to get the lens from Amazon (I'm in Germany) - any experiences how often and w/o problems you can return the lens if the copy is bad?
> 
> ...



Maybe you can contribute a few euro to Klaus at photozone and ask him to test it for you? Most of the lens buyers are in your shoes, they really can spot only the worst errors. Be warned though, he has high standards for quality, so even a lens he gives average marks to can be pretty good.


----------



## dolina (Feb 21, 2012)

Have you ever bought a bad copy?


----------



## dr croubie (Feb 21, 2012)

How far West are you in Germany?

Take a trip over the border to fotokonijnenberg.nl, the guys in The Hague shop are good, but there's a shop closer to Germany i've never been to. They'll possibly let you take each outside for a few minutes to test which is best of the copies they have in stock. Make sure you Live-view MF on a tripod and take a picture of a static subject to see if there are any glaringly bad copies, but I don't think you will be able to find the diamond in the rough as easily/quickly.

Oh yeah, and the most important thing, is that they're cheap. I bought my 70-300L there, best price I could find anywhere (including on net-shops) was in their store.


----------



## Marsu42 (Feb 21, 2012)

Mt Spokane Photography said:


> Maybe you can contribute a few euro to Klaus at photozone and ask him to test it for you?


The photozone site says the testing queue is full: http://www.photozone.de/canon-eos/365-request_canon



Axilrod said:


> I think you're slightly overestimating the importance of hunting for a "good copy" of a lens.


I always like to take advice, but I have to ask: How would you know how many bad or mediocre copies are produced? For example, the lens test at "The Digital Picture" shows significant differences between two "ok" copies.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=738&Camera=453&Sample=1&FLI=0&API=0&LensComp=738&CameraComp=0&FLIComp=0&APIComp=0



Axilrod said:


> I would just try 2-3 different ones and see if you notice any major differences.


That's the problem: If I get a lens through mail order, I have exactly one lens to test... and I am wondering if it is possible at all to compare this to synthetic data. As I wrote, I'd like to get around the other possibility to go to a pro shop, make the guy order 4 lenses at compare them there because of the price premium .



dolina said:


> Have you ever bought a bad copy?


That's the point: I wouldn't know, would I? However, I didn't buy a L lens for 1000€+ yet and thus didn't loose much sleep over it if it "was worth it" (like Ken Rockwell says)



dr croubie said:


> How far West are you in Germany? Take a trip over the border to fotokonijnenberg.nl,


I'm from Berlin, ie too far East :-\



neuroanatomist said:


> Minimally, shoot blue sky wide open to check for symmetrical vignetting (lack of that means decentering).


I've read the 70-300L doesn't show vignetting at all on crop bodies, so that wouldn't help :-o



neuroanatomist said:


> See http://www.canonrumors.com/tech-articles/how-to-test-a-lens/.


Thanks for the link! However, it basically says that you cannot check for overall sharpness - only for a broken lens and for for relative sharpness in one quadrant of a lens in comparison to another. Which is better than nothing, though.

I guess one way of solving this problem is to find another person near me with this lens, get there and compare. Or walk into some electronics market with my test chart and at least get some shots from another 70-300...


----------



## candyman (Feb 21, 2012)

dr croubie said:


> ........... but there's a shop closer to Germany i've never been to. ...............




What is the name of that shop?
Thanks!


----------



## dr croubie (Feb 21, 2012)

candyman said:


> dr croubie said:
> 
> 
> > ........... but there's a shop closer to Germany i've never been to. ...............
> ...



Oops, I meant there's another outlet of Fotokonijnenberg. They've got 3 shops, Den Haag, Den Ham (SW of Emmen, NW of Enschede), and Turnhout (is actually in belgium). Currently €1.199 for a 70-300L (they were cheapest when I bought mine about this time last year, don't know if anyone's cheaper than that now though)


----------



## Mt Spokane Photography (Feb 21, 2012)

You can certainly test the quality of a lens yourself, its just a matter of really wanting to spend the time, money, and self education to do it.

Most people give up when they see how much work it is, and the price. Look at the Demo, print the charts, and photograph them. Obvious problems with a lens may show up, but most issues are subtle.

