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Esteemed Contributor
Posts: 2,846
Registered: ‎06-11-2013

Re: From T2i to ?

The major benefit of the EF-S 17-55mm f/2.8 USM lens is that it can provide a focal ratio as low as f/2.8 at ALL focal lengths in it's range of zoom.

 

The "kit" lenses are typically things like an 18-55mm lens with a variable focal ratio f/3.5-5.6 which means at the short 18mm end it's f/3.5 (which is about 2/3rds of a stop less light - each "stop" represents halving or doubling the amount of light depending on if it's getting larger or smaller).  But quickly shrinks to an f/5.6 focal ratio.  You'd think it wouldn't get down to f/5.6 until you're most of the way to the 55mm end, but most variable focal ratio zooms get to higher value when they are only roughly halfway through the zoom range.    That means somewhere around the 35mm point the lens will already be at f/5.6.

 

An f/2.8 lens is collecting two full stops (FOUR TIMES) more light than an f/5.6 lens.  So it's a huge difference.

 

To pull this off, the lens must be physically larger in diameter and that means it's both heavier and it has more "glass".  Some optical challenges are created when you scale up the size of the glass and that means additional glass elements are needed to correct for those issues.  This drives up the complexity and cost of the lens.  It's harder to make a low focal ratio zoom and still have decent optical quality.  That's why they cost so much more -- they are more complicated.

 

The lens choice tends to be a really big deal in terms of how much it can influence the quality of a shot (the lighting is also a big deal - but that's another topic.)

 

 

Tim Campbell
5D III, 5D IV, 60Da
Esteemed Contributor
Posts: 4,365
Registered: ‎08-13-2015

Re: From T2i to ?


richardp wrote:

Yeah, i've been looking.
Current price for an 80D ( refurb ) body only : 899$.
Current price for the 17-55 lens : 829.99. No Refurbs currently in stock.


They were in stock a few days ago when I first suggested it.   Be patient.  It may take a month, but I would expect the 80D to come back in stock before March.  Maybe less than that.

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Esteemed Contributor
Posts: 3,123
Registered: ‎06-25-2014

Re: From T2i to ?


TCampbell wrote:

The major benefit of the EF-S 17-55mm f/2.8 USM lens is that it can provide a focal ratio as low as f/2.8 at ALL focal lengths in it's range of zoom.

 

The "kit" lenses are typically things like an 18-55mm lens with a variable focal ratio f/3.5-5.6 which means at the short 18mm end it's f/3.5 (which is about 2/3rds of a stop less light - each "stop" represents halving or doubling the amount of light depending on if it's getting larger or smaller).  But quickly shrinks to an f/5.6 focal ratio.  You'd think it wouldn't get down to f/5.6 until you're most of the way to the 55mm end, but most variable focal ratio zooms get to higher value when they are only roughly halfway through the zoom range.    That means somewhere around the 35mm point the lens will already be at f/5.6.

 

An f/2.8 lens is collecting two full stops (FOUR TIMES) more light than an f/5.6 lens.  So it's a huge difference.

 

To pull this off, the lens must be physically larger in diameter and that means it's both heavier and it has more "glass".  Some optical challenges are created when you scale up the size of the glass and that means additional glass elements are needed to correct for those issues.  This drives up the complexity and cost of the lens.  It's harder to make a low focal ratio zoom and still have decent optical quality.  That's why they cost so much more -- they are more complicated.

 

The lens choice tends to be a really big deal in terms of how much it can influence the quality of a shot (the lighting is also a big deal - but that's another topic.)

