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Registered: ‎03-17-2015

Re: Canon 18-200mm zoom lense

Fellas, I'm trying to learn what does the elements, groups, and blades mean, and what makes either better over the other.    I know higher # in any catagory is better than lessor #.    But I run into lens where one lens will have bigger # in one catagory and lower # in another catagory.   Some are Higher # in elements and groups, but less blades.  I know if "all" #' are bigger in all catagory's, it's better lens than another len's with lower #' in all catagory's.   .I'm trying to learn how to determine the better lens when comparing.

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Re: Canon 18-200mm zoom lense


@jazzman1 wrote:

Fellas, I'm trying to learn what does the elements, groups, and blades mean, and what makes either better over the other.    I know higher # in any catagory is better than lessor #.    But I run into lens where one lens will have bigger # in one catagory and lower # in another catagory.   Some are Higher # in elements and groups, but less blades.  I know if "all" #' are bigger in all catagory's, it's better lens than another len's with lower #' in all catagory's.   .I'm trying to learn how to determine the better lens when comparing.


Elements is the number of pieces of glass that light goes through in its traversal of the lens. Groups is the way the elements are arranged in the lens. Neither of those matters to you; it's just bragging. What matters is the lens's actual performance, and that's related to, but not derivable from, the number of elements and their arrangement.

 

Blades is the number of separate sheets of metal that form the lens's variable aperture. More is usually better; because the aperture can be made more nearly round, and a rounder aperture usually makes the out-of-focus parts of a scene more visually appealing.

Bob
Philadelphia, Pennsylvania USA
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Re: Canon 18-200mm zoom lense

[ Edited ]

"... you just bought a new Tamron 70-200mm f/2.8 lens, but you already have the same focal range and aperture lens in a Canon."

 

Yes I did.  I also have/had the Tokina 70-200mm f2.8.  As I have stated "playing" with the gear is where I am at.  I no longer am working with my photography.  Except on a few occasions when the oppertinity is there.

Actually I had the Tokina as it is gone.  It is not ready for prine time and not a buy as far as I am concerned.  The Sigma 70-200mm f/2.8 EX DG APO OS HSM is a "best buy".  It is a very good lens and is a grand less than my beloved Canon EF 70-200mm f/2.8L IS II USM which is the best lens made. Period, nough said.

 

But I bought the Tamron SP 150-600mm f/5-6.3 Di VC USD Lens about a year ago.  I found it to be a pretty good lens for the money.  It is not the best lens. But for the money, it too, is a "best buy".  In the past Tamrons have been pretty much junk.  I would not even say the name let alone use one or, good lord, buy one.  They have made strides that has to have Canon engineeres concerned at least if I were a Canon engineer, I would be.  Sigma and Tamron have been making extremely high quality lenses for less money, usually.  Plus they don't know how a Canon camera works!

Tokina has not gotten the word and still is to be avoided, IMHO, of course.  Tokin's CS is nonexistent.

 

So far the Tammy is showing its stuff.  Pretty hard to complain about it.  It is fast.  It is silent.  And, it is sharp as a tack.

See the horse below.  It is a 100% crop of the eye.  100% is usually considered max and is where you judge a lens' IQ.

 

_DSC5215.jpg

 

This is from a 12 MP camera and is hand held.  Pretty impressive!  No processing except for crop and conversion to jpg from RAW.

As of this moment I still recommend the Sigma as the "best buy" if the Canon's price is out of the question.  But if you absolutely have to have the best there is, get the Canon EF. 

 

Most of the time the number of aperture blades is a non-factor.  It only deals with OOF bachground and Bokeh.

 

A lens is just that, a lens.  It is nothing more than a piece of glass or other transparent substance with curved sides for concentrating or dispersing light rays.  People think that a lens is the big black, or white in Canon's world, tube.  It is not.  It is the piece of glass that is at the front of that tube.  All the other pieces of glass, or elements, are for correcting the point of impact of the various light rays.  Some allow for focus adjustment, too.  The lens, or front element, would do its job whether it had the tube around it or not.

 

A word about not going RAW right off.  There is no reason anymore for not shooting RAW right from the get go.  You got everything you need with your camera to do so.  The conversion is seemless and is done when you transfer to the computer you are so adapt at.  If you had a fire to put out and you had a gallon bucket full of water would you dump half of it on the ground before you got to the fire?  That is what you are doing if you shoot jpg.  You are throwing away a vast amount of picture data before you ever get to use it.  jpg is for cell phones and ipads and Facebook, not for a DSLR.