Start here!
http://www.imatest.com/products/software/imatest-studio/

Even the basic consumer software is not cheap, you can print your own test charts, have them printed, or buy expensive ones.


----------



## K-amps (Feb 21, 2012)

I have not heard of people getting bad copies of the 70-300L so far. I have heard it for other lenses.

I got 1 copy and it was great, and I am a bit fussy... I went through 2 copies of the 70-200mkII and 17-40L because they did not seem sharp to me... or as sharp as the 70-300L.


----------



## ejenner (Feb 21, 2012)

Marsu42 said:


> since these are precision optics well below the price of the hubble space telescope



I have to ask if this was a deliberate tongue-in-cheek poke at NASA considering the Hubble optics were softer than a 17-40 at f4 in the corner and possibly the ultimate example of a 'bad copy'?

If so I definitely appreciated the humor.

On the testing question, personally I can only tell if a lens is sharp compared to something else - either the same lens stopped down, or another lens. For instance my 24-105 seems sharp enough, I suspect it is a decent copy, and people on forums often call it sharp. But if I compare it at 24mm to my TS-E 17mm with a 1.4x, it looks quite mushy. Doesn't look all that sharp compared to my sig 85 1.4 either. I think this is one of the main problems with calling a lens 'sharp' - sharp compared with what?

Anyway, if you have a good idea of roughly how sharp it should be compared to another lens you own (probably a zoom), I would test it against that and unless it is obviously bad, it is very probably a 'good' copy.

If you are one of these people trying to get a super sharp copy for your particular camera then you need some serious testing gear and about 5-10 copies of the lens. If you want the sharpest copy that will also like be one of the sharpest on a future camera, you're going to need 5-10 camera bodies as well and probably more lenses. The of course one copy might be slightly sharper at 70mm and another slightly sharper at 300mm. The point I'm trying to make here is that while there is certainly copy-to-copy variation, the 'bad' copies of any lens are usually obviously bad when compared to other similar lenses.


----------



## Marsu42 (Feb 21, 2012)

ejenner said:


> Marsu42 said:
> 
> 
> > since these are precision optics well below the price of the hubble space telescope
> ...


Um - you're right, this joke was on me :-o ... I nearly forgot the hubble telescope was broken and then fixed by software - however trusty Wikipedia says it was a mirror and not a lens...

What I actually wanted to say that I doubt a commercial company can produce something like the 70-300L at 1k€ by dumping all non-optimal copies - it is more probable they'll try to widen their specs and try to sell as many as possible and get them returned if someone notices. On the other hand, this might be a conspiracy theory.



ejenner said:


> On the testing question, personally I can only tell if a lens is sharp compared to something else - either the same lens stopped down, or another lens.


You're correct, and I think I have at last figured out how to test my new shiny L lens once it arrives w/o having multiple lenses of the same type, this should at least tell me if I have to return it or keep it:

1. determine front/backfocus, have a look for broken bokeh (a German Amazon review states this has occurred with this lens) and then shoot a ISO 12233 chart at different settings

2. compare the lens to itself (i.e. is the top right sharper than the bottom left etc)

3. compare the *differences* of my lens at different apertures to the *differences* of the samples from www.the-digital-picture.com - i.e. does my copy show the expected relative iq improvement/degradation or is for example my lens especially bad at full open?

4. compare the *differences* between my 70-300 any my 100/2.8 (I know this is a very good copy) to the *differences* to be expected between these lenses from the samples from www.the-digital-picture.com


----------



## neuroanatomist (Feb 21, 2012)

Marsu42 said:


> neuroanatomist said:
> 
> 
> > Minimally, shoot blue sky wide open to check for symmetrical vignetting (lack of that means decentering).
> ...



I don't think it says that at all. You certainly can test a lens for overall sharpness, and several suggestions have been offered for doing so. Personally, I use a test chart that costs more than some L-series lenses; there are free versions that can be printed and will work fine. Likewise, there's the Imatest software which Mt. Spokane linked, but if you'd prefer not to spend the money on that, or like me, are a Mac user whereas Imatest runs only under Windows, Norman Konen provides some download links to macros (free) which run in ImageJ (also free, formerly NIH Image) to perform SFR analysis. 

