Your expert recommendation for next lens

SkipD wrote in post #14933717
This is absolutely false.

The "crop factor" calculation is ONLY for comparison of the field (angle) of view of a given focal length on two different format cameras. Since the OP only has one camera, there is absolutely no reason to use the "crop factor" calculation for the lenses used on it unless he is comparing focal lengths with another camera for some reason.

The focal length of a lens never changes when it is mounted on different format cameras. Regardless of the lens design (EF-mount or EF-S mount, for example), the focal length of a lens (or focal length range in the case of zoom lenses) is always what's marked on the front of it.

Skip are you saying if I mount a 70 -200 on a FF and a Crop, its still a 70-200 mm lens. If you are, thats correct. However using it on a crop body, the field angle of view as you call it is then in fact 112-320. Isn't that why some prefer to use a crop body with there longest lens to factor in the 1.6 field angle for extended reach.

Bianchi wrote in post #14936096
Skip are you saying if I mount a 70 -200 on a FF and a Crop, its still a 70-200 mm lens. If you are, thats correct. However using it on a crop body, the field angle of view as you call it is then in fact 112-320. Isn't that why some prefer to use a crop body with there longest lens to factor in the 1.6 field angle for extended reach.

What I put into bold type is wrong. The field (or angle) of view of a camera/lens combination is not measured in millimeters like focal length is.

The proper way to say what you are trying to say is something like this:

A 70-200mm lens on an APS-C format camera provides the same field of view as a 112-320mm lens would on a 35mm film format camera (such as a so-called "full-frame" DSLR).

Because there is no single camera format that is the standard against which all other camera formats are measured, it is critically important to state what format you are referencing another against.

DreDaze wrote in post #14932096
I don't see the point of an f2.8 prime- just get an f2.8 zoom

Agreed. IMO, the advantages of a prime are sharpness and wide aperture. 2.8 isn't exactly a large aperture...

SkipD wrote in post #14936455
What I put into bold type is wrong. The field (or angle) of view of a camera/lens combination is not measured in millimeters like focal length is.

The proper way to say what you are trying to say is something like this:

A 70-200mm lens on an APS-C format camera provides the same field of view as a 112-320mm lens would on a 35mm film format camera (such as a so-called "full-frame" DSLR).

Because there is no single camera format that is the standard against which all other camera formats are measured, it is critically important to state what format you are referencing another against.

Give me a break, the Op referenced a T3i APS-C Format otherwise also known as a crop body. My initial answer was refrenced for that body, no reason to differentiate between the two. Others recommended Ef-s lenses, because the Op said he had a T3i APS-C Format, maybe you want them to also differentiate between Ef and Ef-s because there is more than one type of lens. Personaly I think you want to make something out of nothing.

If the question was more on the line of how does the two in which you are describing above APS-C format & 35mm film format differ, then yes, I most certainly would of differentiated.

I do appreciate you want to bring to the attention of the Op that there is more than 1 format.

Bianchi wrote in post #14937010
Give me a break, the Op referenced a T3i APS-C Format otherwise also known as a crop body. My initial answer was refrenced for that body, no reason to differentiate between the two. Others recommended Ef-s lenses, because the Op said he had a T3i APS-C Format, maybe you want them to also differentiate between Ef and Ef-s because there is more than one type of lens. Personaly I think you want to make something out of nothing.

If the question was more on the line of how does the two in which you are describing above APS-C format & 35mm film format differ, then yes, I most certainly would of differentiated.

I do appreciate you want to bring to the attention of the Op that there is more than 1 format.

The point that I've been trying to make, referencing your suggestions that the OP needs to apply a "crop factor" calculation to his new lenses, is that there is absolutely no need whatsoever to use the "crop factor" calculation UNLESS there is some field of view comparison to another camera format being made.

Telling someone whose first SLR is an APS-C format camera that all the focal lengths he/she will be using are 1.6 times the marked values on the lenses is a total fallacy.

• It is an absolute fact that the focal length of a lens DOES NOT CHANGE when you put it on different format cameras.
  
• The new owner of an APS-C format camera who has no experience with a 35mm film format camera will be experiencing the field of view with various focal lengths for the first time. Why on earth would you want to confuse the new photographer by introducing information about another camera format? That is precisely what you are doing by tossing the "crop factor" into the game.
  
