Canon 18-200mm zoom lense

[jazzman1]

I'm new here.  I have a Canon T3i.  Two kit lenses came with it in a bundle...18-55mm, 55-250mm.  I am considering getting the Canon 18-200mm.  Would the Canon 18-200mm be a good choice to replace both lenses, or are there better choices to replace them with and keep the 18-200mm also?

[ebiggs1 · Accepted solution]

I would not buy one for a few reasons.  One and formost, it is more difficult to make a zoom lens when the zoom range gets very extreme.  18 to 200 is a 11x range and very ambitious to say the least. Not solely in optics but in build quality, too. It will be in the same quality level as the two lenses you have so the only advantage is having just the one lens.  Is that what you require? The top benefit of a DSLR is the ability to have the right lens for the right job.  That usually involves several different lenses.  So you will be defeating that concept somewhat!

I would rather see you get a different level of lens for instance the Canon EF-S 17-55mm f/2.8 IS USM Lens.  Directly replacing your 18-55mm kit lens. Of course this is in case what you have is not working for you. But this move is into a better built, better optics and a little faster lens all of which can be very useful.  Make no mistake the Canon EF-S 17-55mm f/2.8 IS USM Lens is a very good lens and offers a constant aperture.  A super plus in my book.

Unfortunalely these lens upgrades are expensive and replacing the 55-250mm is going to be more so.

[jazzman1]

Hey RobertTheFat.

Please don't hold me to those model #'s, only saw his camera's a minute or two, a few times.  I'm actually going by what I think he told me his camera's were.   I may well be wrong about that.  My friend did say his cameras are old, I think discontinued.  Maybe he said the 5D and 6D.  But he said they were both great camera's in their hayday.  Remember I'm a newbie, and may not remember all the correct model #'s and other stats.  Not like I'm a old head in photography and am firmillar with all the rights terms and terminology.  Could be the 6D and 7D but I know they're both Full Frames.  If it's important I can call him and get the correct info.  But in any event, he's a retired Pro and has good gear, though somewhat dated.  I think he knows his stuff, but I could be wrong on that...I have been before.

Thanks for sharing.

[jazzman1]

Sorry biggs.  In my last post I meant to say my Canon 55-250mm kit lens (not 18-250mm)  And about the focus of the Sigma it was not sharp, kinda out of focus, and diid'nt give much zoom at all.  Everything looked far away, not up close as it was suppose to look fully zoomed out.  On hindsight, I think it was probably defective from the start.  Did'nt want to gamble getting another in exchange and got a full refund.  Bad a lens as you seem to think my Canon EF-S 18-200mm walk around is...it is leaps and bounds over that Sigma.

[ebiggs1]

Not surprised as that is one of the pitfalls of 3rd party lenses.  Hit and miss.  Get a good one and alright but who wants to chance it?

I do hope your 18-250mm is all you want it to be.  It is not for me to say if it is doing what you want it to.  It falls into the class of lenses I have graduated from.  I imagine you will too someday but if you don't see the requirement to, no big deal.  Lots of folks stay where you are at now and a quite happy and produce very nice photographs.  That is why the Rebel line a all its "kit" lenses are the best selling DSLR line in the world.  Great value for the money.

[jazzman1]

Well ebiggs1 you're proably correct in your thinking.  One day I may well graduate from my 18-200mm walk around.  I wanted it mainly for traval and just out taking fun pics.  I felt even after I got all the good lens I'd want, and into taking serious photo's I'd admire, I'd still want my walk around, when just walking around taking fun pics.  Those times when I would'nt take along all my other gear.  But who knows, only time will tell.  My Canon 18-200mm walk around is the one lens out the 6 I have I did'nt feel I'd ever want to replace.

BTW...I saw one of your posts where you gave the Canon 18-135mm walk around some atcolades.  If you still like that lens, what makes it so much better than my 18-200mm???  Is it just because of shorter zoom range???  Is  it better optics???

[ebiggs1]

A few more letters for you to ponder.  One has STM  and one has lots of CA.  STM is good and CA is not.

I am sure zoom range has a lot to do with hard to control CA.  But depending on what you shoot, this may not be an issue to you.

It does all boil down to you.  Is it working for you?  Just because I would not use is little indication that you should not.  I don't happen to recommend it to anyone either.

In my DSLR 101 classes, I have yet to see anybody that comes in with the hardware and gear I use.  Guess what?  They all seem perfectly happy.  I have my preferences based on 40 years of professional day in day out service.  The 18-250mm would not last me a month.  Simply not built that well.  And buld is my top priority.  It has to work and it has to work each and every time.

Also remember times and people change.  I have.  I have changed some very steadfast conditions I used to harbor.  Even since I have joined this forum.

[jazzman1]

hey ebiggs1, now I'm stumped.  I know what a STM lens is...have no idea what CA is or means.  What the heck is CA????/  I'm sure it's something simple, just can't fathom it at the moment.  Without knowing what CA is...1/2 you said makes no sense to me. 

The 18-250 you mention, do you mean to say 18-200 ...my walk around???  If so do you mean it's not built sturdy, will wear out fast???   Ok, I get that, I know you like build quality in your lens.    BTW...what the heck do you do with your gear that puts them through so much stress, wear and tear???     Now what of the optics???   How about sharpness, the pics it takes???   Any good in those areas???  Also, what makes the 18-135 any better than the 18-200???