Copy variation is inherent to the manufacturing process, as made quite evident by Roger Cicala's (lensrentals.com) testing of many copies of various 50mm lenses. On a smaller scale, Bryan at TDP tested three copies of what is currently Canon's most expensive zoom lens, the 70-200mm f/2.8L IS II. Two of the three were sharper at 200mm than at 70mm, the third was sharper at 70mm than at 200mm. Canon's theoretical MTF curves suggest the lens should be sharper at the long end. Does that mean one of Bryan's lenses was a 'bad copy'? Not if you'd want to use it more at the short end than at the long end... But it's an outlier compared to the other two.

I think the point about testing sharpness of a lens that you buy was not that you can't, but that doing so offers no menaingful way to determine if yours is a 'good copy'. No two testing setups are identical, and to compare results across different testers/setups, they would need to be the same. Even so...say, for example, that you duplicated Klaus' photozone.de test setup quite accurately, such that you could compare the MTF50 numbers you obtained to his posted data. What if your new lens was slightly better? Would you think you have a good copy, and stop there? All you'd really know is that your copy was better than the copy Klaus tested - maybe that copy was one of the worst, so your copy would only be slightly better than the worst. Conversely, what if the copy you got didn't perform as well as the photozone copy? Would you return it and buy another one? What if Klaus tested one of the best copies - how many lenses would you go through? What if the next 4 lenses you bought were worse than the first one, but you'd already sent that one back, and of course you would not be able to repurchase that specific copy...

Going back to the original question, "How can I get / test a good copy of a lens?" Basically, there's only one way to do that - establish a robust and reproducible test setup, then buy 10 copies of the lens you want, test them all, keep the best one and send the other 9 back. (Then, the return postage with insurance would probably pay for a 17-40L). Short of that extreme which would be needed for meaningful comparative data, what you can realistically do is not determine if you have a 'good copy' of a lens, but rather, determine that you don't have a defective copy of the lens. If that's the case, then you have a copy that should meet Canon's manufacturing QC standards, and while there are obvioulsy variations in quality within that range, the a difference of a few 10's of LW/PH that you can detect shooting test charts is not going to make a meaningful difference when shooting things out in the real world. Still, I've heard of people who send every lens they buy into Canon service, and some report the lenses are adjusted and come back sharper.

Having said all of that, there is a test you absolutely should perform, and one that will make a whole lot more difference than finding the sharpest copy of a lens. Test the AF performance of your new lens. Assuming you're not one of those MF-only folks, if your camera AF doesn't play nicely with your new lens, that's going to have a real and meaningful impact on your shots, since shots where focus is off are rarely sharp. For example, my 70-200mm II IS delivers very sharp results with my test chart (where testing is done with manual focus, by focus bracketing). On my 7D it requires an AF microadjustment of +2, which means it's off by 1/4 of the depth of focus wide open - in most cases, that's close enough not to notice. But the same lens on my 5DII needs an AFMA of -6 - that's 3/4 of the depth of focus, and means that without that adjustment, many shots would be noticeably back-focused. Given that you have a 60D, where you cannot make those adjustments, AF performance will be very important for you to test. Just keep in mind that if your body is at one end of the range or the other, you might find a lens to match, but if you get a new body later, the lens might be way off. For me, a backfocusing 100L Macro on my T1i/500D was a big part of my move to the 7D, and I'll never buy a body without the AFMA feature.

AFMA _might_ not be such a big deal for this lens - f/4.-5.6 on APS-C doesn't yield a very shallow DoF, and deeper DoF masks focus errors. But having said that, I owned a 70-300mm f/4.5-5.6 DO IS lens, and it required a -7 AFMA setting on my 7D to correct the backfocus. You can see a typical pre-AFMA shot below, focus was not on the eye but rather the plane of critical focus was running through the back legs of the frog - this is a shot at 300mm f/6.3, and the backfocus is evident.