 


My wife and I both have the 17-55 lens and like it a lot, for the reasons that Tim explained. (My wife used hers on a T2i for several years.) But it does have a couple of drawbacks. As Tim mentioned, it's big - so big that it casts a large shadow in the coverage field of the built-in flash, rendering the flash nearly useless. If, like us, you normally use an external speedlite, you won't care. But if you don't already have an external speedlite, it's an added expense. Also, my copy of the lens requires several points of autofocus micro-adjustment, which is no big deal on my 7D's. But the T2i doesn't have AFMA; so if that happened to you, you'd presumably have to send the lens and the camera to a Canon shop to be adjusted. Probably it was a fluke, but it illustrates the point that the 17-55 isn't an "L" lens and isn't held to the manufacturing tolerances that an L lens has to meet. It's one of those goofy ironies: Canon's expensive cameras have AFMA, but the lenses they use almost never need it, while the cheaper Rebels, whose lenses are more likely to require AFMA, don't have it.

Bob
Boston, Massachusetts USA
Honored Contributor
Posts: 7,422
Registered: ‎12-07-2012

Re: From T2i to ?

"...the T2i doesn't have AFMA; ... you'd presumably have to send the lens and the camera to a Canon shop to be adjusted."

 

The big misconception about AFMA is, it makes the lens sharper or it makes the IQ better.  It doesn't.  It simply moves the dead on focus point.  The lens is always as sharp as it will ever be.  The only way the lens can be calibrated differently is by sending it back to Canon where they will disassemble it an re-tune it.

 

A slight focus issue is not noticeable, or is less noticeable, on a 12 MP sensor.  It becomes more noticeable on a 20+ MP sensor cameras. Most of the time you need to view at 100% to even see the focus issue.  It also depends on what you shoot too.  If you are mainly a landscape photographer you may never notice a focus issue.  On the other hand if you mostly do portraits, it is a problem.

 

Again, if it were me, and I woke up in your shoes today, I would go for the EF-S 17-55mm f/2.8 USM lens if $1000 is a strict price limit.  Almost always, it is better to go for glass than camera.  But I agree at some point you will want to upgrade the T2i.

A lot of Canon stuff. Along with, a lot of other stuff.
Occasional Contributor
Posts: 11
Registered: ‎01-28-2017

Re: From T2i to ?

I really appreciate all of your input and the time you are taking in providing guidance.  You guys are amazing.

 

So, I'll probably be heading in the short term direction of upgrading my lens to a f2.8 17-55.  Longer term ( 1 year ), upgrade the T2I.

 

Also a collegue from work also mentionned 3rd party equivalent lenses.  Any opinions ?

Esteemed Contributor
Posts: 3,123
Registered: ‎06-25-2014

Re: From T2i to ?


richardp wrote:

I really appreciate all of your input and the time you are taking in providing guidance.  You guys are amazing.

 

So, I'll probably be heading in the short term direction of upgrading my lens to a f2.8 17-55.  Longer term ( 1 year ), upgrade the T2I.

 

Also a collegue from work also mentionned 3rd party equivalent lenses.  Any opinions ?


When there's a straight choice between two functionally equivalent lenses, the Canon lens is usually better.

Bob
Boston, Massachusetts USA
Esteemed Contributor
Posts: 3,123
Registered: ‎06-25-2014

Re: From T2i to ?


ebiggs1 wrote:

"...the T2i doesn't have AFMA; ... you'd presumably have to send the lens and the camera to a Canon shop to be adjusted."

 

The big misconception about AFMA is, it makes the lens sharper or it makes the IQ better.  It doesn't.  It simply moves the dead on focus point.  The lens is always as sharp as it will ever be.  The only way the lens can be calibrated differently is by sending it back to Canon where they will disassemble it an re-tune it.

 

A slight focus issue is not noticeable, or is less noticeable, on a 12 MP sensor.  It becomes more noticeable on a 20+ MP sensor cameras. Most of the time you need to view at 100% to even see the focus issue.  It also depends on what you shoot too.  If you are mainly a landscape photographer you may never notice a focus issue.  On the other hand if you mostly do portraits, it is a problem.

 

Again, if it were me, and I woke up in your shoes today, I would go for the EF-S 17-55mm f/2.8 USM lens if $1000 is a strict price limit.  Almost always, it is better to go for glass than camera.  But I agree at some point you will want to upgrade the T2i.