Sorry ebiggs, i know, I know, questions, always questions!!!!   Just want to know, just for my info.  How else to learn if not ask...LOL

[RobertTheFat]

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@jazzman1 wrote:

hey ebiggs1, now I'm stumped.  I know what a STM lens is...have no idea what CA is or means.  What the heck is CA????/  I'm sure it's something simple, just can't fathom it at the moment.  Without knowing what CA is...1/2 you said makes no sense to me. 

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Actually, CA means two different things, one bad and the other good. As Ernie Biggs used the term, CA means "chromatic aberration", a result of a lens refracting light of different colors slightly differently. CA is often manifest as a colored fringe on the boundaries of objects in the image. Ernie's point was that if a lens has a long zoom range, it's more difficult to design it so as to keep CA down to an acceptable level.

OTOH, a CA ("constant aperture") zoom lens is one in which the maximum available focal ratio ("f stop") doesn't change as the lens is zoomed in or out. A CA f/2.8 lens, for example, can be set to f/2.8 even when zoomed out to its longest focal length. CA lenses tend to be bulkier, heavier, and more expensive than non-CA lenses; but the CA feature can be a great advantage, particularly indoors where you often need all the light-gathering power you can muster.

For more detailed information, Google the two terms. There's a lot of good information on the Internet if you take the trouble to look.

[jazzman1]

Thanks RobertTheFat.  You kind of explained things, but as you can imagine, me being a newbie to all this stuff, some of it's still kind of fuzzy.  I have seen "chromatic aberration" somewhere, could'nt tell you what it is except you just did.  I can only assume ebiggs felt my lens was suffereng from that, though I had'nt noticed if so.   The other stuff you said went over my head.  But you seem a knowledgeable fellow, tell me what do you think makes the Canon EF-S 18-135mm lens superior over the Canon EF-S 18-200mm???  I'm just curious.  I know it's not well built, not a quality lens.  But what about the optics??? 

Yes, I'll google and have been googling.  Problem is for me when I seem to find conflicting into, which I seem to do alot.  It sure helps to get a question answered sometimes, helps alot.  But yeah, I'll check into it and see what I learn. 

                                                                                       Thanks much 

[ebiggs1]

Yes Bob from Boston explained CA very well. In the spec world CA most commonly refers to chromitic aberation but sometimes a lesser use can be constant aperture.  If CA from your lens or any lens is not a concern than don't worry about.  But you asked me and what I think.

STM stands for the stepping motor used in this lens.  It is very quick and silent.  These lenses have been and continue to be a good value when purchased as a starter lens, but they have never been a strongly desired lens otherwise.  

The 18-200mm lens you bought uses a relatively unsophisticated micro motor system for autofocus, not even the ring-type USM design more commonly seen on this level of lenses.

But in the end is it working for you?  If, yes, forget this techno verbage.  That's one of my problems with DxO Mark.  If it works who cares?

On the "better built" question.  Most of an "L" is metal or very tough materials.  They are built to last a life time and even be repaired if need be.  However, Canon does not only put the best marterials in its L lens but the best optics, too.  A single piece of glass can cost hundreds of dollars, and more!  Consumer grade lenses can even have plastic optics.  They do not put top quality materials in inexpensive lenses because they would no longer be "inexpensive" right?

On the FF vs crop sensor and lens mm, maybe this will help.  First remember they are only numbers and only of any real use if you intend to compare one against the other.

A FF sensor is 24x36 mm.  If you take the diagonal, like the way you measue your monitor, which in FF is 43.3mm.  That is an indication of what a normanl lens is.  A little rounding up and you get 50mm.  A 50mm is considered "normal".

On the other hand your crop sensor is 16.7x25.1mm.  The diagonal is 30.1mm so a 28mm or 35mm lens is considered "normal".

What you need to do is forget the FF numbers and just use the ones that suit your crop sensor size.  Just remember anything below the 28 to 35mm will be WA and anything above will be Tele.  You can carry this even firther. Any doubling of the mm on the tele side increases the appearent magnification (AOA) the same. 

While on this same topic, you only need to remember two numbers to know all the f-stops.  Can you do that if one of the numbers is 1?  Yes, OK, the numbers you must remember are 1 and 1.4.  Each stop is a doubling or halving of the previous number.  For instance, one stop slower than f 2 is f2.8.  How do I know that?  Lets look at this, the f-stops are 1 - 1.4 - 2 - 2.8 - 4 - 5.6 - 8 - 11 - 16 - 22 - 32 - 64 - 128 - 256.  Do you see how I started with f2, doubled the previous number, 1.4, to arrive at f2.8?  Another one, what is one stop slower than f4?  It is f5.6.  Again I took the previous stop to f4 which is f2.8 and doubled it.  If you want to know a faster stop you simply half the previous number.  What is one stop faster than f16?  It is f11, why, because I took the previous number to f16 which is f22 and cut it in half and got f11.  If you need to know more than 1 stop you simply repest the process.  Every f-stop is a combo of either 1 or 1.4 up or down.

This is what I stand up in front of the DSLR 101 class and tell the folks.  Did not do one this past summer, though as I got way too busy.  Maybe I should retire ........... again!

[ebiggs1]

BTW, that reply is generally simplistic as I usually speak it and don't type it.  If you desire further explaniation ask either me or Boston, Massachusetts USA.