----------



## Marsu42 (Feb 21, 2012)

neuroanatomist said:


> Marsu42 said:
> 
> 
> > Thanks for the link! However, it basically says that you cannot check for overall sharpness
> ...



I didn't make myself clear on this, sorry: The article "How To Test a Lens" says what you just wrote: You can test for overall sharpness, but not for a "good copy" with just one lens to test.

However, on reflection I don't think this is entirely true (see my suggestion: compare the differences between two lenses you own (of which one has to be a good copy for the baseline) to the differences between the same lenses from the digital picture) 



neuroanatomist said:


> Having said all of that, there is a test you absolutely should perform, and one that will make a whole lot more difference than finding the sharpest copy of a lens. Test the AF performance of your new lens. [...] Still, I've heard of people who send every lens they buy into Canon service, and some report the lenses are adjusted and come back sharper.



That's interesting, because the guy who sold my macro lens said just that - he had it adjusted by CPS, and it indeed is extremely good.

You don't seem to have first-hand experience, but maybe someone else can comment on this - what is Canon service actually able to do? 

* AF adjustment (Do I have to turn in my non-afma body with my lens)?
* sharpness / ca-improvments?
* Do they do it for free on warranty / how bad does a problem have to be to make them do it for free?


----------



## unfocused (Feb 21, 2012)

Maybe I'm missing something, but is all this agonizing really necessary?

If you buy a Canon lens with an in-country warranty and it turns out to have a problem, just send it back to Canon for repair/adjustment under warranty.

Are we talking about buying a lens and then not knowing if it is sharp or not? If you can't tell, then what's the issue? Are you interested in taking pictures or just owning a lens that meets some idealized standard for sharpness? I'm just not getting the point of this. 

If your pictures are sharp, they are sharp. If they aren't, and after a few months of shooting you are convinced there is a problem with the lens, then send it in for repair. As long as you aren't buying grey market or used, what's the problem?


----------



## Marsu42 (Feb 21, 2012)

unfocused said:


> Maybe I'm missing something, but is all this agonizing really necessary?If you buy a Canon lens with an in-country warranty and it turns out to have a problem, just send it back to Canon for repair/adjustment under warranty.


Well, that's the point, isn't it? How do I know it turns out to have a problem - because it bursts into flames while shooting? Of course you could say "If I don't have a problem, there is no problem", but I'd rather adopt this stance with my mobile phone camera and not a 1k€+ lens. And I never wrote I have to have the sharpest lens on the block (cite me if I'm wrong), but I want to get around a bad copy.



unfocused said:


> If your pictures are sharp, they are sharp.


Maybe I'm a bit macro-lens infected, but either a hair is a line or a blur. If I find out after shooting 50k pictures that these blurs would have been hairs with a properly adjusted lens, it would be somewhat frustrating to me.



unfocused said:


> If they aren't, and after a few months of shooting you are convinced there is a problem with the lens, then send it in for repair. As long as you aren't buying grey market or used, what's the problem?


And how would you know the support doesn't just return the lens stating that to them, it seems to be well inside the qa specs? These guys don't work for free, after all, and have evaluate the possibility to get around a repair.

And most important: I'd rather return it right away if possible, the last time I had a lens repaired it nearly took three (3) weeks - which was exactly the period in which I'd needed it most. If you just grab another lens out of your stack, congratulations - but I am not able to do this.


----------



## unfocused (Feb 21, 2012)

Well, I still don't get it. I guess it's just a difference in perspective. Not saying your wrong. It's your money and if this is really important to you, then by all means, go for it. You might as well get your money's worth out of something, before it all gets spent propping up the rest of Europe.


----------



## Stu_bert (Feb 21, 2012)

unfocused said:


> Well, I still don't get it. I guess it's just a difference in perspective. Not saying your wrong. It's your money and if this is really important to you, then by all means, go for it. You might as well get your money's worth out of something, before it all gets spent propping up the rest of Europe.