 

One more word of caution, don't take pictures of people's (strangers) children.  Never do that! Never do that! Never do that! Never do that! Never do that! Never do that! Never do that! Never do that! Never do that! Never do that! Never do that!

Got the point?  Adults or people of 18 to 20 or so, and older are fair game.  They have no expectation of privacy rights in a public place (park).  However, don't be that guy that gives all photographers a bad wrap.  Be respectful.

EB
EOS 1DX and 1D Mk IV and several lenses!
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Re: Canon 18-200mm zoom lense

[ Edited ]

BTW, if you were in my DSLR 101 class, you would be forced to shoot RAW.  Just to let you know.  I make everybody use it.

So far, you basicly have my course!  Smiley Happy

EB
EOS 1DX and 1D Mk IV and several lenses!
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Re: Canon 18-200mm zoom lense

So Bob, I take it generally round blades would indicate better lens???   And generally more elements & over groups are better also.  But rounded blades are the better indicator of quality!!!!  

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Re: Canon 18-200mm zoom lense

I'll put the tammy on my long range wish list (i like that range) sounds and looks like a goodie, with either the Sigma or Canon 70-200 coming 1st.  Probably be the Sigma since you praise it so much at 1/2 the price of the Canon.   But I do want to stay with Canon much as I can regardless of price...if I can afford Canon.  I love my Canons.  You can't go wrong with Canon my friend.   That pic of the horse's eye does look sharp, how far away were you????

 

  Have no idea what you mean by "playing with the gear".  Were you waiting for me to ask ????   I'm sure you must have known I did'nt have a clue (LOL).  Still in all, I wonder why you have so many lens of the same focal, and aperture range????   Now that don't make sense to me unless you just got the money to burn!!!!!   I do understand liking our toys (LOL)

 

Never said I would'nt get into RAW now, nor is that what I meant.  I just meant I would take things slow so as to absob it well.   You and Bob are giving me alot of info and I don't want to get ahead of myself.  I'm also getting info elsewhere, I do google.  When I learn something I want to know it well and not 1/2 way, and trying to go faster than I'm able to comprehend stuff.  I've known about RAW ever since I got my Rebel, but the files are so big it was difficult to send in email.  Takes longer to upload too.  I stayed with jpeg so files were'nt so big.  But guess I will get into RAW.  But I will have to get PSE 13 st.  I will not get premere at this time since you don't even know what it's for.   That's money I can save if I don't need it for my pics.  It maybe as you say for video's. I'll google it.

 

Thanks for the tip on taking pics of the kids.  I have been guilty of that, but only cause they were in the frame of what I actually was shooting at.  Lots of kids are at the 2 the parks, I go to everyday ( they're about a 1/2 mile apart....same folks go to both), parents who live by bring them to play everyday.  More pre-teens at one than the other though....at the other more adults.   That's one of the reasons I wanted to look for someplace else to shoot.  I'd like a nice setting like this park (which is beautiful) where it won't be so congested with people, especially kids.  They're not very big parks....the well to do who live around them, had the city build them long ago, thought they could keep them private for  themselves.   But the City told them they could not keep the public away cause public funds paid for and built them.   I do understand concerns from parents and just in general taking pics of kids.  I will be extra careful from now on.   Not as many kids on school days while school is in.  Don't know about your town but here (JSV. Florida) almost everywhere one goes you're on camera.  Very few places you won't be on candit camera, from shopping malls, to Downtown, gas stations, to public parks....anywhere any businesses are located.  And I suspect many residential areas have cameras.  Even on traffic lights..

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Re: Canon 18-200mm zoom lense


@jazzman1 wrote:

So Bob, I take it generally round blades would indicate better lens???

 

More blades. A rounder hole is what's wanted; and the more blades you use, the rounder the hole will be. Sometimes they cut a rounded shape into the blades; sometimes not.

 

And generally more elements & over groups are better also.

 

No, I didn't say that. It depends a lot on the skill and preferences of the lens designer. Obviously, the manufacturer wants to keep costs down, and a lens with lots of elements is likely to be more expensive to make. Sometimes special types of glass can be used to cut down on the number of alements, but special glass can be expensive. Some types are very expensive.

 

But rounded blades are the better indicator of quality!!!!

 

No, I didn't say that either. Recall that Ernie Biggs used the word "bokeh" (another esoteric term in photography) in one of his recent posts in this thread. It refers to how pleasing the out-of-focus areas (if any) of the picture are to the eye. Those who specialize in such things claim that a polygonal lens opening results in unpleasant bokeh. So manufacturers try to make the opening as nearly round as possible. But bokeh is only one of many factors that contribute to the overall quality of a lens. A lens can have good bokeh and be lousy in other respects (sharpness, contrast, vignetting, etc.).  