• There is absolutely no difference in focal lengths of EF vs EF-S mount lenses. The focal lengths are simply what is marked on the lenses.

I have a similar dilemma. I have just replaced my 7D with 5D mark III... New 5D is absolutely amazing!
Since I had to get a rid of my EF-S lenses, I have only been left with EF35L f1.4 and EF24-105L f4....
I am now looking to add another lense and have the following dilemma:

I like taking portraits/people as well as sports where I need good zoom. I like EF85L 1.2 and also EF 70-200mm f/2.8L IS II USM ... My thoughts are that my existing lense EF35L is quite good for portraits but not as good as 85L ... So maybe I will be better off to go for 70-200 first.... What would you do?

Any input will be appreciated..

SkipD wrote in post #14937265
The point that I've been trying to make, referencing your suggestions that the OP needs to apply a "crop factor" calculation to his new lenses, is that there is absolutely no need whatsoever to use the "crop factor" calculation UNLESS there is some field of view comparison to another camera format being made.

Telling someone whose first SLR is an APS-C format camera that all the focal lengths he/she will be using are 1.6 times the marked values on the lenses is a total fallacy.

• It is an absolute fact that the focal length of a lens DOES NOT CHANGE when you put it on different format cameras.
  
• The new owner of an APS-C format camera who has no experience with a 35mm film format camera will be experiencing the field of view with various focal lengths for the first time. Why on earth would you want to confuse the new photographer by introducing information about another camera format? That is precisely what you are doing by tossing the "crop factor" into the game.
  
• There is absolutely no difference in focal lengths of EF vs EF-S mount lenses. The focal lengths are simply what is marked on the lenses.

It seems to me that you may not understand what the "crop factor" is all about because the information you've been passing along is simply wrong. My purpose here is to help you realize that you shouldn't be spreading un-truths to the newbies. That does nothing but confuse them and, if they believe the BS, they may then pass it on to other newbies. We need to stop the cycle.

All true, Skip, you are completely correct with this information. But let me pose this question to you to further muddy these waters:

If I buy a compact or point and shoot camera, why do they refer to the focal length of the lens in terms of a 35mm camera?

They all do it. A Canon Powershot A2300 is described and advertised as having a 28-140mm lens, yet the actual focal length of the lens is 5.0mm-25mm. If you dig into the specs, then they tell you it's 35mm equivalent 28-140. This true pretty much across the board with compact cameras.

Truth is that comparing the focal length of a lens to a 35mm camera body is the easiest way for most to relate to the different format sizes, or at least it has become the most popular. I mean there are many different sizes of sensor out there, M 4/3, 2x; Nikon, 1.5x, Canon G, 4.5x, Canon compact, 5.6x, it gos on and on. Either way it's described, whether as a difference in FOV or as a focal length multiplier the end result is nearly the same. A 5mm lens on a Canon compact has the field of view of a 28mm lens on a 35mm format body. Many aren't satisfied when you say it's a wide angle lens, or an ultra wide lens, and the range of telephoto is huge. They want a number, and then most want something familiar to relate to, and for most that is 35mm.

This was a big thing for people moving from film to digital when the digital 35mm interchangeable lens body became affordable. It's certainly the way I think of it, if I put a lens with a focal length of 28mm on my new digital body, it's 45mm in my head, it acts a lot more like a normal lens than it does a wide angle lens. The lens will still have the characteristics of a 28mm lens as far as the scene is concerned, but the FOV says normal lens to me (45mm), and in most cases that's good enough. Certainly you completely correct that focal lengths do not actually change, that a focal length is a fixed length. But to anyone coming from 35mm film, or to anyone wanting a reference number to relate their FOV, it works. It's a semantic argument that's getting a bit old. And contributes to confusion as much or more than just saying "it becomes" an XXmm lens.

casaaviocar wrote in post #14937566
All true, Skip, you are completely correct with this information. But let me pose this question to you to further muddy these waters:

If I buy a compact or point and shoot camera, why do they refer to the focal length of the lens in terms of a 35mm camera?