Having bought a 100-400mm L as my "joint 1st" L lens for my canon and it being a "lemon" then I well sympathize with the OP wanting to ensure he gets a good copy. Back then, I was completely ignorant about differences between lenses, the chance of a poor copy etc, and only through research on various websites and forums did I start to learn there's a lot more to consider. But the bottom line for me, if you are paying for quality, you expect quality (within tolerances). I've had "that" lens in with Canon 3 times, always with the body I shoot it on, and frankly it's still soft as hell but it's so far out of warranty that it's basically not much better than a doorstop.

Point number 2, and this also goes back to my earliest dSLRs, but I remember comparing my 16-35mm to a friends 17-40mm and being disappointed at how his picture (same body) was sharper than mine. Yes, up to that point, I was happy. Then I found there was better. Granted it was a different lens, but if you don't know what "best" is and I would guess most people on here aren't involved in lens manufacturer or testing & therefore wouldn't, then it's not unreasonable to seek guidance on forums like this.

Finally, returning any lens under warranty is just a right pain in the butt, and costly for insurance, especially if you send back you body as well. In fact, I would have to arrange a special courier as returning just a single body & L lens exceeds most standard insurance. I'm just lucky to be an hours' drive from Canon CPS.

Marsu42 - would be interested on how you get on...


----------



## ejenner (Feb 21, 2012)

I think this is what I would do:

1. If I don't have a suitable lens to lest against, buy 2 copies on credit, compare and return one. You might even tell the retailer what you are going to do. This assumes that you/they haven't got a defective 'batch'.
2. Test against a suitable lens you have or can borrow. For instance if you have a lens with a FL of 50-100mm, decide how sharp is should be compared to that lens for you to be satisfied, then test. Maybe it will be a good copy, but still not be what you were expecting?

I totally agree that it's hard to say whether a lens is 'sharp' without direct comparison, although with some experience you should be able to ascertain whether it is sharp enough for you. But again it's too easy to be mislead without a direct comparison IMO.

Bad copies, however, will look obviously unsharp compared with something comparable, even if the FL is not quite the same. Or they will have obvious sharpness variations across the frame (don't pixel-peep the corners at large apertures though - there will likely be some small variations).

I must admit though, for the first time ever I recently bought a second copy of a lens (TS-E 17mm) because I was seeing some effects that I couldn't explain, nor find any info about. Turned out to be exactly the same with the second lens, but hearing all these horror stories does make one a little nervous.

I also had an obvious with my 17-40 when I moved to FF which I never noticed on a crop soft on one side) and after spending $200 and sending it to the shop twice I would say it is 'acceptable', but not great. 

But I also now have enough lenses to test anything I'm going to get so see if it meets my expectations.


----------



## JerryBruck (Feb 22, 2012)

Marsu42 asked,

...-what is Canon service actually able to do?
* AF adjustment (Do I have to turn in my non-afma body with my lens)?
* sharpness / ca-improvments?
* Do they do it for free on warranty / how bad does a problem have to be to make them do it for free?

I've wondered about that also -- since they took the trouble to remove afma from our 60Ds, can and will they correct a mismatch, and at what cost, post-warranty?


----------



## tom_webster (Feb 22, 2012)

For me there are two ways of looking at these issues. The first is that if a lens seems sharp and produces nice pictures then it is ok, nothing more to worry about. The second is that if you are spending a lot of money on purchasing expensive Canon L glass then you should expect it to perform as well as it should and that sample variation should be minimal to the point of being irrelevant.

Half the issue these days I suspect is the fact that it is so easy to pixel-peep and there are also so many internet forums which allow people to rave about the sharpness of their copies or to warn about issues that they have experienced, this then leads you to doubt the quality of the lenses that you have or possibly to expect too much.

I have just been through this process myself. I have a Canon 35L and had a 100L macro on my 5D2. Both performed flawlessly in my opinion and produce images a sharp as I would ever have expected. I then traded by 100L for a new 135L as I though this would be more use to me.

The 135 is great but its sharpness doesn't blow me away in the same way as the 100L did and the 35L still does. I have micro-adjusted it by +8 and this helps but though it still produces great/good images I didn't feel that it lives up to the 'sharpest lens ever', 'truely wonderful' comments that I read so much before purchasing.