 

Bob
Philadelphia, Pennsylvania USA
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Re: Canon 18-200mm zoom lense

Thanks Bob for the info.  I guess there's no good way for me to tell if a lens is really tops, other than trying it for myself and reading reviews. 

 

BTW.... I took some shots today and got varing results.  Most of my shots at the park are all pretty much good, fall in the same space of good shots give or take a back one here or there.  Today I got a chance to take a couple's pic, they posed for me.  My pics were fine around 10 ft away as usual.  But when I moved in close, maybe to a couple ft, the pic was very bright, had a washed out look.  I tried to adjust my exposure compensation with no luck.  The pic came out either too light, or too dark.  What is it I did wrong???   What do I need to do for closeups???    It was very cloudy today, even sprinkled a little rain.  Usually very sunny when I go there.   My pics were fine farther away.   Maybe I should stand back and zoom in with my lens. 

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Re: Canon 18-200mm zoom lense

"Have no idea what you mean by "playing with the gear"

 

I buy gear, lenses and cameras, to play with.  Not to use like most if not all of you out there.  This is my hobby now.  At this point our goals are totally different.  I want to know the ins and outs of as much of this stuff as I can.  If I don't like something, I sell it and move on.  Never used to do that.  The fact that I have dups in several focal lengths is because the lenses are so good they have found a home here.  I just sold my 1D Mk III so that let me buy the Tamron SP 70-200mm f/2.8 Di VC USD Zoom Lens.  So far, just a few days worth, it is going to find a home here, too.  I may even recommend it later on if it still impresses me.  Not made of money or have money to burn.  But remember I did have a company that did.

 

The hourse picture was from about 10 to 12 feet at 70mm.  Pretty darn sharp!

 

"... but the files are so big it was difficult to send in email."

 

You don't email RAW.  If you did people may not be able to see them anyway.  You email the jpg you make from a RAW file.  The RAW file does not exist after your editor.  The difference is you control the output and not your camera.  The camera can not see your photo.  You can.  You decide how it looks.  You decide how it is used and the format.  You are not unusual in this as I have resistance from folks using RAW.  Some just will not.  And if they are that against it, I don't push it any further.  Either you want the best or you don't.  Its your choice.  Are you going to buy that $2500 dollar Canon 70-200mm f2.8 lens and than put black tape over half the front element?  I don't think so but that is what you are doing if you shoot jpg.

 

All camera brands come with a post editor of sorts, if the camera offers RAW support.  I am not versed in every brand as 90% of the people I see, or have seen I mean, use Canon or Nikon.  And Canon is by far the biggest percentage.

 

If this park is as full of kids and children under 18 as you say, you probably do need to find another place to shoot.  If someone complains, you could even be arrested.  I can't stress this enough.

 

One thing that is confusing you so much is your contridiction of views and advise.  It is fine to get different views but at this early learning stage you really need to decide on and depend on one or two.  Of course all this is up to you, using RAW or not, googling everything, reading reviews, f-stops and focal lengths, etc, but not to the point of confusion.

The best thing is to get into a class with a good instructor and do as they inform.  After you get the basic understanding, than you can venture out and get all the opposing views and thoughts.  Just not now.

 

"... the horse's eye does look sharp, how far away were you????"  

 

This statement shows you still do not understand why this photo is significant.  And that is just from not enough experience and knowledge yet.  It will come but I believe you are getting confusing points of view and that is stymining you. Everybody on the web are not as great a teacher as Bob from Boston and me!  Smiley Very Happy  <-----joke inserted here

 

DICISION TIME!!!!!!!!!!!!!

 

EB
EOS 1DX and 1D Mk IV and several lenses!
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Re: Canon 18-200mm zoom lense

"... I take it generally round blades would indicate better lens???   And generally more elements & over groups are better also.  But rounded blades are the better indicator of quality!!!! "

 

This is false of course.  However, Canon will not out top quality parts into a crappy lens.  If they did it would not be "crappy"!

The best lenses get the best.  If that is a 9 blade aperture or a 7, so be it.  There are trade offs and no lens is that elusive holy grail of a lens.  Lenses are simply too complicated with too many different factors to consider. One reason there are so many.  They all fit somewhere.

EB
EOS 1DX and 1D Mk IV and several lenses!
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