They all do it. A Canon Powershot A2300 is described and advertised as having a 28-140mm lens, yet the actual focal length of the lens is 5.0mm-25mm. If you dig into the specs, then they tell you it's 35mm equivalent 28-140. This true pretty much across the board with compact cameras.

Truth is that comparing the focal length of a lens to a 35mm camera body is the easiest way for most to relate to the different format sizes, or at least it has become the most popular. I mean there are many different sizes of sensor out there, M 4/3, 2x; Nikon, 1.5x, Canon G, 4.5x, Canon compact, 5.6x, it gos on and on. Either way it's described, whether as a difference in FOV or as a focal length multiplier the end result is nearly the same. A 5mm lens on a Canon compact has the field of view of a 28mm lens on a 35mm format body. Many aren't satisfied when you say it's a wide angle lens, or an ultra wide lens, and the range of telephoto is huge. They want a number, and then most want something familiar to relate to, and for most that is 35mm.

This was a big thing for people moving from film to digital when the digital 35mm interchangeable lens body became affordable. It's certainly the way I think of it, if I put a lens with a focal length of 28mm on my new digital body, it's 45mm in my head, it acts a lot more like a normal lens than it does a wide angle lens. The lens will still have the characteristics of a 28mm lens as far as the scene is concerned, but the FOV says normal lens to me (45mm), and in most cases that's good enough. Certainly you completely correct that focal lengths do not actually change, that a focal length is a fixed length. But to anyone coming from 35mm film, or to anyone wanting a reference number to relate their FOV, it works. It's a semantic argument that's getting a bit old. And contributes to confusion as much or more than just saying "it becomes" an XXmm lens.

I agree with this.
Fov equivalent is important for a new guy and not focal length(it remains the same but 18mp 1.6 crop sensors give more reach rather than 18-20 mp ff bodies cause of pixel density when you need to crop the subject) isn't it?

casaaviocar wrote in post #14937566
All true, Skip, you are completely correct with this information. But let me pose this question to you to further muddy these waters:

If I buy a compact or point and shoot camera, why do they refer to the focal length of the lens in terms of a 35mm camera?

They all do it. A Canon Powershot A2300 is described and advertised as having a 28-140mm lens, yet the actual focal length of the lens is 5.0mm-25mm. If you dig into the specs, then they tell you it's 35mm equivalent 28-140. This true pretty much across the board with compact cameras.

Truth is that comparing the focal length of a lens to a 35mm camera body is the easiest way for most to relate to the different format sizes, or at least it has become the most popular. I mean there are many different sizes of sensor out there, M 4/3, 2x; Nikon, 1.5x, Canon G, 4.5x, Canon compact, 5.6x, it gos on and on. Either way it's described, whether as a difference in FOV or as a focal length multiplier the end result is nearly the same. A 5mm lens on a Canon compact has the field of view of a 28mm lens on a 35mm format body. Many aren't satisfied when you say it's a wide angle lens, or an ultra wide lens, and the range of telephoto is huge. They want a number, and then most want something familiar to relate to, and for most that is 35mm.

This was a big thing for people moving from film to digital when the digital 35mm interchangeable lens body became affordable. It's certainly the way I think of it, if I put a lens with a focal length of 28mm on my new digital body, it's 45mm in my head, it acts a lot more like a normal lens than it does a wide angle lens. The lens will still have the characteristics of a 28mm lens as far as the scene is concerned, but the FOV says normal lens to me (45mm), and in most cases that's good enough. Certainly you completely correct that focal lengths do not actually change, that a focal length is a fixed length. But to anyone coming from 35mm film, or to anyone wanting a reference number to relate their FOV, it works. It's a semantic argument that's getting a bit old. And contributes to confusion as much or more than just saying "it becomes" an XXmm lens.

I'm fully in tune with your thoughts and don't disagree with any of it.

Before the days of digital cameras, there were 35mm film point-n-shoot cameras. Today, the same people who would have purchased the film point-n-shoot cameras will very likely buy the digital point-n-shoot cameras. If there are folks who knew the focal length range of the (zoom) lens on their film point-n-shoot camera, it would be useful to also understand the "35mm equivalent" focal length range of the digital point-n-shoot cameras they may be looking at. That is why the manufacturers publish the "35mm equivalent" numbers. It's a very reasonable thing to do.