Granted I am comparing it to a macro lens known for sharpness and the 35L which is also very highly rated but something still doesn't sit quite right when I have spend many hundreds of Pounds on the lens.

End result, the lens has been sent in under warranty for calibration (to my camera body which has previously been checked calibrated by Canon) so I am hoping that it comes back working better. If it does not then I hope I shall rest happy knowing that it is at least as good as Canon think it should be.

For me then I guess the question is whether when buying L glass you should almost by default send the lens in for checking/ calibration. This seems ridiculous but without doing so I don't really see how you can know whether the lens is working as well as it should. It may work great but could it work better? 

If you spend as much as these lenses cost then I would expect it to work as well as possible. For me, and most others I suspect, I have no practical way of comparing my 135L against other copies on my camera body or against the same or other copies on different bodies. You therefore either accept it as it is or have it tested by the experts.


----------



## Marsu42 (Feb 22, 2012)

Stu_bert said:


> Marsu42 - would be interested on how you get on...


I've written about my test and experience with the lens here http://www.canonrumors.com/forum/index.php/topic,3359.60.html at page 5


----------



## drmikeinpdx (Feb 22, 2012)

I've spent way too much time testing lenses and sending them in for adjustment. It is the autofocus system that causes most of the problems, but poor assembly of lens elements seems to occur occasionally. The unreliable performance of the current autofocus system (both lens and camera functions) is a real problem for serious photographers.

I don't know of an easy and practical way to determine the inherent sharpness of a particular lens, other than shooting lots of photos under good conditions (tripod, etc...) and pixel peeping.

I have developed a quick autofocus test that works for me. I can describe it if anyone wants to know more.

If a lens focuses well with my camera body, then I try to evaluate the sharpness. Some lenses are sharper than others. The vast majority of photography that I do involves people, not landscapes, and the photos are almost all posted on the web, not made into prints. I really don't need lenses that are as crisp as breadsticks and images that hurt the eyes with razor sharp details. 

I may lust in my heart for a lens that blows me away with sharpness on every shot, but in reality it is not worth chasing. The people who view my photos would not recognize it anyway.

Just my opinion!

Mike in Portland, OR


----------



## Marsu42 (Feb 22, 2012)

drmikeinpdx said:


> I have developed a quick autofocus test that works for me. I can describe it if anyone wants to know more.



Please do 



drmikeinpdx said:


> I may lust in my heart for a lens that blows me away with sharpness on every shot, but in reality it is not worth chasing. The people who view my photos would not recognize it anyway.



That's the difference - the only one who views my photos is me  ... I am macro-infected and am using it as a microscope with 18MP camera behind it. However, even with a tele lens I would like to see detail at 100% that I wasn't able to see with my bare eyes if possible - that's mostly why I want to get a L lens, not because of any 2.8 aperture or quick af (although a precise af does help getting sharp pictures, just as you wrote).


----------



## Stu_bert (Feb 22, 2012)

JerryBruck said:


> Marsu42 asked,
> 
> ...-what is Canon service actually able to do?
> * AF adjustment (Do I have to turn in my non-afma body with my lens)?
> ...



In the UK, when I have my lenses adjusted to the body (started when I had the 5D), Canon do adjustments in the lab which stores it separate to the AFMA data. The technician I spoke to claimed it is more accurate. I can't speak for the lens adjustments as frankly I've only ever asked on one, and it was still rubbish after


----------



## StevenBrianSamuels (Feb 28, 2012)

I use to test all my lenses for a few days after buying until I noticed how much I agonized over it and decide to _just go out and shoot_. Made life a bit simpler.


----------



## EOBeav (Feb 29, 2012)

I know of a couple of landscape pros who 'only' have the 70-200mm f/4 L, non-IS. I shoot with it, and it's one of my favorite lenses. My experience on an XSi is that if you're shooting indoor sports or something similar, you'll have a tough time raising the ISO enough to get a decently sharp image. On a tripod, though, that's a whole different story. Some of my best shots have come from this lens, and I'm always amazed at the amount of detail I get with it. If you get it, you won't be sorry. And you don't have to apologize for having it instead of the f/2.8 IS. Just sayin'.


----------