If misconceptions are the topic, let me try to correct two that could arise from Ernie's commentary on what I said:

 

1)  I didn't claim that AFMA improves image quality, just that it corrects a certain type of focusing problem that a lens can exhibit.

 

2)  What I said about AFMA on my 17-55 lens was not hypothetical; it was entirely reflective of my direct experience. When I bought the lens, I stupidly used it (on an 18MP 7D) to photograph an important award ceremony without testing it first. The pictures it produced were unusable, even in a newspaper (which is, let us say, not a very stringent standard). You certainly didn't need 100% view to see the problem. All that saved me from a very embarrassing situation was that I was also using a second camera, as I usually do at events. With +9 points of AFMA correction, the lens was fine and has given good service ever since.

Bob
Boston, Massachusetts USA
Esteemed Contributor
Posts: 4,365
Registered: ‎08-13-2015

Re: From T2i to ?


RobertTheFat wrote:

ebiggs1 wrote:

"...the T2i doesn't have AFMA; ... you'd presumably have to send the lens and the camera to a Canon shop to be adjusted."

 

The big misconception about AFMA is, it makes the lens sharper or it makes the IQ better.  It doesn't.  It simply moves the dead on focus point.  The lens is always as sharp as it will ever be.  The only way the lens can be calibrated differently is by sending it back to Canon where they will disassemble it an re-tune it.

 

A slight focus issue is not noticeable, or is less noticeable, on a 12 MP sensor.  It becomes more noticeable on a 20+ MP sensor cameras. Most of the time you need to view at 100% to even see the focus issue.  It also depends on what you shoot too.  If you are mainly a landscape photographer you may never notice a focus issue.  On the other hand if you mostly do portraits, it is a problem.

 

Again, if it were me, and I woke up in your shoes today, I would go for the EF-S 17-55mm f/2.8 USM lens if $1000 is a strict price limit.  Almost always, it is better to go for glass than camera.  But I agree at some point you will want to upgrade the T2i.


If misconceptions are the topic, let me try to correct two that could arise from Ernie's commentary on what I said:

 

1)  I didn't claim that AFMA improves image quality, just that it corrects a certain type of focusing problem that a lens can exhibit.

 

2)  What I said about AFMA on my 17-55 lens was not hypothetical; it was entirely reflective of my direct experience. When I bought the lens, I stupidly used it (on an 18MP 7D) to photograph an important award ceremony without testing it first. The pictures it produced were unusable, even in a newspaper (which is, let us say, not a very stringent standard). You certainly didn't need 100% view to see the problem. All that saved me from a very embarrassing situation was that I was also using a second camera, as I usually do at events. With +9 points of AFMA correction, the lens was fine and has given good service ever since.


1)  It was I who claimed that AFMA can make your photos sharper.  The word is photos, not lenses.

 

2). AFMA is very effective on more recent Canon DSLRs because zoom lenses can be calibrated at both the wide end and the long end, not just one adjustment for the entire range.  One adjustment on a zoom lens is pretty useless, IMHO.  The Sigma Dock allows for a 16 Point AFMA on their 150-600mm lenses.  I can take razor sharp photos with my Contemporary lens.  It took a while to calibrate the lens, but I feel the time spent was well worth it.  

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Highlighted
Honored Contributor
Posts: 7,422
Registered: ‎12-07-2012

Re: From T2i to ?

B from B,

"I didn't claim that AFMA improves image quality, ..."

 

I don't believe I claimed you did.  Just trying to educate folks.  Take it or leave it.

 

"The pictures it produced were unusable, ..."

 

It does matter what you were trying to shoot. What was the subject?  The misconceptions are real.  A lot or most people, newbies especially, believe AFMA makes a lens sharper.  It doesn't.  Just like they believe a cropper changes a lens focal length.  It doesn't.

A lot of Canon stuff. Along with, a lot of other stuff.
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