Likewise, any photographer who is comfortable with the field of view provided by various focal lengths on ANY 35mm film camera - be it an SLR or a point-n-shoot - can use the "crop factor" for choosing lenses for a smaller format DSLR.

The camera manufacturers who refer to a "magnification factor" or whatever they call it, always refer to a reference term such as "35mm equivalent" or something similar. This makes the statement about "crop factor" factual and understandable.

There are many new photographers who have never used a 35mm film camera (or a "full-frame" DSLR) and thus don't have a clue as to what a 50mm lens' field of view looks like on such a camera. Thus, unless they are trying to translate focal lengths from a "35mm equivalent" number in their digital point-n-shoot user manual or from focal lengths referred to in photography books which use the 35mm film camera as the basis for their teaching, the newbies really don't need to use the "crop factor" calculation at all.

Many new photographers believe virtually everything they are told by camera sales people and what they read on the web (and, particularly, in forums like this). A lot of these folks actually believe that the focal length of a lens designed for the 35mm film format changes when it's installed on a smaller format camera. They also often believe that the focal length of an EF-S lens is "corrected" for the APS-C format. These things are totally incorrect, of course, and many of us old-timers feel that these new photographers can become better photographers if they understand the truths about their equipment. Thus, we try to help them understand the truths.

Giorgos wrote in post #14937630
Fov equivalent is important for a new guy and not focal length(it remains the same but 18mp 1.6 crop sensors give more reach rather than 18-20 mp ff bodies cause of pixel density when you need to crop the subject) isn't it?

I'm afraid you are opening another bucket of worms.

SkipD wrote in post #14937658
I'm afraid you are opening another bucket of worms.

I would like to know your opinion as you are more educated than me for sure.
When u can enlarge your subject to a higher degree (without pixelisation or how its called) by cropping it isn't something like 'virtual reach' ? (Always speaking comparing 18mp on crop vs 20mp ff)

SkipD wrote in post #14937641
I'm fully in tune with your thoughts and don't disagree with any of it.

Before the days of digital cameras, there were 35mm film point-n-shoot cameras. Today, the same people who would have purchased the film point-n-shoot cameras will very likely buy the digital point-n-shoot cameras. If there are folks who knew the focal length range of the (zoom) lens on their film point-n-shoot camera, it would be useful to also understand the "35mm equivalent" focal length range of the digital point-n-shoot cameras they may be looking at. That is why the manufacturers publish the "35mm equivalent" numbers. It's a very reasonable thing to do.

Likewise, any photographer who is comfortable with the field of view provided by various focal lengths on ANY 35mm film camera - be it an SLR or a point-n-shoot - can use the "crop factor" for choosing lenses for a smaller format DSLR.

The camera manufacturers who refer to a "magnification factor" or whatever they call it, always refer to a reference term such as "35mm equivalent" or something similar. This makes the statement about "crop factor" factual and understandable.

There are many new photographers who have never used a 35mm film camera (or a "full-frame" DSLR) and thus don't have a clue as to what a 50mm lens' field of view looks like on such a camera. Thus, unless they are trying to translate focal lengths from a "35mm equivalent" number in their digital point-n-shoot user manual or from focal lengths referred to in photography books which use the 35mm film camera as the basis for their teaching, the newbies really don't need to use the "crop factor" calculation at all.

Many new photographers believe virtually everything they are told by camera sales people and what they read on the web (and, particularly, in forums like this). A lot of these folks actually believe that the focal length of a lens designed for the 35mm film format changes when it's installed on a smaller format camera. They also often believe that the focal length of an EF-S lens is "corrected" for the APS-C format. These things are totally incorrect, of course, and many of us old-timers feel that these new photographers can become better photographers if they understand the truths about their equipment. Thus, we try to help them understand the truths.

Are you calling me an old timer?

I like this idea, but I'm a bit afraid it's a lot like us trying convert to the metric system. I still see something posted in metric like say 4.5cm and immediately I have to think "2.5 cm to the inch so that's almost 2 inches..." Or that mountain's 3450M high, I convert to a very approximate 10,500 feet or so by multiplying by 3 and adding a random bit more. KM to MPH 2x and a little more...The actual lengths don't really matter once they get longer, but we still want a number we can grab onto. I think the same applies to focal lengths.

