BetterPhoto Q&A
Category: New Questions

Photography Question 
Meghan Gonski



I was wondering why some lenses extend when when focusing and some extend when zooming and some don't extend at all. I have a fantastic lens by canon 70-200mm f/2.8 that does not extend at all. I love that.
I am looking into another lens purchase and there are both extenders for opposite reason. Also one extends at 24mm (lowest mm) (which is confusing) while the other extends at 55mm (highest mm)(makes sense)
The link has the two lens I'm talking about:

Anyway, one of those lenses is an L series and the other one according to reviews online is pretty close to an L series. It seems like they would make these non-extending like my 70-200mm f/2.8 lens.....?

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12/4/2011 3:08:57 AM

Lynn R. Powers   Meghan,
You are reading the chart wrong. They both extend from the lower number to the larger number.

Many of today's lenses were designed long before digital DSLRs were even thought about. The 24-70 f2.8L is one of them. Canon decided there wasn't a need to change to full internal focusing on the lens because of R&D costs as well as passing the additional cost to the customer could reduce its popularity.

Rare earth glass, internal focusing and zooming, constant minimum f stop at all focal lengths and IS/VS are all items that increase the prices on lenses. Sometimes the size of the lens prevents certain alternatives to be viable.

The EF-S 17-55 f2.8 is designed to be used on crop cameras only. The "L" designation, Luxury, only goes on EF lenses which are designed for full frame cameras as well as crop cameras.
They are also more expensive because of better build and better features than the normal EF lenses.

Unfortunately for us the customer the price for all the lenses to have the features, except for weight, of the Canon 70-200 f2.8L IS would be exorbitant.

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12/6/2011 3:22:03 PM

Carlton Ward
BetterPhoto Member Since: 12/13/2005
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Carlton's Gallery Editor's Pick   Bad Hair Day
Bad Hair Day
Bad Hair Day - f/7.1, 1/200, ISO400, 260mm
© Carlton Ward
Canon EOS 40D Digi...
Hi Meghan,
I have the 24-70mm f/2.8L and you are correct as this lens zooms out when shooting at 24mm and shortens when shooting at 70mm. The 3 lenses I carry everywhere are the 24-70, the 70-200mm f/2.8L IS & the 100-400mm f/4.5-5.6L IS and that lens is a push-pull zoom. I have owned the 100-400 the longest and though it is a bit of a light-hog and the push-pull can get a little dust but I do love this lens. When set to f/7.1 the subject is tack sharp and the background is beautiful. The 100-400 weighs the same as the 70-200 f/2.8 but when zoomed out to 400mm - people notice :)
I will soon replace my 17-40mm f/4L with the 16-35mm f/2.8L or preferably the 14mm f/2.8L - if I can afford that one :)
I started with a 20D but knew I would eventually go full frame so I built my lens collection as Lynn mentioned because the EF glass works on either APS-C or full frame.
I have heard positive things about the 17-55mm lens but have no tried that one.
Here is one of my favorite pics with the 100-400 called "Bad Hair Day". This EMU was trying to peck me and the hard light on his head, the detail of the crunchy stuff around his eye and the little hairs/feathers are sharp. The background wall was kinda ugly gray w/crap on the walls but the f/7.1 DOF made it look very blended.

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12/7/2011 2:47:52 PM

Meghan Gonski   Why would someone upgrade to a different camera body if the lens is what really makes the difference?

The better camera bodies (markD etc)I have seen seem really big (I have small hands)and heavy.
That's why I like my RebelXTi because it's lighter and smaller for my hands. BUT I'd like to know about the upgrading so I can decide before I buy one of the 2 said lenses.

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12/11/2011 4:22:08 AM

Lynn R. Powers   When my last 35mm film camera took a dive into the bay I handeld a Rebel XT.
It felt like a limp handshake. I then tried a 20D and it felt more like a camera should to me. But having shot 35mm cameras I knew I was going to go to a FF camera. That didn't mean I was going to get rid of the cropped camera. I still have a 40D for birds and wildlife but I sold a 5D and 24-85mm EF lens in order to be able to purchase a 5DMarkII. I would have liked

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12/11/2011 4:41:46 PM

Lynn R. Powers   (Don't know what happened. I didn't hit submit so I will just continue. :))

As I was saying: I would have liked to keep the 5D but the money wasn't at hand to purchase the new camera.

People find features on the newer cameras that they could put to good use. If I won the Lotto, ROFL,I would
consider a 1DMark IV but not until after I rent one and try it out for a week. I may find that it is too big for my hands (I have small hands for a man}. If so I would stick with the 40D.

You have a heavy lens with the 70-200mm f2.8L. I found that it doesn't balance well on an XXD camera at all. I found it cumbersome and tiring caring around all day. After having one for a year I checked and I had only taken four photos with it using an f stop wider than f4. I now have the f4L IS version and it works well on the 40D and the 5D with no balancing problems even when using a 1.4x TE. It also weighs less than the 24-70 f2.8L.

The XXD, 7D and the 5Ds are all smaller than the 1D and 1Ds series. The Rebel series are not built as well as the above which are a lot more durable.

All of the cameras from the 20D to the new Dx have all of the controls for taking photos in the same place. Only the menues are different.


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12/11/2011 5:23:49 PM

Christopher Budny
BetterPhoto Member Since: 10/3/2005
  I'd say one of the primary reasons many folks upgrade bodies is to go from "crop-sensor" to full-frame sensor format. The sensor is definitely an integral part of the image equation, in addition to the quality of lens used. Everyone I know who has eventually moved to a full-frame sensor camera bodies has been thrilled with the improved noise handling, color rendering, etc.
All the Rebels, plus the xxD models and the 7D use the smaller crop-sensors.
If you build up a serious/pricey collection of EF-S Canon lenses, they will *not* migrate from Rebel/xxD/7D bodies to the 5D/1D full-frame bodies, should you ever decide to get a full-frame body in the future. You'll then have to decide whether you shelve those EF-S lenses, attempt to sell them, or perhaps keep a 2-body kit, thus continuing to make use of the EF-S lenses on the crop-sensor body; they will not work on a full-frame.
My favorite lens so far is the ultra-wide EF-S 10-22; if I ever migrate to a 5Dii (which I'd like to do) I'll really, really miss this lens! (And I would have to buy a new, equivalent ultra-wide EF lens to replace it, to continue getting the ultra-wide-angle shots I like so much.)

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12/12/2011 12:26:22 PM

Meghan Gonski   Thanks everyone so much wonderful information you have for me!

I recently went to my camera store in another town to see what they physically feel like. The 24-70 is heavy but thankfully not as heavy as my 70-200. The 17-55 is nice in weight. I wish one of you had this lens, when I tried it out during autofocus, there was a "clicking" inside that felt like needles dropping on glass which I really didn't like. I wanted to know if other people have experienced that. I will start another thread to maybe catch someone on BP that has the lens.
(The store guy didn't feel what I felt and he said all the lens would be the same.)

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12/25/2011 8:14:49 PM

Meghan Gonski   guess what, I went to the store again, tried out the same lens in a box instead of the display one. It didn't have the peculiar clicking thing! thank goodness.
I think i'm going to get the 17-55mm mainly because of the lighter weight. Even if I do upgrade from my Rebel XTi, I think I will stay in the crop sensor cameras. There are probably a lot of higher grade crop frame cameras than mine. So I could get a really good crop frame when I decide to. Correct?

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12/30/2011 3:13:54 AM

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