Grabbing a number we are comfortable is lot harder for lens focal lengths and FOV, because we can all pretty much agree that an ultra wide, wide angle, and normal are pretty easy to get a picture of in our mind, but it still leaves us with a range and a opinion (like the fallacy that all landscape lenses are wide or ultra wide), telephoto is anything from about 50mm to 300mm on a crop body and super tele is anything longer than that. The range increases dramatically and gets a lot harder to define.

Yeah, there is certainly a lot of poor information disseminated by camera sales people. The quality of sales associate has gone down quite a bit, and in most peoples cases they are purchasing equipment that they have little idea about from retailers that have no idea about. A lot more equipment is purchased on line, and with that we are here, and this is where the questions are asked.

To the OP, sounds like you are looking for a wide angle lens now. Something in the range of a 17-XX will be a good focal length. I'd hang on to your 50mm lens, it's a great lens for lower light situations and blurring the background. As a general rule a lens with a fixed aperture for the whole zoom range, and a larger aperture (smaller number, f/2.8 or f/4) will also be a lens of higher quality. There are a lot of good suggestions here, I would add my suggestion of the Canon 17-40 f/4L a great little lens that won't break the bank, and will upgrade with you if you ever decide a full frame body is for you.

SkipD wrote in post #14937641
I'm fully in tune with your thoughts and don't disagree with any of it.

Before the days of digital cameras, there were 35mm film point-n-shoot cameras. Today, the same people who would have purchased the film point-n-shoot cameras will very likely buy the digital point-n-shoot cameras. If there are folks who knew the focal length range of the (zoom) lens on their film point-n-shoot camera, it would be useful to also understand the "35mm equivalent" focal length range of the digital point-n-shoot cameras they may be looking at. That is why the manufacturers publish the "35mm equivalent" numbers. It's a very reasonable thing to do.

Likewise, any photographer who is comfortable with the field of view provided by various focal lengths on ANY 35mm film camera - be it an SLR or a point-n-shoot - can use the "crop factor" for choosing lenses for a smaller format DSLR.

The camera manufacturers who refer to a "magnification factor" or whatever they call it, always refer to a reference term such as "35mm equivalent" or something similar. This makes the statement about "crop factor" factual and understandable.

There are many new photographers who have never used a 35mm film camera (or a "full-frame" DSLR) and thus don't have a clue as to what a 50mm lens' field of view looks like on such a camera. Thus, unless they are trying to translate focal lengths from a "35mm equivalent" number in their digital point-n-shoot user manual or from focal lengths referred to in photography books which use the 35mm film camera as the basis for their teaching, the newbies really don't need to use the "crop factor" calculation at all.

Many new photographers believe virtually everything they are told by camera sales people and what they read on the web (and, particularly, in forums like this). A lot of these folks actually believe that the focal length of a lens designed for the 35mm film format changes when it's installed on a smaller format camera. They also often believe that the focal length of an EF-S lens is "corrected" for the APS-C format. These things are totally incorrect, of course, and many of us old-timers feel that these new photographers can become better photographers if they understand the truths about their equipment. Thus, we try to help them understand the truths.

One of the best posts I have read on these forums. Very true and informative. I am always surprised when folks assume that an EF-S at 18mm is somehow wider than a EF at 16mm on a crop. Thanks for a very informative discussion.

You guys are just confusing the OP.

For my part I went for the 15-85mm because of the focal range. If you can find a Tamron 17-55mm non VC for under 300$, go for it. If not, the Sigma 17-55 OS will do the job nicely.

However you might be able to get a used 18-55 IS II for a peanut. Like 80$. It is not a bad lens at all and you get IS. It will give you 80% of the Sigma experience for 20% of the price.

Also, as you wanted to "zoom in" more, you migth want to consider one of the superzooms.
The new Tamron 18-270mm Di II VC PZD come to mind as the ultimate compromise between range, size and quality.

http://www.techradar.c​om …15/page:11#arti​cleContent

Earwax69 wrote in post #14940346
You guys are just confusing the OP.

Yeah, all this information is correct and valuable but given the OP's original question I think it has gone into the "tl;dr" domain for them. Anyway, from his last couple posts, it sounds like he has made a good decision.